Open Reel Deck Taste Test
Jukin' Geo
I have been an avid collector of small open reel decks for a while and I
also have aquired a few larger machines as well. In terms of overall sound
and performance, I am curious to know which manufacturer made the best
sounding and best functioning machines. From the information I have
gathered so far, these three manufacturers seem to be in the forefront of
open reel decks:
Akai (Roberts), Pioneer, and Tascam (Teac).
I have used Tascam machines many times before and know them well in studios.
However, I don't know how they fair in comparison to the other two. One
thing I do know is that I very rarely see auto reverse on a Tascam deck.
While they do offer auto reverse on their Teac home line, these machines
seem inferior looks wise when compared to some of the machines made by
Pioneer and Akai.
I currently own an Akai GX747, a Pioneer RT-707, a Pioneer 1100 and a
Roberts 770x. All the machines except the Akai GX747 are broken. But I
would like to know how they compare to each other and which is the best. Up
to now I am very happy the way the Akai works and it can take 10" reels.
Please respond directly to my EM address:
Thank You,
Geo
Fred Nachbaur
Ampexes, a few Sony's, and several Akai (Roberts) decks (all
solid-state, by the way). To my ear, the Ampexes consistently sounded
best, even though "by the specs" the Akai's tended to look better on paper.
Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
| Googlism: "fred nachbaur is de hounddog al |
| rond de 380volt volledig stabiel" |
+--------------------------------------------+
CM
The decks you mentioned are to me "junk"...
The only Reel-2-Reel decks I will use are Studer/Revox like PR99 and A-10
models......
Otari I like second...
I have rebuilt many brands of R-2-R decks and have designed /redesigned a
lot of the circuits for them...
Regards
Chris
Larry W4CSC
shop for $25. The tape player wobbulated something awful! After I
got it home, I accidently tried to spin the rubber pinch rollers, both
of which were bound up in their bearings. Unscrew the screw on them
both and put 2 drops of a light machine oil (I'm an organ service
technician so always use Genuine Hammond generator oil) on the end of
the oillite bearings. Wait a day for it to soak in. Then start
carefully turning the rollers to free the bearings of the shellac
gluing the sleeve bearings together.....
The RT-707 runs perfectly, now, in both directions, in spite of only
having ONE capstan drive motor. The pull from the resistor-loaded
takeup reels is so perfect, I've never heard it slack on the head in
reverse when the capstan is actually feeding, not pulling on the
heads. The drive motors are HUGE, as are the load resistors that set
the tension. No clutches to slip is VERY nice, indeed.....No gears,
no queer plastic parts.
I've owned almost every reel-to-reel recorder and tape deck I ever
saw. The Tandberg I had in the 1960's was a nice recorder, but
nothing compared with the RT-707......even if it was much more than
$25....(c;
I've mounted my RT-707 in an old military receiver 19" cabinet rack
that just fits it. I have no information on the rack or what receiver
was in it. Someone had long ago painted it an awful color. I
stripped it and repainted it Haze Grey. I was in the Navy...(c;
Larry W4CSC and other fine old calls since 1957...
Phil Nelson
sale find from original owner, with a box of about 80 r-r tapes of music
from, well, not my favorite artistes :-). Works fine but the drive belt
slips -- of course -- when you get near the end of a tape. This is after
furious disassembly & cleaning & lubing of all the usual suspects.
Anybody know where to get a replacement belt? I used to have a URL for a
page listing zillions of belts, but it has been lost in the ether. I
understand that I could pull the old belt and measure it and look hither and
yon for something that fits, but I'm lazy and it would be O so much easier
to find an index to the real thing.
Same question for my Telefunken stereo "Magnetophon" M77, although I guess
that's more of a Euro item. If I had to choose between the Telefunken and
the Teac, I'd choose the Tele -- smaller, cuter, cleverer, and it weighs
about 40 pounds less.
BTW, long ago, I read a post about boiling old belts to shrink them and thus
make them grab again. I can testify from experience that it doesn't work!
Regs,
Phil
Steven Dinius
prayed that one would fall in my hands, but DRAT! They were sooooo nice!
I'll bet they still work, long after the station went to CD's. All four date
back to 1976(?)
"John Rethorst" <no...@nowhere.com> wrote in message
news:noone-16010...@02-091.075.popsite.net...
> In article <UwKV9.228773$FT6.36...@news4.srv.hcvlny.cv.net>, "Jukin'
> Geo" <Juki...@optonline.net> wrote:
>
> > I have been an avid collector of small open reel decks for a while
and I
> > also have aquired a few larger machines as well. In terms of overall
sound
> > and performance, I am curious to know which manufacturer made the best
> > sounding
>
> Tandberg
>
> > and best functioning machines.
>
> Revox.
>
> Disclaimer: my opinions only.
>
> --
> John Rethorst
Jiri Placek
> That reminds me (slightly OT), I have a Teac A4010S stereo deck ($5 garage
> sale find from original owner, with a box of about 80 r-r tapes of music
> from, well, not my favorite artistes :-). Works fine but the drive belt
> slips -- of course -- when you get near the end of a tape. This is after
> furious disassembly & cleaning & lubing of all the usual suspects.
>
> Anybody know where to get a replacement belt? I used to have a URL for a
> page listing zillions of belts, but it has been lost in the ether. I
> understand that I could pull the old belt and measure it and look hither and
> yon for something that fits, but I'm lazy and it would be O so much easier
> to find an index to the real thing.
Try THETEACMAN, I cannot find his address but he sells them for about
$10 on ebay:
http://www.stores.ebay.com/id=21843746&ssPageName=L2
It could be useful perhaps if someone would post his email or website
here for future refence.
I had 4010S also, a nice machine after cleaning and lubrication. I
sold it recently since I have been using Nagra IVLS.
Jiri Placek
Boyertown, PA
Stein-Olav Lund
François Yves Le Gal wrote:
On Fri, 17 Jan 2003 03:12:52 GMT, "Jukin' Geo" <Juki...@optonline.net> wrote:
In terms of overall sound and performance, I am curious to know which manufacturer made the best sounding and best functioning machines.
Glad to see you regard the Tandberg TD20A-SE so highly!Best tape recorder ever manufactured: Nagra IV-S QGB and it's derivatives Best pro analog deck: Ampex ATR-102 Best consumer deck: Tandberg TD20A-SE Best tubed deck: Ampex 351 and derivatives Accessits: Sony TC-880-2, Technics RS-1500 Honorable mentions: ReVox/Studer, Stellavox, Hencot
Myself I have a TD20A, not the semi-pro version, but a very good machine.
And, being a Norwegian, I'm patriotic...
Stein
-- *** STEIN-OLAV LUND engineer *** *** Sor-Trondelag College *** *** Dept. of Electrical Engineering Tel. +47 73 55 95 99 *** *** N-7004 Trondheim Fax +47 73 55 95 81 *** *** NORWAY *** *** E-:-) LA9QV *** ************************************************************** +++ Teacher (in pub): Do you serve headmasters? +++ +++ Barman : We serve anybody, sir. +++ +++ Teacher: Good, a beer for me and a headmaster +++ +++ for my dog, please. +++ +++ J. Taylor: The New English Norwegian Joke Book,1990 +++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Gary Glaenzer
we had 4 A77's playing music on AM, 3 Scully 270's on FM. plus a Scully 280,
an Ampex 352 and an Ampex 351 that I outfitted (with help of Frank Zeman of
minneapolis Magnetics, God rest his soul) with a full-track, stereo
half-track, and stereo quarter-track head stack to play 'outside' tapes.
used Opamp Labs modules to build the playback electronics
somewhere I have pictures of that...........
"Steven Dinius" <10...@fmtc.com> wrote in message
news:v2fcoa7...@corp.supernews.com...
Shiva
"Gary Glaenzer" <nobul...@mchsi.com> wrote in message
news:x1UV9.20152$hl1.1668@sccrnsc04...
> you too ?
>
> we had 4 A77's playing music on AM, 3 Scully 270's on FM. plus a Scully
280,
> an Ampex 352 and an Ampex 351 that I outfitted (with help of Frank Zeman
of
> minneapolis Magnetics, God rest his soul) with a full-track, stereo
> half-track, and stereo quarter-track head stack to play 'outside' tapes.
>
> used Opamp Labs modules to build the playback electronics
>
> somewhere I have pictures of that...........
Hi Gary - I'm prob'ly goin' to be a proud owner of a 350x transport, maybe a
440too, depending on how things go, and:
All the electronics are SS, and the deck (440b 1/2track 1/4" ) I'm
[building? frankensteining] for a friend is going to be used as a mixdown
deck. The transport's almost done (no ware anywhere, had to turn down the
idler to get it straight & smooth (only a few thou' taken off), and rotated
the tape-lift horns.) Set the tension by feel, on the heavy side 9tape's
going to be burnt once), but the electronics... What do you think of the
records amps on those decks? I get an unreasonably high nois floor... Am I
just used to dolby systems 7 should accept it? The center (mid-headset)
idler (looks like a capstan) - i have a choice of a non- grooved 9solid
roller) one, and one with a center grove cut - I assume the center-groove
one is a later mod 9ampex likes to "undercut" everything) - which one should
i go with for the "best' (going to my friend) deck? any & all advice
appreciated 9I do have the setup manuals etc...)
-dim
Shiva
"Fred Nachbaur" <fnac...@netscape.net> wrote in message
news:3E27840B...@netscape.net...
> Don't have any R-R decks anymore, but over the years I've had several
> Ampexes, a few Sony's, and several Akai (Roberts) decks (all
> solid-state, by the way). To my ear, the Ampexes consistently sounded
> best, even though "by the specs" the Akai's tended to look better on
paper.
>
> Cheers,
> Fred
Fred, even if they didn't sound best, the full-on military assembly 9just
look at the mil-green cable connectors), the modularity, the sheer sex of
the things (though I'm not a big stain;less steel fan - but hey,
practical) - they win hands down.
-dim 9who's Tapesonic pales in comparison...)
Steve Urbach
Try a Berlant (sp?) Concertone. took 10" reels.
Steve U
On Fri, 17 Jan 2003 03:12:52 GMT, "Jukin' Geo"
<Juki...@optonline.net> wrote:
--- _
, | \ MKA: Steve Urbach
, | )erek No JUNK in my email please
, ____|_/ragonsclaw dragons...@mindspring.com
, / / / Running United Devices "Cure For Cancer" Project 24/7 Have you helped? http://www.ud.com
Chuck Harris
the right amount of stickyness. I wonder if it would work on belts? It
doesn't seem to harm the rubber at all.
(I know, I know, it seems counter intuitive. but it does work on the
paper feed rollers of HP laserjet printers, fax machines, ... anywhere
a roller grabs a piece of paper.)
-Chuck, WA3UQV
Norm Flasch
: Hello all,
: I have been an avid collector of small open reel decks for a while and I
: also have aquired a few larger machines as well. In terms of overall sound
: and performance, I am curious to know which manufacturer made the best
: sounding and best functioning machines. From the information I have
: gathered so far, these three manufacturers seem to be in the forefront of
: open reel decks:
: Akai (Roberts), Pioneer, and Tascam (Teac).
I have a Pioneer RT-707 that I purchased new in the mid 70's and
still use to this day. Just need to clean the switches from time
to timee and take care of the capstain. This is a great solid
machine with pleasing asthetics.
Hovever, before that I had an Ampex reel-to-reel reversing machine
with the cube speakers. When these machines were new the sound
was stunning. I mean just beautiful. There was nothing that size
that sounded nearly as good in that time period. For a comparison,
the sound gave me the same impression that compact disks gave me
when they were first introduced.
However, the machine always needed fixing. Like belts, transistors
and capicitors. Very unreliable, but quite a step ahead in sound
quality for such small speakers. Solid state sound was not at all
impressive before these machines were introduced.
--
Norm Flasch
Northwestern University
Evanston, Illinois
emulsion
in remarkably good shape w/ original manuals, replacement belts and
replacement motor (not installed). I've given it a good cleaning but
it doesn't record bass too well so far. I've yet to demagnetize the
heads (got an Annis Han-d-mag on the way, apparently a must have,
$41). I also haven't done any head alignment yet either.
When I run cd's through it as a preamp before my mkIII's, it seems to
add more detail to the music, very *nice*. It's got 8 original west
german tubes in it I think, 12at7, 12ax7 etc. But recording from cd
lacks bass when played back. I think I can cure this with some more
work. And the main drive belt (short thick rubber, no replacement) is
kinda loose so you have to help it get started rewinding or fast
forwarding. Guess I need to find a match for that belt, anyone know
where to start looking?
Chad
Fred Nachbaur
My experiences were similar. While I never had electronic problems with
the Ampexes, I was constantly replacing those main round belts.
But the sound was just exquisite. I'd have to concur with your use of
the adjective "stunning."
Cheers,
Fred
Gary Glaenzer
that subject
sorry
"Shiva" <help...@666.com> wrote in message
news:1_UV9.23691$_T6....@nwrddc01.gnilink.net...
Shiva
> you know, it's been so long that I really don't feel qualified to comment
on
> that subject
>
> sorry
Hey, no prob - thanks for the reply...
-dim
Bob Groschen
> I apologize for comming off a bit harsh...
> The decks you mentioned are to me "junk"...
Er, well, yeah. I like to think of them as "Consumer Grade" decks.... :-)
> The only Reel-2-Reel decks I will use are Studer/Revox like PR99 and A-10
> models......
Well, since *opinions* are flying around today, I'll put in my $0.02 worth:
Studer decks are OK, but a b*tch to work on, particluarily around the head
block assembly.
> Otari I like second...
Otari, MCI, Ampex in that order for audio. For *real* recording I prefer
Honeywell Model 96. :-)
> I have rebuilt many brands of R-2-R decks and have designed /redesigned a
> lot of the circuits for them...
Yeah, yeah. Been there and done that for 18 years at 3M. If dropped out of
any airplane only two of these would survive: Ampex & Honeywell.
Best Regards,
Bob Groschen
Choky
our Studer and ReVox rtr's are long ago in magazine.
hehe,but my own EMT930st is jolly boy,in full working shape and situation ;)
--
Choky
Prodanovic Aleksandar
YU
"Steven Dinius" <10...@fmtc.com> wrote in message
news:v2fcoa7...@corp.supernews.com...
Bob Groschen
> you too ?
>
> we had 4 A77's playing music on AM, 3 Scully 270's on FM. plus a Scully 280,
> an Ampex 352 and an Ampex 351 that I outfitted (with help of Frank Zeman of
> minneapolis Magnetics, God rest his soul) with a full-track, stereo
> half-track, and stereo quarter-track head stack to play 'outside' tapes.
Now there's a name that takes me back. That and Nortronics. After Nortronics
faded away, 3M picked up several of the survivors. I was fortunate enough
to be able to work for one of these characters (Dr. Steve Benson), easily
one of the best bosses I ever had at 3M.
Best Regards,
Bob Groschen
Gary Glaenzer
block buildings in the 8100 block of Pleasant Ave. S.) were class acts.
Frank's health was getting the best of him by the time I got to know him
(late 73) but he was always willing to sit down and explain things to me
Those explanations helped immensely when I went to work for EMI Music at the
cassette duplication operation here.........I already had thorough
understanding of the 'hows' of the recording process, although we worked
with 64x and later 80x the actual frequencies...........'high end' was
1.2-1.4 MHz; bias frequency was around 12 MHz as I recall.
sometimes the heads, when they got near the end of their life (getting thin
across the gap) and we were running Chrome tape that required a lot of bias,
would get extremely warm to the touch
"Bob Groschen" <bob.gr...@plasmon.lms.com> wrote in message
news:d7e8c80b.03011...@posting.google.com...
Steven Dinius
bought and assimilated by Capps BC (then sold to Journal now Heritage). Last
time I looked there may still be one in the control booth/production room
that used to be the FM studio (very cramped). There is ONE BC turntable for
liners but why they haven't put those LP's on CD yet? I hope they
have--those were good liners!
Steven
"Gary Glaenzer" <nobul...@mchsi.com> wrote in message
news:x1UV9.20152$hl1.1668@sccrnsc04...
Fred Nachbaur
John Rethorst wrote:
> In article <3E27840B...@netscape.net>, Fred Nachbaur
> <fnac...@netscape.net> wrote:
>
>
>>Don't have any R-R decks anymore, but over the years I've had several
>>Ampexes, a few Sony's, and several Akai (Roberts) decks (all
>>solid-state, by the way). To my ear, the Ampexes consistently sounded
>>best, even though "by the specs" the Akai's tended to look better on paper.
>
>
> Do you mean the Ampex 800/1100/2100 series (single motor, dual capstan) or
> the AX 50/300 series (single capstan)?
The dual-capstan ones, single motor. Direction of the motor toggled the
drive assembly to one side or the other. I wasn't even aware of any
single capstan models at the time...
Cheers,
Fred
jakdedert
has ever seen/handled one of these (you don't even have to turn it on--just
*look* at it) I think they'd have to agree that this is one of the highest
precision tape machines ever built.
99% of movie/video location recording was done on these things...they're
(precision) tanks...works of art almost!
jak
"Jiri Placek" <radio...@fast.net> wrote in message
news:20d99877.03011...@posting.google.com...
Robert Mozeleski
"Larry W4CSC" <nos...@home.com> wrote in message news:3e2794e4...@64.154.60.185...
Beloved Leader
> My experiences were similar. While I never had electronic problems with
> the Ampexes, I was constantly replacing those main round belts.
They "melted" with old age, leaving tar-like gunk inside the machine.
I got a quarter-track stereo Ampex 750-something and three LD-700
language lab decks with half-track heads. The LD-700's have no
electronics. I have the factory repair manual for the 750.
Alan Douglas
No one has yet mentioned my two decks: the ReVox B77 and Magnecord
1048. Both 10½" machines. I don't use either one now, though.
The 1048 has tube electronics, with Compactrons yet.
The B77 is a long story. I originally had an A77, bought
second-hand (as was the Magnecord) from an ad in Audio Amateur. I lent
the A77 to the company I work for, to record some 17 kHz sonar signals
at an oil rig somewhere off Honduras. It didn't fare too well in the
tropical humidity waiting to be shipped home, so the company bought me
a B77 to replace it. That worked fine, except it always had a problem
with the motor control logic that crowbarred the AC line when going
from play to forward. Since it had been purchased as an OEM item it
had no warranty, so I just learned to live with it (i.e., a sticky
note on the panel saying "don't do that").
They both handled well and made good tapes, and probably still
would, if I had any occasion to hook them up again. Like wanting to
listen to the BBC radio episodes of Hitchhikers Guide to the Galaxy.
One of these days.
Cheers, Alan
Sven Franklyn Weil
Le Gal wrote:
> They still are. The IVS can be special ordered, the DII is an
> outstanding tape-based HR digital recorder, and the new V, after a few
> initial problems caused by sub par HD ass'y, is now shipping in volume.
Check THIS little demon out!! It's a miniature r2r (uses cassette-size
tape)!
http://www.nagrausa.com/SNSTR.htm
--
Sven
Larry W4CSC
wrote:
>Just picked up a working Akai GX-635D for $25 at the local flea mart.
>
After I got the RT-707 running, I gave my Akai to a ham friend who has
lots of tapes but no player. The Akai was an arm-wrencher model with
the big levers. I don't have the model number but I'm sure the model
number is equally impressive...(c;
The solenoid operated mechanism on the RT-707 is amazingly easy on
tapes. Even rewinding at 24,500 RPM doesn't seem to have ill effects
on them. They apply DC braking current to the drive motors as the
tape flies off the feed spool, either way, which stops them very
quickly!
Tim Mullen
>On Fri, 17 Jan 2003 16:07:13 -0600, "jakdedert" <jde...@bellsouth.net>
>wrote:
>> I think they'd have to agree that this is one of the highest
>>precision tape machines ever built.
>They still are. The IVS can be special ordered, the DII is an
>outstanding tape-based HR digital recorder, and the new V, after a few
>initial problems caused by sub par HD ass'y, is now shipping in volume.
>http://www.nagrausa.com/Nagra%20V.htm
>>99% of movie/video location recording was done on these things...they're
>>(precision) tanks...works of art almost!
>A lot of movies or videos are still recorded using a Nagra.
>:-)
Perhaps. I work for a high-end film-to-tape house in Manhattan
(Company 3), and 99% of the work we do is on DAT. We have a couple
of Nagras floating around, and a Rank Ferrit for full-coat (35mm
or 16mm stock that's covered completely with oxide), but they
rarely get used.
--
Tim Mullen
------------------------------------------------------------------
Am I in your basement? Looking for antique televisions, fans, etc.
------ finger this account or call anytime: (212)-463-0552 -------
Larry W4CSC
<philn...@antiqueradio.orgNOSPAM> wrote:
>That reminds me (slightly OT), I have a Teac A4010S stereo deck ($5 garage
>sale find from original owner, with a box of about 80 r-r tapes of music
>from, well, not my favorite artistes :-). Works fine but the drive belt
>slips -- of course -- when you get near the end of a tape. This is after
>furious disassembly & cleaning & lubing of all the usual suspects.
I did a little google hunting and you should contact the guys on:
http://www.dantiques.com/forums/tapepart/posts/94.html
where there seems to have been some serious discussions on the drive
you have.
Also:
http://www.dantiques.com/forums/tapedeck/posts/82.html
http://forums.djcafe.com/audio.pl/noframes/read/1407
AHA! Here's a PARTS SUPPLIER for Teac decks!
http://www.daeinconline.com/teactalk.html
http://www.daeinconline.com/parts.html
(your drive belt is $12.95)....(c;
Now, about that rear muffler bracket for the 1972 Ford Pinto you were
looking for........
Oscillatus
news:UwKV9.228773$FT6.36...@news4.srv.hcvlny.cv.net:
>
>
While we are all thinking about open reel decks, does anyone know if I
might be able to obtain a replacement set of (play FF REV Rec
etc)pushbuttons for my AKAI GX-620. These are plastic/neoprene
'calculater' style inputs to the logic, and they have become fragile and
broken internally so most do not work anymore.
I could wire in a set of momentary contact pushbuttons, but it would wreck
the appearance.
Oscillatus
news:3e28af5c...@64.154.60.185:
>>Just picked up a working Akai GX-635D for $25 at the local flea mart.
>>
>
> After I got the RT-707 running, I gave my Akai to a ham friend who has
> lots of tapes but no player. The Akai was an arm-wrencher model with
> the big levers. I don't have the model number but I'm sure the model
> number is equally impressive...(c;
>
> The solenoid operated mechanism on the RT-707 is amazingly easy on
> tapes. Even rewinding at 24,500 RPM doesn't seem to have ill effects
> on them. They apply DC braking current to the drive motors as the
> tape flies off the feed spool, either way, which stops them very
> quickly!
My AKAI GX-620 uses 3 motors and they do all the braking, back tension etc
etc as well. This unit is also very kind to tapes, even varies the force
used according to the reel size (10.5 " vs 7"). Punching FF when going full
speed in Rewind, causes a slow down, a pause, then a switch to the
different direction - very gentle. I have a few AGFA 10.5" plastic reels
that use the small normal (for 7") spigot in the model, as opposed to the
larger NAB hubs. I thought they would be under great stress, but they have
survived well due to it's soft handling of tapes.
Oscillatus
news:b09dfs$1uj$1...@bob.news.rcn.net:
> WD-40 works great on the paper feed rollers of printers. It gives just
> the right amount of stickyness. I wonder if it would work on belts? It
> doesn't seem to harm the rubber at all.
My experience is that WD-40 makes belts and idler drives slip like crazy.
Oscillatus
news:458g2vsubvqubupv9...@4ax.com:
> Want realy old!
> Try a Berlant (sp?) Concertone. took 10" reels.
> Steve U
>
I had an old machine that ran the tape from right to left (instead of the
usual way, and the heads were on the 'outside' of the tape. I had to put a
twist in a tape and FF it through to reverse the tape, so I could test the
thing. It was really old, and I guess things were not standardised back
then.
Jeffrey D Angus
>While we are all thinking about open reel decks, does anyone know if I
>might be able to obtain a replacement set of (play FF REV Rec
>etc)pushbuttons for my AKAI GX-620. These are plastic/neoprene
>'calculater' style inputs to the logic, and they have become fragile and
>broken internally so most do not work anymore.
>
>I could wire in a set of momentary contact pushbuttons, but it would wreck
>the appearance.
>
Are the buttons a small black dot under a membrane and make contact
with a pair of traces. Kind of over lapping fingers -E3-
A cheap calculator is a good source for repacement "dots" just pry the
old ones out and glue in the new ones with a spot of crazy glue. Give
the (usually gold plated) finger contacts a good cleaning with DeOxit
and a final spritz with some GoldPro (both from Caig Labs)
Or are there "descrete" switch buttons underneath the operating keys?
Mouser has a bunch of those type switches in their catalog.
Jeff
--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." Benjamin Franklin
"A life lived in fear is a life half lived."
Tara Morice as Fran, from the movie "Strictly Ballroom"
Gordon Pratt
available. I my opinion the best playback deck was the Crown SX-824
(Nortronic Heads) and the best record/playback deck was the Tandberg 64X
(crossfield head). The Ampex 351, Revox G36 & A77, Teac, Otari, Akai
(Roberts), Pioneer, Sony, Viking, Skully, & Magnecord were the sonic also
rans. Only tried Nagra once in the days of Two Track. Quality may have be
limited by the tape available then. My opinion is based purely on sound
quality because the Tandberg was mechanically a piece of crap and the Crown
had braking problems.
"Jukin' Geo" <Juki...@optonline.net> wrote in message
news:UwKV9.228773$FT6.36...@news4.srv.hcvlny.cv.net...
Oscillatus
news:3E28E4B2...@socal.rr.com:
> Are the buttons a small black dot under a membrane and make contact
> with a pair of traces. Kind of over lapping fingers -E3-
Yep.
>
> A cheap calculator is a good source for repacement "dots" just pry the
> old ones out and glue in the new ones with a spot of crazy glue. Give
> the (usually gold plated) finger contacts a good cleaning with DeOxit
> and a final spritz with some GoldPro (both from Caig Labs)
The trouble is the plastic buttons themselves are broken underneath from
people punching them to make them work.
Robert Casey
>
> Now, about that rear muffler bracket for the 1972 Ford Pinto you were
> looking for........
I had one of those. Something broke every couple of months it seemed.
Replaced it with a Honda Civic. Big difference in reliability.
Mike O'Sullivan
strong. Perfectly quiet mechanism. Lovely machine.
"Gordon Pratt" <gord...@attbi.com> wrote in message
news:oq6W9.28680$hl1.2049@sccrnsc04...
Steven Dinius
Next I'm going to compare one with a "Coke" sticker to one with a "Pepsi"
sticker on it.
Now that Pepsi has fired Britney, who will test it?
(Oops, I did it again!)
"Robert Casey" <wa2...@ix.netcom.com> wrote in message
news:3E28FAC7...@ix.netcom.com...
Alan Peterman
was 1968-1986 and I still remember using, repairing and selling them. While the
most popular might have been the Akai and Teac units, I think I would put the
Sony 377, 645, 750 and 760 series in there with the best of them. Every company
made some stinkers, the early Akai GX series with the glass heads that cracked,
the Teac 5500, and the Sony 440/458 were less than wonderful. The Pioneer
707/909 were really quite good, as were the Technics 1500 series. Revox made
good decks, but I sure found lots of them that needed work, the internal trim
pots seemed prone to failure.
And yes, I even had some Nagra and Stellavox decks - they were wonderful. And
since my brother worked at Telex, maker of Viking and Magnacord I saw lots of
them too. Now who else remembers the other weird decks like the Astrocom
Marlux (made on Teac chassis), or the Ferrograph 5 and 7.
Oscillatus
news:ie1i2v4jbqu41qsbi...@4ax.com:
> Every company
> made some stinkers, the early Akai GX series with the glass heads that
> cracked,
>
Thankfully mine are fine. Is ther GX-620 a later model, and safe from
these problems?
Shiva
"Oscillatus" <Oscil...@spamblock.com> wrote in message
news:Xns93079C8D2724DO...@210.49.20.254...
Hi.
Almost all 3-motor decks rely on motor braking to an extent, and provide
tape tension with reel motors (there's usually a couple'o big wire-wound
resistors with a viper to adjust tension, the more elaborate decks (old
Ampex studio/instrument gear, etc.) having stacks of these to adjust for
every possible combination 9like a small reel on one side & a big reel on
the other, tape speed, etc.). This is all well and good, but... when
you're winding the tape at a zillion fps, with full-sized reels, and you
want to be able to stop the tape on a dime 9editing, etc.) - that's where a
*good* transport comes in - even when the reel motors are close to 1HP,
there's simply too muchinertia to overcome without a suplementary braking
system. So... The good transports (err... which are also 8correctly
adjusted*) rely on very complex multi-solenoid brakes on top of motor
braking, to be able to stop the tape almost instantly. <starting yet
another tangent> If you look at old computer decks, *that's8 where really
interesting tape handlin' comes in - the tape had to be wound as quickly as
possible, stopped on a dime, read for a few inches, wound more, etc., etc,
hundreds of times a minute. In some cases, when the handling had to be
supah-fast, tape wasn't even stored on reels or pancakes, it just resided in
two containers on either side of the transport - that way, the only inertia
to overcome was the mass of a few feet of tape...</tangent></tangent>.
Well, now that I've put everyone to sleep, I'm goin' to rifle through your
wallets....
-dim
Gary Glaenzer
"Shiva" <help...@666.com> wrote in message
news:HXcW9.10877$xx4...@nwrddc01.gnilink.net...
(in part)
anyone ever have any experience with the ITC (International Tapetronics
Corp, Bloomington, IL) reel decks ?
they were primarily a low-to mid price machine for broadcast use, but the
transports were built like a tank
with better electronics they would be a very good to great machine
G
Steve Urbach
wrote:
Yea! I inherited one of those. It was a DECK, no electronics. In those
days, preamps had 'Tape Head' inputs <g> (MacIntosh C8 and the
companion C8S). I hand built the record Bias Ocillator, No erase. Had
to use a bulk eraser.
Steve U
--- _
, | \ MKA: Steve Urbach
, | )erek No JUNK in my email please
, ____|_/ragonsclaw dragons...@mindspring.com
, / / / Running United Devices "Cure For Cancer" Project 24/7 Have you helped? http://www.ud.com
Larry W4CSC
wrote:
>
>My AKAI GX-620 uses 3 motors and they do all the braking, back tension etc
>etc as well. This unit is also very kind to tapes, even varies the force
>used according to the reel size (10.5 " vs 7"). Punching FF when going full
>speed in Rewind, causes a slow down, a pause, then a switch to the
>different direction - very gentle. I have a few AGFA 10.5" plastic reels
>that use the small normal (for 7") spigot in the model, as opposed to the
>larger NAB hubs. I thought they would be under great stress, but they have
>survived well due to it's soft handling of tapes.
All my tapes are on 7" reels, so the 7" limitation of the Pioneer
isn't an issue here....nor is the lack of 15 ips, as it only goes 3
3/4 and 7 1/2...switch, not mechanical selectable. There is a benefit
to not having 10" reels in that the entire 18" rack-mount wide tape
deck is only 8 3/4" high, impossible if you have large hubs with large
tapes.
Larry W4CSC
wrote:
>I prefer metal chassis decks to plastic ones. They taste better!
>
>Next I'm going to compare one with a "Coke" sticker to one with a "Pepsi"
>sticker on it.
>Now that Pepsi has fired Britney, who will test it?
>(Oops, I did it again!)
>
If Britney is homeless after being fired, she can come sleep over at
my house........
I only have one bed, however....(c;
Mike O'Sullivan
"Alan Peterman" <a...@dsl-only.net> wrote in message
news:ie1i2v4jbqu41qsbi...@4ax.com...
Joe Bento
>On Sat, 18 Jan 2003 00:44:18 -0700, "Steven Dinius" <10...@fmtc.com>
>wrote:
>
>>I prefer metal chassis decks to plastic ones. They taste better!
>>
>>Next I'm going to compare one with a "Coke" sticker to one with a "Pepsi"
>>sticker on it.
>>Now that Pepsi has fired Britney, who will test it?
>>(Oops, I did it again!)
>>
>If Britney is homeless after being fired, she can come sleep over at
>my house........
>
>I only have one bed, however....(c;
She might have issues with that T-shirt on the floor however....
Joe
Remove the -nospam- to send e-mail
joseph-...@kirtland.com
Oscillatus
> Yea! I inherited one of those. It was a DECK, no electronics. In those
> days, preamps had 'Tape Head' inputs <g> (MacIntosh C8 and the
> companion C8S). I hand built the record Bias Ocillator, No erase. Had
> to use a bulk eraser.
>
Some of the had a 'head' that was simply a permanent magnet, that they used
for erase.
Bob Groschen
"Gary Glaenzer" <nobul...@mchsi.com> wrote in message
news:fgZV9.22364$hl1.1581@sccrnsc04...
> yes, Frank Zeman and Minneapolis Magnetics (in that little row of concrete
> block buildings in the 8100 block of Pleasant Ave. S.) were class acts.
I remember those buildinggs! :-)
> Frank's health was getting the best of him by the time I got to know him
> (late 73) but he was always willing to sit down and explain things to me
I didn't start working at 3M until Feb of '80.
> Those explanations helped immensely when I went to work for EMI Music at
the
> cassette duplication operation here.........I already had thorough
> understanding of the 'hows' of the recording process, although we worked
> with 64x and later 80x the actual frequencies...........'high end' was
> 1.2-1.4 MHz; bias frequency was around 12 MHz as I recall.
As long as you made good head-tape contact they should work perfectly.
However that was the key trick! :-)
> sometimes the heads, when they got near the end of their life (getting
thin
> across the gap) and we were running Chrome tape that required a lot of
bias,
> would get extremely warm to the touch
No surprise!
--
Best Regards,
Bob Groschen
Bob Groschen
> anyone ever have any experience with the ITC (International Tapetronics
> Corp, Bloomington, IL) reel decks ?
You just *had* to bring those up, didn't you Gary? :-)
> they were primarily a low-to mid price machine for broadcast use, but the
> transports were built like a tank
They could certainly put up with the abuse of day after day use, but
electronically
they were nothing special - obviously the "low price" hit hard here.
> with better electronics they would be a very good to great machine
It was so easy to do better, but I could never come up with a good reason
to do it. :-)
Gary Glaenzer
"Bob Groschen" <bobgr...@peoplepc.com> wrote in message
news:v2k2bk4...@corp.supernews.com...
>
> "Gary Glaenzer" <nobul...@mchsi.com> wrote in message
> news:0kdW9.725553$WL3.732872@rwcrnsc54...
>
> > anyone ever have any experience with the ITC (International Tapetronics
> > Corp, Bloomington, IL) reel decks ?
>
> You just *had* to bring those up, didn't you Gary? :-)
>
> > they were primarily a low-to mid price machine for broadcast use, but
the
> > transports were built like a tank
>
> They could certainly put up with the abuse of day after day use, but
> electronically
> they were nothing special - obviously the "low price" hit hard here.
well, they were designed with the average Disc Jockey Mentality in mind,
that's for sure
>
> > with better electronics they would be a very good to great machine
>
> It was so easy to do better, but I could never come up with a good reason
> to do it. :-)
me either..............but I've got 3 of them on a shelf in the
garage..........plus two stereo electronics and a mono
right next to the 'Stereo Statesman' console and a Gates 'Solid Statesman'
FM limiter...............
remember the Gates /ATC cart machines with the metal plug-in modules that
used the metal spacers between the boards as connections ? after about 2000
hours they'd get intermittent and you had to take the cover off and tighten
the nylon screws that went down thru them ? and how badly screwed you were
when (not if) you twisted one off or stripped it ?
where did you work in broadcasting Bob ?
I was at KEEY-AM / FM in the Twin Cities (AM-1400 / FM-102.1) from March 73
to July 76.......had a unique AM radiator because of numerous FM antennas
(3) plus 2-way (4) hanging at the top of the tower..........two quarter
waves of insulated skirt (bonded to tower at tops) stacked around a 5/8 wave
tower, with a honking big vacuum variable at the bottom of the top one.
feed impedance was (I remember it well) 831.1 ohms, and my hat is off to the
guy who measured that last 0.1 ohm ! 'normal' antenna current at 1 kW was
1.10 A, with an upper limit of 1.11 and a lower of 1.08
G
Gary Glaenzer
>
> "Gary Glaenzer" <nobul...@mchsi.com> wrote in message
> news:fgZV9.22364$hl1.1581@sccrnsc04...
> > yes, Frank Zeman and Minneapolis Magnetics (in that little row of
concrete
> > block buildings in the 8100 block of Pleasant Ave. S.) were class acts.
>
> I remember those buildinggs! :-)
>
> > Frank's health was getting the best of him by the time I got to know him
> > (late 73) but he was always willing to sit down and explain things to me
>
> I didn't start working at 3M until Feb of '80.
>
> > Those explanations helped immensely when I went to work for EMI Music at
> the
> > cassette duplication operation here.........I already had thorough
> > understanding of the 'hows' of the recording process, although we worked
> > with 64x and later 80x the actual frequencies...........'high end' was
> > 1.2-1.4 MHz; bias frequency was around 12 MHz as I recall.
>
> As long as you made good head-tape contact they should work perfectly.
> However that was the key trick! :-)
they were Gauss model 1200's, used two capstans with about a 0.0008
difference in diameter to provide a very firm contact
one of the favorite tricks was when someone had the motors out for bearing
changes, to swap the two capstans as he had them laying on the bench, when
he put it back together, it would make a loop that got longer and longer
till it self-destructed..........
Michael A. Terrell
>
> That reminds me (slightly OT), I have a Teac A4010S stereo deck ($5 garage
> sale find from original owner, with a box of about 80 r-r tapes of music
> from, well, not my favorite artistes :-). Works fine but the drive belt
> slips -- of course -- when you get near the end of a tape. This is after
> furious disassembly & cleaning & lubing of all the usual suspects.
>
> page listing zillions of belts, but it has been lost in the ether. I
> understand that I could pull the old belt and measure it and look hither and
> yon for something that fits, but I'm lazy and it would be O so much easier
> to find an index to the real thing.
>
> Same question for my Telefunken stereo "Magnetophon" M77, although I guess
> that's more of a Euro item. If I had to choose between the Telefunken and
> the Teac, I'd choose the Tele -- smaller, cuter, cleverer, and it weighs
> about 40 pounds less.
>
> BTW, long ago, I read a post about boiling old belts to shrink them and thus
> make them grab again. I can testify from experience that it doesn't work!
>
> Regs,
>
> Phil
My reference books show two belts for the Teac A4010S:
A flat belt: 17.0" I/C .315" Wide .045" Thick
PRB # FRX17.0 EV/Game 1407-532
A round belt: 10.1" I/C .070 diameter
PRB # OA10.1 EV/Game 1407-204
No listing for the Telefunken stereo "Magnetophon" M77, but there is
a Telefunken model 77 listed in the PRB book
FR9.7 9.7" I/C .250" Wide .035" Thick
FRM14.0 14.0" I/C .200" Wide .031" Thick
No cross to EV/Game listed for these.
Check with Russell Industries and see if they are still made.
http://www.russellind.com/EVG/belt/flat.htm
http://www.russellind.com/EVG/belt/round.htm
--
Michael A. Terrell
Central Florida
Michael Jack
>
> I have been an avid collector of small open reel decks for a while and I
> also have aquired a few larger machines as well. In terms of overall sound
> and performance, I am curious to know which manufacturer made the best
> sounding and best functioning machines. From the information I have
> gathered so far, these three manufacturers seem to be in the forefront of
> open reel decks:
>
> Akai (Roberts), Pioneer, and Tascam (Teac).
>
> I have used Tascam machines many times before and know them well in studios.
> However, I don't know how they fair in comparison to the other two. One
> thing I do know is that I very rarely see auto reverse on a Tascam deck.
> While they do offer auto reverse on their Teac home line, these machines
> seem inferior looks wise when compared to some of the machines made by
> Pioneer and Akai.
>
> I currently own an Akai GX747, a Pioneer RT-707, a Pioneer 1100 and a
> Roberts 770x. All the machines except the Akai GX747 are broken. But I
> would like to know how they compare to each other and which is the best. Up
> to now I am very happy the way the Akai works and it can take 10" reels.
>
> Please respond directly to my EM address:
>
> Juki...@optonline.net.
>
> Thank You,
>
> Geo
I have been a professional recording engineer for 16 years and work at
one of the best recording studios in Canada....
http://www.phaseonestudios.com
In my opinion Ampex and Studer are the best sounding machines out
there.
MCI also made some wonderful machines in the late 70's, early 80's.
It should be qualified that the tape format (alignment, bias, flux
etc) tape width and speed determines quality of reproduction. I
regularly run my mixes to a half inch, two track machine running at 30
inches per second. For noise reduction, try Dolby SR......Can't beat
it!
I don't know much about consumer decks...
Steven Dinius
"Joe Bento" <joseph-...@kirtland.com> wrote in message
news:fsrj2vg2ld921tvmp...@4ax.com...
Rick Force
I have an Akai GX-636 with excellent glass heads...is this model
concidered an early GX unit? If so, what causes the glass heads to
crack? Rick.
Oscillatus <Oscil...@spamblock.com> wrote in message news:<Xns9307D4A25D848O...@210.49.20.254>...
Fred Nachbaur
I'll send her your way once she's worn me out.
Cheers,
Fred
--
+--------------------------------------------+
| Music: http://www3.telus.net/dogstarmusic/ |
| Projects: http://dogstar.dantimax.dk |
| Googlism: "fred nachbaur is de hounddog al |
| rond de 380volt volledig stabiel" |
+--------------------------------------------+
Alan Peterman
from the early 70's. The GX-220D was probably the worst, I'd say 80% of them
developed bad heads. The GX-260, 280 and 365 were also models I remember doing
heads on. As far as what caused the cracking, it was just normal use, but once
they cracked (which could be seen under magnification as the gap would develop
little cracks and chips) the head would have terrible high frequency response.
Oscillatus
> No both of you have WAY later GX heads. The real problems were on the
> machine from the early 70's. The GX-220D was probably the worst, I'd
> say 80% of them developed bad heads. The GX-260, 280 and 365 were
> also models I remember doing heads on. As far as what caused the
> cracking, it was just normal use, but once they cracked (which could
> be seen under magnification as the gap would develop little cracks and
> chips) the head would have terrible high frequency response.
Well, that seems like a good way to tell. As you say, ours are later
models, and if I ever suffer high freq loss, that cleaning won't cure, I'll
know what to suspect.
Phil Nelson
recorder to leave sitting on the shelf forever.
Regards,
Phil
"Michael A. Terrell" <ter...@mfi.net> wrote in message
news:3E2A1718...@mfi.net...
> > Same question for my Telefunken stereo "Magnetophon" M77
>
> No listing for the Telefunken stereo "Magnetophon" M77, but there is
> a Telefunken model 77 listed in the PRB book
>
> FR9.7 9.7" I/C .250" Wide .035" Thick
> FRM14.0 14.0" I/C .200" Wide .031" Thick
>
> No cross to EV/Game listed for these.
>
> Check with Russell Industries and see if they are still made.
>
> http://www.russellind.com/EVG/belt/flat.htm
> http://www.russellind.com/EVG/belt/round.htm
>
Norm Flasch
: In article <b09e8e$23k$1...@news.acns.nwu.edu>, fla...@news.eecs.nwu.edu
: (Norm Flasch) wrote:
: > However, the machine always needed fixing. Like belts, transistors
: > and capicitors. Very unreliable, but quite a step ahead in sound
: > quality for such small speakers. Solid state sound was not at all
: > impressive before these machines were introduced.
: What model was that?
: --
: John Rethorst
That was many years ago so I don't remember the model number. It was
dark grey and the removeable cube speakers fit in a compartment on the
left side of the recorder. They were about 5 or 6 inch wood cubes.
--
Norm Flasch
Northwestern University
Evanston, Illinois
Tom
Jeffrey D Angus wrote:
> Oscillatus wrote:
>
>> While we are all thinking about open reel decks, does anyone know if
>> I might be able to obtain a replacement set of (play FF REV Rec
>> etc)pushbuttons for my AKAI GX-620. These are plastic/neoprene
>> 'calculater' style inputs to the logic, and they have become fragile
>> and broken internally so most do not work anymore.
>>
>> I could wire in a set of momentary contact pushbuttons, but it would
>> wreck the appearance.
>>
> Are the buttons a small black dot under a membrane and make contact
> with a pair of traces. Kind of over lapping fingers -E3-
>
> A cheap calculator is a good source for repacement "dots" just pry the
> old ones out and glue in the new ones with a spot of crazy glue. Give
> the (usually gold plated) finger contacts a good cleaning with DeOxit
> and a final spritz with some GoldPro (both from Caig Labs)
>
> Or are there "descrete" switch buttons underneath the operating keys?
> Mouser has a bunch of those type switches in their catalog.
>
> Jeff
>
For the rubber button keypads DigiKey sells a repair kit that works
well. I used it on a walkie-talkie. It's a two part mix like epoxy,
mix it up, brush a thin layer on the black butons, let it dry and
re-assemble.
Tom
Now there's a name out of the dark ages. It has to be 40 years ago I
worked in a small shop that sold background music systems for stores.
Pre-Muzak I guess. Those were the first and last Ferrograph decks I
ever saw.
John Stone
1/27/03 9:32 AM:
I agree regarding the Sony decks. While those single motor machines didn't
have the mechanical sophistication of the solenoid operated decks, it was
very hard to argue with their performance. The TC 366 and 377 in particular
were amazingly good sounding machines with very flat response, and low wow
and flutter.
Regarding ferrite (glass) heads, Sony seemed to have a handle on ferrite
heads. They didn't crack or wear, and they still performed well. Still, I
always have preferred standard permalloy heads to ferrite ones. The Akai and
TEAC machines with ferrite heads were dogs,IMO. It was Nakamichi that came
out very strong against ferrite heads, showing how much more easily they
would saturate and revealing the problems with "micro cracks" due to their
being formed under high pressure.
As for Ferrograph, I do remember those machines as very rugged and good
performers. They also made some neat test equipment.
William Sommerwerck
I do! The A-M was touted as the Second Coming in open-reel tape.
Tip Turpin
for the old reel to reel recorders.
Buck Frobisher
alt.binaries.pictures.radio
What a jewel!
Frank
Oscillatus
news:BA5AB605.3E5CF%jms...@attbi.com:
> The Akai and
> TEAC machines with ferrite heads were dogs,IMO
Did AKAI produce machines with ferrite heads? I have only seen permalloy
and glass? I could hear nothing bad from the glass heads BTW.
Randy and/or Sherry
A few observations...
Alan Peterman wrote:
> For 18 years I sold and repaired audio gear and LOTS of Reel to reel
> decks. This was 1968-1986 and I still remember using, repairing and
> selling them. While the most popular might have been the Akai and
> Teac units, I think I would put the Sony 377, 645,
> 750 and 760 series in there with the best of them.
To which John Stone commented:
> I agree regarding the Sony decks. While those single motor machines didn't
> have the mechanical sophistication of the solenoid operated decks, it was
> very hard to argue with their performance. The TC 366 and 377 in particular
> were amazingly good sounding machines with very flat response, and low wow
> and flutter.
> Regarding ferrite (glass) heads, Sony seemed to have a handle on ferrite
> heads. They didn't crack or wear, and they still performed well.
To which I'll add:
While the mid-line Sonys were/are competent performers - it's
interesting that no one has mentioned the "upper class" which were two
series of some of the best consumer / semi-pro decks made - the 650 and
850 series - and their siblings. The 650 are 7" two speed; and the 850
are 10" three speed machines (adding 15ips). The 651 adds Automatic
program Scan - the 650-4 is a four channel quarter tracker; the 854-4S
is a monster of a four channel deck with all the bells and whistles -
and extremely good performance. Of course both series were expensive -
and Sony made little effort to import the 650s to the States- even left
out of many catalogs and brochures - although the heads assemblies were
nearly always mentioned - since the 650 and 850 shared head assemblies.
The head assemblies were rather unique - all of the heads, guides, etc.
are mounted on a large plate - that plugs into the deck and mounts on a
precision attachment point. This allowed you to change heads at will-
and they were already aligned, ready to go. This also gave you the
ability to change functions - for instance - you could put a two channel
assembly on the 4 channel machines - and vice-versa - though in the case
of 4 channel heads in the two channel machine - you had to supply your
own head amps, etc.- though wiring is easy - as the heads are on the
"plug" in the frame... But being made / supplied this way allowed any
one to change the heads as easy as changing the head shell in many phonos.
I've had two TC-651s - the first I bought used in 1973 - and the bought
a new second deck a just before leaving Guam. I loaned the new one to my
Dad - who used it quite a bit. I traded off the first one thinking
Cassettes would eventually be as good and a lot more convenient (WRONG!)
-- and CDs were hitting the scene too... As some may remember - my Dad
died a couple of months back - and I picked a bunch of stuff while back
in L.A. He wasn't technical at all - the while some stuff was in serious
trouble (like the Roberts 770X) the Sony just needed a minor bit of
service - the switches and contacts needed some DeOxit- the controls
some MCL Lube; and some felt on the brake pads (these are three motor
machines - but there are mechanical brakes to hold the reels when
stopped; and to assist in slowing from high speed FF/REWs). Once cleaned
up - it's performing to new specs - which isn't too shabby for a nearly
30 year old deck (sounds fabulous through the JBL Sovereigns - I'd
forgotten just how good R-Rs are!). The heads have no visible wear -
(thankfully - I don't know if Sony can / will still supply them - but
I'm going to see if I can find a set.
The Roberts 770X is one of the original 770s - tube amps, etc. When it
has new heads and clutches in it - it can stand toe-to-toe with most any
consumer deck - BUT - it eats heads like an elephant eats peanuts - and
the clutch almost as bad. Since the supply clutch provides play tension
- it is VERY critical - and even with factory pads - hard to get right.
A couple of times we just replaced the entire clutch assembly - since
Akai would supply those as well - and being factory assembled - they
worked great - while they lasted. The heads were worse (wear wise)-
probably 100-200 hours - maybe. Since I used that machine nearly daily
while preparing for a concert (through the 60's) - it's been through a
double fistful of heads. After I joined the Navy in 1970 - it was
retired to casual duty for my dad - and used only for the occasional 1
7/8" stuff - and for dubbing with the 651. Now - 25 years of that use-
and it's in serious trouble-- a LOT of rubber that's shot - brakes,
clutch and heads - Then heaven knows what kind of caps in those tube
amps - but dimes to donuts - a full re-cap is undoubted needed as well.
Judging from the performance / head problem with this deck - it's
understandable that Akai went to such great lengths to develop their
glass heads... Their early heads suck!
best regards...
--
randy guttery
A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com
Al Gillis
gearshift-style control for play/rewind/ff?
"William Sommerwerck" <will...@nwlink.com> wrote in message
news:v3aot0a...@corp.supernews.com...
Steven Dinius
"Al Gillis" <a...@aracnet.com> wrote in message
news:b17hg...@enews2.newsguy.com...
Steven Dinius
explains it! Hey, I can see better w/o these durn things!
"Steven Dinius" <10...@fmtc.com> wrote in message
news:v3emr4b...@corp.supernews.com...
William Sommerwerck
(Matsushita?) from the early '60s, and the original Norelco Compact Cassette
"Carry-Corder."
I've always liked this arrangement. It's intuitive and fumble-free.
Al Gillis wrote...
> How about the old early '60s Brush machines with the "four on the floor"
> gearshift-style control for play/rewind/ff?
> William Sommerwerck wrote...
Norm Flasch
: How about the old early '60s Brush machines with the "four on the floor"
: gearshift-style control for play/rewind/ff?
I have a very early Brush reel-to-reel in a wooden case. My guess is
late 40's. As I recall it has 3 motors and uses 6SN7 tubes (including
outputs). I got it at the ARCI junker auction and almost stripped it
for parts. But, it is so unique. Almost looks homeade.
: "William Sommerwerck" <will...@nwlink.com> wrote in message
: news:v3aot0a...@corp.supernews.com...
: > > Now who else remembers the other weird decks like the
: > > Astrocom Marlux (made on Teac chassis)...
: >
: > I do! The A-M was touted as the Second Coming in open-reel tape.
--
Troglodite
>I have a very early Brush reel-to-reel in a wooden case. My guess is
>late 40's. As I recall it has 3 motors and uses 6SN7 tubes (including
>outputs). I got it at the ARCI junker auction and almost stripped it
>for parts. But, it is so unique. Almost looks homeade.
Sounds like the "Soundmirror" which was one of the first magnetic tape machines
to appear for sale in the US following WWII. It's a classic. Fix it up and keep
it.
Rancherjim
>
> François Yves Le Gal wrote:
>
> > On Fri, 17 Jan 2003 03:12:52 GMT, "Jukin' Geo"
> > <Juki...@optonline.net>
> > wrote:
> >
> >
> >
> >> In terms of overall sound
> >> and performance, I am curious to know which manufacturer made the
> >> best
> >> sounding and best functioning machines.
> >>
> >>
> > derivatives
> >
> > Best pro analog deck: Ampex ATR-102
> > Best consumer deck: Tandberg TD20A-SE
> > Best tubed deck: Ampex 351 and derivatives
> > Accessits: Sony TC-880-2, Technics RS-1500
> > Honorable mentions: ReVox/Studer, Stellavox, Hencot
> >
> >
> >
> Glad to see you regard the Tandberg TD20A-SE so highly!
> Myself I have a TD20A, not the semi-pro version, but a very good
> machine.
> And, being a Norwegian, I'm patriotic...
>
> Stein
>
> --
>
> *** STEIN-OLAV LUND engineer ***
> *** Sor-Trondelag College ***
> *** Dept. of Electrical Engineering Tel. +47 73 55 95 99 ***
> *** N-7004 Trondheim Fax +47 73 55 95 81 ***
> *** NORWAY ***
> *** E-:-) LA9QV ***
> **************************************************************
> +++ Teacher (in pub): Do you serve headmasters? +++
> +++ Barman : We serve anybody, sir. +++
> +++ Teacher: Good, a beer for me and a headmaster +++
> +++ for my dog, please. +++
> +++ J. Taylor: The New English Norwegian Joke Book,1990 +++
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Stein,
I agree whole heartedly. I had two Tandbergs, but both developed
problems beyond the capabilities of local service shops. They in turn
sent them to factory repair center, which them promptly went belly up.
I lost BOTH of my Tandbergs simultaneously. GREAT SADNESS!!!
Rncher
*** Reply to ranch...@ezsg.com ***
Bob Groschen
Hi Gary,
Sorry for the late reply but things got a bit busy here....
> where did you work in broadcasting Bob ?
Actually I worked *for* the broadacst industry not *in* the broadcast industry.
I spent 16 years at 3M and 2 years at Imation. It was a lot of fun at 3M,
but Imation was no fun at all. 3M used the spin-off as opportunity to unload
tons of non-functional managers. Then they replaced the whole kitt & kaboodle
with IBM types which didn't work any better.
But I thank my lucky stars that I had an opportunity to work with soem really
great talents like Del Eilers, Jerry Walcoz, Steve Benson, Jerry Niels, etc.
Any one of those guys had more smarts in their little finger than I had in my
whole body.
> I was at KEEY-AM / FM in the Twin Cities (AM-1400 / FM-102.1) from March 73
> to July 76.......had a unique AM radiator because of numerous FM antennas
> (3) plus 2-way (4) hanging at the top of the tower..........two quarter
> waves of insulated skirt (bonded to tower at tops) stacked around a 5/8 wave
> tower, with a honking big vacuum variable at the bottom of the top one.
> feed impedance was (I remember it well) 831.1 ohms, and my hat is off to the
> guy who measured that last 0.1 ohm ! 'normal' antenna current at 1 kW was
> 1.10 A, with an upper limit of 1.11 and a lower of 1.08
OH sh*t! One of my favorite stations (the FM one)! BTW, as luck would have it,
I drove past the tower on I-694 just minutes before it fell to the ground. I
thought the news guy on radio was joking when I heard the announcment. I had
to drive bad and see for myself. Seeing all that crumbled steel lying there
was sobering.
Best Regards,
Bob Groschen
Bob Groschen
> they were Gauss model 1200's, used two capstans with about a 0.0008
> difference in diameter to provide a very firm contact
>
> one of the favorite tricks was when someone had the motors out for bearing
> changes, to swap the two capstans as he had them laying on the bench, when
> he put it back together, it would make a loop that got longer and longer
> till it self-destructed..........
One of the new techs did that by accident. I walked in at just the right time
to see the loop grow. Had to run out into the hallway before I busted out
laughing. Then I felt bad about it and walked back in and told him what
happened. His relief was palpable. :-)
Best Regards,
Bob G.
Gary Glaenzer
when ?
G
"Bob Groschen" <bob.gr...@plasmon.lms.com> wrote in message
news:d7e8c80b.03020...@posting.google.com...
Bob Groschen
> KEEY's tower (I-94 and 280) fell down ?????
>
> when ?
Oops! I should have been more specific. I was referring to the big
single antenna they were putting up on the north side of I-694. IIRC,
that's Arden Hills? Or is it New Brighton?
After that monster fell (and after all the lawsuits) they decided to replace
the one really big one with a farm of smaller ones.
Best Regards,
Bob G.
Gary Glaenzer
it fell in spring of 72, before I moved up there
they were working on the second of the twin pair when I got there in 73
G
"Bob Groschen" <bob.gr...@plasmon.lms.com> wrote in message
news:d7e8c80b.03020...@posting.google.com...
Stephen W. Worth
I just got an Akai GX-280D-SS. This is a Quad deck, so I can play all
four channels at once in one direction. I have two tapes here that I am
trying it out with. One is a two track and the other is a four track.
both are stereo.
I am wondering if I can make a high quality stereo track out of the two
track by taking the right channel from the front and the left from the
rear. Looking at the VU meters, those seem to be the dominant channels.
My problem is I can't get the rear left to play properly on the two
track tape I have here to experiment with. I suspect it's damaged. It
was wound on the reel very roughly many years ago and doesn't lay
perfectly flat as it goes through. The front right channel sounds fine.
If it isn't possible to use the rear channel for the left, would it
work to play the tape backwards, capture it into a sound editing
program, reverse it digitally, and then combine it back with the right
channel again?
Thanks
Steve
--
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*
CLASSIC MUSIC FROM ORIGINAL 78s, EXPERTLY TRANSFERRED TO CD!
VIP Records: Dance Bands - British Swing Bands - Opera
Check out the free MP3 downloads at http://www.vintageip.com/records
Randy and/or Sherry
Stephen W. Worth wrote:
> I have a question about R2R formats...
>
> I just got an Akai GX-280D-SS. This is a Quad deck, so I can play all
> four channels at once in one direction. I have two tapes here that I am
> trying it out with. One is a two track and the other is a four track.
> both are stereo.
But if the two-track stereo is recorded "correctly" for two track - the
tracks are NOT the same as any on your deck - they are two wider tracks
down the middle of the tape - rather than 2 and 2 interleaved (which is
standard 4 track 2 channel stereo- and 4 track 4 channel).
It becomes a matter of which "segment" of the 4 track head happens to
"land" on any of the two tracks of the tape (of course it's the tape on
the head - but you get my meaning).
> If it isn't possible to use the rear channel for the left, would it
> work to play the tape backwards, capture it into a sound editing
> program, reverse it digitally, and then combine it back with the right
> channel again?
Worth a try - but unless you are EXTREMELY lucky - it won't stay "in
sync". Slight variations in tape speed - due to anything from capstan
slippage on "rough spots" on the tape - to the tape itself stretching...
Of course doing it digitally - IF you have powerfull enough tools
and the patience to do it- you can time correct them into a usable tape...
Machines that are capable of playing both 2 and 4 track (not channel -
track) tapes - like the Roberts 770 series - (and Akai M8/9 series)
literally shift the heads a fraction of an inch. Other machines have
interchangeable head assemblies - and have half-track heads available
which correctly track the two "middle of the road" tracks.
Mark Robinson
I looked up the track spacing and dimensions in my: "Reference Data for Radio Engineers".
For 2 track stereo/mon:
Track Width = .082"
Track Spacing = .156"
For 4 track stereo/mon:
Track Width = .043"
Track Spacing = .134"
So, if you do some dimensional analysis, you see that the 2T has a gap of .006" from the top and bottom edges of the tape with
a gap between tracks of .074" (.082 +.082 +.074 + .006 + .006 = .250). The 4T version is .003" from top and bottom and a track
to track gap of .024" (I'll leave the math to you). If you use the top and bottom tracks of the 4 track tape (tracks 1 & 4),
you will only miss about .003" of each track due to the smaller distance of the gap from edge to track on the 4T head stack. I
think this will be fine.
The other problem you will have will be a low frequency bump in the playback response due to fringing effects caused by using
the small head track width on a larger recorded track size. I think you could EQ this bump out of the playback. Since you
were not getting any output from one of the tracks, I would check the recorder to see if it has a defect (as you suspect).
Hope this is of some help.
Mark Robinson
"Stephen W. Worth" <ne...@vintageip.com> wrote in message news:070320032013287278%ne...@vintageip.com...
Randy and/or Sherry
Mark Robinson wrote:
[math bit snipped for brevity]
> If you use the top and bottom tracks of the 4 track tape (tracks 1 & 4),
> you will only miss about .003" of each track due to the smaller distance of the gap from edge to track on the 4T head stack. I
> think this will be fine.
The problem is that you are assuming that the recorder that laid down
the track(s) in the first place used the full width of the track. In
reality - the density of the track's signal is centered on the track's
center (the center of the head's gap) - and radiate to the track's edge
from there. While 2 tracks has a larger "target zone" than 4 tracks -
it's not unusual for the actual recorded track width to be not much
wider than a 4 tracks- depending on the condition of the recording head,
etc. Given tracking errors in older decks (the deck most likely to have
recorded a 2 track stereo tape) it's possible - even likely that one
track would come very close to "hitting" one of the 4 tracks on a 4
channel head- while coming close to "missing" the other three. Again -
this is why the early decks that were designed as 4 tracks with 2 track
"alternate" tracking (Roberts 770s Akai M8 & M9s, etc.) - literally
shift the heads towards the center of the tape. I don't recall the shift
"specification" but someone with a Roberts / Akai manual can probably
look it up and see.
That's not to say that a 4 track can't recover a 2 track tape - given
everything is just so... but with a possibly damaged tape (not defective
player) as Stephen has noted - on top of the offsets between the two
formats - it can make it difficult.
Stephen W. Worth
<mark...@verizon.net> wrote:
> If you use the top and bottom tracks of the 4 track tape (tracks 1 & 4),
> you will only miss about .003" of each track due to the smaller distance of
> the gap from edge to track on the 4T head stack. I
> think this will be fine.
Thanks! That's what I suspected, but the only 2 track tape I have here
to test with is a big wrinkly. The VU meters for tracks 1 & 4 were
showing a good strong signal, but there were fluctuating dropouts in
track 4. I think that is due to edge damage on this particular tape.
See ya
Mark Robinson
You are probably correct about the track widths. Getting this to work at all is a compromise. I wonder, did the Roberts/Akai
machines have to shift the heads because it used tracks 1 & 3 (the normal stereo playback tracks)? If you do the math based on
the numbers I provided, track 1 misses by only .003", but track 3 is off .025". Given, as you state, the real world track size
is likely smaller than the .043" 4T and .082" 2T dimensions, you would not get nearly as much output from track 3.
Now consider this situation. If you moved the 4T stereo head stack such that tracks 1 & 3 were centered about the centerline
of the tape path, tracks 1& 3 (with a .134" center to center spacing and .043" track width) would now be inside of the 2T
(.156" center to center spacing and .082" track spacing) with a guard of .0085". This looks much better. To do this, you
would need to move the head stack down .0335". What do you think?
Mark Robinson
"Randy and/or Sherry" <comc...@mississippi.net> wrote in message news:3E6A724E...@mississippi.net...
Steve Urbach
4 Track and 4 channel ar two different beasts. 4 channel uses the
standard 4 tracks, but all in the same direction.
Akai does not use preasure pads:
Edge damage will affect (tape-head) track alignment and
head contact.
Dirt in the guides will skew the tape or curl the tape reducing
contact.
A Magnifier should be used to vew all tape contact surfaces. Clean
them spotles with tape head cleaner or denatured alcohol (not rubbing
alcohol).
Get a good tape.
Steve U
Owner of a GX-40Dss
On Sat, 08 Mar 2003 19:23:09 -0800, "Stephen W. Worth"
<ne...@vintageip.com> wrote:
>In article <VYraa.6002$gi1....@nwrdny02.gnilink.net>, Mark Robinson
><mark...@verizon.net> wrote:
>
>> If you use the top and bottom tracks of the 4 track tape (tracks 1 & 4),
>> you will only miss about .003" of each track due to the smaller distance of
>> the gap from edge to track on the 4T head stack. I
>> think this will be fine.
>
>Thanks! That's what I suspected, but the only 2 track tape I have here
>to test with is a big wrinkly. The VU meters for tracks 1 & 4 were
>showing a good strong signal, but there were fluctuating dropouts in
>track 4. I think that is due to edge damage on this particular tape.
>
>See ya
>Steve
--- _
, | \ MKA: Steve Urbach
, | )erek No JUNK in my email please
, ____|_/ragonsclaw dragons...@mindspring.com
, / / / Running United Devices "Cure For Cancer" Project 24/7 Have you helped? http://www.ud.com
Randy and/or Sherry
Mark Robinson wrote:
> Hi Randy,
>
> You are probably correct about the track widths. Getting this to work at all is a compromise. I wonder, did the Roberts/Akai
> machines have to shift the heads because it used tracks 1 & 3 (the normal stereo playback tracks)? If you do the math based on
> the numbers I provided, track 1 misses by only .003", but track 3 is off .025". Given, as you state, the real world track size
> is likely smaller than the .043" 4T and .082" 2T dimensions, you would not get nearly as much output from track 3.
>
> Now consider this situation. If you moved the 4T stereo head stack such that tracks 1 & 3 were centered about the centerline
> of the tape path, tracks 1& 3 (with a .134" center to center spacing and .043" track width) would now be inside of the 2T
> (.156" center to center spacing and .082" track spacing) with a guard of .0085". This looks much better. To do this, you
> would need to move the head stack down .0335". What do you think?
The heads in those machines move in a strange manner - the erase / bias
heads move in for mono track 3-2; center for 4 track stereo; out for
mono track 1-4; and stay out out plus shifts the record/play head in for
1/2 track stereo. My Roberts 770 is in pieces (being parted out)- but I
checked the "in shift" of the R/P head as it is now (likely not exactly
right) and the shift is just a fuzz between .030" & .035"--- pretty
close to your calculation.
- someone with a service manual for one of these can confirm the
number exactly- but in the meantime - sounds like you have it figured out.
fergus
> Hello all,
>
> I have been an avid collector of small open reel decks for a while and I
> also have aquired a few larger machines as well. In terms of overall sound
> gathered so far, these three manufacturers seem to be in the forefront of
> open reel decks:
>
> Akai (Roberts), Pioneer, and Tascam (Teac).
>
> I have used Tascam machines many times before and know them well in studios.
> However, I don't know how they fair in comparison to the other two. One
> thing I do know is that I very rarely see auto reverse on a Tascam deck.
> While they do offer auto reverse on their Teac home line, these machines
> seem inferior looks wise when compared to some of the machines made by
> Pioneer and Akai.
>
> I currently own an Akai GX747, a Pioneer RT-707, a Pioneer 1100 and a
> Roberts 770x. All the machines except the Akai GX747 are broken. But I
> would like to know how they compare to each other and which is the best. Up
> to now I am very happy the way the Akai works and it can take 10" reels.
>
> Please respond directly to my EM address:
>
> Juki...@optonline.net.
>
> Thank You,
>
> Geo
Hello all.
I'm sorry to resurrect such an old thread but I have one question I was hoping some of you might have an answer to..
I'm wondering if you know of any company who went by the name ITC who may have made mixing consoles in the 70s. I've been in touch with Andy Rector, one of the original International Tapetronics guys, and he doesn't think his ITC company ever manufactured a mixer of any description. This could be a broadcast console for a radio station but is more likely a piece of studio gear.
Any leads would be much appreciated.
Thank you,
Fergus
Bill Graham
fergus
fergus
Thanks anyway!
Johny B Good
<fergus...@gmail.com> wrote:
>> >> I have been an avid collector of small open reel decks for a
>>
>> >> while and I also have aquired a few larger machines as well. In
>>
>> >> terms of overall sound and performance, I am curious to know which
>>
>> >> manufacturer made the best sounding and best functioning machines.
>>
>> >> From the information I have gathered so far, these three
>>
>> >> manufacturers seem to be in the forefront of open reel decks:
>>
>> >>
>>
>> >> Akai (Roberts), Pioneer, and Tascam (Teac).
>>
>> >>
>>
>> >> I have used Tascam machines many times before and know them well in
>>
>> >> studios. However, I don't know how they fair in comparison to the
>>
>> >> other two. One thing I do know is that I very rarely see auto
>>
>> >> reverse on a Tascam deck. While they do offer auto reverse on their
>>
>> >> Teac home line, these machines seem inferior looks wise when
>>
>> >> compared to some of the machines made by Pioneer and Akai.
>>
>> >>
>>
>> >> I currently own an Akai GX747, a Pioneer RT-707, a Pioneer 1100 and a
>>
>> >> Roberts 770x. All the machines except the Akai GX747 are broken.
>>
>> >> But I would like to know how they compare to each other and which is
>>
>> >> the best. Up to now I am very happy the way the Akai works and it
>>
>> >> can take 10" reels.
>>
to resort to a reply to another's quotation of your original posting),
but this used to be a subject dear to my heart.
I've not been in the mood nor had the time to keep up with usenet
this past month so I'm sorry to say I missed your posting.
My experience with tape decks over the past 40 years or so has
largely been with Akai models (and one truly horrible TruVox tape
deck).
My very first Akai was an M8 that I acquired some 40 years ago. In
actual fact, a 'portable' tape recorder. Portable on account it's 50Lb
bulk was possessed of a hard cover and a sturdy carrying handle and
'Tape Recorder' on account it had a 2W per channel output (and a pair
of built in speakers!).
This model was vintage even back then. It was all valve (vacuum
tubes) and sported their patented Crossfield recording bias system (an
extra recording head that was swung to within 12 thousands of an inch
away from the backside of the tape in order to apply the high
frequency bias to the tape during recording).
The crossfield biassing system was dropped from later models with the
claim that the new fangled crystal ferrite recording heads were able
to 'focus' the bias field into the tape coating just as, or more,
effectively than the crossfield biassing system. Personally, I think
it was more a case of marginality and improved (Japanese) tape
coatings making the extra complexity of the crossfield biassing system
no longer justifiable.
After that, I bought a brand new 4000DS which I used for about a year
before discovering that the jerks at Akai's QC had used a single tone
test tape for azimuth alignment which had resulted in an azimuth
mismatch between the record and replay heads. The effect was hardly
noticable when replayed on a stereo system but became excrutiatingly
obvious when mixed down to mono in order to dub onto a cheap mono
cassette recorder.
At the time, I didn't possess a suitable alignment tape nor had I
worked out how to make such a tape[2] with absolute azimuth alignment
accuracy between the track pairs 1/3 and 2/4 that are employed by the
four track stereo recording system of domestic/semi professional reel
to reel tape decks (unlike the stereo cassette system of track pairs
1/2 and 3/4 which was chosen to allow such stereo recordings to be
played back on cheap mono cassette recorders).
I learned a valuable lesson with that experience. "Never trust the
manufacturer of any kit that relies on post production alignment
procedures to get it right". In this case, the adage "If it ain't
broke, don't fix it." is a horrible myth put out by the ignoratti who
would'nt recognise a glaring defficiency if it got up and smacked them
full in the face with a wet haddock.
Another valuable lesson I learned with the M8 was; "Never wait for
your complex electronic/mechanical 'gadget' to go faulty before
ordering said gadget's service manual from the manufacturer.
Hats off to the service department at The Rank Organisation company
who were the UK importers and service agent for Akai equipment. They
promised to supply me with an M8 service manual just as soon as they
could get Akai to ship them one, but in the meantime, please make do
with a photocopy of one of our very own workshop manuals.
As it turned out, it proved impossible for them to import an original
manual from Akai themselves and they landed up compiling a slightly
improved photocopy of the best pages from their own workshop manuals
and shipping it to me about a year later by way of an apology since
they'd already accepted payment. I didn't realy mind being "Fobbed
Off", in fact I was just very grateful to have been supplied with any
sort of manual at all (and having second copy was a bonus).
When I bought the GX630DB I immediately ordered a full workshop
manual from Akai to forestall the problem I'd had with the M8. It was
just as well that I did, not because of it going faulty (although it
did do that some 10 or 15 years later) but more to do with fixing the
several "Schoolby Howlers" in its design.
The real 'Biggy' was due to a "Cost Cutting Exercise" in the dolby
boards (both record and replay) which had severely compromised the
clipping levels to well below tape saturation (a fact that had been
noticed on replay, but not record, in a technical magazine review of
this machine.
Quite frankly, I was immensely disappointed to discover that a
company of Akai's reputation had actually "Amstradded"[1] their
product to such a degree that it would have made Amstrad blush with
embarassment.
What Akai, in their hubris, had done was to eliminate the extra
resistor and capacitor required to provide the necessary feedback in
the output stage of each of the four dolby boards without compromising
the mid point bias voltage level of the output transistor's emitter
terminal. This extremely shortsighte penny pinching resulted in an
emitter voltage of one quarter the supply rail voltage instead of half
the rail voltage as per the original design (which I got sight of in a
Wireless World magazine artice some six months after I'd re-invented
the missing components - smug mode on). What this meant was that the
replay clipping level was now some 6db down on the optimum value as
intended by the original Dolby design.
Since the components were literally just copper's worth of materials
on a gadget with an original retail price tag of £500 or so and my
time was the more costly investment in this remedial exercise, I went
a little further in my improvement by replacing a simple emitter
resistor with a constant current generator which extended the peak to
peak output voltage swing by another volt or so and provide symetrical
clipping for loads as low as 10K ohms (a simple emitter follower with
resistor load creates assymetrical clipping when the load drops down
to just 3 times that of the emitter load resistor which gets worse the
lower the load impedance becomes.
All in all, I'd raised the replay clipping level from the piss poor
+8dbm point to a more respectable +18dbm, safely above that due to
saturation clipping levels of even the modern high output tapes
(Maxell UD and TDK SA formulations) that had become available by that
time.
The recording clipping problem with bass frequencies that I'd
erroneously assumed to be due to a weakness of ferrite over mu-metal
saturation performance also turned out to due to the same cause[3].
modifying the record dolby boards eliminated the gross intermod
distortion that would occur at any level above 0db between the bass
and the mid range frequencies. After modding the record dolby boards I
found I could record to the same levels I'd previously been able to
use on the M8 and the 4000DS machines.
There was no doubt that my investment in a service manual for that
machine had paid a great dividend. In all other respects, that machine
far exceeded all others on the market in terms of speed stability and
wow and flutter performance as well as extremely low 'scrape noise'
due to the very excellent 'zero wear' glass crystal heads.
Once I'd fixed the 'penny pinching' problem with the compromised
dolby boards, that machine had no equal in its class (domestic 4 track
dolby stereo tape deck with 3 3/4 and 7 1/2 ips speeds). However, I
felt it still lacked a few refinements so I added three 12 step rotary
switches on the back panel to give me record sensitivity calibration,
record equalisation and record bias level calibration(with push button
for 4 db drop of bias level to find the optimum treble sensitivity
point - 4 db 'over-bias' being considered the optimum bias level from
the hf optimum sensitivity point) which allowed me to calibrate the
machine to the characteristics of individual tapes in a recordable
format (the reason why I used 12 way rotary switches in the first
place).
With domestic dolby (dolby B, iirc) performance is extremely reliant
on matching record sensitivity levels with replay levels as well as
ensuring an accurate mid to high range frequency response. Replay
output levels and frequency response are supposed to be calibrated to
recorded flux levels on a reference tape for all tape decks with any
adjustment for tape types being applied purely during the recording
process. IOW, aside from gross tape type differences due to chrome or
iron oxide formulated tapes, the replay sensitivity and equalisation
curves are to a fixed calibrated standard.
Now, forgive me for going on at length about my precious GX630DB tape
deck but I felt it was vital to imparting my experiences with such
electromechanical analoge magnetic devices including the famous GX747
which you mentioned and which I found myself purchasing as a
replacement for the GX630DB which had been stolen in a burglary.
Again, when I purchased the GX747, I also bought a service manual.
This time, however, I couldn't find any "Schoolboy Howlers" in the
electronics (no dolby boards to 'Amstrad'[1]). The defficiencies that
I did spot were tape fouling the plastic 'modesty screen' over the
tape heads which I swiftly remedied with a craft knife and the extra
counterproductive expense of a rubber drive belt between the rubber
faced tape idler wheel and the optical wheel used to drive the
electronic 'Footage Counter'.
This last piece of utter madness (compromising performance by
spending unnecessary pounds) just simply left me totally
flabbergasted. There was absolutely no sane reason why that rubber
faced tape idler wheel couldn't have driven the optical sensor wheel
directly, neatly eliminating, not only cost, but additional random
variations in counter accuracy due to slippage between the little
rubber drive belt and the pully grooves on the optical wheel and
rubber faced tape roller.
This last bloody minded act of design vandalism is one I was never
able to find a satisfactory solution to. It irks me to know that a
direct drive sensor would have reduced the 15 to 30 seconds worth of
variation between play through and rewind back to start to something
in the region of just one or two seconds.
All that aside, I would say the GX747 is an otherwise excellent
machine notwithstanding the lack of any built in noise reduction. That
was an issue I was intending to address with an external dolby B
and/or DBX unit. However, about 12 to 18 months later, I managed to
buy my beloved GX630DB back "No questions asked". I was only too
grateful to get the opportunity to recover my uniquely enhanced
GX630DB still in good shape (just some very slight scuff marks).
As a result, the GX747 got packed away, virtually unused. I still
have it to this day. I simply can't bring myself to part with it
despite having a much stronger attachment to the GX630DB which, whilst
it sits ready for action, hasn't been used in anger for the last 12
months or so.
Mind you, it did get some use over the last decade or so during which
time I've had it develop a fault in the capstain motor servo board
where one of the four diodes in the bridge rectifier circuit went
short circuit. Not a big problem when you happen to possess the
service manual to guide you in your diagnostic and repair effort. I'm
not certain but I think I've had to effect this repair twice. The last
time I replaced all four diodes with higher rated ones to effect a
more permanent cure.
The only other fault has been intermittent signal routing switch
contacts (source / output monitoring) which, fingers crossed, I
addressed by using miniature sealed contact relays.
[1] "To Amstrad" = "To spoil the ship for a ha'pence of tar". This
describes the common practice by Amstrad to leave out components not
deemed absolutely essential to the basic operation of the electronic
kit under ideal conditions. e.g. TV sets which illegally received CB
radio transmissions from CB users several streets away either by
interference tp picture or sound or both due to missing filtering
components (ferrite bead inductors and / or nanofarad ceramic
capacitors costing pennies) otherwise deemed essential by sane
manufacturers.
[2] I did eventually figure out how to make a white noise based
azimuth alignment tape to align the left and right heads to an
absolute azimuth alignment with each other.
The procedure relied upon the extreme thinness of triple play tape to
allow the recorded mono white noise source to be detectable when the
tape was reversed and flipped over so that the replay head was
'listening' to the back side of the tape.
A few iterations of the recording/playback procedure were required to
arrive at an absolutely aligned test recording which could then be
used to align the replay head to an absolute azimuth (mixing the
stereo replay down to mono which temporary azimuth displacement using
finger pressure would reveal by phasing/skying effect on the tone of
the replayed white noise which would indicate whether the head was
optimally aligned or not). Once the replay alignment was completed, it
was just a simple matter of recording a mono source of white noise in
stereo and mixing the replay down to mono and then adjusting the
record head to eliminate any phasing/skying effect.
Once you'd reached this stage of head calibration on the machine, you
could then make as many copies of white noise calibration tapes on
more standard (and robust) tapes as you desired.
[3] In the case of the recording clipping on bass frequencies (but not
mid range and above), this came about due to where in the recording
amplifier chain the bass equalisation had been applied. Needless to
say this took place _before_ the signal entered the dolby processor
circuit (with the treble boost portion of the record amp equalisation
being applied after the dolby processing). Result, clipping of bass
frequencies within the dolby board before it reached the recording
head.
One might be tempted to question the philosophy of applying bass
recording boost equalisation before the dolby processing stage but the
frequencies being boosted are well below the range being processed by
the dolby B processor. Provided the clipping range in the dolby board
does not compromise the tape saturation clipping level, this is no
more risky than the situation where both the bass and treble record
equalisation curves have been applied after the dolby processor board.
In this case, bringing the record dolby boards up to standard rather
neatly solved the bass clipping issue on record.
--
Regards, J B Good
Bill Graham
one of the best waews my Akai 3609D. But I have to say that my little $175
Tascam GT-R1 digital machine is so noise-free and small, convenient and
portable, that it puts all of my reel-to-reels to shame. I am afraid that
the new digital equipment makes all of the tape machines woefully obsolete.
Johny B Good
wrote:
>I owned several reel-to-reel decks during my hi-fi lifetime. Thge last, and
>one of the best waews my Akai 3609D. But I have to say that my little $175
>Tascam GT-R1 digital machine is so noise-free and small, convenient and
>portable, that it puts all of my reel-to-reels to shame. I am afraid that
>the new digital equipment makes all of the tape machines woefully obsolete.
The only remaining (non-trivial) use for such kit is to provide the
means by which to audition the old tape collection whilst digitising
them onto modern storage media.
Whilst one could still make use of the recording features, this would
involve the expense of buying additional reels of tape (not cheap for
the good stuff, especially so when buying it on 10 inch reels), or
recycling your existing tapes (and committing the "BBC lost Doctor Who
Episodes" sin[1]).
I've digitised several reel to reel recordings over the past decade,
mostly of borrowed commercial vynil but also most (if not all) of my
live and "studio" recordings of a few local bands. I'd guess I've only
digitised around a quarter of my "analogue memories" thus far and
intend to digitise the rest before I expire from old age.
I don't intend to 'recycle' any of the processed tapes since my hope
is that I'll be able to afford much better quality kit than the
soundblaster 16 sound card I'd initially started with and the
AWE64GOLD card that currently resides in the PC reserved for this
function by virtue of having a MoBo old enough to still sport the
single ISA 16 expansion slot required for the AWE64 card.
Unlike their PCI contempories, these venerable ISA soundcards do have
the virtue of line input clipping levels of some 12 and 14 dbm
respectively and the ability to actually digitise right up to the 0db
FSD mark without the input buffer clipping some 3.5db below FSD as is
common with every single PCI card I tried (and the built in MoBo sound
chips based on the same PCI sound card reference design where the same
schoolboy howler of 'jumpering' the chip to apply the 6db de-sense on
line input in a misguided ploy to improve the S/N by that same factor
without regard to the effect of only having a mere 5v to power the
line input buffer amp - hence the inability to drive the ADC to FSD
values without gross clipping on the analogue input port).
That bad experience with PCI and on-board sound chips happened a
decade back and the outlook was rather bleak. However, when I was
testing a more recent, but cheap, usb adapter last year, I discovered
that the line input clipping issue had vanished. It seems that the
penny did finally drop and the problem finally resolved.
Testing the line input on more recent MoBos suggests this is also
true with on-board sound chips so I can now give serious thought to
giving the downstairs PC[2] a long overdue MoBo/CPU/RAM upgrade and
bid a tearful farewell to that venerable AWE64GOLD soundcard that had
cost better than a hundred quid at the time (even with the cashback
offer - hence the tears).
Of course, I could always use a standalone purpose made digital
recorder like your Tascam GT-R1 to capture all those old analogue
recordings for transfer to any PC for further processing (pop and
click elimination for the vinyl sourced stuff, whether direct from the
record deck's line out or via a tape recording) and, hopefully, using
a DSP version of dolby replay decoding calibrated to the exact dolby
encoding characteristics that had actually been applied to the tape
recordings[3] rather than relying on that approximated by the analogue
dolby replay boards in the tape deck itself (hence the desire to
retain the original tape recordings for a second chance to digitise to
the best possible capture quality).
[1] The BBC, in a misguided attempt at cost cutting decided to recycle
some of their very expensive VTR tapes (apparently some 70 quid a
pop), forgetting the IP value in the recordings themselves, let alone
the much larger production costs of each episode which far outweighed
that of a mere 70 quid tape. It was rather like emptying out BabyCham
bottles un-drunk just to be able to use them to make fizzy pop with a
SodaStream (at least, it made about as much sense to perpetrate an act
of such staggering stupidity).
[2] This PC is kept in the front room where the record and tape decks
reside but has been used by my wife as a general purpose web surfing
tool. The MoBo is now some ten years old and remains un-upgraded
simply for the sake of the AWE64GOLD ISA soundcard that was fitted
specifically to allow me to digitise my analogue recordings. As a
result, despite sticking with win2k, it's starting to show its age and
the wife now keeps reminding me that it isn't fast enough for _her_
needs and "Isn't it about time it was upgraded to a better machine?".
This thorny issue of the "Long Overdue Upgrade" has been troubling me
these last 3 or 4 years. On the one hand, I'd like to create a compact
PC box with an ISA slotted MoBo that I can transfer the sound card to,
and. OTOH, I'd like to find such a compact system, complete with
suitable MoBo. The inevitable result of this is that I've been
procrastinating over taking such a major step and nothing has
happened.
I reckon a more practical solution is to ditch my outdated thinking
that a PC with soundcard is the most cost effective solution and look
at the more dedicated alternatives that have now finally become
economically viable. IOW, do some research on what is currently
available in HiFi digital audio recording devices and acquire one.
[3] I've been using CoolEdit Pro this past decade or so to record and
process my analogue recordings. It's been a very effective tool for
this purpose right from the days of 486DX100 and on.
It has various filtering/processing features but doesn't offer the
almost 'no brainer' 'bleedin' obvious' one of dolby B replay decoding.
I think I may even have looked for such a filter as a downloadable
plug-in (I can't honestly remember), but if I did, I obviously failed
to find one. My hope is that a renewed search will reveal such a
utlity (whether standalone or a plug-in), preferably with the
"Bleedin' Obvious" calibration feature that allows the perfect
reciprocal of the actual Dolby B encoding used in the original
recordings to be applied.
Calibration would consist of recording a special test signal to an
unused part of the tape using the eq/sensitivity/bias settings noted
for each tape which would then be analysed by the calibration software
to derive the actual replay decoding filter algorithm required for a
perfect cancellation of the record encoding distortion that had been
applied. In this case, the decoding filter would also take care of the
additional distortions generated in the basic magnetic
recording/replay process itself.
This would require access to the original recording tapes as well as
the original tape deck the recordings were created on. This alone is a
very good reason to hang onto both the original tapes and the
recording equipment used.