Scott 299C in triode mode / Scott Integrateds - General
mbq...@notiac.net
"Bob Fitzgerald" <bf...@capital.net> writes: > In looking through an old Welborne Labs Catalog, (1993) I saw a schematic
> The sound is great - big improvements in the bass, (much tighter and
> deeper) soundstage, etc. across the board, all was better. Welborne
> suggests this now makes the amp have 50% less power, but in my setup, I saw
> very little difference -
Is there any better value out there than an H.H. Scott integrated?
In use daily:
(1) 299 w/ original tubes
(Biased only.)
(1) 299-B w/ original tubes
(Replaced fuse & biased.)
In use periodically:
(1) 296 w/ 7581A's
(Replaced selenium stack & biased.)
When I think about hotrodding the 299, I open it up, gaze at the
incredible rats nest of wiring and interlaced components, close
it back up, and continue to use it as is. I am not suffering for
its lack of couth. While it is not the only tube amp in my house,
and far from the most "accurate" its easy nature gets it the most
air time. Herman did it right!
Leif
Bob Fitzgerald
mbq...@notiac.net wrote in article <5v95kv$r...@news-central.tiac.net>...
> "Bob Fitzgerald" <bf...@capital.net> writes: > In looking through an old
Welborne Labs Catalog, (1993) I saw a schematic
> When I think about hotrodding the 299, I open it up, gaze at the
> incredible rats nest of wiring and interlaced components, close
> it back up, and continue to use it as is. I am not suffering for
> its lack of couth.
some of us can't resist - it's in the nature.
>While it is not the only tube amp in my house,
> and far from the most "accurate" its easy nature gets it the most
> air time. Herman did it right!
>
> Leif
I was _shocked_ when I first played my Scott. My wife was in disbelief.
I just played pure clean music. My Scott was free, given to me by my wife's
dad after he did an attic clean out.
I immediately bought another. These amps are an incredible deal, especially
compare to dynacos selling for 275.-?, scotts can be had for 175. and
include a 12AX7 based preamp.
For the record, I would advise most people to at least replace the bias
resistors which are carbon stock with new ones. I found mine had drifted
20-30K ohms on a 330K unit (some high, some low). Also, the carbon units
are VERY temperature dependent - I held one between my fingers and watched
the resistance change as my body temp heated it up. I used 1% metal film,
and carefully matched all 4 tubes for idle bias. Also, of course, the
selenium rectifier also needs attention.
Last, I recommend people play with different brands of 12AX7 tubes in the
preamp section feeding the amp. I found these influence the sound in a big
way(Suprise!) so don't settle for "pot luck" - try different things. I have
tried NOS Mullard, Telefunken, and new Sovtek 7025s, against NOS GE
US(horrible) - all had a little different sound. These minor things can
help tune the sound without major hot rodding.
Bob
Rick Young
Bob Fitzgerald wrote:
>
> mbq...@notiac.net wrote in article <5v95kv$r...@news-central.tiac.net>...
> > "Bob Fitzgerald" <bf...@capital.net> writes: > In looking through an old
> Welborne Labs Catalog, (1993) I saw a schematic
>
> > When I think about hotrodding the 299, I open it up, gaze at the
> > incredible rats nest of wiring and interlaced components, close
> > it back up, and continue to use it as is. I am not suffering for
> > its lack of couth.
>
> some of us can't resist - it's in the nature.
>
> >While it is not the only tube amp in my house,
> > and far from the most "accurate" its easy nature gets it the most
> > air time. Herman did it right!
> >
> > Leif
>
> I was _shocked_ when I first played my Scott. My wife was in disbelief.
> I just played pure clean music. My Scott was free, given to me by my wife's
> dad after he did an attic clean out.
> I immediately bought another. These amps are an incredible deal, especially
> compare to dynacos selling for 275.-?, scotts can be had for 175. and
> include a 12AX7 based preamp.
Lucky dog for getting the free Scott !!! I paid $110 for my Dynaco
SCA-35, & had much the same reaction to it's sound. I did make some
minor mods (it's not *quite* a rat's nest, but close). I did all I felt
capable of doing, mainly replacing caps & a minor biasing scheme mod.
The upgrade was worth it in my case, but I don't know if I'll go
further. I like listening much more than tinkering!
I'd like to get a Scott sometime & compare w/ the SCA-35 ... Regards,
- Rick.
Tim Reese
In article <341C59...@worldnet.att.net>,
Rick Young <rkjy...@worldnet.att.net> wrote:
>Bob Fitzgerald wrote:
>> > When I think about hotrodding the 299, I open it up, gaze at the
>> > incredible rats nest of wiring and interlaced components, close
<snip>
>SCA-35, & had much the same reaction to it's sound. I did make some
>minor mods (it's not *quite* a rat's nest, but close). I did all I felt
Gosh, "rat's nest"? I have a few Scott pieces (including a 299C, which
is in the queue for refurbishment) and they seem quite organized and
neat to me. They are very neat compared to, say, a wire-wrapped computer
backplane. cheers tr
--
---------------------------------------------------------------
Tim Reese, MGH NMR Center re...@nmr.MGH.harvard.edu
mbq...@notiac.net
Rick Young <rkjy...@worldnet.att.net> writes: > Bob Fitzgerald wrote:
> >
> > mbq...@notiac.net wrote in article <5v95kv$r...@news-central.tiac.net>...
> > > "Bob Fitzgerald" <bf...@capital.net> writes: > In looking through an old
> > Welborne Labs Catalog, (1993) I saw a schematic
> >
> > > incredible rats nest of wiring and interlaced components, close
> > > its lack of couth.
> >
> > some of us can't resist - it's in the nature.
> >
> > >While it is not the only tube amp in my house,
> > > and far from the most "accurate" its easy nature gets it the most
> > > air time. Herman did it right!
> > >
> > > Leif
> >
> > I was _shocked_ when I first played my Scott. My wife was in disbelief.
> > I just played pure clean music. My Scott was free, given to me by my wife's
> > dad after he did an attic clean out.
> > I immediately bought another. These amps are an incredible deal, especially
> > compare to dynacos selling for 275.-?, scotts can be had for 175. and
> > include a 12AX7 based preamp.
> > Bob
>
>
> Lucky dog for getting the free Scott !!! I paid $110 for my Dynaco
> minor mods (it's not *quite* a rat's nest, but close). I did all I felt
> The upgrade was worth it in my case, but I don't know if I'll go
> further. I like listening much more than tinkering!
>
> I'd like to get a Scott sometime & compare w/ the SCA-35 ... Regards,
> - Rick.
My Scott 299 (no suffix) bested my SCA-35 in the bass region quite
easily. I was using a sealed box 8 Ohm loudspeaker for eval and
under any musical condition I tried the Scott just plain sounded
better. At the time I wondered if it had more to do with the power
supply than the output iron. The Scott had about 0.25" of lamination
but I doubt that was what I was hearing. The Dynaco just seemed to
run out of steam earlier than the Scott.
Leif
William Bittle
Tim Reese wrote:
>
> In article <341C59...@worldnet.att.net>,
> Rick Young <rkjy...@worldnet.att.net> wrote:
> >Bob Fitzgerald wrote:
> >> > incredible rats nest of wiring and interlaced components, close
> >SCA-35, & had much the same reaction to it's sound. I did make some
> >minor mods (it's not *quite* a rat's nest, but close). I did all I felt
>
I always found H.H. Scott's point to point wiring quite neat. I have a
299 and 2 299C's and found them refreshingly easy to service as compared
to the Dyna equipment I have. ( I hate those gimpy circuit boards)
As for making a 299C into a triode amp.. WHY?????????? Personally, if
you want to do that I'd suggest selling the Scott and looking for
another amp. The 7591 was designed to run as a pentode. Besides, what is
wrong with the way the 299C sounds? I use all 3 of mine on a regular
basis, and have pretty much retired all my other equipment,,,both tube
and solid state,, since I got all the Scotts up and running.
If you do want to convert it, I'd suggest pulling the 7591's and
replacing them with either 6L6's or EL34's (in the case of the latter,
you will have to do a few changes in the bias circuitry to increase it's
output lest you fry the EL34's). Then wire them as triodes.. Bear in
mind that the pin-outs of the 7591's are different from that of the 6L6
and El34. Also, the 6L6 and EL34 will not fit in the wood case.
B.B.
Rick Young
mbq...@notiac.net wrote:
>
> Let's cut to the chase here.
>
> Agreed that the Scott sounds pretty good in stock form.
>
> Why hotrod?
>
> Why bother!
>
> It is a cheap integrated amp (its intended role in life)
> that sounds very good in the delivered form. While not
> pretending to be a high end design, the combo of parts
> does a great job of sounding musical with a wide range
> of loudspeakers. Why fool with it at all?
>
> OK, to tweak is to live. Sure, why not?
>
> Well, most reading here have the ability to build either an
> established "good" amplifer using triodes, triode connected,
> or tetrode/pentode/beam tubes, or they can go out on there
> own and explore their own way to do it.
>
> To my own way of thinking (which I am sure will be "wrong"),
> let do with the Scott and spend the effort on something that
> is to the way you would want it if it didn't have a selenium
> stack, tone controls a go go, bias & filaments / no waiting,
> ceramic and/or paper caps in the signal path, and sometimes
> tinned steel wire. Ouch!
>
> What Scott did is educate me to what the Brits have known for far
> longer. That is, how much sense a well thought out integrated
> amplifier makes. For the AM java dose listening to NPR, the Iguana's,
> or Los Lobos, the Scott on a set of mini's works just fine. <Gasp, I
> even have the loudness control on!>
>
> This Scott can remain untweaked.
>
> Leif
I agree with most if not all of your points. For me, the SCA-35 was, and
will be for the forseeable future, the center of my system. (I take the
tape output from the SCA into my old 'main' amp, a Yamaha A-700
integrated, which drives a <100Hz filtered subwoofer. The SCA is run
full-range to my sealed-box small main speakers.) I don't have the
funds, time, or inkling to collect & work on amps.
I'm not really a tweaker, but when I heard the 'magical tube sound' that
the SCA (or, I'm sure, a 299 would have if I'd found it first) made in
my system, I started reading in RAT & elsewhere that at least replacing
the caps would improve the clarity of the amp. Since I never used the
tone controls or filters I decided to bypass those for improved sound.
Even figuring out how to do that, or if it was possible in this amp,
took me a while!
So I spent $100 on the amp, and another $75 or so & a few (more than I'd
like to admit) hours on 'tweaks'. I'm satisfied. Redoing the whole thing
isn't for me. My wife already rags on me for spending so much time at
the computer! But she does agree that the tube amp sounds lots better
than the old A-700 setup ...
My next step is to get some Canare cable & RCA's & make some new
interconnects & speaker cables. Maybe sometime I'll try some NOS or
other tubes in the unit, or maybe even some (gasp) exotic >$5 coupling
caps. Some day I'll get that nice new C-J (or old McIntosh) system, but
for now, I'm a happy camper!
- Rick.
mbq...@notiac.net
Bob Fitzgerald
William Bittle <nosf...@sprynet.com> wrote in article
<341DB4...@sprynet.com>...
> As for making a 299C into a triode amp.. WHY?????????? Personally, if
Look at the schematics on for Paul Grahams 1992 Glass Audio Article -
Originally from the RCA Tube Manual - OK, it was for a 7868, (=7591), but
it looks kinda close to the Scott setup in triode mode, with plate and
screen at 390V, using 7199 phase splitter.
http://www.infomaniak/~bonavolt/7868.htm
While thinking about it I'll probably take the Scott back to Pentode, as
the autotransformer is a boat anchor to drag around. And I wondered if it
would not be better to to use 4 - 4800 ohm resistors, in paralell, (each
one feeding a 7591 tubes screen) vs. the one 1200 ohm unit feeding all. By
using 4, it may provide some tube to tube isolation and possibly improve
the separation / imaging / soundstage.
I have found the sound very good in either triode or pentode mode, getting
the bias right on all 4 tubes makes a difference.
BTW I put a 50K pot in front of each 100K DC balance pot so each channel
can be independently adjusted for idle bias. (It is easier to find 2 tubes
that match than 4) They fit in the Z support channel underneath on of the
output t-x. Bought them at the "Shack" for 1.29.
> you want to do that I'd suggest selling the Scott and looking for
> another amp. The 7591 was designed to run as a pentode. Besides, what is
> wrong with the way the 299C sounds? I use all 3 of mine on a regular
> basis, and have pretty much retired all my other equipment,,,both tube
> and solid state,, since I got all the Scotts up and running.
That's quite a testament to the Scott equipment.......
BTW, neither of my Scotts are for sale. Now if only Svetlana would hurry up
and get the 7591 line going....
Bob
Ned Carlson
<mbq...@notiac.net> wrote:
>Let's cut to the chase here.
>
>Agreed that the Scott sounds pretty good in stock form.
>
>Why hotrod?
>
>Why bother!
>
>It is a cheap integrated amp (its intended role in life)
A Scott 299C cost more new than a PAS2+ST70
together. Per Allied 1964 catalog.
More than a MC225 cost at the time..
Cheap integrated amp, my ass.
Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
ph:773-871-7459 fax 773-871-7938 "where da tubes are"
Email catalogs: email our CataBot: cat...@triodeel.com
Frank Harrison
> Why hotrod?
>
> Why bother!
I suppose one might say that nothing is so good it can't be made
better.
I recently pulled my 299C out of the heap where it had lain since that
fateful day in 1982 when it went POW!, releasing a small white cloud
of evil-smelling smoke. A new filter cap, a few squirts of contact
cleaner, some 12ax7's, and by golly that sucker sounds _good_, even
with the faded 7591 outputs. If I do nothing else to it at this point,
I have an eminently listenable little unit.
My only real complaint about the sound is that the RIAA equalization
seems to be a little off. I will probably fix that sometime in the
coming fifteen years or so, and hopefully someone will start manufacturing
7591's again and save me trouble of re-wiring and re-biasing.
Frank Harrison
Bob Fitzgerald
> Look at the schematics on for Paul Grahams 1992 Glass Audio Article -
> Originally from the RCA Tube Manual - OK, it was for a 7868, (=7591), but
> it looks kinda close to the Scott setup in triode mode, with plate and
> screen at 390V, using 7199 phase splitter.
Soory the 1st post did not get this correct - this should work
> http://www.infomaniak.ch/~bonavolt/7868.htm
Check out all the other schematics, plus the GREAT newbie to Tube operation
section as well.
Bob
mbq...@notiac.net
> Cheap integrated amp, my ass.
>
> Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
> Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
> ph:773-871-7459 fax 773-871-7938 "where da tubes are"
> Email catalogs: email our CataBot: cat...@triodeel.com
Alright Ned!
You are welcome to buy mine at its extended 1964 to 1997 dollar ratio.
Or, I can index it to the going rate of an EICO HF-81.................
Cheers,
Leif
PS:
My response to tweaking a Scott was not meant to gore anyone who has
done so. Far from it. Everyone starts somewhere. Tweaking a Scott will
probably get you more insight (an enjoyment) than doing up an ST-70.
mbq...@notiac.net
Rick Young <rkjy...@worldnet.att.net> writes: > mbq...@notiac.net wrote:
\
>"but for now, I'm a happy camper!"
> - Rick.
And that IS what it's all about.
Leif
Tim Reese
Ned Carlson <postm...@triodeel.com> wrote:
>>It is a cheap integrated amp (its intended role in life)
>
>A Scott 299C cost more new than a PAS2+ST70
>together. Per Allied 1964 catalog.
>More than a MC225 cost at the time..
Man, I just _have_ to follow up to Ned's pithy reply... on first look at
these amps, I thought HHScott spent a lot on that fancy folded aluminum
chassis. Neat mechanical layout, solid feel (esp. with those heavy xfmrs
and being held together with screws) and logical layout. Nope - not cheap.
BTW, these amps have wax/paper screen bypass caps and a lot of "Ceracaps"
for coupling and other places that need an nF-range cap. Cera implies to
me that they are ceramic, but they look like wax/paper in ceramic tubes.
I could cut one in half... anyone know these caps?
Bob Fitzgerald
>
> My response to tweaking a Scott was not meant to gore anyone who has
> done so. Far from it. Everyone starts somewhere. Tweaking a Scott will
> probably get you more insight (an enjoyment) than doing up an ST-70.
>
interstage transformer coupling as a first project. & )
It is pretty interesting, though, there are 29 Mod kits, 73 mod articles
and schematics, and at least 7 major features on mod kit evaluations
written on the Dynaco ST-70.
The Tube community authority has "approved" the unit suitable for
modification.
Take another popular unit of the same vintage, same power, like the Scott
299C, and maybe because it is an integrated, this one is pretty much deemed
by some as "HANDS OFF".
Whatever...
Bob
Ned Carlson
re...@larmor.nmr.mgh.harvard.edu (Tim Reese) wrote:
>Man, I just _have_ to follow up to Ned's pithy reply... on first look at
>these amps, I thought HHScott spent a lot on that fancy folded aluminum
>chassis. Neat mechanical layout, solid feel (esp. with those heavy xfmrs
>and being held together with screws) and logical layout. Nope - not cheap.
I'd guess that a point to point wired"minimalist"(no tone controls)
version ofthe 299C nowadays would set you back $1500 to $2000.
A cheap integrated in 1964 would have been a Knight-KA-55
with 6973's: $79.95,or $5 a month on the easy payment plan.
>
>BTW, these amps have wax/paper screen bypass caps and a lot of "Ceracaps"
>for coupling and other places that need an nF-range cap. Cera implies to
>me that they are ceramic, but they look like wax/paper in ceramic tubes.
>I could cut one in half... anyone know these caps?
Mylar on the inside.
Jim Kroger
In article <01bcc31e$b02b6380$23aa...@capital.net.capital.net>, "Bob
Fitzgerald" <bf...@capital.net> wrote:
> It is pretty interesting, though, there are 29 Mod kits, 73 mod articles
> and schematics, and at least 7 major features on mod kit evaluations
> written on the Dynaco ST-70.
do you have a list of all those?
Thanks,
Jim
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William Bittle
Tim Reese wrote:
>
> Ned Carlson <postm...@triodeel.com> wrote:
> >>It is a cheap integrated amp (its intended role in life)
> >
> >A Scott 299C cost more new than a PAS2+ST70
> >together. Per Allied 1964 catalog.
> >More than a MC225 cost at the time..
> >Cheap integrated amp, my ass.
>
> these amps, I thought HHScott spent a lot on that fancy folded aluminum
> chassis. Neat mechanical layout, solid feel (esp. with those heavy xfmrs
> and being held together with screws) and logical layout. Nope - not cheap.
>
> for coupling and other places that need an nF-range cap. Cera implies to
> me that they are ceramic, but they look like wax/paper in ceramic tubes.
> I could cut one in half... anyone know these caps?
>
> --
> ---------------------------------------------------------------
> Tim Reese, MGH NMR Center re...@nmr.MGH.harvard.edu
If you are talking about those white tubular capacitors used as grid
coupling capacitors, they are the 'paper' type. the ceramic part is the
case. I havn't had one fail in either of my 299C's, but I figured that
in a 36 year old amp it wouldn't be a bad idea to change them. I mean,
at $160 - $200 a set for 7591's why take a chance on having one short
and wipe out some very expencive output tubes. (not to mention the
possible damage to the bias circuit). I'm not sure about the other
capacitors. Scott made nice sounding amps, but, as in all mass market
equipment, they had to make a product that was affordable too. I'm sure
that upgrading coupling capacitors to a higher grade would only help.
I'll say one thing for Scott, their amps have proven to be far more
durable then other vintage tube amps I have or have used. Their biggest
weakness is that bias rectifier and the can capacitor in the first
filter stages of the power supply. (every one of my Scott amps needed
that capacitor).
B.B.
mbq...@notiac.net
Well it didn't look like a hornet's nest when I kicked it............
Ok, a quick check of my Lafayette, Allied, Radio Shack, and Cramer
catalogues pre '65 show the the 299C in the $224.00-249.00 price
range. It also shows the unbuilt LK-72 ~70.00 less. Possibly the
gross labor costs to assemble one in Maynard, MA.
Further, the unbuilt LK-150 is within $10.00 bucks of the LK-72. The
built price of the 299C is more than a Marantz 2 and within $15.00 of
an 8B! What?
Opening up my LK-150 and comparing the parts count to that of my 299
is not even close. The LK-150 is sparsely populated next to the bustling
electronic metropolis within the 299. The inside of my MC275 is fairly
barren as well next to the 299. The inside of the MC275 contains a lot
of air.
Since we are well off the topic of sound now, what does all this prove?
Not a damn thing except price to value comparo's don't mean squat. If
that told the whole story I would have sold my 299's rather than my 2's
the last time I got into debt for 30 years.
All in fun,
Leif
There are no sacred cows (only scared ones!).
Frank Harrison
"Bob Fitzgerald" <bf...@capital.net> wrote:
>
> >
> It is pretty interesting, though, there are 29 Mod kits, 73 mod articles
> and schematics, and at least 7 major features on mod kit evaluations
> written on the Dynaco ST-70.
> The Tube community authority has "approved" the unit suitable for
> modification.
> Take another popular unit of the same vintage, same power, like the Scott
> 299C, and maybe because it is an integrated, this one is pretty much deemed
> by some as "HANDS OFF".
> Whatever...
> Bob
Could it be that the 299C doesn't have as much wrong with it to begin with?
FH
Ned Carlson
Frank Harrison <Rama...@vt.edu> wrote:
>
>Could it be that the 299C doesn't have as much wrong with it to begin with?
I'd say it's because it doesn't have a PC board you can swap out in30
minutes....
Frank Harrison
trio...@ameritech.net (Ned Carlson) wrote:
>
> Frank Harrison <Rama...@vt.edu> wrote:
>
>
> >
> >Could it be that the 299C doesn't have as much wrong with it to begin with?
>
> I'd say it's because it doesn't have a PC board you can swap out in30
> minutes....
>
>
Makes good sense. I think you may have something there.
Frank