Which sounds the best?
Darryl
various valves used as SE outputs. I have been reading so much about
300B's and 2A3's and 45's etcetc.... then someone said the EL34
sounds very good (comparable to 300B).
So what else sounds good, and has anyone ever compared them to the
'standards' like 300B?
My first SE amp (recently completed) using 6AQ5's as triodes(a nice
cheap start) sounds much better than my SS amps. So how much better
would a 300B sound?
What other unusual SE's have been tried? Is it worth rating them
against each other, or are other variables going to confuse the issue
(like transformer quality)?
How about other pentodes used as triodes, such as 6550's? What about
multiple parallel smaller valves?
__ \ \ __ /__ / \
| | _ \ / / _ \
| | ___ \ / / ___ \
____/_/ _\____|____|_/ _\
Marc Legare
Then someone said the EL34
sounds very good (comparable to 300B).
The person who told you that, must have a major chirurgical operation
to it's ears or he's never heard DHT tubes like the 300 B.
Cary has a monoblock with a 845 that is driven now by a 300B driver. Years ago, that driver tube was a triode connected EL34 at the place of the 300B. That modification made a major sounding improvement to this amplifier.
The EL34 triode connected is not a bad sounding tube but there's no comparaisons with DHT.
Try it !!!
Regards
Marc Légaré
Darryl
You were saying......
>The EL34 triode connected is not a bad sounding tube but there's no
>comparaisons with DHT.
What makes DHT sound all that different to indirect?
>
>Try it !!!
I might, but I refuse to break the budget if it ain't gonna sound all
that much better than what I've got (damn I like these 6AQ5's). Hence
I am asking for opinions.... It's a pity I can't just go down to the
hifi store to audition a few myself.
SB9090
triode) in a Williamson configured PP amp. The response from friends who heard
it was that the sound was very different but the majority opinion leaned toward
EL34's. In my case I was using AC on the 300B fils, I've heard people really
prefer that sound. I have also listened to amps (SE) with 300B's of different
types, VV52B's, and SV811. Properly driven, I prefer the VV52's, but 300B would
be my next choice. By the way, in my VV52B amp I use an EL34 to drive it.
Steve Brown
Ron Bales
(Darryl) wrote:
>
>What makes DHT sound all that different to indirect?
Don't know. IMO the bigger difference is between true triodes and
altered pentodes.
>I might, but I refuse to break the budget if it ain't gonna sound all
>that much better than what I've got (damn I like these 6AQ5's). Hence
>I am asking for opinions.... It's a pity I can't just go down to the
>hifi store to audition a few myself.
How about picking up some triodetubes that can be used in your 6AQ5
amp without much change.
12B4A is an indirect heater number uses 6 or 12V on the heater.
A 71A IHT needs a filament supply but isn't expensive and probably not
hard to adapt.
Or 6CK4, indirect heated is another option.
I'm in a bit of a hurry, but these recommend themselves.
ROn
Grover Gardner
dkl...@removethisbit.ieee.org wrote:
> I have been wondering if anyone has collected together a comparison of
> various valves used as SE outputs. I have been reading so much about
> 300B's and 2A3's and 45's etcetc.... then someone said the EL34
> sounds very good (comparable to 300B).
>
> So what else sounds good, and has anyone ever compared them to the
> 'standards' like 300B?
>
> My first SE amp (recently completed) using 6AQ5's as triodes(a nice
> cheap start) sounds much better than my SS amps. So how much better
> would a 300B sound?
>
> What other unusual SE's have been tried? Is it worth rating them
> against each other, or are other variables going to confuse the issue
> (like transformer quality)?
>
> How about other pentodes used as triodes, such as 6550's? What about
> multiple parallel smaller valves?
For starters, there's no guarantee that you will like the 300B better than
what you have. It depends on the quality of the 300B, the output
transformer and the driver circuitry, among other things. Secondly, if
you are accustomed to the harmonic spectrum presented by pentodes,
triode-strapped or otherwise, you're going to find some adjustment
necessary to true triodes, which have a very different signature.
Thirdly, power triodes generally require more voltage swing to achieve
full output, and this means more stages with the resulting increase in
distortion and harmonic additions.
But if I had to answer why I personally am completely, utterly sold on
DHTs, I would put it this way: There's your source (CD, LP, tape,
whatever), and there's your speaker. Between them is the amp. This is
your system, and we know it's a illusion, right? Okay. As you change
from PP to SE, you remove one level of "veiling" or distancing from the
source. Then change from pentodes to triodes, and another level of
immediacy is achieved. Finally, use a directly-heated tube and, properly
set up, the sense of "reproduction" begins to vanish entirely. A piano
ceases to be a "thing" that is making sounds up and down the scale, but
instead becomes an instrument being played by a person. The "illusion"
takes on a whole new character, and seems suddenly to be less of an
"illusion" than you thought. It's not about bandwidth, "imaging",
"resolution" or any of those canards. The actual reproduction may be
imperfect, due to the limitations of power and the difficulty of achieving
the ideal SE DHT circuit, but I'm happy to accept those limitations when
what I get instead is a far more satisfying sense of having listened to a
person making music, as opposed to a recording of some things.
What you find so often with people who switch to SE DHTs, is that they
stop FUSSING. The "hunt" is over. Yes, they hear limitations, and they
sense there's room for changes or improvements, but the anxiety about
"missing something" from the music suddenly disappears, because what you
hear is so much more musically gratifying, regardless.
--
Grover Gardner
Grover Gardner
(SB9090) wrote:
In a PP circuit, this doesn't surprise me. I'm not convinced that a
Willimason circuit will drive the 300Bs adequately, and I think, what with
the harmonic cancellation going on, that the pentodes will display a more
pleasing signature in PP.
I'd be interested what your friends would have thought of the difference
between the two in an SE circuit. In this case I personally prefer the
harmonic spectrum presented by a true triode.
--
Grover Gardner
Andre Jute
> I have been wondering if anyone has collected together a comparison of
> various valves used as SE outputs. I have been reading so much about
> 300B's and 2A3's and 45's etcetc.... then someone said the EL34
> sounds very good (comparable to 300B).
>
> So what else sounds good, and has anyone ever compared them to the
> 'standards' like 300B?
>
> My first SE amp (recently completed) using 6AQ5's as triodes(a nice
> cheap start) sounds much better than my SS amps. So how much better
> would a 300B sound?
>
> What other unusual SE's have been tried? Is it worth rating them
> against each other, or are other variables going to confuse the issue
> (like transformer quality)?
>
> How about other pentodes used as triodes, such as 6550's? What about
> multiple parallel smaller valves?
Darryl
I can answer some of your questions. But you should know up front that I
live in Ireland and because of the difficulty of getting tubes, I like
current production tubes, or those with vast stocks.
References depend on where you are and who you are, I suppose.
Non-American Anglo-Saxons of a certain age group have as their
references the KT66 and the EL34; a not necessarily younger group would
also use the KT88.
The American equivalent to *all* these tubes is the 6550. (Anyone want
to make a case for the 807?) The one common tube across the Atlantic is
the EL84.
The 300B is a minority taste that is nowhere a reference except in Japan
and France, and in very recent times in a small niche market around the
world. If you consider how many people can afford valve amps, then the
10k annual production of WE 300B is a drop in the bucket.
Taking the DHTs first. and talking SE unless otherwise stated.:
2A3. I have little 2A3 experience and what I have heard does not incline
me to become a believer in the small and delicate, but then I am a high
current man. The best sounding 2A3 I ever heard was the Audio
Innovations push-pull. The charms of 2 and 3W 2A3 are entirely lost on
me. 2A3 fans will no climb out of the woodwork so you will not be short
of a contrary opinion.
45. No 45 experience at all but others can help you. Getting rare and
expensive.
300B. A sort of a standard, but in my opinion by default because people
don't or didn't want to mess around with kV amps. Pleasant, warm, a
superior sort of tube in an understated way. You can easily make a PP
EL34 Class A1 amp sound as good as almost any SE 300B amp by simply
spending a lot of money on the transformers and the caps. It is no great
secret that a push-pull 300B amp, unless it is incompetent, under a
great many conditions, perhaps the majority if you play symphonic music
a lot, is superior to an SE 300B. On the other hand, the best SE amps
are impossible to beat for chamber music, voices, acoustic music,
instrumentals, jazz, etc, etc. Those who pine for panels but can afford
only Lowthers can have that liquid midrange with a 2A3 or a 300B. It is
an important advantage.
211. The fans of Kondo will tell you this is the reference. It's a
hateful tube that you have to run at 1250V to get any sense out of.
Anything lower and it runs mostly in A2, which is pointless in the
highest reaches of audiophilia because a lot of people can hear the grid
starting to draw current--the sound coarsens up perceptibly on sustained
fortes. This tube is surely incisive, in that it was developed for
maximum clarity in aircraft communications under war conditions.
845. This, with the Svet SV572-xx, is your actual reference tube. You
still need a kV to run any of these, and the 845 requires 150V of drive
and hefty current on the driver. But it is a warm enveloping, hedonist's
tube. I toured the US by Greyhound in the 1960s and heard all those
wonderful AM jazz stations. When I came into tubes, Joe Roberts told me
that they used 845 as their broadcast tube. I believe it.
SV572-xx. The -3 can be run all the way in A1, the -10 almost, and the
-30 is probably best viewed as an A2 tube; I don't quite see the -160 as
an audio tube but I could be wrong. These tubes all have different sorts
of sound. The -3 is quite delicate, somewhere between a 211 and 845, the
-10 has a beefier sort of sound and is more akin to the 845 but a lot
cleaner. There are also cheaper SV811 cousins which I understand merely
lack a small edge of the refinement of the SV572-xx series.
Others, run SE:
EL34 run as pseudo-triodes are absolute giant killers. You'll purr. You
can run an EL34 as SE but I think that is a step backwards. Matter of
opinion, okay? Try it, you might like it.
KT88 in SE gives 3W and is quite pleasing. I don't like KT88 much--its a
brutish British sort of the 6550 equivalent which isn't a favourite but
in SE they are acceptable with a good horn.
If you have horns or other truly sensitive speakers:
437A which is also 3M/167 makes a 1W SE amp of great simplicity and
quality. Rare and expensive.
417A/5842 also makes a single-tube amp of quality if you can get good
tubes.
EL84. A tube that can do no wrong whatever you do to it. Fleapower SE
but very nice. True delicacy. There's an AudioNote circuit available
somewhere that I have heard in their Oto, which was widely considered a
bargain in the UK. Good modern equivalent tube is Svet's SV83, which Al
and I use as CCS.
6SN7 is a power tube! You can make a grand small SE amp out of one.
HTH.
Andre
--
Andre Jute an...@indigo.ie COMMUNICATION JUTE
http://indigo.ie/~andre/ComJuteF1.html
"an unbelievably comprehensive web site containing
vital gems of wisdom" -- Stuart Perry :: Hi-Fi News & Record Review
Darryl
You were saying......
>How about picking up some triodetubes that can be used in your 6AQ5
>amp without much change.
>
>12B4A is an indirect heater number uses 6 or 12V on the heater.
>
>A 71A IHT needs a filament supply but isn't expensive and probably not
>hard to adapt.
>
>Or 6CK4, indirect heated is another option.
>
>I'm in a bit of a hurry, but these recommend themselves.
Thanks for the suggestions.
Darryl
You were saying......
>
>For starters, there's no guarantee that you will like the 300B better than
>what you have. It depends on the quality of the 300B, the output
>transformer and the driver circuitry, among other things.
Yes, that was always my worry when people talk about how good a
particular valve sounds. It probably won't sound the same in 'my'
circuit because of all the other variables.
>Secondly, if
>you are accustomed to the harmonic spectrum presented by pentodes,
>triode-strapped or otherwise, you're going to find some adjustment
>necessary to true triodes, which have a very different signature.
Seems I'll have to prototype a few and try them for myself.
>Thirdly, power triodes generally require more voltage swing to achieve
>full output, and this means more stages with the resulting increase in
>distortion and harmonic additions.
Yes, and it goes against the minimal component count philosophy
(whther that is right or wrong?).
>
>But if I had to answer why I personally am completely, utterly sold on
>DHTs,
Well at least you admit bias! :-)
>I would put it this way: There's your source (CD, LP, tape,
>whatever), and there's your speaker. Between them is the amp. This is
>your system, and we know it's a illusion, right? Okay. As you change
>from PP to SE, you remove one level of "veiling" or distancing from the
>source. Then change from pentodes to triodes, and another level of
>immediacy is achieved. Finally, use a directly-heated tube and, properly
>set up, the sense of "reproduction" begins to vanish entirely. A piano
>ceases to be a "thing" that is making sounds up and down the scale, but
>instead becomes an instrument being played by a person. The "illusion"
>takes on a whole new character, and seems suddenly to be less of an
>"illusion" than you thought. It's not about bandwidth, "imaging",
>"resolution" or any of those canards. The actual reproduction may be
>imperfect, due to the limitations of power and the difficulty of achieving
>the ideal SE DHT circuit, but I'm happy to accept those limitations when
>what I get instead is a far more satisfying sense of having listened to a
>person making music, as opposed to a recording of some things.
>
>What you find so often with people who switch to SE DHTs, is that they
>stop FUSSING. The "hunt" is over. Yes, they hear limitations, and they
>sense there's room for changes or improvements, but the anxiety about
>"missing something" from the music suddenly disappears, because what you
>hear is so much more musically gratifying, regardless.
Hmmm.. you do make it sound good :-)
JHPage
dkl...@removethisbit.ieee.org says...
> I have been wondering if anyone has collected together a comparison of
> various valves used as SE outputs. I have been reading so much about
> 300B's and 2A3's and 45's etcetc.... then someone said the EL34
> sounds very good (comparable to 300B).
>
> So what else sounds good, and has anyone ever compared them to the
> 'standards' like 300B?
>
> My first SE amp (recently completed) using 6AQ5's as triodes(a nice
> cheap start) sounds much better than my SS amps. So how much better
> would a 300B sound?
>
> What other unusual SE's have been tried? Is it worth rating them
> against each other, or are other variables going to confuse the issue
> (like transformer quality)?
>
> How about other pentodes used as triodes, such as 6550's? What about
> multiple parallel smaller valves?
>
>
Sometimes you can look at this a different way; are you looking for a
finished amp to listen to long term or maybe a "something different and
fun project"? If you're looking for an amp to be your main listening amp
and sound is top priority, then 300Bs are great (also VV32B) but, IMO
their ratio of cost to sound can be poor. The Svetlana sv811-3&10 make
great sounding SE amps and their cost and parts requirements are very
reasonable. Very good quality 6B4Gs (6v, octal 2A3) can be found in the
~$35 each range and these can also sound great. For something different,
I have a pair of RCA 843s on order ($33 each) for my next fun project.
They need a 10K ohm transformer and should sound very similar to a 10
triode, so I have high expectations for them. Take a look through some of
the tube web pages, you can find all kinds of good sounding, unpopular
tubes. "there's gold in them thar hills"
Three of my favorite sites for hidden treasure are:
Tube World http://www.tubeworld.com
Vacuum Tubes, Inc. http://www.vacuumtubesinc.com
Angela Instruments http://www.angela.com
Happy Hunting,
Joseppi
bobcx
JHPage <jhp...@wwa.com> wrote in message
news:MPG.12310635f...@news.supernews.com...
>
> Sometimes you can look at this a different way; are you looking for a
> finished amp to listen to long term or maybe a "something different and
> fun project"? If you're looking for an amp to be your main listening amp
> and sound is top priority, then 300Bs are great (also VV32B) but, IMO
> their ratio of cost to sound can be poor.
There has been a great deal of "writer speak" on the sound of different
tubes in this thread, but...One thing that has to be understood. In reality
this is all system dependant, it is irresponsible to speak about the sound
of tubes and amps in a vacuum.
As you say... And, IMO if you are looking to build a "high end" SE (for
lack of a better term) amp, and you have or intend to purchase appropriate
speakers, a 300B or "300B type" tube is by far one of the best way to go.
There are many choices available, some are even pretty cost effective.
Triode wired (fill in the blank) or any other non DHTs no matter what anyone
here tells you, are not the same. I would even choose a cheap Chinese 300B
over a SE EL34 any day of the week. IMO there is no contest. Of course if
you never listen to the tubes the differences are much less obvious.
This is not to say that other tubes cannot sound good, because they can and
do. But they are all different, not the same, wishful thinking and fiction
aside.
> Very good quality 6B4Gs (6v, octal 2A3) can be found in the
> ~$35 each range and these can also sound great.
6B4Gs are nice IMO 2A3s are nicer, and my favorite tube is the SP 2A3.
I have not been lucky enough yet to hear some of the rare European SP
triodes, but they are also reported to be wonderful. I think Grant and a few
others can hopefully comment on them.
BC
John Byrns
<bo...@SPAMearthlink.net> wrote:
[Snip]
>
> As you say... And, IMO if you are looking to build a "high end" SE (for
> lack of a better term) amp, and you have or intend to purchase appropriate
> speakers, a 300B or "300B type" tube is by far one of the best way to go.
> There are many choices available, some are even pretty cost effective.
> Triode wired (fill in the blank) or any other non DHTs no matter what anyone
> here tells you, are not the same. I would even choose a cheap Chinese 300B
> over a SE EL34 any day of the week. IMO there is no contest. Of course if
> you never listen to the tubes the differences are much less obvious.
>
> This is not to say that other tubes cannot sound good, because they can and
> do. But they are all different, not the same, wishful thinking and fiction
> aside.
Bob,
This is all very interesting! It seems you have had a change of heart, as
you have said here on more than one occasion, once quite recently, that
tubes have no sound. What happened to change your mind?
Regards,
John Byrns
Surf my web pages at, http://www.enteract.com/~jbyrns/index.html
Darryl
You were saying......
>Darryl
>
>I can answer some of your questions. But you should know up front that I
>live in Ireland and because of the difficulty of getting tubes, I like
>current production tubes, or those with vast stocks.
Can't be harder than Australia! :-)
>
>References depend on where you are and who you are, I suppose.
>
>Non-American Anglo-Saxons of a certain age group have as their
>references the KT66 and the EL34; a not necessarily younger group would
>also use the KT88.
>
>The American equivalent to *all* these tubes is the 6550. (Anyone want
>to make a case for the 807?) The one common tube across the Atlantic is
>the EL84.
That one just keeps getting a mention doesn't it?
>
>The 300B is a minority taste that is nowhere a reference except in Japan
>and France, and in very recent times in a small niche market around the
>world. If you consider how many people can afford valve amps, then the
>10k annual production of WE 300B is a drop in the bucket.
It does get used in a lot of designs that I see as I browse the web
though.
>
>Taking the DHTs first. and talking SE unless otherwise stated.:
>
>2A3. I have little 2A3 experience and what I have heard does not incline
>me to become a believer in the small and delicate, but then I am a high
>current man. The best sounding 2A3 I ever heard was the Audio
>Innovations push-pull. The charms of 2 and 3W 2A3 are entirely lost on
>me. 2A3 fans will no climb out of the woodwork so you will not be short
>of a contrary opinion.
You are right.... many people like them.
>
>45. No 45 experience at all but others can help you. Getting rare and
>expensive.
>
>300B. A sort of a standard, but in my opinion by default because people
>don't or didn't want to mess around with kV amps. Pleasant, warm, a
>superior sort of tube in an understated way. You can easily make a PP
>EL34 Class A1 amp sound as good as almost any SE 300B amp by simply
>spending a lot of money on the transformers and the caps.
Is this why many people buy ST70's and 'fix them up'?
>It is no great
>secret that a push-pull 300B amp, unless it is incompetent, under a
>great many conditions, perhaps the majority if you play symphonic music
>a lot, is superior to an SE 300B. On the other hand, the best SE amps
>are impossible to beat for chamber music, voices, acoustic music,
>instrumentals, jazz, etc, etc. Those who pine for panels but can afford
>only Lowthers can have that liquid midrange with a 2A3 or a 300B. It is
>an important advantage.
<stuff snipped for brevity>
>
>Others, run SE:
>
>EL34 run as pseudo-triodes are absolute giant killers. You'll purr.
Seems to be many conflicting opinions on that :-(. I see things out
there using it (like the Randall Amp - using 2 in parallel), and I am
tempted.
> You
>can run an EL34 as SE but I think that is a step backwards.
You mean as a pentode?
>Matter of
>opinion, okay? Try it, you might like it.
Easy to do, I have an experimental mono amp with two EL34's in
parallel. Trouble is, it started as an experiment for a guitar amp,
therefore the output transformer is not a 'hifi' one necessarily
(although it is a very well made one). Still it may be good enough
for initial experiments. I will ask the guy that made it if he has
ever tested it's bandwidth? (he may laugh :-))
>
>KT88 in SE gives 3W and is quite pleasing. I don't like KT88 much--its a
>brutish British sort of the 6550 equivalent which isn't a favourite but
>in SE they are acceptable with a good horn.
What about the 6550 then? Used in triode, would it sound good?
>
>If you have horns or other truly sensitive speakers:
>
>437A which is also 3M/167 makes a 1W SE amp of great simplicity and
>quality. Rare and expensive.
>
>417A/5842 also makes a single-tube amp of quality if you can get good
>tubes.
>
>EL84. A tube that can do no wrong whatever you do to it. Fleapower SE
>but very nice. True delicacy. There's an AudioNote circuit available
>somewhere that I have heard in their Oto, which was widely considered a
>bargain in the UK. Good modern equivalent tube is Svet's SV83, which Al
>and I use as CCS.
Maybe not different enough to the 6AQ5's I'm currently using.
>
>6SN7 is a power tube! You can make a grand small SE amp out of one.
>
>HTH.
>
>Andre
Thanks for the comments
Ron Bales
Yikes, I was in a hurry. 71A is a DHT, that was the point, I wanted
to suggest one to go along with the IHTs. Anyway, none of those cost
a lot and I really like the sound of the 12B4s
ROn
On Fri, 27 Aug 1999 23:39:28 GMT, dkl...@removethisbit.ieee.org
(Darryl) wrote:
>Hi Ron Bales,
>
>You were saying......
>
>
>>How about picking up some triodetubes that can be used in your 6AQ5
>>amp without much change.
>>
>>12B4A is an indirect heater number uses 6 or 12V on the heater.
>>
>>A 71A IHT needs a filament supply but isn't expensive and probably not
>>hard to adapt.
>>
>>Or 6CK4, indirect heated is another option.
>>
>>I'm in a bit of a hurry, but these recommend themselves.
>
>Thanks for the suggestions.
>
>
Andre Jute
It's real simple if you have horns, and don't need much power. The
output stage is two or more 6SN7GTB plates parallelled. The output
transformer I used was a Tango "universal" 808 (from memory-- this was
years ago), so most versions used only two plates parallelled on taps
that reflected 2-3K. The input was a 6SL7 with its plates parallelled
and a transistor constant current load sucking on 450V, which is what I
also ran the 6SN7GTB at. For the input think of SRPP and replace the top
tube by silicon and you get the idea. RC coupling. Enough output volume
to drive a horn. I had another one with 6SN7 input and driver, two
stages, which in some ways was superior but it didn't sound so
pleasantly warm--well, the truth is, that many 6SN7 in a row ripped your
ears off with their "studio precision". I want to enjoy my music, not
stand to attention listening for errors! The power supply was a hefty
500-0-500 rectified with a GZ37, Solen 630V 51uFs, Lundahl double chokes
20H in total, and the fils were just straight AC. The whole thing,
including space for some ITs we also tried that cost more than the rest
of the amp, fitted on a 10x17in Hammond ali chassis. We also bought some
trannies at surplus in the States somewhere (does Ford Surplus sound
right?) which coupled 600 ohm to 600ohm (or something like it) and some
other taps, all useful for headphones. Beat the hell out of a couple
commercial OTL headphone amps I had on test at that time.
Eric Barbour's Brute Force linestage, Glass Audio 4/95 and also on the
net somewhere, is pretty similar to the input I describe above, but with
tubes as the mu-follower load and no need for output iron if you have
600ohm headphones. With a small output tranny and CD input, this would
be a real *flea*power amp! The 12SN7 he uses is just 6SN7 with 12V fils.
His regulated supply is worth looking at because what kills fleapower
amps used with ultra high sensitivity speakers or headphones is noise.
If you're going to take this seriously, get a copy of Allen Wright's
Pre-Amp Cookbook--sources on my netsite at
http://indigo.ie/~andre/Audiobookreviews1.html
--and copy his SuperReg (cheaper, easier and tighter regulation than
Eric's tube implementation) and read what he says about silicon CCS, or
get Morgan Jones's Valve Amplifiers, which has a brief section about
them.
HTH.
While I am on amps useful for headphones.... If you have 6DJ8 in
abundance, you can easily make a sane-voltage headphone amp with several
of them, the output via the cathode to get down to those insane 32ohm
impedance so many goodsounding headphones have. I tried it and it didn't
sound as good as the 6SN7 but was altogether a saner and cheaper
project. Lotta designs on the net for this type.
Andre
Raymond Koonce <rko...@zzztyler.net> wrote:
> I'd sure like to see a schematic of 6sn7 SE amp. I have a load of NOS
> 6sn7s. I'd like to try them out.
>
> Raymond
>
> Andre Jute wrote:
>
> > <snip>
> >
> > 6SN7 is a power tube! You can make a grand small SE amp out of one.
> >
> > HTH.
> >
> > Andre
> > --
> > Andre Jute an...@indigo.ie COMMUNICATION JUTE
> > http://indigo.ie/~andre/ComJuteF1.html
> > "an unbelievably comprehensive web site containing
> > vital gems of wisdom" -- Stuart Perry :: Hi-Fi News & Record Review
>
> --
> "As many of you know, I was very instrumental
> in the founding of the Internet" --AL Gore to Katie Couric
>
> Spam buster: remove zzz to reply
Andre Jute
> Hi Andre Jute,
>
> You were saying......
>
>
> >Darryl
> >EL34 run as pseudo-triodes are absolute giant killers. You'll purr.
>
> Seems to be many conflicting opinions on that :-(. I see things out
> there using it (like the Randall Amp - using 2 in parallel), and I am
> tempted.
No. Everyone in his right mind agrees that UL EL34 are great and triode
EL34 are giant killers.
The controversy is whether EL34 run triode in PP can sound as good as
300B. Clearly people who paid for their 300B amps will not agree that a
cheap little pentode can sound as good. They have an (in)vested
interest! But I'm a professional sceptic who gets most of his amps free:
I do not ask what it cost, but what it sounds like.
> > You
> >can run an EL34 as SE but I think that is a step backwards.
>
> You mean as a pentode?
No. Almost no-one in hi-fi runs EL34 straight pentode style any more.
That's for guitar johnnys. Most hi-fi EL34 run in ultralinear. The very
best EL34 amps run them PP in pseudo-triode. (When I say "best" I
invariably mean Class A1 unless otherwise noted.) That is the sort of
amp I consider beats the hell out of a lot of run of the mill 300B amps,
and even a few good ones.
To run the EL34 in SE, first triode link it, then run it single-ended.
I have transfer curves for the EL34 running in triode taken with SOFIA
if you are interested.
> >Matter of
> >opinion, okay? Try it, you might like it.
>
> Easy to do, I have an experimental mono amp with two EL34's in
> parallel. Trouble is, it started as an experiment for a guitar amp,
> therefore the output transformer is not a 'hifi' one necessarily
> (although it is a very well made one). Still it may be good enough
> for initial experiments. I will ask the guy that made it if he has
> ever tested it's bandwidth? (he may laugh :-))
Do you know Lucas Cant in Melbourne? He is a custom winder highly spoken
of by my Australian correspondents who don't wish to brave the flame
wars on the Joenet and here on RAT.
Thordarson television type trannies are cheap and good at surplus and
available all over the world, and will allow you to discover if a
project is worth spending custom winding money on.
> >KT88 in SE gives 3W and is quite pleasing. I don't like KT88 much--its a
> >brutish British sort of the 6550 equivalent which isn't a favourite but
> >in SE they are acceptable with a good horn.
>
> What about the 6550 then? Used in triode, would it sound good?
Don't know; sorry. Ask the Americans. Someone must have tried it.
Darryl
You were saying......
>I have transfer curves for the EL34 running in triode taken with SOFIA
>if you are interested.
Yes I would like to see them please.
Acrosound
>>If you're going to take this seriously, get a copy of Allen Wright's
Pre-Amp Cookbook--sources on my netsite at
<A
HREF="http://indigo.ie/~andre/Audiobookreviews1.html">http://indio.ie/~and
re/Audiobookrews1.html</A><<
Does anyone here have the direct url to Allen Wright's website. Much
appreciated. thanks.
Andre Jute
Correct URL for review:
http://indigo.ie/~andre/Audiobookreviews1.html
where you can also find a link to Allen Wright's website.
bobcx
John Byrns <jby...@enteract.com> wrote in message
news:jbyrns-2708...@216-80-34-13.d.enteract.com...
>
> This is all very interesting! It seems you have had a change of heart, as
> you have said here on more than one occasion, once quite recently, that
> tubes have no sound. What happened to change your mind?
>
Try hooked on phonics it might improve your reading comprehension.
BC
bobcx
Acrosound <acro...@aol.com> wrote in message
news:19990828002627...@ng-fn1.aol.com...
> Andre Jute wrote:
>
>
> >>If you're going to take this seriously, get a copy of Allen Wright's
> Pre-Amp Cookbook--sources on my netsite at
> <A
> HREF="http://indigo.ie/~andre/Audiobookreviews1.html">http://indio.ie/~and
> re/Audiobookrews1.html</A><<
>
> Does anyone here have the direct url to Allen Wright's website. Much
> appreciated. thanks.
>
>
tcw
Darryl
You were saying......
>There has been a great deal of "writer speak" on the sound of different
>tubes in this thread, but...One thing that has to be understood. In reality
>this is all system dependant, it is irresponsible to speak about the sound
>of tubes and amps in a vacuum.
This is becoming obvious to me, yes.
>
>As you say... And, IMO if you are looking to build a "high end" SE (for
>lack of a better term) amp, and you have or intend to purchase appropriate
>speakers, a 300B or "300B type" tube is by far one of the best way to go.
>There are many choices available, some are even pretty cost effective.
>Triode wired (fill in the blank) or any other non DHTs no matter what anyone
>here tells you, are not the same. I would even choose a cheap Chinese 300B
>over a SE EL34 any day of the week. IMO there is no contest. Of course if
>you never listen to the tubes the differences are much less obvious.
It may be asking a hard question, but if you've listened to an EL34
triode wired, and a 300B type in similar systems (at least same
speakers), is it possible to describe how they sound better. What
things make you like them? I only ask, because there's no easy way for
me to get to hear them myself.
JHPage
bo...@SPAMearthlink.net says...
>
> JHPage <jhp...@wwa.com> wrote in message
> news:MPG.12310635f...@news.supernews.com...
> >
> > Sometimes you can look at this a different way; are you looking for a
> > finished amp to listen to long term or maybe a "something different and
> > fun project"? If you're looking for an amp to be your main listening amp
> > and sound is top priority, then 300Bs are great (also VV32B) but, IMO
> > their ratio of cost to sound can be poor.
>
> tubes in this thread, but...One thing that has to be understood. In reality
> this is all system dependant, it is irresponsible to speak about the sound
> of tubes and amps in a vacuum.
>
> lack of a better term) amp, and you have or intend to purchase appropriate
> speakers, a 300B or "300B type" tube is by far one of the best way to go.
> There are many choices available, some are even pretty cost effective.
> Triode wired (fill in the blank) or any other non DHTs no matter what anyone
> here tells you, are not the same. I would even choose a cheap Chinese 300B
> over a SE EL34 any day of the week. IMO there is no contest. Of course if
> you never listen to the tubes the differences are much less obvious.
>
> do. But they are all different, not the same, wishful thinking and fiction
> aside.
>
> > ~$35 each range and these can also sound great.
>
> 6B4Gs are nice IMO 2A3s are nicer, and my favorite tube is the SP 2A3.
>
> I have not been lucky enough yet to hear some of the rare European SP
> triodes, but they are also reported to be wonderful. I think Grant and a few
> others can hopefully comment on them.
>
> BC
>
I'm not sure what you mean by "it is irresponsible to speak about the
sound of tubes and amps in a vacuum" but I have listened to Svetlana,
J.J./Tesla and vintage (1950s) W.E 300s in the same amp through the same
speakers and they all sounded great. I do not believe I could justify the
high price of the W.E. tubes, they did not sound that much better to me.
That would be a poor ratio of cost to sound, IMO. In one of Darryl's
earlier posts he mentions he does'nt want to "break the bank" so a
thought to cost does'nt seem out of line. I would agree that all tubes
sound different, even tubes of the same manufacture and type.
Transformers also sound different, so do speakers.
I have not heard single plate 2A3s but by all accounts they sound better
than the 6A3/6B4G types and cost quite a bit more as well.
BTW I got to hear a set of KR VV32Bs for about 15 minutes in a stereo
shop in Columbus, WOW! I had to be dragged out, they sounded fantastic. A
pair of these are way up on my wish list.
Joseppi
Darryl
You were saying......
> In one of Darryl's
>earlier posts he mentions he does'nt want to "break the bank" so a
>thought to cost does'nt seem out of line.
This is true! :-)
I see two ends of the spectrum. I could build an amp with SE triode
wired EL34's with $20 hammond universal OT's, or I could save up for
300B's and $200 boutique OT's. It's a factor of 10 or more in cost.
I am not going to spend 10 times the money and only get a small
improvement. If everyone tells me it's 5 to 10 times better sound ,
then I will have to consider it.
bobcx
> >
> Bob,
>
> I'm not sure what you mean by "it is irresponsible to speak about the
> sound of tubes and amps in a vacuum" but I have listened to Svetlana,
> J.J./Tesla and vintage (1950s) W.E 300s in the same amp through the same
> speakers and they all sounded great.
Joe,
First off, I was agreeing with you. I am sorry if I was not perfectly clear,
about the "vacuum". What I am saying is that if you are going SE you have to
go "all the way" and go with SE friendly speakers. IMO it makes little sense
to try and drive inefficient speakers, or electrostatics with a SE amp.
Unless... you build something like a 212 amp or double 845s. I have a friend
who "really" uses Quad 63s, a SE 300B is not the way to go. IMO Horns,
Lowthers, Diatones, Fostex, Vintage Tannoys, and other high efficiency
speakers, etc, are good choices. IMO if you hook up your 86db speaker to a
45 amp, prepare to be disappointed.
>I do not believe I could justify the
> high price of the W.E. tubes, they did not sound that much better to me.
I like WE 300Bs, but they are expensive. I also have Svetlana 300Bs and they
are very nice. I have not listened to the JJ tubes, but I have heard good
things about them.
What differences, if any did you hear between the 300Bs?
> That would be a poor ratio of cost to sound, IMO. In one of Darryl's
> earlier posts he mentions he doesn't want to "break the bank" so a
> thought to cost doesn't seem out of line.
True, and he could build a very nice amp with inexpensive parts, tubes etc,
and be very happy. I was going a bit further, as I feel that DHTs bring you
closer to the music, and are worth the extra effort and expense... Just as
long as one does not blow the rent money and end up living on the street
with their 300B amp.
BC
bobcx
news:37d57f64...@news.mpx.com.au...
> Hi bobcx,
>
> You were saying......
>
>
> >
> >lack of a better term) amp, and you have or intend to purchase
appropriate
> >speakers, a 300B or "300B type" tube is by far one of the best way to go.
> >There are many choices available, some are even pretty cost effective.
> >Triode wired (fill in the blank) or any other non DHTs no matter what
anyone
> >here tells you, are not the same. I would even choose a cheap Chinese
300B
> >over a SE EL34 any day of the week. IMO there is no contest. Of course if
> >you never listen to the tubes the differences are much less obvious.
>
> triode wired, and a 300B type in similar systems (at least same
> speakers), is it possible to describe how they sound better. What
> things make you like them? I only ask, because there's no easy way for
> me to get to hear them myself.
I have not personally listened to SE EL34s, but I am basing my opinion on
sources I trust. People that I know that have listened, and tested, and say
things that make sense. Please understand I am not saying that the other
amps can't sound nice, it's just not my preference. If it is not within the
budget at this time, and it is either build the cheaper project, or
nothing... I would build the cheap amp. When the time comes you could pass
it on to a friend, and build something better.
BC
Acrosound
Try <A HREF="http://www.vacuumstate.com/">http://www.vacuumstate.com/</A>
to which andre responded and supplied the:
>Correct URL for review:
and noted further:
>where you can also find a link to Allen Wright's >website.
thanks to each of you for the pointers. Is there a US distributor for Mr.
Wright's products? And if it is not asking too much is there a url for the
American distributor?
Recently I lost my whole list of bookmarks for audio websites. I prefer,
generally speaking, direct connections to company websites as they are most
likely to have the most up-to-date info available about their products and
services.
but, again, thanks to each of you.
MSL
tcw
JHPage
dkl...@removethisbit.ieee.org says...
> Hi JHPage,
>
> You were saying......
>
>
> >thought to cost does'nt seem out of line.
>
>
> This is true! :-)
>
> I see two ends of the spectrum. I could build an amp with SE triode
> wired EL34's with $20 hammond universal OT's, or I could save up for
> 300B's and $200 boutique OT's. It's a factor of 10 or more in cost.
> I am not going to spend 10 times the money and only get a small
> improvement. If everyone tells me it's 5 to 10 times better sound ,
> then I will have to consider it.
>
>
I see your dilemma. I would agree with bobcx that the difference between
DHTs and pentodes wired as triodes, is significant. One question would
be: how much power do you have to have? 1 EL34 in SET would give you
about 2-3W RMS at less than 5% distortion with a Hammond universal
transformer 125E? I have used this transformer with my 6BL7GTA (both
triode sections in parallel) project and it sounds pretty bad. An SE amp
based on one of the 2A3 type tubes and an inexpensive transformer such
as: an Electra-Print TM3KB, a MagnaQuest TFA-204 or an Audio Note Trans-
144, could be a real alternative. This would give you a little more power
out, cost would be reasonable (less than $300 for a pair of tubes and
transformers) and would sound at least 20 times better. When you wanted
to move up to better sound you could sell any of these transformers for a
good percentage of what you paid for it and have extra cash for better
iron later.
I don't want to go to far out here, but, you could also wind a pair of
transformers yourself. It's not as hard as you might think and if you
have the time to do it right they will sound very good and cost less than
any of the above. I don't know if you could sell used DIY transformers
though.
Joseppi
bobcx
> >
> Darryl,
>
> I see your dilemma. I would agree with bobcx that the difference between
> DHTs and pentodes wired as triodes, is significant. One question would
> be: how much power do you have to have? 1 EL34 in SET would give you
> about 2-3W RMS at less than 5% distortion with a Hammond universal
> transformer 125E? I have used this transformer with my 6BL7GTA (both
> triode sections in parallel) project and it sounds pretty bad. An SE amp
> based on one of the 2A3 type tubes and an inexpensive transformer such
> as: an Electra-Print TM3KB, a MagnaQuest TFA-204 or an Audio Note Trans-
> 144, could be a real alternative. This would give you a little more power
> out, cost would be reasonable (less than $300 for a pair of tubes and
> transformers) and would sound at least 20 times better. When you wanted
> to move up to better sound you could sell any of these transformers for a
> good percentage of what you paid for it and have extra cash for better
> iron later.
Makes a great deal of sense Joe. Don't forget the Chinese 2A3s. I have not
used them, but they are very cheap, and many people say they sound good.
They won't last forever but the price is right at approx. $20ea.
Good used old stock 2A3s can be found pretty reasonably, and will last a
long time.
The new VV SP 2A3 and their 300B also are fairly priced at approx. $125.
BC
JHPage
bo...@SPAMearthlink.net says...
My apologies, I must be getting paranoid in my old age. :) I agree, a
whole system based on a low power SET is the way to go. As I posted in
my reply to Darryl, I think anyone would be much better off spending a
little more on better parts up front that could be sold to help pay for a
better system down the road. I would also say the 2A3 / better quality
transformer combo would sound at least 20 times better than the EL34 /
Hammond Universal transformer combo.
I thought the WE 300s sounded a little laid back (warm, very nice sound
stage), the J.J./ Teslas were much more foward hotter top end, the sound
was almost in front of the speakers, the Svetlanas were in between in
sound, nice sound stage. If it were my money the Svetlanas would be the
choice. BTW this system used Klipsch speakers and a very nice home built
amp.
Darryl
You were saying......
>Darryl,
>
>I see your dilemma. I would agree with bobcx that the difference between
>DHTs and pentodes wired as triodes, is significant. One question would
>be: how much power do you have to have?
I have 2 watts at the moment with the 6AQ5's, so 5 to 10 woould be
sufficient.
>1 EL34 in SET would give you
>about 2-3W RMS at less than 5% distortion with a Hammond universal
>transformer 125E?
Why so low? I have looked at the curves, and played around with a
spreadsheet I have, and I believe you can get 5 watts or more with
sufficiently high voltage (say 400 volts).
>I have used this transformer with my 6BL7GTA (both
>triode sections in parallel) project and it sounds pretty bad.
I needed to hear that. In what way is it bad? Does it lack freq.
response? Does it distort? What plate load did you configure it for?
>An SE amp
>based on one of the 2A3 type tubes and an inexpensive transformer such
>as: an Electra-Print TM3KB, a MagnaQuest TFA-204 or an Audio Note Trans-
>144, could be a real alternative.
Doesn't the 2A3 only produce 2-3 watts?
>This would give you a little more power
>out, cost would be reasonable (less than $300 for a pair of tubes and
>transformers) and would sound at least 20 times better.
Well thanks for being venturesome enough to try to put a figure on it.
You're the first. 20 times is a lot of improvement. Would it be that
much better than an EL34 with the good transformer though?
>When you wanted
>to move up to better sound you could sell any of these transformers for a
>good percentage of what you paid for it and have extra cash for better
>iron later.
>I don't want to go to far out here, but, you could also wind a pair of
>transformers yourself. It's not as hard as you might think and if you
>have the time to do it right they will sound very good and cost less than
>any of the above. I don't know if you could sell used DIY transformers
>though.
I'd be willing to attempt this. Any pointers to designs and suppliers
of the basic parts (core iron, bobbins etc etc)?
Thanks
Ron Bales
(Darryl) wrote:
>>An SE amp
>>based on one of the 2A3 type tubes and an inexpensive transformer such
>>as: an Electra-Print TM3KB, a MagnaQuest TFA-204 or an Audio Note Trans-
>>144, could be a real alternative.
>
>Doesn't the 2A3 only produce 2-3 watts?
More like 3-4W. I can say from experience, comparing my 1.2W 12B4A
amp to my 2A3's that this is a very significant increase in power.
Still need 90dB speaks and a small or lively room.
ROn
JHPage
dkl...@removethisbit.ieee.org says...
> >1 EL34 in SET would give you
> >about 2-3W RMS at less than 5% distortion with a Hammond universal
> >transformer 125E?
>
> Why so low? I have looked at the curves, and played around with a
> spreadsheet I have, and I believe you can get 5 watts or more with
> sufficiently high voltage (say 400 volts).
>
With a better transformer you could get a little more power, but from
quickly looking at the specs. for an EL34 (Svetlana), I think you're
going to have quite a bit of distortion at 5W RMS.
> >I have used this transformer with my 6BL7GTA (both
> >triode sections in parallel) project and it sounds pretty bad.
>
> I needed to hear that. In what way is it bad? Does it lack freq.
> response? Does it distort? What plate load did you configure it for?
>
The Hammond 125E has a pretty small core and the pri and sec are single
layer wound (I took one of mine apart to how it was made) so it has very
little HF above about 5KhZ and with 62ma at 300v DC across the pri at
2.5W output, a sine wave at 80hZ was very distorted.
> >An SE amp
> >based on one of the 2A3 type tubes and an inexpensive transformer such
> >as: an Electra-Print TM3KB, a MagnaQuest TFA-204 or an Audio Note Trans-
> >144, could be a real alternative.
>
> Doesn't the 2A3 only produce 2-3 watts?
>
I would expect more like 3-4W from a 2A3 type and a little more from a KR
2A3 premium tube.
> >This would give you a little more power
> >out, cost would be reasonable (less than $300 for a pair of tubes and
> >transformers) and would sound at least 20 times better.
>
> Well thanks for being venturesome enough to try to put a figure on it.
> You're the first. 20 times is a lot of improvement. Would it be that
> much better than an EL34 with the good transformer though?
>
No, any of the transformers I listed before would make also make a great
improvement in the sound of your EL34 wired as a triode, say a 15 times
improvement, but the 2A3s would sound better yet. Having said that, with
good transformers I move from a "provable fact" type statement to more of
a "my opinion is" type statement regarding the tubes, so consider that.
:)
> >When you wanted
> >to move up to better sound you could sell any of these transformers for a
> >good percentage of what you paid for it and have extra cash for better
> >iron later.
> >I don't want to go to far out here, but, you could also wind a pair of
> >transformers yourself. It's not as hard as you might think and if you
> >have the time to do it right they will sound very good and cost less than
> >any of the above.
You could contact one of the local (Australia?) transformer winders,
sometimes they will sell you laminations and bobbins if you ask very
nice. You would need to make sure you get M6, 0.0140" laminations though.
I also have some 1.125 and 1.5 inch core M6 laminations and bobbins that
I would be willing to sell you. I would guess shipping via USPS Airmail
would be $30-$40 USD from Chicago to Australia for 2 sets. If you want
more info on these and directions on how I wound my transformers, e-mail
me at jhp...@wwa.com
BTW, I am very jealous of your find of cool tubes, what great fun you're
going to have! ;)
Regards,
Joseppi
Acrosound
>the Hammond 125E has a pretty small core and the pri and sec are single
>layer wound (I took one of mine apart to how it was made) so it has very
>
>little HF above about 5KhZ and with 62ma at 300v DC across the pri at
>2.5W output, a sine wave at 80hZ was very distorted.
do you remember or have written down what the core size was? I am assuming it
was built on an EI lamination. did it have an airgap? And did you count the
number of primary turns?
If you know the pri turns, the air gap, the lamination size and thickness of
stack, as well as the amount of DC current going through the device you should
be able to calculate out both the DC flux density and AC flux density.
another strategy for someone perhaps using this trans is to parafeed it.
Parafeed would remove the DC flux density off of the core and thus provide much
more AC magnetic flux headroom. Bottom end should improve (assuming proper
values of plate loading choke and cap)... though the top end will still
probably be hampered from the winding pattern you mention above.
just some thoughts.
MSL
Darryl
You were saying......
>> Why so low? I have looked at the curves, and played around with a
>> spreadsheet I have, and I believe you can get 5 watts or more with
>> sufficiently high voltage (say 400 volts).
>>
>With a better transformer you could get a little more power, but from
>quickly looking at the specs. for an EL34 (Svetlana), I think you're
>going to have quite a bit of distortion at 5W RMS.
About 1 to 1.5% by my calcs.
>
>
>> >I have used this transformer with my 6BL7GTA (both
>> >triode sections in parallel) project and it sounds pretty bad.
>>
>> I needed to hear that. In what way is it bad? Does it lack freq.
>> response? Does it distort? What plate load did you configure it for?
>>
>The Hammond 125E has a pretty small core and the pri and sec are single
>layer wound (I took one of mine apart to how it was made) so it has very
>little HF above about 5KhZ and with 62ma at 300v DC across the pri at
>2.5W output, a sine wave at 80hZ was very distorted.
Gee that's bad. Why do they make such a bad transformer, I wonder?
I took some old ones (made by Rola in 1967)out of an old console
stereo (obviously made cheap to a budget) and tried them (with 6AQ5's)
and they have usable response from 50 to 15kHz (where my ears start to
fade anyway :-)). Now if these cheap trannies do that well, why
don't hammond ?
Ron Bales
(Darryl) wrote:
>>The Hammond 125E has a pretty small core and the pri and sec are single
>>layer wound (I took one of mine apart to how it was made) so it has very
>>little HF above about 5KhZ and with 62ma at 300v DC across the pri at
>>2.5W output, a sine wave at 80hZ was very distorted.
>
>Gee that's bad. Why do they make such a bad transformer, I wonder?
Firstly, it is very inexpensive and the measurements here, well 62mA
is quite a lot of a little tranny like that.
Much of Hammond's business is suppying guitar amp builders. They are
pretty tolerant of HF roll-off and the instrument doesn't go below
80Hz anyway. Run at 40mA and it might be just fine for that
application.
>I took some old ones (made by Rola in 1967)out of an old console
>stereo (obviously made cheap to a budget) and tried them (with 6AQ5's)
>and they have usable response from 50 to 15kHz (where my ears start to
>fade anyway :-)).
Some pretty good work went into a lot of that stuff. I've done a lot
of experimenting with some SE 5K trans that came from an Akai reel to
reel tape deck. Good fun.
Ron
Michael Appelt
Ron Bales schrieb in Nachricht <37ca7e7...@news.gte.net>...
>On Mon, 30 Aug 1999 07:58:48 GMT, dkl...@removethisbit.ieee.org
>(Darryl) wrote:
>
>
>>>The Hammond 125E has a pretty small core and the pri and sec are single
>>>layer wound (I took one of mine apart to how it was made) so it has very
>>>little HF above about 5KhZ and with 62ma at 300v DC across the pri at
>>>2.5W output, a sine wave at 80hZ was very distorted.
>>
It compares to EI54 or EI60 cores, which are rated for 10-20 watts as a
power
transformer without gap. I believe that's saying all.
Regards,
Michael
Darryl
You were saying......
>>
>>>>The Hammond 125E has a pretty small core and the pri and sec are single
>>>>layer wound (I took one of mine apart to how it was made) so it has very
>>>>little HF above about 5KhZ and with 62ma at 300v DC across the pri at
>>>>2.5W output, a sine wave at 80hZ was very distorted.
>>>
>
>It compares to EI54 or EI60 cores, which are rated for 10-20 watts as a
>power
>transformer without gap. I believe that's saying all.
Sorry Michael, but I don't understand what you were trying to say.
Michael Appelt
Isn't it obviously, that a 12 watt (maybe its 20 watts at saturation
with enhanced core material) power transformer core used
as a SE transformer does not / should not be used for more
than a few watts ?
With lower cutoff frequency than 50/60 cps the undistored
power becomes even lower, the DC adds continous flux is also
not available to AC transformations, so you should not expect
too much from these cheapies.
With non-optimal speaker impedance matching its getting worse.
Probably with some higher NFB the bandwidth gets linearized
so the sound might improve to listening quality.
BTW I'm in a similar situation, where the core is small, the coils wound
too simple, and I decided to use 2 E irons with the 2 coils mounted with
their heads (gaps) toward each other to almost double the core size.
This just fit into my special SE design (split loading) and will more
than double the primary inductivity to enhance lower cutoff frequency.
Now I have more iron and copper than the hammond you have, I
use less DC current (36mA) and expect only 2-3 watts on a regular
speaker. Hopefully I'll finally use it with a hi impedance headphone
in a autotransformer arrangement (or dismiss it at all).
Reagrds,
Michael
Darryl schrieb in Nachricht <37cc95f5...@news.mpx.com.au>...
Darryl
You were saying......
>When I see an OT I compare them roughly to PTs at first sight.
>
>Isn't it obviously, that a 12 watt (maybe its 20 watts at saturation
>with enhanced core material) power transformer core used
>as a SE transformer does not / should not be used for more
>than a few watts ?
No. As I understand it, we are not using power transformers as SE
OT's. These are built as SE transformers with gaps (I believe), so
they don't saturate just because of the DC bias current.