Hello All,
I'm in the process of choosing & assembling the parts for a SRPP 2A3 SET.
I'm having a tough time choosing and locating sources of good OT's.
This is what I've sourced out from the net so far:
Hammond ESE @ $32.00US ea.
One Electron UBT-3 @ $80.96US ea
Hammond 1627SE @ $85.00US ea.
MagneQuest TFA-204 @ $125.00US ea.
Tamura F-475 @ $143.00US ea. ($$$ for shipping)
I do have a budget that I'm tryng to follow so big $$$ OT's are kind of out....unless can convince my wife other wise
Thanks for your time
Mike
I'm in the process of choosing & assembling the parts for a SRPP 2A3 SET.
I'm having a tough time choosing and locating sources of good OT's.
This is what I've sourced out from the net so far:
Hammond ESE @ $32.00US ea.
One Electron UBT-3 @ $80.96US ea
Hammond 1627SE @ $85.00US ea.
MagneQuest TFA-204 @ $125.00US ea.
Tamura F-475 @ $143.00US ea. ($$$ for shipping)
I do have a budget that I'm tryng to follow so big $$$ OT's are kind of out....unless can convince my wife other wise
Thanks for your time
Mike
like you i started on the affordable side and got a hammond 125ESE (2.5K, 5K, 10K) for my je labs 2A3 (srpp). it sounds good for the amount i paid. i have moved on to a different iron now, which is a magnequest DS-025 (2.5K) and i believe it was a step forward in sonic improvement.
i have used a 1628 (5K) but that's for a 300B and now on my 807 amp, and it sounds good too.
if you ask my current favorite, that will be a Tamura F-475 (5K) which i used on my 245 amp. just be careful not to exceed the current rating of the transformer. if you bias your 2A3 at 45 operating point (34mA), the current will be ok for the F-475 and you get a gemini amp (2A3/45 switchable) with the proper cathode resistor, though not optimized for the 2A3 (less power).
i have used a 1628 (5K) but that's for a 300B and now on my 807 amp, and it sounds good too.
if you ask my current favorite, that will be a Tamura F-475 (5K) which i used on my 245 amp. just be careful not to exceed the current rating of the transformer. if you bias your 2A3 at 45 operating point (34mA), the current will be ok for the F-475 and you get a gemini amp (2A3/45 switchable) with the proper cathode resistor, though not optimized for the 2A3 (less power).
I was a little disappointed in the 125ESE, they were ok but not great... good to start with i guess.
I would recommend spending a bit more on the output iron first, you won't regret it...
Also I have tried the srpp and the loftin white and they didnt sound too good imho... The one I would recommend is the angela.com 2001 edition 2A3, its the best circuit i have tried so far.
SET amps are definitely good sounding tho, i would recommend them...
I would recommend spending a bit more on the output iron first, you won't regret it...
Also I have tried the srpp and the loftin white and they didnt sound too good imho... The one I would recommend is the angela.com 2001 edition 2A3, its the best circuit i have tried so far.
SET amps are definitely good sounding tho, i would recommend them...
Hi,
We can try...
Here goes, IMO the Hammond OPTs are good value for money but what good is it to save money on an OPT if you're going to be left wondering: What if I had....?
After all 85% of a classic tube amp's quality is determined by the iron it's made of, right?
From your list the Tamura is no doubt excellent but maybe too expensive.
Both One Electron and Mike Lefevre's Magnequest are no doubt among the best US winders I know of.
Then there are some superb European OPTs made by Bartolucci, Tribute, AE, Sowter and no doubt a few others that slip my mind right now.
Last but not least Luddahl from Sweden has an enviable reputation for good iron at a reasonable price.
The best source I know of (incidentally in my backyard so to speak) is Benny Glass' shop Aquablue in Antwerp.
More often than not he can offer the Lundahl xformers for less money than Lundahl themselves is selling for.
Feel free to mention my name in case you want to get in touch with him:
LUNDAHL OPT
It's only a suggestion of course, I'm sure there's plenty of other good iron about.
Cheers,
We can try...
Here goes, IMO the Hammond OPTs are good value for money but what good is it to save money on an OPT if you're going to be left wondering: What if I had....?
After all 85% of a classic tube amp's quality is determined by the iron it's made of, right?
From your list the Tamura is no doubt excellent but maybe too expensive.
Both One Electron and Mike Lefevre's Magnequest are no doubt among the best US winders I know of.
Then there are some superb European OPTs made by Bartolucci, Tribute, AE, Sowter and no doubt a few others that slip my mind right now.
Last but not least Luddahl from Sweden has an enviable reputation for good iron at a reasonable price.
The best source I know of (incidentally in my backyard so to speak) is Benny Glass' shop Aquablue in Antwerp.
More often than not he can offer the Lundahl xformers for less money than Lundahl themselves is selling for.
Feel free to mention my name in case you want to get in touch with him:
LUNDAHL OPT
It's only a suggestion of course, I'm sure there's plenty of other good iron about.
Cheers,
Can't make any solid recommendations as I haven't used different transformers in the same 2A3 circuit. But these transformers are also worth researching: Electra-print and Audio Note.
I owned a Moth Audio s2A3 amp for a couple of years, and this used Electra-print OPTs. Sounded really good. Welborne Labs amps also use the Electra-print OPTs in their amps.
I also own the Audio Note Kit One. This is a 300B amp so there may not be a direct comparison here, but in a shootout for 300B OPTs in Vacuum Tube Valley several years back, the Audio Note OPT used in the Kit One was judged a best buy, sounding very good for the price. I agree!
I also have a Sun Audio SV300BE, again a 300B amp. This one uses Tamura iron and sounds very good, as well. Different circuit, so I can't directly say which is preferable.
In the 300B OPT shootout, it seemed that the big Electra-print unit they tested was much preferred over the other transformers, which included some units by Tango, Tamura, Audio Note, Bartolluci, One-Electron, Magnaquest (?), and a few others. Of course, other units from the same manufacturer may be better or worse than the shootout suggests.
Look into Electra-print and Audio Note, though.
Good luck,
KT
I owned a Moth Audio s2A3 amp for a couple of years, and this used Electra-print OPTs. Sounded really good. Welborne Labs amps also use the Electra-print OPTs in their amps.
I also own the Audio Note Kit One. This is a 300B amp so there may not be a direct comparison here, but in a shootout for 300B OPTs in Vacuum Tube Valley several years back, the Audio Note OPT used in the Kit One was judged a best buy, sounding very good for the price. I agree!
I also have a Sun Audio SV300BE, again a 300B amp. This one uses Tamura iron and sounds very good, as well. Different circuit, so I can't directly say which is preferable.
In the 300B OPT shootout, it seemed that the big Electra-print unit they tested was much preferred over the other transformers, which included some units by Tango, Tamura, Audio Note, Bartolluci, One-Electron, Magnaquest (?), and a few others. Of course, other units from the same manufacturer may be better or worse than the shootout suggests.
Look into Electra-print and Audio Note, though.
Good luck,
KT
tfa-204 thoughts
I have used the Magnequest TFA-204 and like it very much. The bass is better than I thought it would be, and the mids and highs are fantastic.
I am planning to upgrade the amp using the TFA-204 to parallel feed because I want to see how good it can be. for this I want to use the TFA-2004 parafeed output and a suitable plate choke, maybe EXO-003. This is more iron than your budget (and my initial budget) would allow, but I really dig this amp and want to see how far I can take it.
My suggestion is to be sure you leave room on the chassis for bigger transformers and perhaps a pair of plate chokes for parallel feed. That way you leave you options open for future upgrades. I am bummed because I am out of topplate real estate and ewant to add another pair of chokes, a 1uF paper in oil power supply cap, and a pair of Vitamin Q parafeed caps And my chassis is already 12" x 24" I guess I'll have to mount some of these beauties under the hood. Such a shame.
Oh, and if you buy "nice" iron, and want to upgrade, you should have no trouble selling it off to your friendly neighborhood tube nerds - so the upgrade costs can be fairly incremental.
Here is the amp in question:
http://boozhoundlabs.com/monkey/
This amp uses tons of surplus power supply iron, which can usually be found cheap. If you can get some good deals on stuff like this, it will leave you more money for output iron and plate chokes and stuff that you can't get surplus. I haven't bought a new power transformer in years, except for projects that must use readily available parts.
jsn
I have used the Magnequest TFA-204 and like it very much. The bass is better than I thought it would be, and the mids and highs are fantastic.
I am planning to upgrade the amp using the TFA-204 to parallel feed because I want to see how good it can be. for this I want to use the TFA-2004 parafeed output and a suitable plate choke, maybe EXO-003. This is more iron than your budget (and my initial budget) would allow, but I really dig this amp and want to see how far I can take it.
My suggestion is to be sure you leave room on the chassis for bigger transformers and perhaps a pair of plate chokes for parallel feed. That way you leave you options open for future upgrades. I am bummed because I am out of topplate real estate and ewant to add another pair of chokes, a 1uF paper in oil power supply cap, and a pair of Vitamin Q parafeed caps
And my chassis is already 12" x 24" I guess I'll have to mount some of these beauties under the hood. Such a shame.Oh, and if you buy "nice" iron, and want to upgrade, you should have no trouble selling it off to your friendly neighborhood tube nerds - so the upgrade costs can be fairly incremental.
Here is the amp in question:
http://boozhoundlabs.com/monkey/
This amp uses tons of surplus power supply iron, which can usually be found cheap. If you can get some good deals on stuff like this, it will leave you more money for output iron and plate chokes and stuff that you can't get surplus. I haven't bought a new power transformer in years, except for projects that must use readily available parts.
jsn
output transformers
Electra-Print output transformers are some of the best. Jack will also work with you on whatever your needs are. He will make recommendations and answer questions if you have any doubts. His prices are very reasonable for custom wound iron. I highly recommend contacting him. Elecrta-Print phone no. 702-396-4909. E-mail electaudio@aol.com
Electra-Print output transformers are some of the best. Jack will also work with you on whatever your needs are. He will make recommendations and answer questions if you have any doubts. His prices are very reasonable for custom wound iron. I highly recommend contacting him. Elecrta-Print phone no. 702-396-4909. E-mail electaudio@aol.com
For the Hammonds i think you will find that Electro-sonic has the best prices (and are the Canadian distributor)
http://www.e-sonic.com/acc/home.aspx
dave
http://www.e-sonic.com/acc/home.aspx
dave
hi shifty, can you please tell me, if you still remember, the sonic difference between the SRPP (Steve's EZ-2A3) and this 2001 edition?SHiFTY said:
gang, other transformers that are possible alternatives include the Tango U-808 which i heard on a friend's "Darling" amp. and then Mike Le Fevre has these new "Robin Hood" series which is tempting at $75.
i have a friend with a Jack Elliano made DRD 300B and of course using Jack's OPT and they sound really clean when i hooked it up to my system
must be the circuit or the OPT or both.
Hi,
Same mistakes over and over again: never use a stage with poor PSRR in an amp wich itself uses a topology that has hardly any PSRR to speak of....
Unless of course you're prepared to regulated the whole shebang, don't blame a particular topology unless you know why it fails to deliver....
Cheers,
Same mistakes over and over again: never use a stage with poor PSRR in an amp wich itself uses a topology that has hardly any PSRR to speak of....
Unless of course you're prepared to regulated the whole shebang, don't blame a particular topology unless you know why it fails to deliver....
Cheers,
Hey man, if you have heard something you like, then by all means imitate it! Most of us build stuff that intuitively seems like a good idea to see if we like it or not, and many times we don't!
http://www.electra-print.com/images/2A3DRD.jpg
You want a 2a3 amp and like DRD design... Well go for it. You can get the exact output transformer used in this circuit for $145 each.
Designing a direct coupled monkey circuit like this takes a few more iterations of ohm's law than a simple RC coupled circuit, but that shouldn't stop you.
Disclaimer: I think the DRD topology makes a lot of sense, and the few SRPP driver amps I have built, I haven't liked much - but it might not be the SRPP at fault (was that a disclaimer inside the disclaimer?). Oh, and my latest amp is essentially DRD topology, though I would probably call it "ultrapath monkey" or something because there are already so many redundant circuit topology terms in use today.
jsn
hi frank,fdegrove said:Same mistakes over and over again: never use a stage with poor PSRR in an amp wich itself uses a topology that has hardly any PSRR to speak of....
Unless of course you're prepared to regulated the whole shebang, don't blame a particular topology unless you know why it fails to deliver....
does this mean the SRPP has poor PSRR for use with the 2A3 stage which itself has low PSRR?
Hi,
The SRPP and mostly all stacked tube configurations I know of have poor PSRR so they really need a stiff, well filtered PS to work optimally.
SE amplifiers don't benefit from the PP noise cancelation effects either and have essentially their entire PS in series with the circuit.
Combining both SRPP and SE topology without paying attention to the PSRR problem inherent in both is just begging for a poor performance IMO.
People like John "Budda" Camille, Denis Boyle, Lynn Olson et all, are well aware of this and go through an awful lot of trouble to avoid this pittfall by using regulated supplies.
Preamplifiers, being usually SE designs suffer from the very same problems which is one reason why I so often insist on paying attention to PS design: it is a modulated power supply you'll be listening to in the end.
Cheers,
The SRPP and mostly all stacked tube configurations I know of have poor PSRR so they really need a stiff, well filtered PS to work optimally.
SE amplifiers don't benefit from the PP noise cancelation effects either and have essentially their entire PS in series with the circuit.
Combining both SRPP and SE topology without paying attention to the PSRR problem inherent in both is just begging for a poor performance IMO.
People like John "Budda" Camille, Denis Boyle, Lynn Olson et all, are well aware of this and go through an awful lot of trouble to avoid this pittfall by using regulated supplies.
Preamplifiers, being usually SE designs suffer from the very same problems which is one reason why I so often insist on paying attention to PS design: it is a modulated power supply you'll be listening to in the end.
Cheers,
Tubes come and go, Transformers are a lifetime investment
I second that DRD recommendation. I went from cap-coupled SRPP to one of John 'Buddha' Camille's Direct-Coupled Monkey/DRD designs from Valve. I use a CCS instead of an inductor, but it's serving the same function.
Runs hotter, sounds better.
They say "Buy the best and you only cry once" (for me, that was spending the equivalent of a month's rent on Magnequest iron....) but I'd have no second thoughts about Electraprint either, I own & enjoy both.
At the very least, pay heed to the advice about leaving room on the chassis.
jsn said:
I second that DRD recommendation. I went from cap-coupled SRPP to one of John 'Buddha' Camille's Direct-Coupled Monkey/DRD designs from Valve. I use a CCS instead of an inductor, but it's serving the same function.
Runs hotter, sounds better.
They say "Buy the best and you only cry once" (for me, that was spending the equivalent of a month's rent on Magnequest iron....) but I'd have no second thoughts about Electraprint either, I own & enjoy both.
At the very least, pay heed to the advice about leaving room on the chassis.
thank you again frank. since the brushed aluminum top plate on my 2A3 tarnished due to my acidic sweat, i am about to disassemble it (just after a few months ) and have them chromed. that will give me an opportunity to change the circuit from the SRPP to the Angela 2001 edition, and hopefully hear the difference.
) and have them chromed. that will give me an opportunity to change the circuit from the SRPP to the Angela 2001 edition, and hopefully hear the difference.
I think 1/2 6SL7 is just not grunty enough to drive a 2A3 with low distortion. I tried this, didn't sound good. Weak bass, low power. The driver stage seems to run out of puff before the output stage.
SRPP is just replacing the plate resistor with a triode, and it is still the bottom 1/2 6SL7 that drives the grid of the 2A3 (as I understand it.) and therefore suffers from the above problems to a lesser degree.
A cathode follower is a much better driver for a power triode, indeed the famous ongaku amplifiers use them in this way. Even a humble 1/2 6SL7 -> 1/2 6SL7 cathode follower -> 2A3 is a nice driver for the 2A3 when used in this way. (See the angela.com 2001 edition)
I was literally blown away when i compared this as a driver, sounded far better. The sound is clearer with much better bass, higher power output and just more of a hi-fi sound rather than a "SET" sound.
I still don't think its the end of my search, I might try a tube like the 6EM7 dual triode as a driver, massive overkill but why not
SRPP is just replacing the plate resistor with a triode, and it is still the bottom 1/2 6SL7 that drives the grid of the 2A3 (as I understand it.) and therefore suffers from the above problems to a lesser degree.
A cathode follower is a much better driver for a power triode, indeed the famous ongaku amplifiers use them in this way. Even a humble 1/2 6SL7 -> 1/2 6SL7 cathode follower -> 2A3 is a nice driver for the 2A3 when used in this way. (See the angela.com 2001 edition)
I was literally blown away when i compared this as a driver, sounded far better. The sound is clearer with much better bass, higher power output and just more of a hi-fi sound rather than a "SET" sound.
I still don't think its the end of my search, I might try a tube like the 6EM7 dual triode as a driver, massive overkill but why not
FWIW... Ask yourself first if this amp is going to be your final amp and/or are you willing to stick with 2A3s and the like if you decide to build something else. My reason for asking is that if you want to expeimment with other circuit designs you might want to get the cheaper Hammond 125ESE with different input impedences. Getting, for example a One-Electron UBT-3, this will lock you in with a 3k iron.
In my case, I went with the 125ESE because I want to try building all types of SE amps to find out what I like. I figured that when I do find a circuit that I like then I will go out and spend the big bucks for the best iron. I haven't found the "best" circuit/tube yet but its still fun, therefore, haven't had to spend the big bucks. I'll eventually settle down with a final design but for now I'm just enjoying the jouney building and listening to DIY tube amps. It's what this hobby is all about IMO...
In my case, I went with the 125ESE because I want to try building all types of SE amps to find out what I like. I figured that when I do find a circuit that I like then I will go out and spend the big bucks for the best iron. I haven't found the "best" circuit/tube yet but its still fun, therefore, haven't had to spend the big bucks. I'll eventually settle down with a final design but for now I'm just enjoying the jouney building and listening to DIY tube amps. It's what this hobby is all about IMO...
that's great point @rockysdad. i see the 125ESE as an "investment" in prototyping. with its multiple taps, that really helps a lot. when you get the circuit going and like the sound, putting in a better iron steps up the sonics IME.
shifty, thank you very much for the insight. that will be an easy conversion (from SRPP to 2001 edition) so i'll take up on it and hear what i'm missing i also noticed that all of Joseph Esmilla's amps are CF with 76 in front. although my 300B is the DX version (76-6SN7-300B) i never bothered using the 2001 circuit, until now.
shifty, thank you very much for the insight. that will be an easy conversion (from SRPP to 2001 edition) so i'll take up on it and hear what i'm missing
i also noticed that all of Joseph Esmilla's amps are CF with 76 in front. although my 300B is the DX version (76-6SN7-300B) i never bothered using the 2001 circuit, until now. 
HI
I know measurement fail to predict sonic.
it`s not rare (from personal experience) that a poor mesuring circuit sound better than a good measuring one...
I just think about a DHT driver choke load VS a srpp. Never want to hear SRPP again, and it`s the same for Cathode folower
But some measure are more important...
http://www.sacthailand.com/transformerTest1.html
For your driver, Try an 6c45pi,5842,437A choke load, you might be surprised. Even better, build an 3 stage like this 26,IT (1:2),10y,LC, 2a3
Hope this help.
I know measurement fail to predict sonic.
it`s not rare (from personal experience) that a poor mesuring circuit sound better than a good measuring one...
I just think about a DHT driver choke load VS a srpp. Never want to hear SRPP again, and it`s the same for Cathode folower
But some measure are more important...
http://www.sacthailand.com/transformerTest1.html
For your driver, Try an 6c45pi,5842,437A choke load, you might be surprised. Even better, build an 3 stage like this 26,IT (1:2),10y,LC, 2a3
Hope this help.