Hello everybody, as usual, I am being my indecisive self. I am now exploring using the Power Triode in my next amplifier. I have come to this possible solution for a few reaons.
1.Push-pull 2a3s should give me a little more umph than the my current El34 SET.
2.I don't need very much power (the other people on my floor agree with this more than myself), the fact is that I can't turn anything up very loud at all, so even a 2a3 SET would give me a good power.
3. A Loftin White design looks close to the difficulty level that I am looking to build
4. power triodes look bad a**, who can deny this?
5. Equiping good OPTs to a 2a3 design would be easy, just some $90/pair transcendar 300b transformers would do nicely
I am debating between SE and PP (as always) I want to build PP because its something I have never done before, and the Iron will be cheaper.
I have seen some conflicting numbers regarding the 2a3 as well. Some say that you can get a good 6-7 WPC out of one 2a3 in SE, however the plate dissapation is only 15 watts according to this site does anyone have any solution to this problem?
In addition to any thoughts anyone has, could anyone point me in the direction of a good 2a3 PP schematic? I can find plenty of SE ones, but Push-Pull is proving difficult.
-Moose
1.Push-pull 2a3s should give me a little more umph than the my current El34 SET.
2.I don't need very much power (the other people on my floor agree with this more than myself), the fact is that I can't turn anything up very loud at all, so even a 2a3 SET would give me a good power.
3. A Loftin White design looks close to the difficulty level that I am looking to build
4. power triodes look bad a**, who can deny this?
5. Equiping good OPTs to a 2a3 design would be easy, just some $90/pair transcendar 300b transformers would do nicely
I am debating between SE and PP (as always) I want to build PP because its something I have never done before, and the Iron will be cheaper.
I have seen some conflicting numbers regarding the 2a3 as well. Some say that you can get a good 6-7 WPC out of one 2a3 in SE, however the plate dissapation is only 15 watts according to this site does anyone have any solution to this problem?
In addition to any thoughts anyone has, could anyone point me in the direction of a good 2a3 PP schematic? I can find plenty of SE ones, but Push-Pull is proving difficult.
-Moose
Hi Arnoldc
You talk about the PP 2A3 from Fdegrove. I already read about it, but have never seen it - and I am reading a lot from those threads. So, can you maybe give us the thread? Or at least a schematic?
I searched, but well, a search for PP 2A3 gives lots of results - and I am afraid it's not a thread on itself, but rather hidden somewhere.
Thank you
Erik
You talk about the PP 2A3 from Fdegrove. I already read about it, but have never seen it - and I am reading a lot from those threads. So, can you maybe give us the thread? Or at least a schematic?
I searched, but well, a search for PP 2A3 gives lots of results - and I am afraid it's not a thread on itself, but rather hidden somewhere.
Thank you
Erik
I think a SE amp with 2a3 output tube is mostly around 3 watts.
I'm going to build a SETH PP2A3 one of these days.
http://www.magnequest.com/diy_lessard_circuit_2a3pp.htm
Hi Bas
You are right! I see people selling their diy stuff because they can't get their project to work properly, etc. They lose money, time - and maybe even get a trauma
The author of the TTSETH PP2A3 did a very good job keeping the thing simple, very simple, and with a very good building manual (I looked at it).
Erik
You are right! I see people selling their diy stuff because they can't get their project to work properly, etc. They lose money, time - and maybe even get a trauma
The author of the TTSETH PP2A3 did a very good job keeping the thing simple, very simple, and with a very good building manual (I looked at it). Erik
Hi Shoog and all
I was exactly thinking about the toroidal approax while I read about your positive experiences with them (and also from other people who used toroidal either as interstage or as OPT). But your approax is using it as, you say, an interstage transformer. I am curious if a toroidal with two 110V could also be used as a center tapped choke for an application as the TSETH PP2A3: both primaries in series, and the center point grounded? I would say that if it got sufficiente inductance to work as a interstage it would also have enough inductance to act as a center tapped choke, but I am just guessing here.
Erik
Am I right thinking that welbornelabs also have a center tapped choke that can be used for a EL84 push pull? I couldn't find it at their website anymore...
I was exactly thinking about the toroidal approax while I read about your positive experiences with them (and also from other people who used toroidal either as interstage or as OPT). But your approax is using it as, you say, an interstage transformer. I am curious if a toroidal with two 110V could also be used as a center tapped choke for an application as the TSETH PP2A3: both primaries in series, and the center point grounded? I would say that if it got sufficiente inductance to work as a interstage it would also have enough inductance to act as a center tapped choke, but I am just guessing here.
Erik
Am I right thinking that welbornelabs also have a center tapped choke that can be used for a EL84 push pull? I couldn't find it at their website anymore...
Hi Bas
that is right, electraprint was the one. I remember that I saw it at a site that was related with DRD amps, and that's why I went to welbornlabs. But, as I understand well, welbornlabs uses trafo's from electraprint!? Well, all too expensive for me, if I were to buy something in the US Edcor comes closest to my budget
Erik
that is right, electraprint was the one. I remember that I saw it at a site that was related with DRD amps, and that's why I went to welbornlabs. But, as I understand well, welbornlabs uses trafo's from electraprint!? Well, all too expensive for me, if I were to buy something in the US Edcor comes closest to my budget
Erik
My guess is Yes it should work as a center tapped choke as in the 2a3 SETH amp. There isn't any standing DC which would be the main problem. The only slight concern I would have is the possability of ringing in the unused windings. At a pinch you could go for a smaller transformer (say 6V) and strip the secondaries off. My small technical understanding says that, within limits, the inductance is greater the smaller the transformer. Other than that it might work even better than as an interstage.
Remember though these do not perform stock as well as an proper interstage, and need some hard core driving to give of their best. Still I found the result is well worth it. Low level detail married to PP bass control.
Shoog
I once read a comment by John Broskie: the perfect and the complex are enemy of the built. I sure make myself guilty, always thinking of 'improvements' even before building the device...that's what led me to think about the borg collective but it has voltages exposed, it is big, and so on. So now I am working on a rack which I will protect with a cage (shown as attached picture). I bought Morgan Jones Building valve amplifiers to see if I can apply some more theory on this project.
But, one of my first plans for this prototyping concept is to build and compare different gain and buffer stages, to drive my headphone (a very good tool to compare circuits, I think). Now I am thinking that it would not be hard to add a self splitting PP power stage, like the SETH 2A3 PP or the electraprint EL84. The driver would have low output impedance, needed to drive the 120R headphone, so it would probably drive the centertapped choke too. I will try it out - just have to find a small toroidal with double primaries (the dutch second hand market is saturated with toroidals, but most have just one 230VAC primary).
Well, lets see how it turns out.
Erik
But, one of my first plans for this prototyping concept is to build and compare different gain and buffer stages, to drive my headphone (a very good tool to compare circuits, I think). Now I am thinking that it would not be hard to add a self splitting PP power stage, like the SETH 2A3 PP or the electraprint EL84. The driver would have low output impedance, needed to drive the 120R headphone, so it would probably drive the centertapped choke too. I will try it out - just have to find a small toroidal with double primaries (the dutch second hand market is saturated with toroidals, but most have just one 230VAC primary).
Well, lets see how it turns out.
Erik
Attachments
ErikdeBest said:
Here it is, adapted from an original by Triode Dick:
http://www.diyaudio.com/forums/showthread.php?postid=595177#post595177
and for the 2A3 heaters, use a modified version (for proper voltage) of the bottom portion of this schematic:.
http://www.diyaudio.com/forums/showthread.php?postid=576995#post576995
My father wouldn't like to see a parakeet. He has lots of canary's, in all colors. Once he started to expalin the difference between two: both were yellow, but one a little smoother texture, varying between yellow and white. Then I thought that people around here do exactly the same: the outside world see PP, pentode, triode, transistor as a crowd of yellow canary, while people here see (hear) al slight variations.
Sorry for the philosophy, have still to wake up
Erik
Sorry for the philosophy, have still to wake up
Erik
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