Jack over at Electraprint has phase splitter chokes, and schemos demonstrating their use. Even though he uses a 6BX7, there's no reason you couldn't adapt to 2A3s.
There was a previous discussion on this forum of phase splitting autoformers---
http://www.diyaudio.com/forums/showthread.php?postid=1396766#post1396766
might be worth a review.
MSL
http://www.diyaudio.com/forums/showthread.php?postid=1396766#post1396766
might be worth a review.
MSL
hey-Hey!!!,
Heyboer TX in Michigan can also wind these. They have a design of mine in their books. It is based on the same interleave of the prototype Mike and I worked out for his 173PPS. Balanced capacitance and most importantly balanced and mimimum leakage L is how these things work.
cheers,
Douglas
Heyboer TX in Michigan can also wind these. They have a design of mine in their books. It is based on the same interleave of the prototype Mike and I worked out for his 173PPS. Balanced capacitance and most importantly balanced and mimimum leakage L is how these things work.
cheers,
Douglas
Jaime said:
could this have been the 2A3 PP amplifier you saw....
http://www.magnequest.com/diy_lessard_2a3pp.htm
MQracing said:
I think you need to let this go. Jack's plate loading chokes, as listed on his site, have between 50H and 100H. Your bringing this "concern" up every time someone mentions Electra-Print just sounds like badmouthing another manufacturer.
dsavitsk said:
I think your jumping the gun a bit here.... and pulling the trigger long before you have your sights set on the bull's eye....
the reactors\plate chokes you reference are two terminal devices....
they are not Jack's phase splitters.
the phase splitting autoformers (3 terminal devices) that Jack makes are instead listed at http://www.electra-print.com/specialuse.php
and my mention of the 10 henries of L (for the psa-2d) is no slight or injury at all to Jack's product--- but a recognition that the driving source impedance of the phase splitter should be chosen with this value of L in mind.
msl
Can I just add that since that last thread, I have converted my toroidal power transformer phase splitter to a center tap choke. This has extended the high frequency response considerably by lowering the effective interwinding capacitance.
Shoog
Shoog
Yes, I saw the SETH amplifier and others in the MQ forum ( the nice Keto amps.....), but others in Japan and Russia Webs.
It is an old very good idea.
Best regards Jaime
It is an old very good idea.
Best regards Jaime
Jaime said:
Yes... Keto's circuits are really innovative--- he just kept blowing my mind with the evolution and refinements of his push-pull circuits. A good sharp mind. And a real life musician (orchestral violinist) to boot. I have to collate his various circuits and get them organized into a folder.
Gordon Rankin has also published on our AA forum some PP circuits that use a ct autoformer\choke for phase splitting duties--- by memory I think Gordon's circuits used EL84\6BQ5 output tubes.
The earliest example I have seen myself of an autoformer phase splitter was done in the Peerless A-100 amplifier from the early fifties IIRC.
If you have some vintage schematics or can provide url to some early examples of a ct autoformer/choke being used as a phase splitter I'd love to see them.
Out of curiosity--- are you fimiliar with the "compact" type amp circuit--- where essentially the phase splitting is done in the PP output stage itself---- it is yet another approach worth exploring.
MSL
I have such a project on the back burner. Mine will be based on a design that appears on the diyparadise site. It seems that the secret of getting the output to work well is to place a CCS in the tail, this effectively turns it into a differential output stage.
Those that have built the diyparadise design have reported a sound very like a SE amp, but with PP bass grunt. In this case it would seem that the second output tube is working as a DC servo to keep the PP transformer balanced. Some have said it sound better than a conventional PP amp.
When I get around to it (maybe years), I am expecting very good results.
Shoog
Brett said:
I'll have to look it up, I did not find the trade-offs in line with my preferences. I prefer to do the phase splitting elsewhere( CCS-ed LTP ). It was a fun exercise, but not one I found useful in the end.
IIRC the leakage L got down to ~1% v. 1/2 the coil( the driven portion ). That leaves reasonable response from the inverted end.
cheers,
Douglas
MQracing said:
Mike, you say the nicest things...and I dug this up just in case you wanted to see how well your choke mesured.
http://www.audioasylum.com/forums/tubediy/messages/4/48463.html
cheers,
Douglas
Shoog said:
I did an 832A PP first using a CT choke for phase inversion and it worked fine, sounded better than my LTP phase inverter based on the coldwar project at ultranalog.
Then Yeo of diyparadise.com suggested to use the output self phase inversion which I tried. It sounded excellent and is as good as the CT choke phase inversion.
In the end, I took off the CT choke phase inverter (I will be using it on another PP project either an EL34 or KT88 PP).
The CT choke phase inverter is really nice to use, lessen the number of parts that the signal must go through. 😀
Bandersnatch said:
http://www.audioasylum.com/forums/tubediy/messages/60993.html
You can troll and roll out as much bait as you want Dougie and I'm not game for your games.
I know (isn't it obvious) that you enjoy riding on my coattails--- you keep on baiting and trolling for a response from me--- you use my name and my company's name in posts as often as you can--- but it won't work----
MSL
Guys, if you want to argue about stuff from another forum, do it there, not here.
alexg said:
The 'compact' version of Yeo's that you tried--- how did you tie down the cathodes? which output tubes did you use?
Your the first person I've heard who has tried both ways. And I find it encouraging that you liked the results of each approach.
Next week I'm stacking some remaining Z-565 coils that I have--- pp guys for EL84's with UL taps--- I'm going to have to try the compact myself after admiring it for such a long time on paper.
Did you try Yeo's circuit with the EL-84 triode as the voltage amp?
If so--- was it quiet enough? Other feedback I've gotten from people is that the EL-84 T is noisy when used as a small signal
driver tube.
In terms of simplicity--- the compact is hard to beat. And if your on a budget at all it would seemingly also recommend itself highly.
msl
- Status
- Not open for further replies.