My son is just building a 2A3 PSE kit ( http://www.worldaudiodesign.co.uk/wadproducts/2a3.html ) and, by way of comparision, I want to build a push pull 2A3 amplifier.
Can the members suggest any good designs I should consider basing my design on. I am very impressed with Lynn Olsens approach but haven't really reasearched modern thinking on push pull designs - my last effort was 25years ago and ultralinear pentode based!
All advice gratefully recieved.
regards
James D.
Can the members suggest any good designs I should consider basing my design on. I am very impressed with Lynn Olsens approach but haven't really reasearched modern thinking on push pull designs - my last effort was 25years ago and ultralinear pentode based!
All advice gratefully recieved.
regards
James D.
Hi James,James D. said:
Lynn's work is excellent, thorough and highly recommended. PP amps seem to be spurned at the moment, mainly by the rabid setheads who don't know that topologies other than pentode/UL Williamsons exist, so there isn't the energy going into refining the topologies in the same way as set. Pity as IMO/IME PP can have all of the benefits in clarity of a set with none of the distortion and bandwidth limitations, and op points that roam around with load variation.
A simpler SE-IT-PP DHT is the Ralph Power amplifier discussed in a thread here previously.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=2604&highlight=ralph+power
I read elsewhere that Garry Dahl designed the first version of this amp and gave it to Ralph. If you've looked a Lynn's site recently, you'll see he and Gary are friends, with those really nice Aurora's on Lynn's page being Gary's units. For much more info on this design, as well as Lynn's amps, do a search on Audio Asylum, especially in the various tube forums, for post on Ralph Power/Amity/Aurora and under Lynn Olson and gdahl monikers. Tons to harvest there.
I have a PP - IT - 813PP (trioded DHT) amp under construction, very similar in many ways to Lynn's amps (inspired by them) and good for maybe 50W
Cheers
Hi Brett,
Many thanks for the pointer to Audio Asylum. I hadn't checked there.
The Ralph power is interesting but I'm a sucker for the balanced throughout design. I found out with SS designs that pp is much better when full symmetrical all the way through...
BTW I have been playing with the idea of running the output slightly unbalanced (just to contradict the previous statement I made!) - since no real stage is fully dynamically balanced - is it possible to make a virtue of it and re-introduce some even harmonic distortion and lower the odd harmonics at the same time. It's a tempting thought and I've got Swoter to quote me on some pp OPT with up to 10mA of unbalanced d.c.current through them...
Your 813pp sounds a bit of a beast
Hope you enjoy it lots!
Ciao
Many thanks for the pointer to Audio Asylum. I hadn't checked there.
The Ralph power is interesting but I'm a sucker for the balanced throughout design. I found out with SS designs that pp is much better when full symmetrical all the way through...
BTW I have been playing with the idea of running the output slightly unbalanced (just to contradict the previous statement I made!) - since no real stage is fully dynamically balanced - is it possible to make a virtue of it and re-introduce some even harmonic distortion and lower the odd harmonics at the same time. It's a tempting thought and I've got Swoter to quote me on some pp OPT with up to 10mA of unbalanced d.c.current through them...
Your 813pp sounds a bit of a beast
Hope you enjoy it lots!Ciao
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