Balanced vs Unbalanced?

Ralph, thanks for the excellent comments and explanations. FWIW, I am in complete agreement.

I would just add the thought that in principle it is certainly possible to use active devices, as alternatives to the transformers you mentioned, to fully achieve the benefits of balanced interfaces with designs that are not balanced internally. However, as you indicated most examples of that approach are not in compliance with the 600 ohm standard and/or are poorly implemented.

Best regards,
-- Al

I would like to point out that it's not all lollipops and roses. One unmentioned difficulty is that for everything to work as designed you have to have a circuit capable of producing 2 signals that are exactly the same except for their polarity. I agree that using a differential circuit makes it easier but there are still a lot of things that can cause an imbalance. If there were not the CMRRs achieved would be much higher than they are.

The other problem I see with Atmasphere amps is the OTL output. Ralph has done an admirable job of overcoming the stability problems experienced by earlier designs but I don't think you can overcome the inherent problems caused by paralleling a bunch of tubes and using them in a push-pull circuit. I have no explanation but cathode follower amps have never sounded as good to me as common cathode.

I have 3 directly coupled triodes and an output transformer between my source and my speakers which I believe leads to much better sound than you can achieve with a more complex circuit. Of course, if anybody wants to send me an OTL amp to try I would be happy to entertain them.

While I do agree with Ralph's explanation of the technical side of things I disagree that this leads to circuits that sound better than an SET, but of course this is a debate that cannot be won on either side.

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06-01-10: Sidssp
IMHO, SETs are distortion generators. They can make a Yamaha violin sounds like a Stradivarius.

So can poorly designed/executed push-pull circuits(tube & solid state). Well designed/executed SE circuits in properly associated systems can also make Stradivarius sound like Stradivarius. The same can be said for most other well designed/executed circuit topologies.

Sidssp, There are many forms of distortion. SETs are the most linear devices on the planet. How does that equate to distortion generator? I lived through the distortion wars of the 80's where we ended up with vanishingly low distortion on amplifiers that would make your ears bleed.

The problem with SET amps, low power. The solution, highly efficient speakers.

Good source + triodes + good horn speakers = bliss

Sitting with a smile on your face and your toes tapping or dancing around the room are the defining factors. Audiophile nerds who sit frozen in one spot, never moving, never physically reacting to the music, discussing how black the background is and how much air there is around the instruments have so completely missed the point that they are hopeless. I hope you aren't one of these nerds.

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