Tube Amps with Balanced Inputs

Check out Atma-Sphere amps. SE, OTL's, will probably give you the sound your looking for in spades, with good bass response as well. Fully Balanced. Just my opinion, hear them for yourself. Highly recommended. Happy Listening.

A true balanced amp processes the inverted and non-inverted components of each channel of each balanced input through seperate circuits (including discrete volume control sections). The amp responds to the difference in signal across the inverted and non-inverted components.

SET amps are just that - single ended. By definition they cannot process seperate inverted and non-inverted signal components since there is only one signal path. To properly (note the word "properly") handle a balanced input an SET would have to supply fron end circuitry to invert the inverted component and add it to the non-inverted component to yield a single ended signal for the remainder of the SET to process. This circuitry would be more complex than the SET itself and is most easily implemented by an op amp, though it could be done with tubes. Either way you've lost the minimalist philosophy that is one of the appeals of these amps.

If you must use balanced inputs then use an adapter. Typically these connect only the non-inverting signal component to the single ended input, thus destroying the key technical advantage of balanced connections: interference rejection.

Mcfarland,

Thanks for the tip. I'll take a look.

Ghostrider,

Ah, I hadn't thought of that. I'm running long interconnects to the amps, and it seems running balanced from the preamp to the amps is considerably less noisy than with a single-ended connection.

I don't think a true 'balanced' output is possible with a single-ended amp. George Wright's Mono 10 amps use a pair of 2A3's in Push/Pull and are one of the closest things to a SET sound I've heard from a P/P. Great little amps, but don't know what you are specifically looking for (price range, power, system matching, etc). The Mono-10's have both balanced and RCA connections and were wonderful amps in my system.

Marco

Jax,

Thanks for the tip. I don't know anything about their amps, but the price is certainl right. Basically, I'm currently using AES (Cary) Sixpac Amps (with KT-66 tubes), and just switched to Zu Tone speakers, which are very sensitive (claimed 101db). I'm using a BAT VK-5i, which is a balanced preamp, and thought of switching amps to try to get that SET magic I keep reading about. I really want to stay fully balanced, which was the reason for my post to begin with.

You mentioned that these sound close to SET amps. What amps have you compared them to?

- Stew