balanced preamp

Atmasphere, If preamps are balanced and differential then at the spot where summing takes place (input of power amp or speakers) common mode interference will appear as signal. For instance, if one leg has gain of 30 and the other gain of 30.3 than your gains are mismatched 1% meaning your CMRR is limited to poor 40dB and 1% of junk goes thru. We can take for comparison input module in my Rowland 102 with THAT1200 instrumentation amp (instead of transformer) with CMRR=85dB (DC-20kHz).

Many people like warm sound. Removing even harmonics might not to be to their liking. Main beef is with odd harmonics that are left intact (perhaps not big problem in tube amp).

In case of your amplifiers - power supply has to be way heavier while number of tubes and output transformers and expensive capacitors doubles, chassis gets much bigger etc. It should cost a lot more. Your amps are state of the art and might not meet objectives of typical person (most bang for limited bucks).

Kijanki, we don't have any output transformers so we don't have that expense anyway...

Is it me or is 85 db a poor CMRR figure?

Like I said a lot depends on an effective CCS circuit. I have to say I am quite surprised to see how poor they are in most differential circuits I see. Poor CCS leads to poor CMRR response! You can't do it with a single-stage CCS...

Dsremer,

"I have tried my P.S.Audio PW DAC 11 via the Balanced out directly to the M.L.336 and was impressed with the results, I do not want to take a step back the First Sound pre does a lot of things right.."

Theres absolutely nothing wrong with wanting to go balanced. Most of my components are. After reading your above post, though, I can't help but think that there is a lot more going on as to why you are hearing differences besides the PS Audio being balanced. The 2 units are very different from each other in many ways. I'm just suggesting that there are other factors that make them sound different besides being balanced.

Not only cost of tubes but they also require more power.

Where are you going with that?? That does not have anything to do with CMRR... and is not accurate. The tubes we use are not expensive, and usually cost less than a set of tubes for a transformer-coupled amp of the same power.

From your other comments though it really sounds like the circuits you are used to measuring have poor CCS circuits. 85 db is not a hard figure to attain.