Passive Bi-Amping with Different SS Amps

You need to add a potentiometer to lower the signal to the lower gain amp, the McCormack.

Where can I purchase a potentiometer suitable for this?
Will it degrade the sonics of the Mccormack amp?

1. You can buy a stereo audio-taper pot from The Parts Connexion (http://www.partsconnexion.com/catalog/controlsswitches.html). 10K should do. There are many other sources.

2. Unlikely if it's a decent pot.

Hello Daltonlanny -

Kr4's answer is essentially correct - you need a way to turn-down the input level on the higher-gain amplifier to match the level from both amps. The gain difference is only 2dB, but this is still enough to throw-off the coherence of the speakers. The problem is the one we always have to face: if you add anything to the signal path, it may affect sound quality in some way. But, if you use good parts and cables, the loss should be minimal.

I suggest that you take a look at the Axiom passive preamp for sale here on Audiogon. It looks like a good basic level control at a very reasonable price, and it will save you the hassle of trying to build your own.

Please give me a call if you would like to discuss this further.

Best regards,

Steve McCormack
www.SMcAudio.com