Does the volume control effect sound quality?

Hi Dave, thanks for clarifying my confusion. I have your autoformer preamp(Bent Audio TapX), which competes with some of the best preamps out there (both active and passive), as long as you keep the interconnects short and impedances appropriately matched. However, I think an autoformer will work even better installed directly in the input of the amp, as I have found with resistor stepped attenuator.

Atmasphere, I am not talking about a preamp. I'm talking about a stepped attenuator or autoformer in the input of a tube amplifier. I have a stepped attenuator in my amplifier, and this configuration sounds better than any preamp I've had in my system. Now, I want to try a autoformer in my amp.

The Atma-Sphere M-60 amps are available with a volume control upgrade that IIRC is implemented at the amps input. Pretty sure it is a stepped attenuator as well.

Yes, VC upgrade in M-60 are stepped attenuator using Caddock resistors, I think.

Funny, the original poster is absent on this thread. My comments have been directed to the issues raised in his post.

To that effect, George, I think you are mistaken- this was indeed about the Dynaco PAS-3 and the installation of a replacement volume control.