Does the volume control effect sound quality?

The oringal question was not so much about his Dynaco preamp for showing up the differences in volume control sounds, which will be magnified to a larger extent with higher rez amps.
But the reasons why they sound different! And why he was not imagining things.

Cheers George

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.