Does the volume control effect sound quality?

Yes you are right with these TVC's as well, they do also have inductances, have you ever seen what happens to 20khz square wave through them, they can either ring their brains out or be severly bandwidth limited. What goes in doesn't come out unscathed in nearly all ones I have tested on the bench.

Cheers George

I'm sure the signal is not as well preserved as resistor attenuator or LDR units. But music isn't composed of square waves and I don't make a of habit of listening to 20 kHz square waves. I have heard your LDR unit and like it a lot, but you don't sell a kit that can be installed in an amp..have you considered it?

No but it's what all and I mean all audio desigers use, it's a good indication of if what your looking/measuring at is as close to a "piece of wire" nothing added or taken away, and all designers use these non musical wave forms to see what's going on.
No I don't do kits but here I show all how to build one themselves.
http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp.html

Cheers George

10K square wave on every tap (unloaded) of one particular inductive volume control.

http://www.intactaudio.com/forum/files/slagleformer_558.gif

Same test on another popular inductive volume control.

http://www.intactaudio.com/forum/files/0db_129.gif

So yes I have seen the high frequency performance at 10K of a number of inductive volume controls. My take is you cannot lump them all together.

Understanding the nature of square waves, moving to 20Khz in frequency would tell you the same about one and less about the other. Moving to 1Khz would still tell you the same story about far and far more about the other.

dave

Hi Dave, thanks for posting the square waves. Have you ever had any complaints of frequency response loss due to Miller effect (raised by Atmasphere) from using your autoformer volume control at the input of an tube amp? Apologies to the OP if this is too off topic.