Does the volume control effect sound quality?

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.

Almost all rotary switches have a stiff disc wiper made out of a different material to the springier metal that the leaf/leaves are made out of.

'Almost all' *but not* all. I can think of several off the top of my head that use similar metals and some of those are not even 'high end' parts.

This is for a control going in a PAS-3 or similar circuit. If the values are not observed there will be a price paid in the form of bandwidth.

Hey Dracule1

Never had a problem with miller effect and inductive volume controls. Mainly because with an autoformer, worst case is at full volume when the output impedance of your source drives the miller directly. As you attenuate the autoformer transforms the excess voltage into current so things just get better. I have seen situations where an autoformer actually extends the bandwidth of a device over a resistive based attenuator because of its ability to increase drive as you attenuate to better deal with things like miller and cable capacitance.

dave