[chadh]

My current system:

SB2 with Bolder Cable's analogue mods
Space-Tech-Labs QA-001 preamp (using RCA black label 6SN7 tubes)
Channel Islands VMB1 monoblocks
Omega Super 3 XRS speakers

Typically I use the digital volume control on the SB2.  But since I started using Inguz's DRC plug-in, the output from the SB2 has dropped, and I'm having to do more adjustments with the pre-amp volume control.  What I'm finding is that I often get all sorts of pops and crackles through the system when I'm adjusting the pre-amp volume control.  More recently still, I've been getting occasional buzzes through the system that seem to disappear when I make tiny adjustments of the volume control.

What do you imagine is wrong?  Is the potentiometer just dirty?  Any chance this is a tube-related problem?

I probably should contact Albert at Space-Tech-Labs about this directly, but I'm sort of scared he'll ask me to ship it back to Canada so he can check it out.

Chad

[avahifi]

Several possibilities here:

Could be that the volume control body has a poor ground contact to the chassis (mounting hardware might not be tight enough).

Could be that the active circuit ahead of the volume control has a bit of DC offset on it.  This will definitely cause noise.

Could be as simple as dirty contacts in the control, a shot of Caig Labs DeoxIt D-5 contact cleaner may fix that.

Could also be a poor contact elsewhere (switch or cable connection) that is being disturbed by the vibrations of using the control.

Can you simplify the system down to just the suspect component and the amp and speakers to see if the noise goes away, or substitute another source for the SB2 and see if the noise stays or goes away?

Lots of things you can try yourself.

Hope this was of help.

Frank Van Alstine

[chadh]

Yes, thanks Frank.   Very helpful.  I'll try playing around with things.

Chad

[tigzstudio]

I have this exact same issue with my Qinpu 1.0x amp.

I only get cracks or pop when adjusting volume... and usually for some reason its when i first turn the amp on 9in the first few minutes of it being on and adjusting volume.... (its an integrated amp)

please let me know if you find out what is causing it.

[chadh]

Problem is now solved. A little spray of Caig's did the trick.  Albert at Space-Tech-Lab said the carbon pot in the pre-amp tends to get like this if it's not used much.  The implication seems to be that this might be a little chore that must be undertaken every few months.

Chad