Static from C-40 preamp using vol. knob or tape buttons cause?

marsblk

New Member
Good day to you all on AK.

I am in need of some help with a newly acquired C-40 preamp...the person who sold it to me put a note inside stating "to ground the C-40 to a 'good earth' ground" if I hear static coming from the volume knob.

I hear static a little bit but not all the time when I was turning it up and down or wiggling it a bit...I noticed the tape 1 and tape 2 buttons made a small static noise too when I was just pushing and testing all the buttons as I just got it.

This has been recapped and it running very nicely (IMO), but I just want to ask (as I am very new to audiophile stuff)...is where to I run this 'good ground' to? I see there is a ground bolt for the TurnTable but my power amp does not have a ground screw on it?

I do not think I will be touching the volume much and it is a bit minor but I wanted to ask you guys if there is an issue that this static causes or if it is even somewhat normal?

Thank you all in advance!
 
Welcome to AK mars
.the person who sold it to me put a note inside stating "to ground the C-40 to a 'good earth' ground" if I hear static coming from the volume knob.
Boy is he trying to blow smoke up your wazoo.
The volume control is dirty and needs a good cleaning. I use CAIG Deox-it products.
The switches are dirty as well. Those may be a bit more difficult to clean> I frequently have to remove and disassemble most switches and controls.
 
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The volume control is not dirty. It has been deoxited to the nines. There is static in the control that immediately disappears if the case of the unit is grounded. Run a wire from the chassis to the screw on a standard wall recptacle and the static disappears.
 
Have you tightened the nut that secures the volume/loudness control to the chassis?
I know poor physical contact can cause noise in some amps.

I've got a C-40 here and there's no noises when using any of the buttons or knobs so I can tell you it's not normal.

Could be a bad solder joint somewhere, maybe worth looking over the boards including the volume one.
 
The volume control is not dirty. It has been deoxited to the nines. There is static in the control that immediately disappears if the case of the unit is grounded. Run a wire from the chassis to the screw on a standard wall recptacle and the static disappears.
Then its likely a poor ground solder connection within the pre-amp.
 
Then its likely a poor ground solder connection within the pre-amp.

Possibly. I always reflow solder points on ground connections when doing a general recap. The grounding wire tip does work and completely silences the static - hopefully the OP tries this out.
 
It may quiet it down. But.. Its just masking the issue at hand. The C-40 has a 2 - prong plug and was not intended to be "earth grounded". Otherwise it would have had a 3-prong plug. The binding post on the rear panel is intended to connect your TT grounding point.
 
You say it's recapped.

Perhaps there is a bad solder joint in that work.
Some people can't solder worth a damn.
 
Sorry for the delay in response guys, looks like I am out of luck on trying to figure this one out even though minor I try to go to the great site to find some insider info.

I rarely use my system right now, but I thank the seller for being on here and everyone else for their thoughts. If we were not on Earth we would not need this "ground"...bad I know but it goes with my 'handle'!!!
 
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