Need Help with scratchy volume knob on headphone amp

Aug 21, 2019 at 11:38 PM Thread Starter Post #1 of 11

JBThazard

Head-Fier
Joined
Jun 29, 2011
Posts
77
Likes
27
I have the Maverick Audio Tube Magic D1+ and for a while now the volume knob creates a crackling or scratching noise when I turn it. I tried a lot of different advice, like turning the knob with the amp off or opening up the case and dusting it out, but none of it has worked.

I think the problem is more structural as I've noticed that the little plastic base inside the amp where the knob is connected to is a little wobbly. The volume knob itself is also a little wobbly, so I think that the scratching noise is being caused by the knob coming into contact with something it isn't supposed to.

Any advice on what I should do? I haven't tried contact cleaner but I don't think that will help. I don't know how to remove the knob from the amp so advice on doing that would be great as well.
 
Aug 22, 2019 at 7:23 AM Post #4 of 11
Haven't tried any contact cleaner, I want to unscrew the knob from the Bk100 and see if I can clean it or screw it back into an optimal position
The symptom definitely sounds like a dirty contact .
 
Aug 22, 2019 at 12:14 PM Post #5 of 11
The symptom definitely sounds like a dirty contact .

So I borrowed some contact cleaner from a neighbor and try to see if that fixed the issue but it didn't. I think there's less of a "static" sound now but the crackling noise still happens when I twist the knob, still looking for someone to teach me to remove the knob and get to the bottom of this
 
Aug 22, 2019 at 6:47 PM Post #6 of 11
So I borrowed some contact cleaner from a neighbor and try to see if that fixed the issue but it didn't. I think there's less of a "static" sound now but the crackling noise still happens when I twist the knob, still looking for someone to teach me to remove the knob and get to the bottom of this
How did you apply it? Did you take the case top or how else it comes apart off ?
 
Aug 22, 2019 at 7:03 PM Post #7 of 11
How did you apply it? Did you take the case top or how else it comes apart off ?

Yes, I removed the top lid of the case and sprayed the cleaner around the BK100 connector thing that's attached to the knob. I noticed that some static was reduced so it definitely cleaned something out, but I still get that right channel cut-off or the scratching noise while turning in certain spots
 
Aug 23, 2019 at 10:12 PM Post #8 of 11
Try changing the tube. What you describe can be a dirty volume pot. However, it can also be the tube oscillating. With a tube in the circuit, oscillation very often sounds the same as a dirty volume pot.
 
Aug 23, 2019 at 10:43 PM Post #9 of 11
Try changing the tube. What you describe can be a dirty volume pot. However, it can also be the tube oscillating. With a tube in the circuit, oscillation very often sounds the same as a dirty volume pot.

I see, never considered that. I've had the same tube for about 3-4 years now, could it be getting too old? I was actually planning on upgrading to a Tesla 6CC42 pretty soon
 
Aug 23, 2019 at 11:14 PM Post #10 of 11
I see, never considered that. I've had the same tube for about 3-4 years now, could it be getting too old? I was actually planning on upgrading to a Tesla 6CC42 pretty soon
Yes, it could be getting old. However, you should always have spare tubes to check symptoms you may notice in the life of an amp based on tubes.

Don't buy a really expensive tube thinking that may solve the problem. You may be disappointed. I simply pointed out another cause of a scratchy volume pot. We're all still just guessing.
 
Aug 23, 2019 at 11:15 PM Post #11 of 11
A scratching sound often results when adjusting the volume knob if there is some DC offset voltage present. Not so often just a dirty pot. Try a different tube and see what happens.
 
Last edited:

Users who are viewing this thread

Back
Top