Peavey Artist VT Reverb Hum

[misterc57]

I need help to figure out where this hum is coming from. Sounds like a ground hum.

Reverb works fine. When I toggle on the foot switch to turn reverb on I get the hum. Intensity of hum kind of aligns with the reverb pot.

Thank you! Mark

[Enzo]

Disconnect the reverb pan from the cables. Any help? Disconnect the cables from the amp chassis. Any help?

[misterc57]

Disconnect the reverb pan from the cables. Any help? Disconnect the cables from the amp chassis. Any help?

In both cases, still have hum. Reverb pot at zero is no hum, turn the pot up and hum increases.

[Enzo]

So the only thing in the circuit is U6 and U16. Is ther DC voltage on pin 1 of U6? Pull U6 from its socket, still hum? Is there DC voltage on pin 1 or 2 of U16? Pull U16, still hum?

[52 Bill]

Make certain that the tank is mounted with the output side as far away from the power transformer as possible.

[misterc57]

So the only thing in the circuit is U6 and U16. Is ther DC voltage on pin 1 of U6? Pull U6 from its socket, still hum? Is there DC voltage on pin 1 or 2 of U16? Pull U16, still hum?

DC voltage on pin 1 of U6 = 0.0 VDC
Pull U6 from its socket, still hum? No

DC voltage on pin 1 or 2 of U16? 1 = 0.0 VDC, 2 =16.7 VDC
Pull U16, still hum? No

I notice a tiny amount of play on the U16 socket (maybe some solder issue). Whereas the U6 socket had none.

Should I monitor for noise at U6 input and output pins?

Thank you. Mark

[misterc57]

Make certain that the tank is mounted with the output side as far away from the power transformer as possible.

Will do. However I have the noise with or without the tank connected.

[misterc57]

Here is the latest.

Only have noise when reverb is at 4 or higher. Noise increases and becomes more apparent as reverb pot increases towards 10. This noise is independent of input volume settings. I am starting to wonder if it is just a normal or noisy reverb circuit.

U6 (not U16) socket felt like it had some play in it. Inspected backside and all solder joints are clean and tight. Maybe the play (which is very slight) is in the socket itself.

I swapped both U6 and U16 with other ICs on the board. No changes.

I also noticed that the reverb only works when using the bright channel, not the normal channel. Is this by design?

.

[misterc57]

Here is the latest.

Only have noise when reverb is at 4 or higher. Noise increases and becomes more apparent as reverb pot increases towards 10. This noise is independent of input volume settings. I am starting to wonder if it is just a normal or noisy reverb circuit.

U6 (not U16) socket felt like it had some play in it. Inspected backside and all solder joints are clean and tight. Maybe the play (which is very slight) is in the socket itself.

I swapped both U6 and U16 with other ICs on the board. No changes.

I also noticed that the reverb only works when using the bright channel, not the normal channel. Is this by design?

.

Glad to see our database is back!

I am no longer wondering if the noise is normal. It cannot be. Any more thoughts, suggestions on this?

Thank you

[misterc57]

Video showing problem... https://youtu.be/4GMdERQDu88

[Enzo]

So it makes reverb and also hum. Pull teh pan from the cab and move it as far from the power transformer as the leads will allow. ANy help?

[misterc57]

This has been a moving target. I found a problem that needs attention. If I move the connector cable around, the output cable makes noise. Also I seem to have intermittent reverb.

I think it is because of a poor connection inside the 4 pin white plastic housing (see pic).

How can I rework the connections inside this 4 pin connector? Is there a procedure to push them out, fix, and put them back inside its housing?

Thank you.

[Enzo]

Unless the crimp has failed, don't push them out. (They make extractor tools for that) The females are the ones that get loose, so treat them like tube socket pins. I use a pointed object, and push it down between the pin and the housing wall to tighten the circular pin grip.

[misterc57]

It looks like the crimp is the issue. Suggestions? Thank you

[Enzo]

Get an extractor tool, remove the offending pin, get a new pin and crimp it on.

Or

Cut off the connector, and put new crimp pins on the wires and push them into a new housing.

Or

Cut off the connector, bare the wire ends, and solder them to the pins on the board.