Help with troubleshooting...

[TremoJem]

Tremoverb is acting odd.

I strum the guitar and then palm mute all strings to silence them.

The amp produces a low hum, almost like fan or rumbling noise and then stops.

I continue with the strumming and palm muting and inspect the power tubes.

All four look good and do not react to a pencil tapping them individually.

Any ideas, other than looking at the preamp tubes.

I am in Bold and Silicone Diode mode.

 

[vick1000]

Try another guitar, cables, eliminate any other variables such as pedals, etc...

Could be a microphonic preamp tube.

 

[ryjan]

I had a similar problem with a Splawn Nitro.
Turned out to be power tubes.

 

[TremoJem]

Thanks.

Very true...eliminate everything and go direct from guitar to amp.

No FX loop...no pedals in front.

All good tips.

I literally just recently as last Friday changed to Silicon Diode/Bold...so that I could get really clean cleans. I even cloned the Orange channel to be Red, for more headroom.

The cloning did not really add a better clean as much as it removed the blanket from the tone.

 

[ryjan]

Is it a rumble noise like you brushed against a live mic? That's the best way I can describe the noise I had.

 

[TremoJem]

Yes, kinda like that.

 

[domct203]

Sounds like a microphonic tube. This is a combo right?

Dom

 

[TremoJem]

Yes it is.

 

[domct203]

Do you still have both combo's?

If so plug your guitar into the "good" amp, then plug it's FX send into the "bad" amp's FX return. This will bypass the "bad" amp's preamp so if the noise is still there it is most likely Powertube related. If the problem goes away, it is most likely Preamp tube related (which you can test by hooking everything up vice-versa).

Good luck,
Dom

 

[TremoJem]

Yes, I do.

Thanks, I will try that.

 

[TremoJem]

I swapped (power) tube pairs with each others position.

This seemed to work. I have not had a chance to run it thru the riggers of a practice session, as I had other responsibilities, but hope to really test it tonight.

Thanks.

 

[TremoJem]

Everything is working great.

Thanks for the help.

 

[domct203]

Everything is working great.

Thanks for the help.

Great to hear it!

What was the root cause of your issues?

Dom

 

[TremoJem]

Must have been poor connection.

All I did was swap inner set with outer set.

The act of removing and re-inserting must have cleaned up the poor contacts.

What is odd is that I bought a can of the expensive contact cleaner "DeOxIT" and cleaned both Tremoverbs, only six months ago.

I cleaned all pots and ALL sockets (tube).

So go figure.

 

[domct203]

I would be more inclined to think that the powertube socket contacts are loosening up.

When you used the DeOxIt, did you insert a tube in & out a few times? While this is the correct way to use the DeOxIt it is also a good way to spread those contacts open if you are not careful.

Dom

 

[TremoJem]

Yes, I did the "in & out" method...very carefully.

I should be able to disconnect power, remove tubes and then gently persuade the sockets to be a little tighter.

But, I won't mess with this until absolutely necessary.

Yikes...I just googled this and I guess you have to "discharge" the caps. HOW??? Back to google.

Geez, according to goolge, I was supposed to discharge the caps when I cleaned the sockets. What the...?

Your thoughts?

 

[domct203]

ALWAYS, ALWAYS, ALWAYS check and discharge stored voltage from the PS filter caps. It's more an issue of personal safety than anything else. The voltage potential is enough to be lethal.

You probably didn't do the amp any damage, if that's what you are worried about.

Dom

 

[TremoJem]

Yes, you are right. I need to get a pic from this forum and make sure I am identifying them correctly.

Do you have a suggested resistor value to use inline to ground?

I believe the caps lined up in a row at the end of the board by the cloning switch are the ones. In any event, if I grab the hot leg from the last one in that series and connect to gnd with a resistor in series, it should take care of the entire unit...right?

 

[vick1000]

You don't need to worry about discharge when using a tube to work the socket clean, just when you want to tighten up the contacts. You do not need to open the amp to do this, just use a mulit meter set to read DC voltage, and put the red probe in pin 3 of a power tube socket, and the black to a ground point. Pin 1 is the first clockwise hole from the key notch, they accend clockwise in number from there. Make sure the meter reads below 9v before proceding. You can also make a tool to discharge by putting a high Ohm resistor in the pin 3 to ground circuit. Use probes, and put a resistor between them.