clean channel problem

[Sevenstringer]

FIXED

 

[Elpelotero]

Just going to poke around some...

Are the pots/knobs physically damaged? Have you tapped the tubes with a pencil to see if they make noise? Have you tried a new cable? Does your guitar use batteries?

BTW, be careful when you "poke" around inside the amp. You can get electrocuted.

Hopefully someone with a similar problem can help out.

 

[Sevenstringer]

None of the pots are damaged
I have replaced the tubes and
I am using passive guitars, several guitar cables(only happens on clean channel.....would be on both if either of those was an issue)

 

[Elpelotero]

None of the pots are damaged
I have replaced the tubes and
I am using passive guitars, several guitar cables(only happens on clean channel.....would be on both if either of those was an issue)

Ok. But remember that new tubes can be affected, too. Check the Mesa diagram as to which preamp tube affects the clean channel and give that one a few pencil taps. If it makes a horrid loud noise, it's the culprit.

 

[3124+]

Maybe the LDRs?

 

[shredding]

Here do a quick test for me. Can you switch the orange channel to "more gain" in the back? Does the problem still exist? IF not I can narrow down the problem to a few resister/capacitors.

I've been studying this 2 channel schematics for a whole day today to track a humming issue on the clean channel.

Let me know.

 

[Sevenstringer]

..........

 

[snapascrew]

my neighbours dual rec had this problem. we tried firecrackers in the fx loop (put them in then light) and it seemed to make things worse :shock:

 

[shredding]

OK test complete
Happens in any mode on Ch 1
IE bold/spongy, vacuum tube/diode, clean/hi gain
Any help is MUCH apprciated. I appreciate all you guys have done for me thusfar

It's much more complicated in that case.

The following LDRs (and its functions) are different between the red and orange channels:

LDR 5: select Red gain pot
LDR 6: select orange gain pot
LDR 8: select Red tone caps
LDR 9: select orange tone caps
LDR 14: select Red master pot
LDR 15: select orange master pot

That being said, do you have a scratchy orange gain pot or master pot? Do you have scratchy tone pots on the orange channel? If not, it might be the orange tone caps, which are C5 (500 pf), C25 (.02), C26 (.02)

You can take it to a tech and ask if it's the problem.