Volume drop on Maverick 2x12 Lead Channel

[ajhops]

Volume will suddenly fall dramatically. It has happened before but things would return to normal after a bit of a cooling off period. This time it doesn't seem to want to come back. The only troubleshooting I've done is to plug the effects out into a different amps effects in and the problem seemed to still be there.

I know I can take it to a technician, I'm just wondering if these are common symptoms for a common problem.

 

[et888]

I am experiencing the same problem only my rig is a dual rectifier and the volume usually returns to normal after a bit on standby or shut down/cool/power on again. I recently flipped the switch and tried using the silicon diode circuit to learn if the volume drop issue is still an issue. I haven't put it through but minimal time and at minimal/moderate volume but I'm leaning to the belief that the problem has been neutered or avoided by using the diode option thus The tubes are the likely culprits. (brilliant deduction I know) Anyway as you can tell I don't know **** about this subject but ............ I hope my banter helps a little and when you diagnose/remedy your issue please post as it may help others.

 

[ajhops]

Thanks for the input.

I have switched power tubes a few times but never preamp tubes. I wonder if bad preamp tubes could cause this behavior.

 

[ajhops]

one question for et888 - when you had this problem did yours occur on both channels? Since bypassing the vacuum tube rectifier fixed the problem yours must have affected both channels. Mine only seems to be the lead channel.

 

[et888]

I haven't had time to investigate my problem much or see if the volume drop affects all channels. I'm currently trying out a King Amplification Rocket 88 Head for "clean" tones so I only really been using the Recto for my "usual" and mainstay tone in the high gain nasty crunch vain. I'm going to be playin around with my rig and trouble shootin tonight. I've got new replacement Power, RECTO, and pre-amp tubes and going to do the 1 at a time swap with known good to hopefully pinpoint and rectify the cause. I'll post what I learn/outcome tonight-ish.

 

[et888]

sounds like a bad pre-amp tube (V1, V2 , V3, etc). A bad preamp tube may not cause microphonics even if it is faulty (some good tube may cause microphonics). buy some new pre-amp tubes (good to have spares) and swap the first three or all preamp tubes. you will know if your problem is related to the preamp tubes. Then swap one tube at the time with your previous tubes to determine the culprit. this way if more then 1 tube was bad you'll know and the tubes that are good are now your spares.

spax7-a, 12ax7-a or whatever your into

 

[Monsta-Tone]

I would definitely try swapping out the preamp tubes for that channel with a tube that you know is good. Not just a new one, I've seen several new tubes that were bad right out of the box.


Your manual should have a tube chart. If it doesn't, PM me with your email and I'll get you a drawing.

 

[lyman]

Your manual should have a tube chart. If it doesn't, PM me with your email and I'll get you a drawing.

I don't think the manual has a tube chart. At least not one that tells you what each tube is responsible for.

In the Maverick, the lead channel begins with V2 (the 2nd preamp tube from the right when looking at the back of the amp). Here is a link to schematics:
http://www.freeinfosociety.com/electronics/schemview.php?id=288

I haven't run into that problem so I don't have any other ideas, but checking out the preamp tubes as somebody suggested is a good first step! Good luck.