Bugera V22 Issue

[dorrisant]

I have one on the bench. I changed out the tubes... One power tube had shorts. Replaced the screen grid resistors. Voltage all look normal. It plays, all controls functional, but the volume is a bit low and sounds like poo, especially when the master is turned up past half... worse as it goes up. Both channels same crapiness. Spitty and blatty... Switch the power off and it instantly sounds fine and loud. That is until it drains the caps a bit and fades out.

I checked for bad solder joints, touched up a few but nothing noteworthy. Bias seems to be set fine (it is adjustable on this 2x EL84 amp). Schematic looks suspiciously like a Classic 30 with two tubes. No fun to diagnose due to component side of the board being hidden (upside down).

Just wondering what you guys think...

Tony

[pompeiisneaks]

You could see if this looks like the schematic:

http://www.tremolo.pl/Firmowe/BUGERA/Bu ... ematic.png

You could see if its the preamp or power amp by putting a signal into the effects return, or sending the preamp out to some separate power amp etc. something to see where the poop is happening.

~Phil

[Stevem]

Have you looked at the output wave form?
Pull out one output tube at a time and I bet that you will find that removing one of them does not change the issue much!

[dorrisant]

Phil, already tried that... It seems to be post FX loop.

Steve, I haven't tried that but will as soon as I get it back on the bench.

Thanks guys, I will report back soon.

[jhaberly@gmail.com]

I'm interested in how this turned out. I have a Bugera V22 Infinium to repair. One of the tube fault LEDs goes on and there's no sound. The "Infinium" bias circuitry is obviously finding an issue.

Anyone seen any schematics or know anything about these?

Thanks!

[dorrisant]

Turned out to be a broken connection from the OT to one of the plates. Soldered the plate leads to the socket pins and all is well. The owner tells me how much he loves it every time I see him.

[jhaberly@gmail.com]

Thanks for the info.. These are nice sounding amps! I'm having trouble finding info. on any differences in the Infinium version. I have the available V22 schematic (original non-infinitum). The Infinium amp I have looks to be the same or very similar but the component designators have all been renumbered. I see 202 Volts at the plates (+A) which is far below the 348V seen on the original V22 schematic. This is also the case with all tubes removed. I can get sound out of the amp but the fault lights start blinking then it cuts out. It's very unstable. I'm testing with an audio source plugged into the affects return.

Do you know by any chance if the power supply voltages are different in the Infinium version with that auto-bias circuitry?
Any thoughts greatly appreciated.

Cheers!
Jim

[dorrisant]

I don't know of any difference, but keep in mind I never had the Inf version on my bench.

Also, I confirmed that one I had on my bench is exactly the same as a Peavey Classic 30. If you are showing that low of a voltage with no tubes in, there is something very wrong in the power supply. Test further and post results, we can figure this out.

[Stevem]

Bad power tube and crap out of both channels? My money's first off is on a shorted primary in the OT, or a bad plate resistor in the PI section.

[Roe]

Turned out to be a broken connection from the OT to one of the plates. Soldered the plate leads to the socket pins and all is well. The owner tells me how much he loves it every time I see him.

same issue on the amp on my bench - thanks for the info!

Edit: problem did not go away here

[Roe]

I have one on the bench.... Voltage all look normal. It plays, all controls functional, but the volume is a bit low and sounds like poo, especially when the master is turned up past half... worse as it goes up. Both channels same crapiness. Spitty and blatty... Switch the power off and it instantly sounds fine and loud. That is until it drains the caps a bit and fades out.

I checked for bad solder joints, touched up a few but nothing noteworthy. ..

Just wondering what you guys think...

Tony

Same problem here. The problem keeps reappearing. Any ideas?

[dorrisant]

Turned out to be a broken connection from the OT to one of the plates. Soldered the plate leads to the socket pins and all is well. The owner tells me how much he loves it every time I see him.

[Roe]

Turned out to be a broken connection from the OT to one of the plates. Soldered the plate leads to the socket pins and all is well. The owner tells me how much he loves it every time I see him.

Tried it but it doesnt work here unfortunately

[Roe]

It was the OT primaries that was the problem. The problem comes and goes as you move the primary wires. Am thinking of opening the OT

[lmstudio]

Hi guys, I'm just an owner of a Bugera V22 Infinium. Since I bought it, it burns the power tubes very fast.

Usually, after 15 min playing, the orange front light starts to flash. Also, one or 2 of the tube replace lights are on. I've sent it to 2 techs already and they can't solve the issue. Does this happens to you as well? Any ideas? Thank you.