Two amps broken in 30 minutes... help with diagnosis?

[Fifth_Horseman]

Hey guys,

today at band rehearsal I had more bad luck than in the previous five years combined, as not one, but TWO amps gave up on me today... and I'm having a gig on friday.

First was my ENGL Fireball, that one already didn't work correctly when I switched it on (worked fine last week, nothing changed at all since then).

There's still sound coming out of it, but only at a fraction of the normal volume. Preamp still works, as I could change between clean and distorted and the sound is pretty much as normal, master volume does change the volume, just the overall volume can't get much higher than speaking level on maximum. No sound pressure.
I had my GT-10 hooked up in 4-cable method, but same problem direct in. I tried different cables, a different cabinet, different guitar, same problem.

The tube malfunction LEDs didn't light up, tubes look normal.
I actually also had replacement power tubes with me and put them in, that also didn't make any difference.

So that was the first one... anybody got an idea what could be wrong?

Well, I then gave up on the Fireball and plugged into the Peavey XXL which belongs to the guitarist of my other band.
Worked normal at first, after one song the sound suddenly completely disappeared.
However this time the power stage does still work... with the GT-10 bypassing the preamp of the XXL I could still get normal sound and loud volume.
Just the preamp didn't work anymore (only quiet static noise), also tried going direct in.

Now the most important question: Could there be any reason for that other than massive bad luck? Bad power, wrong current from GT-10, anything that could do damage to the amps? I'm kind of afraid of borrowing another amp and using it with the same equip/in the same room...

I'm lost here because IMO something like a power spike from the outlet should blow the fuses of the amp... bad impedance from the cab should maybe cook the tranny or something, but those still work.

Ah well, I'm trying to bring it to a local store tomorrow and have my favourite guitar tech look at it... hope he knows amps as well as guitars.

BTW, when I came home one of the light bulbs in my room flickered for a few seconds... damn I'm scared now.

 

[colonel kurtz]

you think that's bad? i once killed a 5150 and triple recto in about 10 minutes.

that was last time i plugged that guitar into ANYTHING

 

[53Crëw]

With the Engl, it could be a preamp tube. Swap them out one at a time with a good spare and try to isolate the bad tube.

Generally speaking, the most common cause of tube amp problems are related to tubes going bad.

 

[Potshot]

My 6505 suffered the same fate just the other day, I'm not sure if ENGL's are anywhere near as finnicky, but any crap in certain jacks on a 5150/6505 (fx loop, hi gain/lo gain jack, etc.) will cause similar behaviour. Initially I sprayed contact cleaner in each jack and fucked them with a cable for a bit, which failed to resolve the problem. Subsequently I removed all the tubes and sprayed contact cleaner into the sockets and massaged them back in, sprayed the jacks once more with a second round of fucking, and presto, working again and sounding even better.

So in conclusion, try contact cleaner in all jacks and tube sockets first, if no luck, take it to a tech!

 

[devouredremains]

Thats some harsh luck you guys!

This thread should be dedicated to anyone who creates false Bugera reliability claims on other forums and acts like pricier amps are invincible.

 

[DevilJaw]

no this should be to anyone who thinks there is such a thing as good electronics, they are all commodities, the cheaper to make the better, therefore more profit.

but guess what electronics are not magical, learn a little and fix it yourself.

 

[devouredremains]

no this should be to anyone who thinks there is such a thing as good electronics, they are all commodities, the cheaper to make the better, therefore more profit.

but guess what electronics are not magical, learn a little and fix it yourself.

Your right. With the exception of true boutique amp makers this is probably true 90% of the time.

 

[Wolfeman]

Your right. With the exception of true boutique amp makers this is probably true 90% of the time.

Still happens with the boutique amps too. Not as much, but more often than you think. There are just less of them out there so it doesn't look so bad. Just take a look at the Diezel forums. Shit happens, it's just part of life.

 

[Fifth_Horseman]

Thanks for the answers!

Well, I never said my ENGL is invincible, but it worked fine for more than three years, except for one preamp tube going microphonic.
However I'm pretty astonished that this shit happened twice and directly before a gig... Murphy's Law I guess.

I don't think it's preamp tube related, because I get the same problem when bypassing the Fireballs preamp with the GT-10. But I'll try the trick with the contact cleaner, thanks alot!

 

[STINNETT]

Concerning the ENGL, I've seen that happen before with a bad effects loop jack, and jumping from the send to the return with a patch cable fixed it.

Just a thought. You may have tried that already.

Edit: I just noticed you said you were using the 4 cable method - so I guess that rules it out.

 

[devouredremains]

Thanks for the answers!

Well, I never said my ENGL is invincible, but it worked fine for more than three years, except for one preamp tube going microphonic.
However I'm pretty astonished that this shit happened twice and directly before a gig... Murphy's Law I guess.

I don't think it's preamp tube related, because I get the same problem when bypassing the Fireballs preamp with the GT-10. But I'll try the trick with the contact cleaner, thanks alot!

I didn't mean that you thought your engl was invincible. It was a jab at tons of people on the Harmony Central Forums.

Everyone on this forum is great and very knowledgeable.

 

[greyskull]

mesa's break a lot too!

 

[Fifth_Horseman]

Found out they have a dedicated amp tech at the local store, who happens to be just as friendly as the other guy.
He had found my problem in minutes... a phase inverter tube gone half bad (kudos to 53Crëw, he was right). The tech put a new tube in, Fireball loud again.

I then, happy as a pig in shite, brought the amp back to the rehearsal room, turned it on, and for the first time in my life I saw how it looks when one of those tube monitor LEDs lights up... not a quiet occurence either, as the tube went with a loud pop.

Since serial murder of tubes sounds like there's some deeper problem beneath the surface, I decided not to take chances with the gig coming ahead tomorrow. So I went back to the store and bought an ENGL Invader 100. May the force be with it.

 

[AdamWathan]

Expensive solution man haha...