#1
Started playing and after about 20 seconds, my amp (Peavey JSX > Harley Benton G212 Vintage Cab) started to make these smouldering sounds, as if something was burning and it was getting louder as I left it. Needless to say I quickly switched it to standby and then shut it off. So, anyone know why my amp was making some smouldering/burning sounds?! I'm scared....
#2
Was it just sounds, or could you smell something burning?
Spin 'round carousel when your horse isn't screwed in.

My band:
Fractured Instinct
(For fans of Death/Groove/Prog Metal)

Ibanez RGA42E
Ibanez S420
LTD H-301
Ibanez RG520
Peavey Predator USA
Douglas Grendel 725
Line 6 Pod HD500X
#4
How long have the current tubes been in it?
Spin 'round carousel when your horse isn't screwed in.

My band:
Fractured Instinct
(For fans of Death/Groove/Prog Metal)

Ibanez RGA42E
Ibanez S420
LTD H-301
Ibanez RG520
Peavey Predator USA
Douglas Grendel 725
Line 6 Pod HD500X
#5
Quote by Offworld92
How long have the current tubes been in it?

Only got it a few months ago and the previous owner swapped out the tubes a bit before. So maybe around a year?
#7
Quote by ethan_hanus
Does your cab and head have matching ohms and a pretty close wattage rating?

How hard were you running it?

Have you checked to see if all the tubes are seated properly?

Resistance was right, wasn't running it hard what so ever. I'll check the tubes.

It happened once before and it stopped when I played it again but I'm afraid to ignore it.

EDIT: Just in case, here's my cab, I have it in mono. What should the resistance be set too on my head? 4,8,12?
Last edited by conor-figgy at Jun 13, 2011,
#9
Quote by polishedbullet
The back of the cab says 8 ohm impedance, so the impedance on your JSX should be 8 as well.

Yeah I got it right....but what the hell is the burning sound?
#10
I'm not an amp tech OK? I've heard of a few similar circumstances on here regarding JSXs (coincidence) - I'll see if I can find it.

In the mean time - is it a burnt rubber smell, metal or plastic? If you are not comfortable opening up the chassis and risky shock to your body- take it to a tech and ask for a free estimate.

Something like a blown resistor may not be too bad to fix but a blown transformer or the like is not so fun. Do you remember what your 4 big power tubes looked like last?


PS: the Burning 'sound' is FFFFFFUUUUUUUUUUUUUUUUUUUUU! ok jk tnx bai
#11
Quote by 311ZOSOVHJH
Do you remember what your 4 big power tubes looked like last?

Yeah, pretty normal. No discolouration. I've no problem opening it up, what should I look for if I do?
#12
What exactly is a burning sound?

You would smell something burning before it got hot enough to make pops and crackles. Is it dirty pots? Crappy cable, bad inputs on the guitar or amp, bad electronics in the guitar, bum speaker in the amp?

Do you mean pops and crackles coming from the speaker or inside the amp itself?
Quote by CodChick


Seriously, I'm not a fan of iphones and guitars mixing.
#13
Quote by conor-figgy
Yeah, pretty normal. No discolouration. I've no problem opening it up, what should I look for if I do?

OK. Well, after you slide the chassis out and have a safe place to flip it on its side or upside down just give it a visual inspection for scarring. Don't touch anything on the inside obviously. Take pictures. If you get real brave fire it up and look at all your tubes real good.

Tip: grab the transformers when putting back in not the insides of the chassis.


here was one of the threads I was thinking of. after all the crap at the end we find out it was a blown tranny.
https://www.ultimate-guitar.com/forum/showthread.php?t=1115746&page=1&pp=20

Good biasing tutorial: (i just found an old thread of yours on biasing)
http://forums.peavey.com/viewtopic.php?f=19&t=4263&view=previous
Last edited by 311ZOSOVHJH at Jun 13, 2011,
#14
Quote by ecvMatt
What exactly is a burning sound?

You would smell something burning before it got hot enough to make pops and crackles. Is it dirty pots? Crappy cable, bad inputs on the guitar or amp, bad electronics in the guitar, bum speaker in the amp?

Do you mean pops and crackles coming from the speaker or inside the amp itself?

It's coming from the speaker. It's not the inputs, tested those.

Quote by 311ZOSOVHJH
OK. Well, after you slide the chassis out and have a safe place to flip it on its side or upside down just give it a visual inspection for scarring. Don't touch anything on the inside obviously. Take pictures. If you get real brave fire it up and look at all your tubes real good.

Ok, will do. I'll take it out, inspect it, then fire it up, if nothing shows, I'll just clean everything.
#15
^ OK. Well, people don't really clean the insides of an amp. The more you spend time messing around in there the more like you are to get shocked (unless you are dead certain the filter caps are discharged). If I had to guess there was maybe a poor bias running and you blew a screen grid resistor. When/what was the last known good bias? If the tubes get real bright that means they are red-plating. Shut your amp off immediately.