Bass Amp Making Chirping Sound… Rumble

[Tele-beeb]

Like when I dig in, it sounds like I shocked a cricket.
Ideas?
Oh… Rumble 500 combo. Well used.

 

[PhredE]

Like when I dig in, it sounds like I shocked a cricket.
Ideas?
Oh… Rumble 500 combo. Well used.

Playing guitar or bass ?

Edit: My instinctive answer right away is a speaker issue; but it would take some more investigating to isolate it as the cause. Have you tried to output from same amp to different speaker?

 

[Pete Farrington]

Probably oscillation, which would probably be due to a bad electrolytic cap, which given the symptoms, would probably be in the power amp / power supply.

 

[Tele-beeb]

Playing guitar or bass ?

Edit: My instinctive answer right away is a speaker issue; but it would take some more investigating to isolate it as the cause. Have you tried to output from same amp to different speaker?

Thanks… bass.
Happened last weekend and I turned down and ignored it. I run two matching 500’s and just forgot to check it.
Last night same chirping. Now it has my attention. Will get it out of the trailer in a bit. Thanks, I’ll check those.

 

[Tele-beeb]

Probably oscillation, which would probably be due to a bad electrolytic cap, which given the symptoms, would probably be in the power amp / power supply.

That’s actually what I’m afraid of. These amps have been pretty good and neutral, but the Chinese connection has made me queasy all along.

 

[Tele-beeb]

Well… I just did a quick test at gig volume without my wireless, preamp board and effects. No chirp. I am considering bypassing the front end and just go into the return with my Geddy preamp.

 

[CoolBlueGlow]

Recently had a Rumble with this problem. I replaced the common electrolytics. It went away. Not very hard to fix. Mine was in the PSU, but same chirping as you describe.

So, just swap out the obvious electrolytics with fresh cookies. Dollar to a dime it'll go away.

 

[corliss1]

Well… I just did a quick test at gig volume without my wireless, preamp board and effects. No chirp. I am considering bypassing the front end and just go into the return with my Geddy preamp.

Always isolate first. Remove as much from the equation as possible - bass -> cable -> amp. Much easier to troubleshoot when there are fewer variables.

 

[Dostradamas]

On or off?

This would be my first check

 

[Tele-beeb]

Always isolate first. Remove as much from the equation as possible - bass -> cable -> amp. Much easier to troubleshoot when there are fewer variables.

Yes, so far this has fixed the chirp.

 

[Tele-beeb]

View attachment 1328203

On or off?

View attachment 1328204

This would be my first check

Good thought… it was off, my guitar player says it was proximity. I agree, but add in all the complications and fluorescent lighting.