I have just bought my first tube amp recently, and not knowing much about them, i would like some advice on a problem i am having.
At first it was fine and i was able to play it with no problems, but recently there has been a squealing noise when i put it on. It sometimes stops after being on for a couple of minutes but 90% of the time it doesnt stop and i have to turn it off.
I notice when i tap the silver part where the volume knobs are (just above where the tubes are) that it has a break in between each squeal.
I have never changed the tubes, as i was told they were brand new when i bought it (2nd hand) and ive had the amp for about 6 months.
Would the best action be to change ALL of the tubes at once and see if that rectifies the problem?
Or, is there a way i can isolate it to see which tube it is that needs to be replaced?
.... if it is in fact as easy as changing the tubes, could it be a different problem?
I have searched the forum, and although there are threads on the 'squeal' from an amp, most of what i read was the squeal from other members amps occurs at a higher volume. The squeal in mine occurs even when all the volume levels are turned to zero.
😕
Kinda hoping someone can reassure this complete newbie lol.
Thanks in advance for any suggestions you may have.
At first it was fine and i was able to play it with no problems, but recently there has been a squealing noise when i put it on. It sometimes stops after being on for a couple of minutes but 90% of the time it doesnt stop and i have to turn it off.
I notice when i tap the silver part where the volume knobs are (just above where the tubes are) that it has a break in between each squeal.
I have never changed the tubes, as i was told they were brand new when i bought it (2nd hand) and ive had the amp for about 6 months.
Would the best action be to change ALL of the tubes at once and see if that rectifies the problem?
Or, is there a way i can isolate it to see which tube it is that needs to be replaced?
.... if it is in fact as easy as changing the tubes, could it be a different problem?
I have searched the forum, and although there are threads on the 'squeal' from an amp, most of what i read was the squeal from other members amps occurs at a higher volume. The squeal in mine occurs even when all the volume levels are turned to zero.
😕
Kinda hoping someone can reassure this complete newbie lol.
Thanks in advance for any suggestions you may have.
Umm, well ive bought tubes anyway, hopefully they'll be here by the weekend.... and hopefully they'll be what the problem is.
Just giving this a bump incase anyone has an opinion on what else it could be. (sorry if bumping is frowned up here)
Just giving this a bump incase anyone has an opinion on what else it could be. (sorry if bumping is frowned up here)
Tubes (especially 12AX7 preamp tubes) are quite likely, especially if it responds to tapping/knocking.
Another really frequent problem with Peavey (& Fender) is the power supply capacitors. The grey IC (Illinois) axial type are often used, and these can have a short life (I have seen as bad as 5 years).
Not a really high priced job, but it's best to have them all renewed, if any are bad. If they are 10 years old, they will be sounding bad, as well. Well-chosen new power caps sound better than a set of new valves, in many amps. Get your tech to fit Nichicon VX series 22uF/450v (they can take 500v unloaded) in the preamp section, and Panasonic TSHA (or TSUP) in the position after the rectifier.
Good luck!
Another really frequent problem with Peavey (& Fender) is the power supply capacitors. The grey IC (Illinois) axial type are often used, and these can have a short life (I have seen as bad as 5 years).
Not a really high priced job, but it's best to have them all renewed, if any are bad. If they are 10 years old, they will be sounding bad, as well. Well-chosen new power caps sound better than a set of new valves, in many amps. Get your tech to fit Nichicon VX series 22uF/450v (they can take 500v unloaded) in the preamp section, and Panasonic TSHA (or TSUP) in the position after the rectifier.
Good luck!
Used, right? Get some spray cleaner, no lube. Remove all tubes. Spray all tube connections and all pots...turning the pot switch'es and spraying again to really clean. Get some spray lube for pots and pots only. Check/clean tube pins ( be careful ). Check all internal wiring for breaks or looseness. Normal caveats apply for electrical hazards. If you don't know what you're doing, take it to someone that does.
Isolate the problem. Turn it on, get it to squeal.
Now, do ANy controls have ANY effect on the noise? (That helps localize which part of the circuit is doing this)
Tap on each tube, going down the row. DO any respond to the tapping?
GO down the row and firmly grasp each tube and hold it. Use a rag or glove if they are too hot for you. Does gripping a tube have any effect. (We are looking for microphonic tubes)
SInce tapping on the chassis affects the noise, then if it is not a tube (most likely it is a tube) there is a loose connection somewhere inside.
Now, do ANy controls have ANY effect on the noise? (That helps localize which part of the circuit is doing this)
Tap on each tube, going down the row. DO any respond to the tapping?
GO down the row and firmly grasp each tube and hold it. Use a rag or glove if they are too hot for you. Does gripping a tube have any effect. (We are looking for microphonic tubes)
SInce tapping on the chassis affects the noise, then if it is not a tube (most likely it is a tube) there is a loose connection somewhere inside.
- Status
- Not open for further replies.