MARSHALL SUPERBASS MKII "pinging"

[rayc]

Hi out there,
I have a Marshall Superbass MKII, from the late 70's I think. It's a huge, powerful beast & is great for guitar as well as bass BUT a "pinging" sound is emmitted every few minutes.
It still sound great but the ping can spoil an otherwise satisfactory, for my skill level, take.
I've made various assumptions but they are just that.
Any diagnosis & prognosis from the knowledgebase?
Cheers
rayC

 

[rayc]

Anyone?
Is the tubes?
Help?
Cheers
rayC

 

[Zaphod B]

Well, any time a tube amp starts making noise, my first suspicion is the tubes. If it's been a while since you've replaced them, it couldn't hurt.

You may also need a re-cap job considering the age of the amp.

My 0.02: hope that helps!

 

[mandocaster]

Hi out there,
I have a Marshall Superbass MKII, from the late 70's I think. It's a huge, powerful beast & is great for guitar as well as bass BUT a "pinging" sound is emmitted every few minutes.
It still sound great but the ping can spoil an otherwise satisfactory, for my skill level, take.
I've made various assumptions but they are just that.
Any diagnosis & prognosis from the knowledgebase?
Cheers
rayC

The periodic nature of the pings makes me wonder if there is some cap problem.

I know nothing, however.

 

[ggunn]

The periodic nature of the pings makes me wonder if there is some cap problem.

I know nothing, however.

The usual caps to go out in a tube amp are the big electrolytic filter caps, and when they start to go bad what you usually get is 60 Hz hum. Occasional pinging or popping can be arcing in the power tubes, and needs to be looked at, as arcing can be very hard on the output transformer.

it could also be a microphonic preamp tube. With the amp on and warmed up, and the volume up, tap very lightly on the preamp (small) tubes with a pencil. If a tube reproduces the sound you are hearing when you do that, replace it.

 

[rayc]

Thankyou gentlemen,
I was beginning to think I was in a parallel universe or being subtly told to PING off.
Right - possibly capacitors, possibly preamp tubes. I'll tap & see.
Cheers
rayC