Need help, which tube is it?

[AP515]

I've got an SE50 with EL34's. Today the clean channel started sounding a lot like the dirty channel. Then it started popping and spitting and at the last the volume decreased on both channels until it had hardly any volume at all. I've got preamp tubes I can swap out until I find the bad one, but I don't have any EL34's. Can anyone tell from the symptoms if it's a power tube?

 

[AP515]

Decided not to wait. Ordered a matched set of EL34's.

 

[dmatthews]

an you "A/B" the power tubes one at a time?

 

[AP515]

Can you "A/B" the power tubes one at a time?

No, I have spare 6L6's but no EL34's. They are now on order however.

 

[elvis]

Try replacing the phase inverter as well. It can give symptoms of power tube failure even if the power tubes are good. And it's cheap.

 

[AP515]

Try replacing the phase inverter as well. It can give symptoms of power tube failure even if the power tubes are good. And it's cheap.

Thanks for the suggestion!

 

[László]

Usually popping and spitty sounds are preamp tubes.

 

[AP515]

So now I'm back to having to test everything...

I asked the question so if someone knew I wouldn't need power tubes, I could fix it without ordering them, but then I went and ordered them anyway.

I'll swap out the 12ax7's tonight and if I don't need the power tubes they'll keep until I do.

Thanks all.

 

[SteelHorse]

I would bet a preamp tube or PI also.