Valve Fuse keeps blowing on my sovtek - need help

[spencedontknow]

I got a sovtek mig50 off ebay a couple months ago, been using it just for practice, not very hard. This is my first tube amp by the way. I was looking for a more original sound and this seemed to fit that. Anyway, couple weeks ago, it blew a fuse. I just got around to getting replacements today. Only the valve fuse had blown, but i replaced both. I plugged into channel II and within a few seconds there was a popping noise and it cut out. I put another fuse in, and tried plugged into the first channel, and the same thing.

I'm sure the fuses are rated right. The seller had labeled them, and I checked the models of the fuses I took out when I bought replacements. The seller also said that he never had problem with fuses when I asked him if he could throw some in.

I'm really at a complete loss as to what the problem is and I really don't want to take it to a shop if I can fix this myself, and I don't want to waste more fuses. The seller also said he had put new pots in before selling it, so could having wrong pots have anything to do with it? Even thought I don't think that would explain why it is suddenly blowing fuses.

Thanks for any help.

[acorkos]

take the power tubes out and see if the fuse still blows. if not, you likely have a bad power tube.

[spencedontknow]

take the power tubes out and see if the fuse still blows. if not, you likely have a bad power tube.

Looks like that's the case. I did that, didn't blow. I also took a look the tubes that were in there and they looked really gnarly, so looks like they definitively need to be replaced.

Kind of a bummer that I'm going to have to shell out a decent amount of cash, but at least it's still functioning good.

Thanks for your help.

[Enzo]

When buying any used tube amp, you should expect to have to replace the power tubes.

[tubeswell]

... And then keep a spare set of new tubes handy for emergencies.