Hey everyone, I've got a question that I need an answer to ASAP. I have a Blackstar HT-20 combo, and I was practicing the other night, and all of a sudden the volume dropped till nothing came out of the speakers anymore. The power light was still on, just no sound came out. This is my first tube amp, and I've had it for about a year so I'm thinking that the tubes need to be replaced. However there are both preamp, and power tubes, and I don't know which to replace. Just to clarify, I know which TYPE of tubes I need for each, EL34's for the power, and ECC83's for the preamp. I just don't know which tubes need replacing. I need to know soon because my band has a big gig coming up (opening for Kittie and The Agonist!), and I need my amp to work! Hopefully that's enough information for you all to help me out. I won't be able to respond for about an hour or two, so if you need more info I'll be back then.

Thanks in advance!
If you can, replace them all. But do the power tubes first, since they'll be more likely to be worn out. If that doesn't work, replace the preamp tubes, but first take one ecc83 that you know works and try it in each of the preamp slots to determine if there's one particular tube that is bad. If it's just one, you can swap that one out and be good to go for the time being. You should definitely have plenty of spare tubes at hand if you're going to be gigging.
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