I was playing at home on the lead channel about 1 master, pre 6ish and the amp suddenly went to about 1/2 volume. I kept playing and turned it up a bit, 2 mins later the fuse blew. I assume a tube issue? * At the time the amp was on it's side to fit where I had to put it...not something I'll do again!, with the effects loop on the top side...maybe heat from the tubes fried the top one?
So I went to the music shop and they have a Groove Tubes, so should I get a whole set or just the power tubes?

Also they have different prices, the 6L6 are made in 3 versions, I was thinking the middle priced ones?

Would I have to bias it too?

anything else I should check?

Last edited by Tempoe at Jun 12, 2014,
I'd replace the fuse first if it blew, they're super cheap. If that doesn't fix it start with the pre amp tubes then the power tubes. Replace one at a time and see if you can isolate the problem tube. I'd recommend JJ tubes. No need to bias that amp.
^^Yep, replace the fuse. Also, since it dropped in volume, that suggests a power tube problem. I wouldn't get new preamp tubes just yet unless you've got the money.

Also, don't buy Groove Tubes. They are just re-branded from other manufacturers and then sold at a higher price. You're better off just buying JJ 6L6 GCs from a reputable tube dealer online (I recommend TubeDepot). JJs will sound much, much better than the stock tubes that come with that amp anyway.

If you've got money, JJ makes excellent preamp tubes as well. I'd heartily recommend their 5751 for V1, and regular 12AX7s everywhere else. That 5751 is a bit lower in gain but improves clarity and your cleans. I also run a JJ 12AT7 in V5 (phase inverter) which has an even lower gain-factor. It also improved my cleans. The lead channel is still devastating.
Thanks guys, I'll get the full set of JJs anyways and try a 5751 too!

Is there an internal fuse as well as the one in the back?
Quote by Tempoe
Thanks guys, I'll get the full set of JJs anyways and try a 5751 too!

Is there an internal fuse as well as the one in the back?

I'm pretty sure there are fuses inside the 6505+ combo
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Just out of curiosity, do you know how old the tubes are in your amp? The power tubes need to be replaced periodically anyway.
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