major volume loss at gig last night - help?

[bigjilm]

Hey, all. My Nitro lost major volume last night. I'm assuming tubes going bad? I had to crank the volume to 1 o'clock - usually run it 9-10 o'clock. It's a KT88 head, just two power tubes in it set for 1/2 power. Bought it this way. Is this a power tube issue, do you think? My buddy has a bias device, probably gonna retube it with all 4 power tubes, and new pre-amp tubes as well. I had noticed a decline in the "balls" of the amp at practice last week.

Does This sound like a tube issue? If so, what KT88's do y'all reccomend that won't break the bank? What 12ax7's?

Any advice would be really helpful! I'll probably call Scott Monday and get his take.

Thanks!

[rocknrolla]

Sounds like a power tube problem. I've had really good luck from Bob at Eurotubes.com. A matched quartet of JJ kt88's is about $150. Their high gain 12ax7's are really nice also. I've never heard them in a Nitro but I had a set in my old Triaxis and I liked them. You can get the Sino kt88's from Scott for $150 also.

[bigjilm]

Thanks! Yeah, I'll call Scott. I think I have a pair of winged c's in a box somewhere too.

[splawndude]

def sounds like power tubes.

i wouldn't worry about the preamp tubes unless you know they have gone bad.

Eurotubes is fine if all you want is JJs. I bought my bias probe from Bob.

I would recommend contacting Laura at www.valvequeen.com or Doug at www.dougstubes.com. I have =C= in my Quick Rod and I also run at half power.

Question: are you cutting you ohm load in half of what you would normally run at?

[banenis]

If you've been runing at half power for a while it may be worth the experiment to pop out your 4 tubes and put the outside 2 on the inside to spots and vice versa. If you've been in half power for a while and you continue to be then this should solve you're problem because you basically be getting fresh tubes in there. If it doesn't solve your problem, then your problem might not be tubes after all. (but then again, it might still be tubes).

Call Scott and ask what he thinks.

[bigjilm]

Yeah - Running at 1/2 power I cut the ohms in half - 8 ohm cab head set for 4 ohms. As far as using the other 2 tubes, my head only has the two middle tubes - I bought it used like that. Thanks for the links, too - I'll order some Monday.