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[Jeid]

I was at band practise last night and when I'd stopped playing, I noticed that some dude was faintly talking through my amp. So, time for new tubes.

I have a Mesa Boogie .50 Caliber+ Head. Its a beast.

It has Groove tubes in the power section just now, but it looks like the original stock pre amp tubes.

Any recommendations for this beast? I've been looking at Svetlana's and JJ's.

I need 2x 6L6's, 4x 12AX7's and 1x 12AT7.

[lame guitarist]

how does the amp sound when you play?

You sure its not just signal interference?
Picked up everything from taxis to police radio through various pieces of gear over the years but its never meant that my tubes on the amps were gone

[Jeid]

I'm pretty sure its the tubes. Its starting to fizz on the overdrive channel, even at lower gain settings. And the clean channel just sounds a bit flabbier than it used to.

[Frosty Jack]

Your tubes may be on the way out, but I don't think that has anything to do with picking up strange voices, does it?
We once recorded a practice, and listening back discovered a note perfect trumpet solo from some European radio station. It fitted absolutely perfectly, so we kept it.

Originally Posted by Eriatarka

I was at band practise last night and when I'd stopped playing, I noticed that some dude was faintly talking through my amp. So, time for new tubes.

I have a Mesa Boogie .50 Caliber+ Head. Its a beast.

It has Groove tubes in the power section just now, but it looks like the original stock pre amp tubes.

Any recommendations for this beast? I've been looking at Svetlana's and JJ's.

I need 2x 6L6's, 4x 12AX7's and 1x 12AT7.

Preamp tubes don't tend to wear out. You'd only have to replace them if one or more have gone microphonic - a lot of vintage amps are still on the original preamp tubes. You can test microphony by tapping them VERY lightly using a chopstick with the amp on. As Frosty and Lame said, this wouldn't account for picking up radio interference. Ever seen Spinal Tap?

If the amp is losing headroom and starting to crap out, the power valves may flagging. Replacing them wouldn't affect the interference though. Groove Tubes are pretty overpriced but the bonus is that once you have your amp biased for them, you can just plug in new ones of the same power rating (they have their own scale). Watford Valves' Harma line seem to be highly regarded and are used by Radiohead and some other folk. Derek Rocco selects the best of current production valves, tests them rigorously then rebrands them. Make sure you get your amp rebiased.

mine has no headroom, and craps out almost imediately.

Do you think if i replaced my power valves with the same type i'd need to get it rebiased?

[Bass Cadet]

Do you think if i replaced my power valves with the same type i'd need to get it rebiased?

Yes you probably will - I've got a WEM in the same state. I got new valves but they just run a bit too hot. It's like playing plugged into a farrier's forge! Mmmmmm...... I must get round to sorting that out........

bah! it's such a hassle! it doesnt even have a trim pot, i guess its proabbly the perfect excuse to stick one in.

[Jeid]

Mesa's don't need re-biasing do they?

i know some brands have auto biasing technology, but i dont know if that includes mesas, you'd have to check the model hand book or website.