#1
Hi this is for anyone who has owned a Mesa Lonestar head or combo. I bought one late last year, and i noticed a slight squealing or hissing sound coming out sometimes. i took it back to the shop but they could find the problem. Recently it's gotten worse and now occurs on all teh power settings 10/50/100watts.

This isn't general hiss. The amp is overall very quiet, but this weird sound comes through now, it's hard to describe. But has anyone else found this with their ones or knows what the problem could be?

Thanks.
#3
I'd say almost certainly that tube(s) need replacing. I will let someone more knowledgable on Mesa amps advise further though as I know Mesa's are somewhat unique in the tubes they take and the way they are biased.
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#4
Sounds like power tubes alright, you could do the pencil test to confirm, but given the problems, I'd just replace the whole lot of power tubes.
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#5
Quote by ragingkitty
Sounds like power tubes alright, you could do the pencil test to confirm, but given the problems, I'd just replace the whole lot of power tubes.


Thanks for the replies, i should probably add to the description, that it NOT the output section cause when i bypass this it still happens. And it's also somehow tied in with the power selection. i.e. it used to only happen with the 10 watt selected then the 100w and now its with all 3.

So if the "power tubes" people are talking about are the tubes that are to do with power ratings then I'd confirm that and say it's probably the power tubes.

Any more ideas are appreciated.
#6
Another possibility could be that one of your preamp tubes have also gone microphonic... possibly the V1 or the phase inverter (if your's is a push-pull amp) given that these are the 2 most used preamp tubes.

When was the last time the tubes were changed?
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#7
Squealing is very often a microphonic phase inverter. Start there.
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