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Lone Star channel 1 weirdness

Posted: Thu Dec 08, 2016 1:32 pm
by frpax
OK, so I got this Lone Star. On Channel 1, I'm getting beautiful, big full clean tone. I'm loving life! Then after 5 or so minutes of playing, and without touching any knobs on either guitar or amp, my big full tone goes somewhat muffled, a teeny bit of volume loss, and a bit more gain most noticeable on the B & e (unwound) strings. Then after a minute or two of that weirdness, it goes back to normal! I want as much clean headroom as possible, so I have channel 1 at 100 watts, silicone diode rectifier mode.

Is this a sign of impending tube failure?

[edit] I don't know it it is important or not, but it is a 2x12 combo, 10/50/100 version made in 2011.

Re: Lone Star channel 1 weirdness

Posted: Thu Dec 08, 2016 4:33 pm
by The Lo Lands
frpax wrote:OK, so I got this Lone Star. On Channel 1, I'm getting beautiful, big full clean tone. I'm loving life! Then after 5 or so minutes of playing, and without touching any knobs on either guitar or amp, my big full tone goes somewhat muffled, a teeny bit of volume loss, and a bit more gain most noticeable on the B & e (unwound) strings. Then after a minute or two of that weirdness, it goes back to normal! I want as much clean headroom as possible, so I have channel 1 at 100 watts, silicone diode rectifier mode.

Is this a sign of impending tube failure?

[edit] I don't know it it is important or not, but it is a 2x12 combo, 10/50/100 version made in 2011.
Hard to say but most likely! Is it a new amp or do you have it for some years now? I'm asking because if its a new amp you should contact Mesa (warranty) and if you haven't changed tubes lets say the last years it's maybe time for a re-tube.

Re: Lone Star channel 1 weirdness

Posted: Thu Dec 08, 2016 5:27 pm
by frpax
The Lo Lands wrote:
frpax wrote:OK, so I got this Lone Star. On Channel 1, I'm getting beautiful, big full clean tone. I'm loving life! Then after 5 or so minutes of playing, and without touching any knobs on either guitar or amp, my big full tone goes somewhat muffled, a teeny bit of volume loss, and a bit more gain most noticeable on the B & e (unwound) strings. Then after a minute or two of that weirdness, it goes back to normal! I want as much clean headroom as possible, so I have channel 1 at 100 watts, silicone diode rectifier mode.

Is this a sign of impending tube failure?

[edit] I don't know it it is important or not, but it is a 2x12 combo, 10/50/100 version made in 2011.
Hard to say but most likely! Is it a new amp or do you have it for some years now? I'm asking because if its a new amp you should contact Mesa (warranty) and if you haven't changed tubes lets say the last years it's maybe time for a re-tube.
I bought it used. It was made in October of 2011. No idea how old the tubes are.

Also on Channel 2, I get an awful squealing howl if I turn the Gain up past 10:00 and the same if I turn the Master up past about 10:00. I'm assuming this is a tube issue as well. Could they be the same tube? I'm not overly anxious to replace every tube at this point.

Re: Lone Star channel 1 weirdness

Posted: Thu Dec 08, 2016 8:25 pm
by frpax
OK. So I was doing some more fiddling around and I discovered that all that howling & squealing on Channel 2 was doing it if I had the reverb switch in the "Bright" position. "Warm" was better. Better still was unplugging the reverb tank altogether!

Any ideas, guys? Bad V4? Bad reverb tank? Could I have had the reverb tank plugged in backwards?

Re: Lone Star channel 1 weirdness

Posted: Thu Dec 08, 2016 11:06 pm
by frpax
I may have solved the problem.

Re: Lone Star channel 1 weirdness

Posted: Fri Dec 09, 2016 2:16 pm
by The Lo Lands
Microphonic tubes. Squealing sounds can happen when preamp tubes go bad or if you use to much preamp gain. For the reverb issue the tube should also be replaced for a new one. I would advise to install a new set of fresh preamp tubes.