Lonestar 2x12 Chan 1 died during show

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Bottle Rocket
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Lonestar 2x12 Chan 1 died during show

Post by Sg1 » Sun Nov 26, 2017 8:28 pm

Hey All.
I played a show last night with my Lonestar 2x12
half way through the second set I switched over to chan 2 for a solo.
when I switched back (footswitch) to channel 1 it was virtually gone.
producing about 7% of the volume it should and horribly distorted.
Channel 2 (drive) was still normal. (full volume)
I limped through the song and then did some quick troubleshooting.
pulled the foot switch out of the loop. switched in and out of standby a couple of times.
Swapped cables, I don't use a pedal board but I bypassed the tuner and plugged directly in
The one thing I didn't do was power down the amp.

This morning back in my studio I powered the amp up and it operated completely normally.
I had recently checked all tubes and replace the rectifier tube (trying to skunk out a different issue)

I would have preferred the amp was still broken so I could simply get it repaired.
Now I have a classic Ghost in the machine.
got some big shows coming up. any Ideas what to look for??
Thanks folks.

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Single Recto
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Re: Lonestar 2x12 Chan 1 died during show

Post by plan-x » Fri Dec 01, 2017 3:45 pm

Possibly....clean the jacks/plugs to the FS with contact cleaner. Spray the plug and insert many times quickly, you know, like you're doing your gal. That has solved many weird intermittent issues with my pedals.
Fillmore 25 head
Lonestar Classic (LSC) 2x12

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Donating Member
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Re: Lonestar 2x12 Chan 1 died during show

Post by screamingdaisy » Fri Dec 01, 2017 8:10 pm

Are both channels operating at 100w? Or was channel 1 on 100w and channel 2 on 50w?

Your problem (loss of volume with severe distortion) sounds like a failed/failing power tube (loose part inside shorting out), which can be diagnosed with the tap test.

My question would be why it only affected the clean channel and not both channels, and 50w vs 100w is the only answer I can come up with.
Ignore the hype and trust your ears. Play more, buy less = better tone.

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ricardo loma vista
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Re: Lonestar 2x12 Chan 1 died during show

Post by ricardo loma vista » Fri Dec 01, 2017 8:29 pm

I experienced a similar problem with my Lonestar Special during a gig. I set up the amp using channel 1 for cleans (30 watts, 4 tubes, silicon diode rectifier) and channel 2 for overdrive (15 watts, 2 tubes, tube rectifier). I set the volumes so that Ch 2 was boosted relative to Ch 1. About 5 songs into the first set Ch2 suddenly became harsh, thin, and lower in volume than Ch1. I was using a pedal board so I switched to ch1 and used the pedal board for overdrive and got thru the gig that way.
I checked out the amp the next day, and like you, found it ok. But poking around the tubes, I found the left outboard power tube was half out of the socket. Apparently, it would work normally until it heated up and then the tube would cut out of the circuit (probably from expansion). Since I was running only 2 tubes on channel 2, having one out made a big impact. With 3 of the four running on channel 1, it sounded ok.

You could also have an intermittently failing power tube that could cause symptoms that would be much more pronounced if Ch 1 was running on low power (one or two tubes.) How did you check out the tubes? Unless you checked by replacing with known good ones or have a tube tester, you may have a bad tube.

Rectifier tube: Much less likely since it was recently replaced, but could possibly be intermittently bad. Was one channel running on the rectifier tube and the other on silicon diode rectifier? If everything was running on silicon diode then the rectifier tube would not be at fault.
Things are never as good or bad as they sound when you first hear them.

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