Mystery volume drop out on Lone Star Special.

[R George]

Has anyone had problems with a Lone Star Special having a slight drop in volume for about 10 seconds, then returning to normal volume? this happens after I've played the amp for about 20 to 30 minutes. Of course my amp tech could not get the amp to do it. He suggested replacing tubes but didn't really think that would be the problem. The amp is only 1 year old. Any thoughts?

 

[ylo]

This won't help you much, but you could have a sticky relay, or a bad solder joint to a relay. Take a look at the schematic for the Lone Star at the schematicheaven website. This is almost identical to the LSS. The relays at V1 and V2 for channel switching and gain changing could cause your symptoms. The tough part is confirming whether this is the true problem and identifying which relay, especially if it is intermittent as opposed to completely out.

Has your tech tried the trick of spraying coolant on the PCB connections to expose bad solder joints?

 

[R George]

Thanks a lot for your suggestions. I'll mention this to the tech and see if he'll check it out for me. This is frustrating. Like driving a car that makes a weird noise but won't do it for the mechanic!

 

[user 1198]

I have a Carvin Legacy head that was exhibiting some of the same behaviors. It turned out to be dirty contacts of the effects loop jacks. I cleaned the jacks and everything was fine.

Try hard bypassing the effects to see if the problem goes away.

 

[R George]

You know what? That might be it. After reading your suggestion, I flip the hard bypass switch and played for about 30 minutes with no drops in volume. Playing for a longer period will be the true test. Thanks man!