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Hello again,
I have a nifty Ampeg / Lee Jackson VL-502 head that has a problem that I can't get my chopsticks around. Thought I would solicit some help from the experts here. Thanks in advance for reading my ramblings....
About the problem: After playing for an inconsistent amount of time and at varied volume (whisper to stage+ level), the sound will become thin and lose all "balls". I had it on the bench and went over the pc boards with my trusty chopstick (while it was acting up & in normal state) but could not affect the sound. I can't force the amp to act up with increased volume (i.e. increased heat). But I can bring the amp out of the problem by engaging the FX loop switch to the In & Out position. Once I realized this, I hit the FX loop board with the 'ol chopstick and again (both states of function) & no luck. I've retubed everything except the power tubes with new or known to be good tubes. The problem was active with the old tubes as well. Cab Impedance is correct.
About the head: 50 watt ch. switcher, built-in attenuator (not in use), tube everything....fx loop, 'verb (removed tank); EL-34 powered, neat-o light up logo on the front of the head (I'm easily amused....shiny lights...) I have no schematic available.
Think that's it....Any advice is always appreciated.
Cheers,
Lonzo
I have a nifty Ampeg / Lee Jackson VL-502 head that has a problem that I can't get my chopsticks around. Thought I would solicit some help from the experts here. Thanks in advance for reading my ramblings....
About the problem: After playing for an inconsistent amount of time and at varied volume (whisper to stage+ level), the sound will become thin and lose all "balls". I had it on the bench and went over the pc boards with my trusty chopstick (while it was acting up & in normal state) but could not affect the sound. I can't force the amp to act up with increased volume (i.e. increased heat). But I can bring the amp out of the problem by engaging the FX loop switch to the In & Out position. Once I realized this, I hit the FX loop board with the 'ol chopstick and again (both states of function) & no luck. I've retubed everything except the power tubes with new or known to be good tubes. The problem was active with the old tubes as well. Cab Impedance is correct.
About the head: 50 watt ch. switcher, built-in attenuator (not in use), tube everything....fx loop, 'verb (removed tank); EL-34 powered, neat-o light up logo on the front of the head (I'm easily amused....shiny lights...) I have no schematic available.
Think that's it....Any advice is always appreciated.
Cheers,
Lonzo
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