| Author | Message | ||
     Jan Nørby |
My 410 HD- 130 starts after 5 - 10 minuts of playing to clip and lose treble on the trem/rev channel. What could be my problem??? | ||
| mike kaus |
Obviously, you are facing a heat related issue. It could be something as simple(?) as a screen resistor that is cracked and opens up under heat. 50c part and%^&*$#^ a long time to find. I'd look at the amp under the heated condition and check the bias at the tubes first. Which 130? Solid state driver or 12ax7? It does make a dif. Let me know what you've got. | ||
| Jan Nørby |
It's a 12ax7.... | ||
| mike kaus |
If it's clipping bad, I would probably look at the bias circuit first and verify that as it gets hot, you retain the proper bias voltage at pin 5 that you started with. The caps in that amp, if they haven't been changed, could be going south and the bias could be uncontrolable. After that, you might want to look at re-tensioning the sockets to see if it's a connection thingy. THen, start looking for cracked resistors. Are the tubes remaining the same color, not turning cherry red? If turning red, its a sure sign of under bias/loss of bias. Or bad power tube. Mike. |