Hi there everyone....what a great place to visit for some info....i'm new to this....if any one can help me with a problem on one of those dsl 100w things.... you know... the early ones with the bias drift circuit board....i think i have fixed the bias drift..but the other problem i have is when i power up the amp in play mode .... the tubes go very blue and hum ..then red plate...in the early stages the amp would crackle a bit then quickly calm down and only one tube would be really blue for a short moment and then go normal......the amp would hold a steady bias and play very well....even if you turn it off then shortly after back on again.... but if you let the amp cool totaly... the crackle comes back and the tubes takes off. Now the problem has gone to all the tubes...(red plate)
With the power tubes out of the amp and not in play mode...i have -15v on (i think it's called pin 5) on v5 and v6... and -2v on pin 5 on v7 and v8..... bridge rectifier tested good...new coupling caps....the resisters were replaced with metal film before the crackling started....all solder joints have been done... if anyone would like to help ....that would be so good.... thanks
With the power tubes out of the amp and not in play mode...i have -15v on (i think it's called pin 5) on v5 and v6... and -2v on pin 5 on v7 and v8..... bridge rectifier tested good...new coupling caps....the resisters were replaced with metal film before the crackling started....all solder joints have been done... if anyone would like to help ....that would be so good.... thanks
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