Hi, I have a slight 100hz hum in one channel of my Forte 3 amp, this channel also runs warmer than the other channel, I have grounded the input but the hum persists, it doesn't get louder when I have turned up the input volume from my signal generator. Any suggestions?, thank you, Neil
I'd also like to see the phots.
Without photos... the bias on one channel is off and/or the input diff. transistor pair is no good (assuming the amp has them... not familiar with its circuit), one of a transistor, causing a bad power supply noise rejection. If there are zeners, check the voltage across them and make sure it's not too high...
Without photos... the bias on one channel is off and/or the input diff. transistor pair is no good (assuming the amp has them... not familiar with its circuit), one of a transistor, causing a bad power supply noise rejection. If there are zeners, check the voltage across them and make sure it's not too high...
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Thank you for your responses, I have now fixed the AC hum and the warmer issue. I believe it was a result of one of the 2SA1302 output transistors drawing more current than the others when I checked the voltage across the emitter resistors. Once replaced I have had no further issues, neil
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