UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Mullard 5-10 amplifier

Hartley118 · 9th Jul 2019, 2:41 pm

I'm afraid I'm working without a circuit diagram and jumping to a conclusion from:

"I have tried replacing the 2.2M resistor but it made no difference."

If the input resistor is actually less than this then the noise should be reduced pro-rata.

The evidence that with "the 5-10 BNC input shorted to deck the hiss practically disappears" suggests that it's thermal noise in the input resistor.

Martin

9th Jul 2019, 2:41 pm	#108
Hartley118 Nonode Join Date: Aug 2015 Location: Cambridge, Cambs. UK. Posts: 2,198	Re: Mullard 5-10 amplifier I'm afraid I'm working without a circuit diagram and jumping to a conclusion from: "I have tried replacing the 2.2M resistor but it made no difference." If the input resistor is actually less than this then the noise should be reduced pro-rata. The evidence that with "the 5-10 BNC input shorted to deck the hiss practically disappears" suggests that it's thermal noise in the input resistor. Martin __________________ BVWS Member