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Re: OK, where's that hum coming from?

7/5/2005 3:52 PM
loudthud	Re: OK, where's that hum coming from? Sounds like something is out of balance in the output stage. Unfortunately, that's probably what makes it sound good. Do you have the bias pot setup like the AA864 or the balance pot of the AA165 ? I assume you've tried a different set of tubes. Any difference there ? How do you set the bias ? Check the 6L6 sockets for good tention. Check the voltage across the 470 ohm screen resistors and the voltage on the grids. If you can't find something that's out of balance, the output transformer is suspect.

7/5/2005 3:52 PM

loudthud

Re: OK, where's that hum coming from?

Sounds like something is out of balance in the output stage. Unfortunately, that's probably what makes it sound good.

Do you have the bias pot setup like the AA864 or the balance pot of the AA165 ? I assume you've tried a different set of tubes. Any difference there ? How do you set the bias ?

Check the 6L6 sockets for good tention. Check the voltage across the 470 ohm screen resistors and the voltage on the grids. If you can't find something that's out of balance, the output transformer is suspect.