01-06-2012, 01:23 PM
Can I have another Errrr?
It looks to me as though the pot simply varies the bias on the 6BA6, like my MM does. The 68R is there to stop the bias going down to zero.
Why it's returned via the Aerial coupling winding I couldn't say, but as it's decoupled at the junction of the 68R and the pot there won't be much feedback, not that you'd want much or it would oscillate.
Alan
It looks to me as though the pot simply varies the bias on the 6BA6, like my MM does. The 68R is there to stop the bias going down to zero.
Why it's returned via the Aerial coupling winding I couldn't say, but as it's decoupled at the junction of the 68R and the pot there won't be much feedback, not that you'd want much or it would oscillate.
Alan
