[NJARC] Deactivating AVC on Atwater Kent Radio?
George B. Shields, Jr.
george-shields at msn.com
Mon Oct 24 20:04:00 EDT 2011
Hi All,Still working on a 1931 AK82 cathedral with the "infamous" control tube with AVC. I have completely rebuilt the resistor network and cleaned the volume control. I have swapped out the controal tube (UX224) THREE times and have replaced all of the bleeder resistors. There has been very little if ANY improvement in the volume instability in the set. The voltage across the resistor network to which the volume control is connected fluctuates between 21 and 19 volts at "normal" listening volume. Now, this is more than sufficient to drive the control tube from little volume control (unbearably loud) to full cutoff and back again seemingly whenever it wants to.
So, I have read several comments about how bad this primitive AVC / volume control arrangement actually was in practice and that it can be circumvented, thereby rendering the volume control much more stable in daily operation. But how do I do it?????? Can someone who has worked with this condition tell me what needs to be done to bypass (or otherwise deactivate) the AVC circuit so this set will operate with more stability when tuned to a station? Other than accounting for the normal minor voltage fluctuations which exist in the AC line current in my home, I cannot find anything in this set which would account for the significant fluctuations in the resistor network (and yes, one-two volts represents a MAJOR fluctuation of voltage in this circuit!)
Ideas welcome!
-George-
STUDEBAKER: Where Pride of Workmanship Still Comes First!
More information about the NJARC
mailing list