[mboessen]

Hi, Arran:

Thanks for taking the time to think about my problem.  Someone here did send me a schematic for a Philco 38-14, where they threw in a couple of resistors in the "power supply" kind of sort of in parallel with the ballast resistor, to bias the cathode.  I considered it, but the way it was done looks like a major rewiring job.  I fooled with this for 3 hours last night and decided I will just modify it for an LR44 cell and move on.

I read the part about replacing the ballast resistor with diodes or capacitors.  Did I read that correctly?  I've never heard of that.  Can you elaborate a little more on that?  Maybe post a sketch?

I'm having trouble with my audio in this set as well, which was one of the reasons I have been trying so hard to get this bias thing right.  My audio is not clean.  It is a little garbled, sounding like there is 60 cycle hum mixed in with it.  I replaced all the caps and any resistor outside 10%.   I've swapped out all the tubes.  There is about 2v of ripple on the B- relative to chassis, and I see it on the 75 tube grid and plate.  Not so much on the 43 plate.  I don't know if this ever happens to you, but I have become so frustrated with this set that I am going to set it aside and cool off for a while.  I've got a model 20 to start on, but first I need to repair the transmission in my brother's tractor/backhoe, which should keep my mind off of this for a couple of weeks.  If I don't get inspired beforehand, I will try to post more details about the audio problem in a separate thread.  I am beginning to suspect a problem with my bench setup, as I have had this problem on 2 other sets and never could get it satisfactorily resolved.

Again, Thanks!

Mike