thornev
Super Member
The posts since post 35 in the "Need help installing to a 500-C on-off switch a CL-60 current limiter" thread dealt with this subject, but I don't want to derail the thread anymore than I already have, so I started this thread.
I did the screen protector mod where I moved the C91D bias supply wire from pin 8 of V8 to V8 pin 1 and them wired all the pin 1's on the power tubes together. I also inserted a 100 ohm 1/4 watt resistor to tie each power tube's pins 1 and 4. After completing this mod it seems that the receiver puts out a little more power. I haven't measured the power tube outputs, but I will to see how the new numbers compare to the old numbers I took before the mod.
But now that the bias supply from C91D doesn't provide power to all 4 power tubes (well, not to the same pins on each tube), doesn't it mean that each tube will generate power independently from the other tubes which, in turn, means each tube should be "tuned"? That's why we have the IBBA and IBAM circuits, right? I guess I'll have to see if the tubes need re-biasing based on the new output numbers. Enough for one day !
Thank you All for providing all these fun mods and for all your support of my amateur adventures. I'm having a lot of fun with this stuff and of course the sound, oh the sound ! A 500-C with two AR-2Ax's and a subwoofer is going to be heaven on earth !
Thorne
I did the screen protector mod where I moved the C91D bias supply wire from pin 8 of V8 to V8 pin 1 and them wired all the pin 1's on the power tubes together. I also inserted a 100 ohm 1/4 watt resistor to tie each power tube's pins 1 and 4. After completing this mod it seems that the receiver puts out a little more power. I haven't measured the power tube outputs, but I will to see how the new numbers compare to the old numbers I took before the mod.
But now that the bias supply from C91D doesn't provide power to all 4 power tubes (well, not to the same pins on each tube), doesn't it mean that each tube will generate power independently from the other tubes which, in turn, means each tube should be "tuned"? That's why we have the IBBA and IBAM circuits, right? I guess I'll have to see if the tubes need re-biasing based on the new output numbers. Enough for one day !
Thank you All for providing all these fun mods and for all your support of my amateur adventures. I'm having a lot of fun with this stuff and of course the sound, oh the sound ! A 500-C with two AR-2Ax's and a subwoofer is going to be heaven on earth !
Thorne