1966 BF Champ update

jb1911 · January 5th, 2005, 08:53 AM

I just finished my 1966 Champ project and it sounds unbelievable. I got it on eBay a couple of months ago and it was all original except for a Weber 8A125. With all the help I got from you guys, I was able to do the following:

Replaced 2 prong cord with a grounded cord, wired as per Vintage Jon. Removed the "death cap".

Replaced the cap can.

Replaced the 3 electrolytic caps with Sprague Atoms (2 – 25uF@50v and the cathode bypass cap was a 2uF@25v, I replaced it with a 2uF@50v).

Replaced the .1 and .047 tone caps with Sprague Orange drops.

Installed a 1 Ohm @ 1% 6.5W xicon cement resistor on pin 4 of the power tube.

Changed the cathode bypass resistor to a NOS Allen Bradley 1k@2watts to bring the cathode down from 18.38 watts to 12.416.

Of course I saved all the parts I took out of it in a zip lock bag for posterity.

Maybe you guys could tell me if I got this right. The cathode voltage is 32v. My plate voltage is 420v. My bypass resistor is a 1kohm.

32/1000 = .032
.032 x (420-32) = 12.416 watts

Is that correct? Does that sound like a good number for a 6V6GT to be running at? It sounds really great and the bass tightened up quite a bit.

Also, the screen voltage was 7 volts higher than the plate voltage before I added the screen resistor, and now it's still 7 volts higher. What's up with that?

Thanks for all the help.

January 5th, 2005, 08:53 AM	#1 (permalink)
jb1911 TDPRI Member Join Date: Jun 2004 Location: Chicago area Posts: 92	1966 BF Champ update I just finished my 1966 Champ project and it sounds unbelievable. I got it on eBay a couple of months ago and it was all original except for a Weber 8A125. With all the help I got from you guys, I was able to do the following: Replaced 2 prong cord with a grounded cord, wired as per Vintage Jon. Removed the "death cap". Replaced the cap can. Replaced the 3 electrolytic caps with Sprague Atoms (2 – 25uF@50v and the cathode bypass cap was a 2uF@25v, I replaced it with a 2uF@50v). Replaced the .1 and .047 tone caps with Sprague Orange drops. Installed a 1 Ohm @ 1% 6.5W xicon cement resistor on pin 4 of the power tube. Changed the cathode bypass resistor to a NOS Allen Bradley 1k@2watts to bring the cathode down from 18.38 watts to 12.416. Of course I saved all the parts I took out of it in a zip lock bag for posterity. Maybe you guys could tell me if I got this right. The cathode voltage is 32v. My plate voltage is 420v. My bypass resistor is a 1kohm. 32/1000 = .032 .032 x (420-32) = 12.416 watts Is that correct? Does that sound like a good number for a 6V6GT to be running at? It sounds really great and the bass tightened up quite a bit. Also, the screen voltage was 7 volts higher than the plate voltage before I added the screen resistor, and now it's still 7 volts higher. What's up with that? Thanks for all the help.