fender 5c3 static

[baddog]

I converted my bogen vp-17 into a 5c3. Everything sounds good but i am getting a little buzzing through the amp . Could it be a filter cap issue ( maybe increase the size) ? I made it exactly like the schematic except its point to point wired. Any Thoughts


Baddog

[dwhutchens]

Are those new filter caps? Is there a center tap on the 6.3v filament wires? If so is it grounded? If it doesn't have a center tap try a 100 ohm resistor from each side of the heater filament circuit to ground. I tried rewireing a couple of old amps and both of them buzzed or hummed, not very loud but annoying. My first attempt was a Bogen PA I rewired as a 5E3 but point to point with no circuit board. I blew out the recifier tube with too big a capacitor trying to kill the hum. I built another one from scratch with a 5E3 fiber eyelet board and followed the Fender layout and it came out dead quiet. I tried again with a power amp from an old record player and it buzzed, the chassis was really small and cramped so I took all the parts and put them in a larger Hammond chassis, still wired point to point and it still buzzed and hummed so I pulled all the parts back out and put them on a generic fiber board and followed the Fender 6G3 layout as much as possible. Hum and buzz gone!

What I learned from all of this is if youre going to convert an old PA or other old amp for guitar don't mess with the layout, just replace the filter caps or any other parts as needed to get it working first. Now tweek the tone stack and change the input and output connections to suit your needs. If you want to gut it and make something else out of it try to find an eyelet board, they're available for most old Fenders and some others and follow the original layout as much as possible, those guys that designed them either knew what they were doing or they spent many, many hours rearranging the layout to make an amp quiet.

Good Luck,
David

[baddog]

Hi David

The 6.3 voltage is grounded and the caps are new so i guess i will have to take a look at the amp again and check out the wiring. The next amp i am doing is a Knight PA to a Fender Pro amp. I have a turret board i removed from an organ That i can use.

Thanks for the input
Keith