ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: Jag I've got a BF Bassman (tube chart s... -- 1120495731

Re: OK, where's that hum coming from?

7/5/2005 9:30 AM
R.G.	Re: OK, where's that hum coming from? In no particular order: 1. Check the ripple on the bias supply. 2. Loosen, clean, then retighten every jack, pot, and ground connection screw to the chassis. 3. If it uses a CT connected to ground on the heater supply, replace that with two 47R 1% 5W wirewound resistors in series across the heater supply, then ground the center of the two resistors. 4. Set the thing up so you can insert a 1/8" thick plate of steel (like from Home Depot) between the tubes and transformer, and between transformers. Experiment with placement. 5. Check on the twisting of the AC power wires. They must be twisted tightly together, including the heater wires.

7/5/2005 9:30 AM

R.G.

Re: OK, where's that hum coming from?

In no particular order:

1. Check the ripple on the bias supply.

2. Loosen, clean, then retighten every jack, pot, and ground connection screw to the chassis.

3. If it uses a CT connected to ground on the heater supply, replace that with two 47R 1% 5W wirewound resistors in series across the heater supply, then ground the center of the two resistors.

4. Set the thing up so you can insert a 1/8" thick plate of steel (like from Home Depot) between the tubes and transformer, and between transformers. Experiment with placement.

5. Check on the twisting of the AC power wires. They must be twisted tightly together, including the heater wires.

Replies:

loudthud Sounds like something is out of bal... -- 7/5/2005 3:52 PM
Eric H [QUOTE]2. Loosen, clean, then retig... -- 7/5/2005 9:19 PM