Metallic pops when on full volume even heard quietly when no speaker is plugged in!

[nedhogan]

I think it may well have been oscilllation! I put the 220K pot in and it still did it to an extent, until I separated all the wires and it stopped.

In regard to Bill, I was refering to the solder lugs on the pot as if looking from behind the pot, like you've taken the back off your amp, numbered from left to right, I don't think I written it correctly anyway. But yes I am using it to replace the grid bia resistor.

When the powers on and when a component is in situ isnt the best time to measure the resistance anyway. Everything was probably fine! Just severe oscillation or signal bleeding to somewhere it shouldnt, or whatever.

Problems always sound worse when they come from tube amps!
Still can't believe it was oscillation! wierd

[J M Fahey]

Post the schematic anyway.
The one you actually built, not a link to Lar Mar or whatever.
Some closeup picture showing the wiring, lead dress, etc. would be fine too.
Thanks.

[nedhogan]

I simply replaced the two 330k grid resistors with a potential divider consisting of a dual 250k pot. The whole amp is wired point to point without turret board, it was made in the 60's, I just repaired it and messed around with it. Currently trying to get more distortion out of the pre-amp section, so itll take OD pedals and not just do a volume jump, if you know what I mean. It was a cheap HiFi amp but was often used back in the day as a guitar amp its called a Linear Conchord.

Its guts look horrible I wouldn't like to post them, obviously whoever made it back then wasn't worried about looks! .. No wonder it went into oscillation when I added that MV. Should really have used shielded wires but its fine now.