TMB first gig

[stevesuk]

The JA/Richie TMB I finished a couple of weeks ago had it's first 2 hour gig last night. It came through with flying colours.
Setting-
A medium size carpeted Pub/Blues club in London.
Temporary stage of plywood with bare plywood backing.
Three piece band.
Blues/Rock.
The MV channel used, with most controls at 3/4.
Volume controlled from guitars.
First set, 1965 Telecaster Esquire (not squire) and 1959 LP Junior for second. Tele wasn't at all jangly or sharp as it tends to be with some bigger amps, chords and single notes clear and sweet.
Junior very different, rich, organic, lots of complex harmonics.
Tiny bit lacking in sustain on both guitars.
Over 3/4 volume on amp a high pitch whistle/feedback.
Any suggestions for mods to get a bit more sustain and cure for the whistle problem Steve UK

[bnwitt]

Steve,
my suggestion on eliminating the squeal is to redo your grounding scheme. I noticed in your gallery photos that you used a star ground on one of the trannie bolts. I did that one time with a 5F6-A and had the exact same problem, a nasty squeal at higher volumes. I checked that amp up one side and down the other for days trying to find out what the culprit might be, and everything was fine. I should mention that I had used the exact grounding scheme numerous times before with no problem. Then I separated the grounds into two sections (preamp on one star, power section on another) and the squeal dissapeared. The only problem left was some objectionable hum. Removing the power section star ground from the trannie bolt and putting it on it's own drilled chassis ground point fixed that problem. Good Luck.
Barry

[stevesuk]

Thanks Barry, I did wonder about starring everything together. I have heard before about seperating ' power ' grounds and ' audio ' grounds. As you say, never had a this sort of problem before. I'll give it a try, because the Amp is well worth getting perfect.
Steve UK

[wayneosnochas]

Ive gone round and round on this on a few amps and splitting the ground like Barry says helps

1ground for earth
1ground for power/filters
1 ground for preamp/imput

also keep the ground runs lenght short as possible using large or 2 thin guage wires

wayne

[jersey_aaron]

I seperated them as well. No squealing either.