Help needed!! Bluesbreaker re-build problem!! Help?

[thebloosman]

Hi guys,

I'm attempting to get my amp going for the first time, it's a....

Jtm 45 bluesbreaker re-issue-re-build with point -point board, & marstran RS OT, all wiring good, tested fine until power tube test section, i did had a few problems, now sorted but I have created/made another problem,
All tested fine until power tube test, got the tubes in place, speaker connected, all pots to 0, turn standby on and I get this "MASSIVE Loud farting/motorbike noise! WTF??

Any ideas guys??

[David B]

Got pictures?

[thebloosman]

[thebloosman]

What do u need to see guys???

Just a thought....I'm using JJ 6l6gc POWER TUBES, as I'm waiting on my kt66's arriving, will this make any difference???

[thebloosman]

SHE'S ALIVE!!! Whoooohoooooo!!!

The primary wires were around the wrong way...
I swapped them over and the loud hum has gone, great!!!!

But.....

The bias is off....I'm using 6l6's in place until my kt66's arrive but the bias is only around 25-26 on the meter with the bias pot completely counter clockwise....any ideas there????

[neikeel]

I don't wish to sound particularly arsy but there were two other threads that had answers to your questions and no follow up reply from you then another thread in another section

The bias setting will depend on the method you are using and the plate voltage. If you are using the stock PT and a modern GZ34 then 400V will be about right on pin 3 so 45mA would be your target.

As a rule KT66s will draw more so you can alther the bias resistor now for these tubes or play it as is and wait for the definitive valves or..........