My millett doesn't amplify

[GregVDS]

Is this the case for both bias adjustment? I remember one of the board version had one of the trimpot leg not connected (it happens sometimes in eagle, a trace vanish without an explanation).

What is your power supply? how much voltage you give?

did you put some led behind tube? if so, how did you connected it?

Try to follow the schematic of the Millett, following supply voltage, and check the legs of the components directly connected to the power supply (leg 3 of VT1, leg 4 of VT1, leg 3 of VT2, leg 4 of VT2, all compared to ground).

All the best,

GregVDS

 

[~AZ~]

Both bias to the same...around 19...ok I also checked the leads on the R5 positions and get about 3.3v on each side and they are 1k resistors.

It is being ran off a tread with a unregulated ac 24v supply and I am running 24v from the tread to the amp.

There are no led's under the tubes.

 

[NeilR]

What exact part are you using for the CCS (D2LA or D2LB)?

 

[~AZ~]

I'm using vishay J503 at d2la and d2lb

 

[NeilR]

Quote:

Originally Posted by ~AZ~ I'm using vishay J503 at d2la and d2lb

You should populate D2LA or D2LB (and D2RA or D2RB) BUT NOT BOTH.

Is this the problem?

 

[~AZ~]

OK I pulled D2LA and now the right channel is still low and the bias can only be set to about 19v at it's lowest and the left channel is nothing but intermitent distortion and the bias reading is about .78v

 

[~AZ~]

oops hold on...I forgot to populate d2 lb

 

[n_maher]

Quote:

Originally Posted by ~AZ~ oops hold on...I forgot to populate d2 lb

Hold the phone, as Neil said you are only supposed to populate either D2LA or D2LB, NEVER BOTH! Same thing with D2RA and D2RB, one or the other, NEVER BOTH!

 

[~AZ~]

I'm an idiot...but at least now I'm a happy idiot!!!

I had those positions fubar but all is well now.

THANK YOU ALL FOR THE HELP!!!

 

[mb3k]

Woot woot

So which positions did you populate in the end?

 

[~AZ~]

I originally had populated d2la and d2ra with the J503 instead of the obvious d2rb and d2lb. Everything is running great now...the amp is perfectly silent, no hum or anything...sounds great too!

 

[Jam_Master_J]

Quote:

Originally Posted by Clutz Are you sure the input RCA jacks are wired correctly? The outer wire is ground, the inner wires are signal (e.g. connect the inner part to either L or R pad, and the outer part of the wire to ground). If you did this the opposite way, you wouldn't get any signal amplification (I don't think) because you'd be amplifying the ground (return) instead of the signal (incoming).

I think only the phase would be reversed.