should i put tubes in?

[dvbme]

I built an express as per RLW1.8 but get a 0Ma bias.

v1 1-188 3-1.62 4-3.25 6-168 8-1.2 9-3.25
v2 1-235 3-2.41 4-3.25 9-3.25
v3 1-181 2-22 3-33 4-3.25 6-180 8-32.8 9-3.25
v4 2-3.1 3-349 4-345 5-0Ma/-20vdc 7-3.1
v5 same

bias 0Ma
control grids pin5 -20vdc

Pam-Ot
PRIMARY: 7.5K Ω CT
POWER: 30W
Pam Pt
YEL/GRN 250V

[martin manning]

Above readings are with preamp tubes but no power tubes installed? You will not see any idle current flowing until the power tubes are installed. If you are asking if the voltages look good enough to put the power tubes in, I'd say yes but I'd like to start with lower (more negative) voltage on pin 5's.

[dvbme]

Yes 12ax7s. no el34s yet, so how much lower?

[martin manning]

Maybe -35V? Isn't your bias voltage adjustable? Can you turn it down? I'm guessing you might need something around -30V when biased correctly.

[dvbme]

I can't seem to get above 30. I've tried the 150k resistor but no change mostly 20's. went back to 220k I'm using the Bourns 3329H-1-253LF 25k wondering if using the 22k might work?

[martin manning]

Reducing the value of the resistor connected to the high voltage AC should get you lower (more negative) voltage. Is there a reason that your B+ is 350V instead of 400V, like perhaps you are using a non-standard power transformer?

[dvbme]

i'm using pacific trannys. i put in the 150k and changed the 10uf-100 to 10uf-150 and the pin5-1500 to 1w
and now have -035vdc.

[martin manning]

Not exactly sure what you did there, but if you can get say -25 to -35V at pin 5's by adjusting the bias pot you should be good to put tubes in and set bias.

[dvbme]

well i put them in and go a squeal no sound otherwise. turned trimmer till it stopped at -038 still no guitar tones

[martin manning]

Often that indicates that the OT primary leads are reversed and you are getting positive feedback. I'd try swapping them, or see if the squeal is still there after temporarily disconnecting the feed back.

[dvbme]

Well that helped a heap. wow.

[dvbme]

Thanks so much. I played for an hour and it was phenomenal. and the transformer was still cold. got me wondering why the rocket i built power transformer gets so hot 62c after 3 hours.

[Reeltarded]

Part of the heat is soaking from the tubes, the capacity of the transformer is some more.

62C is 150+°F.. that is too much.

[dvbme]

Thanks for all your help. I made a video of the from lean to mean thing it does so well.
https://dvbme.com/pics/Video/Lean%20to%20mean.mp4