Argentum 1212 biasing and info

J

Jachiro

New member
Hi. I just got my Argentum 1212 pcb. There’s no documentation available but it seems like a straightforward build. Is there a drill template for this pcb or is it the same as a different pcb on one the site which has documentation available?
 
Ok. So I just finished putting everything together and there’s some things I’m unsure about since there’s no documentation available.

I assume the trimpots are for biasing the J201 transistors? Since there’s a TC1044 in the circuit, I take it that VDD=18V and the bias voltage for the transistors will be around (VDD/2)=9V. Is that assumption correct?

Also if anyone who has built this pedal has info on what control each pot on the board corresponds to, that would be great. Having that is a lot better than me having to turn pots and guess.

If anyone has a schematic and/or layout of this circuit and pcb that would be great too. Thank you!
 
Jachiro said:
Ok. So I just finished putting everything together and there’s some things I’m unsure about since there’s no documentation available.

I assume the trimpots are for biasing the J201 transistors? Since there’s a TC1044 in the circuit, I take it that VDD=18V and the bias voltage for the transistors will be around (VDD/2)=9V. Is that assumption correct?

Also if anyone who has built this pedal has info on what control each pot on the board corresponds to, that would be great. Having that is a lot better than me having to turn pots and guess.

If anyone has a schematic and/or layout of this circuit and pcb that would be great too. Thank you!
Click to expand...
The build doc is up. The 2 b1m are for bass and treble, volume a100k, gain a1m. Also yes, 9v for each j201. I started at 9 on all and then did minor tweaks by ear. Have fun playing this pedal, it's fantastic.
 
mralanmorgan said:
The build doc is up. The 2 b1m are for bass and treble, volume a100k, gain a1m. Also yes, 9v for each j201. I started at 9 on all and then did minor tweaks by ear. Have fun playing this pedal, it's fantastic.
Click to expand...
Is there a recommended gain and volume setting at which we bias the transistors?
 
Jachiro said:
Is there a recommended gain and volume setting at which we bias the transistors?
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Using a multimeter you bias the jfets to 9v each. From there you may be able to tweak a little bit too get a touch more volume, but I wasn't able to achieve much more drive.

Sorry, I misunderstood the question. No. The pedal needs power, but it doesn't matter where the knobs are at.
 
Jachiro said:
Is there a recommended gain and volume setting at which we bias the transistors?
Click to expand...

Volume - no.
Gain - I'd set gain to max and short the input to GND. You don't want any signal going through the pedal while measuring voltages.
 
I just built one and found that 9V sounds best to me. I'm getting very close to exactly 18V from the charge pump. Interesting sound! I kinda like that it doesn't sound like everything else. It makes a killer boost for a Strat into another OD but can get quite sludgy with HBs.
 
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