Chickenhead - Bias

[FormulaFourteen]

Hi gang

About to build a Chickenhead.

Can someone talk me through setting the bias using the trimmer?

(even better, can someone point me at any pedalpcb docs that explain it, if they exist - teach a man to fish, etc etc).

I actually have the same question about the Clandestine Preamp but for the benefit of future searchers I'll post them separately.

Thanks

 

[szukalski]

Chuck sums it best here.

Set per science, then season to taste.

Get the values around right, then test using the range max/min to see if you like a bit hotter or colder.

 

[FormulaFourteen]

Thanks.

Where on the PCB do I measure the voltage?

And do I need to measure the input voltage like in some other biasing operations?

 

[szukalski]

Set your DMM to measure voltage (20V range).
Attach the DMM ground to a ground point on the PCB.
Measure against the collector of the transistor. On the board, it's the right-most pin of the transistor. The tab is for the emitter.

Socket your transistors if you're not a seasoned pro, and you will thank yourself later.

 

[FormulaFourteen]

Thanks.

Annoyingly I've got the whole thing ready to go, except I don't have any DC jacks the right size, so now I need to wait for the postman...