Missing Build Docs / Schematics

jimilee

Well-known member
Thank you. This is my first build without documentation, I really appreciate it.
Absolutely. The PPCB boards are all like that. You can find another board with the same pot layout for a drill guide. Robert uses a basic template layout for his boards. Makes things easier to build.
 

Robert

Reverse Engineer
Staff member
Measure the DC voltage on the drain of each JFET while adjusting it's corresponding trimpot.

You can use either the through-hole or SMD pad as a test point (whichever is more convenient), regardless of which type transistor you have installed.

1670001451692.png
 

bowanderror

Well-known member
Measure the DC voltage on the drain of each JFET while adjusting it's corresponding trimpot.

You can use either the through-hole or SMD pad as a test point (whichever is more convenient), regardless of which type transistor you have installed.

View attachment 37185
Is this circuit sensitive to JFET specs? I usually socket SMD JFETs on an adapter PCB, but I'm tempted to just solder them directly if it's not picky.

I've tested & used a bunch of this SMD J201 batch, so I'm not worried about them being super out-of-specs or fakes.
 

szukalski

Well-known member
Is this circuit sensitive to JFET specs? I usually socket SMD JFETs on an adapter PCB, but I'm tempted to just solder them directly if it's not picky.

I've tested & used a bunch of this SMD J201 batch, so I'm not worried about them being super out-of-specs or fakes.
I didn’t find any issues, it’s not a massive gain monster and biased easily.
 
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