7. Install the bias adjust trim pots, transistors and voltage regulator
Install the bias adjust pots (R17 & R18), three small transistors (Q1, Q2, and Q3) and a
voltage regulator IC (U3). Note that Q1 is a 2N7000 MOSFET, and Q2 & Q3 are 2N3904
NPN transistors
– they look almost the same, but you can read the part number on the
device. You need to slightly bend the leads of the transistors and voltage regulator then push
them into the PCB. Bend the leads slightly on the back, solder, and trim the leads.
(Note that Q1 i
sn’t visible in this photo – it is off to the left).