"I see lots of wires that should be stripped back 1/4" but are stripped back more like 1" This can cause unpredictable reliability issues and may require some rework on your end.
The last power supply cap that lays down against the chassis needs to be installed closer to the terminal strip so it fits inside the wood base."
Will work on that, thanks.
"You have your power transformer wired for 110V or less which is rather uncommon, what is your wall voltage? "
I just checked the instructions again and I seem to have followed the 110-120 volts. Namely I have a wire going from 33 U to terminal 4 (red). Please let me know if this is wrong.
"The 220 ohm resistors on the octal sockets are not installed as instructed in the manual."
In what way? Do you mean just the way they are positioned?
"The white wires leaving pins 2/8 on each socket are stripped back way too much (as mentioned above), and if they touch pins 2 or 7 you will destroy your preamp."
Will work on that.