TTSH (ARP 2600 clone) build notes - VCA (DIY)

The VCA build of the TTSH synthesizer. 

This is part 9 of my TTSH (Two thousand six hundred) build which is an ARP 2600 clone synth.
You can see my full build thread HERE

There are two awesome TTSH threads in Muffs.
2600 clone - Two Thousand Six Hundred (TTSH)
and
Two Thousand Six Hundred (TTSH) Project General Build Thread

The DSL-Man site has a very good TTSH thread

And of course the official build thread is here

The ARP 2600 used 4010 & 4019 sub-modules in the VCA section.
There were matched transistors (TZ-581 & TZ-81)  and a Op Amp (LM 301) at the output stage.

The TTSH uses the TZ-581 & TZ-81 modern equivalents (2N3904 & 2N3906)
The LM301 is unchanged. :-)
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 Front PCB (pre population)

Back face of PCB

 Resistors, Diodes then Caps.

Unmatched transistors.

 

Matched transistors & the LM301 op-amp