Thanks Paul! I really appreciate all the hard work you did.
Today is one of those rare moments that I got the work bench cleaned off enough to take a decent picture.
I'm about to build the last PC board set so the tidiness won't last long.
This is the "test jig" that I'm using until I box the EQ/Monitor Switcher:
Phono Transfer System RIAA EQ Monitor Switcher on the Workbench
Connections
The soundcard/DAW connections are the RCA connections.
Red and Black feed the DAW A/D; the D/A output used for playback monitoring is Green and Yellow.
The connections to the monitor amp are Grey and Black.
The remote preamp tie lines are the grey shielded twisted pair.
The DC connections have a purple band.
Relay Mode Switching
I don't have switch connections to the relay coils made yet because for general listening they aren't needed.
The EQ Monitor Switcher powers up with all the relays NC.
When powered up, the phono input feeds flat to record and RIAA EQ to monitor.
For general listening or needle drops the Phono Transfer System "wakes-up" with it's input from the turntable and RIAA EQ applied to the monitor out.
The relay coils can be interconnected differently depending on how you in tend to use the unit.
The connections to the individual coils can be "wire or" or "diode or" by paralleling the coils directly or through diodes.
If flat recording is the norm, then the only relay requiring routine operation is RY2 which switches from monitoring the record path to monitoring the DAW output.
There are lots of possible routes through the inputs, EQ, Record and Monitor Outs:
Flow diagram for Phono Transfer System with remote flat phono preamp and RIAA EQ monitor switcher.
Last night I listened to the A-Side of King Crimson's "In the Court of the Crimson King."
Amazing recording.
I've got some restoration work to do but probably not as much as if I had JR's copy.