Thanks Jay, nice simulations!
The improved version of the biasing voltage divider looks like this:
Here the idea is to shunt resistor-noise from the divider R2/R3 to ground via C5.
So as not to short-circuit the signal also to ground we need a 'T' shape with new resistor R9 (50R here).
If you have time and interest, could you run your simulations for this biasing circuit also?
Having said that, my v3 design uses split supplies and is inspired by the Symmetricom 6502B teardown. I am now working on the linear regulators and powersupply input filtering. The idea is to use TPS7A47 and TPS7A33 LDOs, BNX025 filters, and maybe a discrete LC-filter and/or common-mode choke as well. Ideas welcome.
The plan is to use something like a Traco Power TMT for +/- 12V and feed that to the LDOs
http://assets.tracopower.com/TMT/documents/tmt-datasheet.pdfStay tuned, v3 boards, assembly, and measurement results hopefully within 2-3 weeks...
Anders