root42 wrote on 2020-03-10, 15:11:
Then I would suggest to make a smaller order: 3 PCBs at Aisler; because the SIDs will be expensive. The RCA jacks will have to be found (where?) and the 558 -- which we could leave out for the time being, since it would be a beta test. So you never built the card?
The RCA jacks, NE556 in SSOP14 package and the Keystone bracket are available from e.g. Mouser, probably Digikey, as well.
No, so far, I have never built the card. I published the design as soon as it looked presentable.
However, I am reasonably confident that the MOS6581+NE558 configuration is identical to the original card, because all the visible traces are identical and the schematic makes sense.
MOS8580 configuration should also work, as far as the layout is concerned, but I'm not entirely sure about the values of the resistors that set the voltage of the adjustable voltage regulator.
The problem with these 3-pin adjustable regulators is that the output voltage can drift depending on the load and how much it drifts depends on how large or small the resistor values are.
When it comes to the STM32-based version, some resistor values are still unknown, because their purpose is fine tuning of the card's output levels.
For the time being, I would suggest to wait with PCB orders and to take another close look at the schematics and layout to compare them to existing board photos.