(Apologies for large pictures, not sure how to size them down in Audio Circle posts)
Materials arrived as planned:
Most importantly - high precision capacitors for passive RIAA:
Unfortunately, these capacitors are not manufactured anymore, so when this batch is gone, the RIAA will have to be recalculated and analyzed for values that are still available.
Lastly.... the Printed Circuit Boards arrived about two weeks after the order was placed. Small quantity is sufficient for the first prototype run. If everything goes well, it's easy to order more. If something is to be modified, now is the time to find out....
Top side:
Bottom side:
Results of a quick inspection are quite satisfactory - etching quality is good, gold plating smooth and even, through-hole plating is robust and solder mask is heat and scratch resistant. Some of the reference designators need to be moved or rotated for better readability, but overall, the boards came out very good.
Wasting no time, I populate Surface Mounted Components (SMT).
Please note the coin - it is an integral part of the design that enhances aural perception of visceral involvement in low level detail. The best results are obtained with South Dakota Quarter Dollar (available for sale at incredibly low $99.99). Or, you can use it as an illustration of how small the SMD parts really are.
Next come the through-hole components on the top side:
Main gain stages, centered around U1 and U2 are placed on the front, close to the connectors, while offset cancellation op-amp (U3) is in the shadow, right behind U2. As it does not participate in the sound quality it is soldered onto the board, while U1 and U2 are mounted on sockets, for easier replacement during experiments.
