Took the opportunity of yesterday's crummy weather to dead-bug a passive RIAA pre using the LM4562 -- I got out the old RLC bridge and went through the component bin to get close to exact values for the network:
An externally hosted image should be here but it was not working when we last tested it.
Looking forward to the rest of the story.
Here's a first shot at the performance:
I'm using Walt Jung's values from "The Op Amp Applications Handbook".
An externally hosted image should be here but it was not working when we last tested it.
I'm using Walt Jung's values from "The Op Amp Applications Handbook".
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No, I didn't put in the servo -- yet -- and it is DC coupled. The AD745 is a shown on Walt's schematic is a BiFET opamp and the LM4562 isn't so some belts and suspenders will probably be needed. I will probably have to get the Dremel out and put the servo on the bottom!
Dead-bug on copper is great because you have the ground plane, you have a heat sink and the P2P means that there aren't little gremlins running around on the fiberglas. The easiest way to nail down the opamps is with the ceramic bypass caps on pins 4 and 7.
Put a little LPF on the tail -- it could be tweaked a bit -- but this should tame clicks and pops:
An externally hosted image should be here but it was not working when we last tested it.
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