I hope that it's not really your intention to apply 1vrms at 1kHz into the preamp phono input (that would be bad...). The input should be 5.5mv rms at 1kHz and conform to the RIAA preemphasis curve if you deviate from 1kHz. The output from the new phono stage is intended to be c.1vrms.I've got my ARC SP3-A1 on my bench.
I've got a low noise oscillator from my HP339A,
I can set at 1kHz at 1Vrms to start.
I'll fee that into the phono circuit of the SP3-A1
I'll take the phono output and run it through
my distortion analyzer. And notate the result.
I can try a couple of different test frequencies
lower, higher. Measure them.
At least I'll have a baseline from which to compare
to when my boards arrive and I build them (longer time frame)
compare them to your known measurements of your AD797 phono (short time frame).
Other's might be interested in following along and it would be measuring
prior to the board I make.
Later when the board is finished, I'll do the same tests
using the same equipment. I can also take pics of the
set up etc.
Theoretically, the distortion should be more or less unmeasurable using the new design. However, it might be interesting to explore the overload characteristics.
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