"Serge Auckland" wrote in
message

I've read and re-read John Byrne's arguments and still
think he's wrong. Every RIAA amplifier I've ever designed
and every one I've measured has a voltage amplitude
response that boosts the bass end and cuts the treble
end.

Or if one prefers, a RIAA playback preamp for a magnetic (velocity)
cartridge is roughly an integrator above 50 Hz, except for a bump in
response between about 500 and 2122 Hz.

If one uses a pickup that does not respond to velocity but instead responds
to amplitude, then you don't need the integrator, but you do need the bump.

The RIAA curve calls for a 19.36dB boost at 20Hz, and a 19.95dB cut at
21kHz. Both are relative to 1kHz.

Agreed.

The IEC
curve is identical to the RIAA curve with the exception
of the extreme low end which is boosted less on replay to
act as a built-in rumble filter.

Agreed.

No curve I've ever seen has a 12dB boost to the treble.

Agreed. The two possible alternatives for treble cut are either 20 dB cut
above 2122 Hz for a velocity-sensitive pickup, or no cut for an
amplitude-sensitive one.

If John is so precise, I can't understand for the life of
me what curve he is referring to. You only have to put a
generator to any RIAA input stage to see that the curve
is as above, with 19 odd dB boost at the bess end and
almost 20 dB cut at the top.

Been there done that, many times.