On 4/19/2015 2:36 PM, Tom Fine wrote:
> Why does the EQ module have to have active EQ? Why not take the
> pre-amplified signal from the preamp module, do passive EQ and then end
> the EQ module with a gain stage to bring it back up to line level?

What you're desribing is a standard configuration for a phono pramp (or
at least one standard configuration).

By the way, most mic preamps found in 500-type modules wouldn't work for
phono use, because the input impedance is typically 1.2k - 2.5k, while
moving-magnet cartridges need 47k in parallel with a certain amount of
capacitance (which varies from cartridge to cartridge). Therefore, you'd
need a transformerless 500-type module with altered input stages for
the catridge, and another with high input Z to follow the de-emphasis
networks.

There are only two advantages that a 500-series rack offers:

1. It has the power supply built in.

2. It's already certified by Underwriters' Laboratories, meaning a
manufacturer of a modeule needn't go through that slow, expensive process.

Reason 2 is why 500-series modules have become as popular as hotcakes in
the last several years.

Could someone build such modules for a 500-series rack? Of course; I
suspect the only reason no one does is that there isn't sufficient market.

Peace,
Paul

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