My NE5532 balanced RIAA

[Calvin]

Hi,

if You feed the MM-Pickup directly into the inverting stage than indeed the inverting stage is a lot noisier if You take a measurement bandwidth of 20kHz. Because of the lowpass-character of the amplitude response the effective Bandwidth is much lower than 20kHz, probabely something around 2kHz. So in praxis the audible differences between a noninverting and the inverting stage are small. In our case the source impedance the inverting stage would see would be small and so the noise contribution would be snmaller than with a MM-Pickup as source.
The inverting stage shows some desirable properties. Its much less affected by overload conditions, its common mode input voltage remains very small and it follows the equalization curve without the need of an additional RC-filter stage.
One reason why it became less popular in modern times is probabely the noise penalty. To get really good nouse figures, many manufacturers offered measurements with shortcircuited inputs (Yamaha for example) instead of reallife source impedances. Under such circumstances the noninverting stages appeared very superior to the inverting stages, though in practise they weren´t.
So a first linear gain stage -maybe with variable gain- with either active or passive DC-blocking and followed by a inverting gain-stage using a parallel RIAA-Feedback structure is a truely fine solution regarding performance, flexibility and low parts count.

jauu
Calvin

[assembled]

Thank you for your posts. I shall revise my schematic according to what is said and repost it. Thank You.

[assembled]

I have replaced RIAA stage with inverting one.
I see following To-Do:
insert DC blocking. Active or passive? Won't DC servo induce additional noise compared to simple DC blocking cap? Is it worth it?