NYAN (Not Yet Another Neve) EQ =^x^=

[krabbencutter]

NYAN has evolved!
What started as a 1073 clone with gyrator circuits, has now become my take on a "best of Rupert Neve" EQ (and this time my prototype *actually* works).

The Shelving filters are based on the 1073. You get a fixed 12kHz high shelf and a low shelf with four selectable frequencies (35Hz, 60Hz, 110Hz, 220Hz). Where things get interesting is the mid band. It is a fully parametric band, based on Rupert Neve's design in the AMEK Mozart RN Modules. The frequency range has been adjusted to cover the range from 315Hz to 9kHz. It's a proportional Q design similar to the AMEK 9098 and Portico 5033. The high pass filter is a 12dB per octave Sallen-Key butterworth filter and variable from 14Hz to 240Hz. Last but not least the EQ features a flat frequency response up to 50kHz. As always, the EQ is built around modern & readily available parts.

You can find the KiCAD & LTspice files on my GitHub:
https://github.com/greyboxaudio/NYAN-EQ/

 

[Ricardus]

I'm still onboard.

 

[krabbencutter]

This is only the beginning Some time next year I will add an Arduino and replace the Frequency & Q pots of the mid band with digipots. That way it can be switched between fully parametric as well as the responses of many classic & modern Neve EQs. Be it the 1073, 1084, 1081 or even the 551 & Shelford.

 

[Ricardus]

Cool. But at some point I'd like to build some.

 

[DarkSky]

Schema looks interesting and has a few applications. Not sure if the Arduino and digipots route does much for me (FWIW) -- I'd probably prefer to commit to a variant at the design stage and have fewer choices at 'crunch' time...

Meanwhile, looks like your prototype (and schematic) is running unbalanced input and output. Are you planning to add trafo in/out, or will you use this with unbalanced lines?

 

[krabbencutter]

If you want fewer choices you can just stick with the default Mozart mid band
I'll add symmetrical I/O at a later stage but it will be active balanced I/O.

 

[DarkSky]

If you want fewer choices you can just stick with the default Mozart mid band

Yes - that would probably be my preference. On the occasions in the past when I've worked on a Mozart board I quite liked the curves of the RN eqs. These days I have a stack of 5033 modules, which I like for similar reasons (actually, I think I prefer them to the Ameks, but I haven't directly compared them...).

I'll add symmetrical I/O at a later stage but it will be active balanced I/O.

Gotcha. And that avoids having to mess with trafos (which add their own sound, for better or worse - though I do like the isolation).

 

[krabbencutter]

Trafos can be nice, but I like to keep my projects as affordable as possible and a nice input transformer probably costs as much as all the other parts combined The active balanced I/O from the Mozart does a solid job and I've already drawn a schematic of the AT8 Hybrid Line driver: Amek AT8 Hybrid Line Driver Questions Once I had time to build & test it, as well as the Amek's TLA Input, I will include them in the NYAN schematics. And after that I might do a PCB.
The Arduino mod will kind of be an optional add-on to the actual circuit.

 

[macleod69]

Hi,

I found a new "Eq Only" PCB here:
https://proaudiogc.com/en/pcb-gc-73-eq-neve-clone-eq-1073

regards

 

[porkyc]

For all my seemingly poo-poo'ing this project on an alternative thread, well done.
PC