Finished second Don Classics NV73EQ

Finally got around building my second Don Classics NV37EQ (first on described over here).  Aren’t they pretty? This time I took some more pictures during the build. Highly recommended, used it on a few sessions since with great results. Getting great feedback too from engineer friends who borrowed it on their own sessions.


Studer 169 EQ Build

Next in my modest assembly line: a 500 series Studer 169 EQ, created by GroupDIY member audiox. Got the idea from browsing the GroupDIY forum and decided to do the  full-on mojo build with Discrete Opamps and Transformer balanced input.

This is what the finished pair looks like:

studer duo finished

Since the frontpanel had an extra hole provisioned for an LED I had to swap the DPDT switch on the build plans with a 3DPT switch. The LED takes voltage from the nearest 16+ rail point i could “hook” into and returns to an unused solder pad nearby that returns to ground.


Although the potmeters provide a means to attach a frontpanel to the PCB I decided to go for something a little more sturdy and mounted the PCB on L-brackets.


First mounting of the front panel. The switch I used first didn’t really fit the frontpanel’s hole, so a little rework needed to be done.

Mounted the frontpanel…jup, something's not quite right..

My initial, unmodified build:

Studer 169 EQ PCB fully populated

List of materials/sources:

I love the sound of the hi/lo shelf on these!