I did a quick test just to see if all the FAB Modules work and play well together.  I’m very pleased with the results…. The modules were quiet, and even with a long signal chain as you can see in the picture, there was hardly any noise I could hear.  (For testing, I hooked up a condenser microphone and connected the outputs to a KRK RP8 8″ Monitors. No humming, no RF noise, nothing.)

Everything works… the logic control Phantom Power, -20dB Pad, Polarity Reverse, and the +6dB Boost (1:2 Transformer Ratio).  To get the FAB4312 Non-Inverting Amplifier working, I hooked up a small 10K potentiometer so I can adjust gain.  For now, I just used a jumper and connected the Phantom Power Logic control inputs directly to a spare V+ terminal on the FAB1215 PSU module.

I’ll design a Switch Module which will contain the necessary switches to control all the logic functions, and also serve as mounting for the potentiometer.

The fun part with FAB Modules is once you have a complete signal chain, you’ll be able to play with it, by swapping different kinds of Input Transformers, or Output Transformers, or amplifying modules/opamps/PDIP or Discrete Opamp, etc.