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with McCurdy AU300 Preamps

Logo Ottawa copy

This has certainly been my most ambitious project, and has taken many years. How many I’m not sure, but I believe it was some time around 2006 when I began acquiring and restoring AU300 tube preamplifiers. As the number of these grew, I decided to build a console to allow for mixing, rather than just using the preamps as a front-end for tracking. With the exception of the Master/Global section (not yet finished), it is currently a fully functional mixer.

Console 2

The design is very basic, each channel having a meter select, 2 aux sends, an 11 step switched-pan, and a switch sending the signal to either the Stereo Bus, Direct Out, or Off. The signal flow for mixing is fully passive. The only op-amps used are unity gain buffers, which ensure that the Aux Sends remain entirely discreet from the main channel outputs. The summing amps (Stereo L-R, Aux 1-2) are McCurdy AT350 program amps.

The math for the design was gleaned by studying the writings of Howard Tremaine, Geoff Tanner (his design guide was very helpful), Douglas Self, Steve Dove, John Roberts, as well as a host of great designers who share their ideas on the internet.

The McCurdy parts have been cobbled together from here and there. I made one of the AU300 racks, and the other is an original. The one I made is upside down (at that time, I never thought there would be an original one to compare it to). Each rack is accompanied by a huge McCurdy power supply. One of them was designed to work with the AU300s, and the other was designed to go with an old McCurdy mixer. The 4 McCurdy cabinets that serve as the frame for the console came from the CKCU radio station in Ottawa (with help from my good friend David Sarazin). The patchbays are McCurdy (mostly ex-CBC), as are the meters. The metal sides of the console were cut from the doors of an old elevator control panel. Many of the Painton faders came from Norway, while others came from England.

The top portion of the console is new and original, as are the interface racks below (mic/line 48v, pads etc.). This required among other things, a fair bit of welding, metal bending, cutting and fabrication.

Wiring all of this up was a formidable task, but thanks to the “fantastic” work of Mina Ghamari (who became my partner in crime building this thing), it all finally did come together. Thanks so much Mina! She and I have also been co-producing an EP for her awesome metal band “Aenigma”. We’ve begun doing the backing vocals using the SCOUTCO console. Such fun!

Console 5

View Fabrication Photos:

McCurdy AU300/Power Supply Restoration

AT 305 Bus Amps Before Restoration

Phantom Power

Painton Faders arrive from Norway

Building Frame

Frame Done

Channel Modules

Panels Begin

Marking and Cutting Panels

Frame and Panels Done – Unpainted

Frame and Panels – Painted & Silkscreened

Installing Modules

Interface Between Modules & Amplifiers

AT 305 Bus Amps Finished


Fitting Bumper

Bumper and Bus Amps Installed




  1. marty jones marty jones

    wow steve looks great must sound awesome

    • Steve Steve

      Thanks Marty!

  2. David Sarazin David Sarazin

    I am guessing there is no need for a space heater in the winter with all of those tubes!

    • Steve Steve

      It does keep the room pretty toasty…

  3. c austin c austin

    absolutely incredible! what a beautiful console

  4. Wyatt Avery Wyatt Avery

    That’s an incredible task, I’d love to do something similar one day.

    • Steve Steve

      Thanks Wyatt! It’s all been great fun, and I hope you pursue that inclination!

  5. Will Will

    I have a number of these AU300 modules. Great pre-amps. If you’re looking for vintage tube outboard I have quite a bit for sale.



    • Simon Gauthier Simon Gauthier


      Do you still have your McCurdy AU-300 for sale?

      Have a great day!


    • Davide Di Renzo Davide Di Renzo

      Hi will. Hoping this message finds you well. Would you still happen to have any au300s for sale? Kindly let me know and be well. Thanks

  6. Tom Tom

    Great job!
    I have a very similar project going, well on and off.
    R.E.D.D. inspired for sure.


    • Steve Steve

      Thanks Tom! I’d love to see pictures of your project!

  7. Ian Ian

    This is so awesome. Incredible job!

    – a fellow AU300 owner (though only 8 :/ )

    • Steve Steve

      Thanks Ian! Great to hear from a fellow McCurdy fan!

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