Gates Mixer

This unit was a remote mixer for broadcast purposes. It came to me modded with the bottom XLR input wired to an input transformer for balanced line input, controlled by the attenuator on the front with the different input levels. I left it as-is. This unit had a 3 tube mic preamp circuit with 5879, 12AY7, and 12AU7 tubes. I upgraded the power supply and added another mic circuit with an EF86 and a 12AY7 fed by a UTC A-11 transformer. It uses an Altec 15095 output transformer. So now there are 2 separate mic preamps. The original mic preamp is mixed with the balanced line input via the controls on the front. They share an output. The new mic preamp has its own output.

On the left you can see the Phantom power LEDs and switches. (I added a phantom power module.) The cue switch has been repurposed as a mic pad. There is a "meter select" switch to select which output (there are 2) feeds the meter. There is also a negative feedback control. The "phones" plugs are TRS 600 Ohm balanced outputs for the 2 channels (new mic preamp + original mic preamp and/or balanced line input.)

This is the "before" pic:

I used these nice turret sockets for the new mic preamp. They are mounted to a rubber mounted floating platform.

One of my phantom power modules:

I think the original mic preamp circuit is interesting enough to be worth sharing: