Friday, May 1, 2020

Aikido Cathode Follower Preamplifier

After all that work removing hum from the Aikido ACF-2 board (see the previous post), it would be a shame not to make a complete preamplifier with it, and this is what I did.

The enclosure is from Modushop with front and rear panels custom made and engraved by Front Panel Express.

The rear panel has three pairs of gold plated RCA input connectors and two pairs of outputs (connected in parallel), plus an AC power inlet.
Inside, besides the ACF-2 board, are a toroidal power transformer, an output muting board from Pete Millett, a volume control, and and input switch. The input switch is mounted in the rear and is connected by a shaft extender to the front panel knob. All connections are made by teflon insulated, sliver plated copper wire.
The front panel has a sub-panel holding the volume control potentiometer (ALPS RK27) and the bearing for the extended switch shaft. The sub-panel allows hiding the bottoms of the knobs inside the front panel for a more professional look.
The tubes are E88CC.