The initial prototype of the CLA-2a was built in an old CBS Audimax III enclosure and was painted with automotive paint from K-mart! The wiring was all point-to-point and all of the components were of similar vintage to the original versions of the Teletronix LA-2A. Also, it was an unbalanced unit with no transformers on the input or output. Because of my inexperience with building and modifying tube gear at the time, I didn't put a bleeder resistor on the output and the lack of output transformer meant that DC built up on the output while the unit was warming up. The result was a nasty shock if you turned the unit on without having it plugged in, and then accidentally touched the tip of the 1/4" plug connected to its output! I and a few of my friends were very surprised to discover this kind of tube warmth!
It was noisy but had some good sonic qualities to it. In particular, the compression was remarkably smooth when used on female lead vocals. In spite of its shortcomings I got impressive results with this unit using it on vocals on several records I did, especially when driven by the Kenetek VTMP-2b tube mic preamp I built. It proved that the LA-2A was a design worth pursuing and improving.
The flip-down front panel inherited from the design of the Audimax III case meant that I could hide the Meter Zero and Stereo Adjust pots behind the front panel, and these adjustments were available without having to take the unit out of the rack.
The circuit was completly stock, as I strictly adhered to the original LA-2A circuit diagram faxed to me by Mercenary Audio. (Thanks, guys!) The power transformer was a Hammond unit I got from Old Colony Sound (I'm pretty sure - it's been so long I don't remember for certain.)
This picture shows the unit with the original 0 - 1 mA meter movement left over from the Audimax III. It didn't work very well with the original meter circuitry so I ended up replacing it with a proper API 361 VU meter, which was the exact dimensions of the original meter. The API 361 is an exceptional VU meter and one I highly recommend if you're building any vintage audio gear which requires a meter with true VU characteristics.
More photos of the initial CLA-2a prototype
The Blackface CLA-2a: The Production Version -->>