Even with all its shortcomings I considered the prototype CLA-2A a success and decided to continue with the evolution of the design. This time around there were several things about the original design that I didn't mind updating. I took the liberty of incorporating fully filtered and regulated DC power supplies for both the filament and B+ voltages, I upgraded the quality of the components dramatically, using metal film resistors, Wima polypropylene capacitors, Mogami cable and other, top-quality parts. I also went to great lengths to create optimized PC board layouts for the audio and control circuits, as well as for the power supply and meter circuits. Another thing I did which I think contributes to the transparent sound of the unit is to eliminate all connectors inside the unit, in both the audio path and power supply. Although this makes the unit a little harder to service should anything break, it enhances sound of the unit and makes the unit more reliable. I'm sure manufacturers who are putting out hundreds or thousands of units a year can't do this, but I'm glad I did. These changes resulted in a 10 dB improvement in the unweighted signal-to-noise ratio of the units compared to a stock, vintage Teletronix LA-2A.
I also went to great lengths to design a unit with both balanced and unbalanced inputs and outputs, this time with no shock value :-) My thinking was that an LA-2A-style compressor might come in handy in an instrument signal path, such as a bass or synth. As it turned out, I don't know of a single instance where any CLA-2A was ever used this way, and I eventually did away with the unbalanced ins and outs as they were a pain in the butt to wire, particularly if nobody was using them.
I also upgraded the looks of the unit, going with a 3/16" thick, black, anodized front panel with engraved nomenclature. The front panel also featured die-cast, black, anodized aluminum handles, which made getting the unit in and out of the rack much easier. I also used premium quality gold-plated XLR and 1/4" connectors on the rear panel, which really helped give the unit a quality look and feel.
Other enhancements included a Stereo Link switch so that two units could easily be configured for either independent or linked use without removing the units from the rack, a 1/4" Stereo Link jack on the back instead of terminal strip connections, a 120/240 volts select switch on the rear panel, a 3-1/2 inch backlit Sifam VU meter, ceramic tube sockets with gold-plated contacts and military-grade, sealed conductive plastic pots for Gain and Peak Reduction. In short, I designed and built these units as if cost were no object and so they would last a lifetime.
I was greatly rewarded for my efforts. The Blackface CLA-2A's are exceptionally good sounding units, and everyone who has bought one (most people bought two) continue to rave about them. I've heard from many people that their CLA-2A's are their compressors of choice when tracking vocals, even though they own racks of Neves, SSL's and every other compressor under the sun. I have to agree; when tracking vocals the CLA-2A is smoother, and at the same time airier and warmer than anything else I've ever heard. I only wish they weren't so expensive and labor-intensive to build. Because it takes over 40 hours to build each unit, it's very likely that the 31 or 32 (I don't remember exactly) Blackface CLA-2A's that are out there are all there will ever be, although I still have the sheet metal for one more.
More pictures of the Blackface CLA-2A -->