Prior to the development of the widely accepted DL disco mixer Bozak, in 1971, toyed with several factory designs before the final DL version ever appeared. The first 2 dedicated DJ club mixers built and offered were a long style chassis CMA 10-2D with no VU meters and a modified mono input stereo output CMA-6-2S that had similar internal workings as the CMA Chou Morris designed 10-1 and 10-2 mixers with VU meters. The main board used in the special factory modified CMA 6-2S unit was a physically cut down 10-2 board with 8 mono channels. The input channels went from mono to stereo by using mono channels 1 & 2 with mono phono preamp cards installed becoming stereo phono channel 1. Stereo phono channel 2 developed stereo signal from mono channels 3 & 4 with mono phono preamp cards also installed. Auxiliary channel 1 stereo signal came from mono channels 5 & 6 with jumpers installed making a 3rd phono channel possible if required. Auxiliary channel 2 was a direct hard wired potentiometer that bypassed the main board. Microphone 1 and 2 used the remaining 2 main board mono inputs to become stereo microphones by using a switch to send the mono signal to both left and right channel internal output amplifiers. A small number of these custom factory units were modified and put into service while designers worked on the new to be released CMA 10-2D that was a physical cut down version of the modified CMA 6-2S without meters and developed exclusively for disco-tech DJ use.
Enter the CMA 10-2D. The idea behind the CMA 10-2D was to bring a production unit with the features disco-techs required in a more compact package. It would be a smaller rack mount chassis, have the features being requested, and be easily field serviced. The mixer was not developed as fast as anticipated and required more man hours to assemble than originally planned. The mixer still incorporated mono channels that became stereo as the original modified CMA 6-2S. It was produced in limited quantities even though orders for the club mixers became demanding. In house development of the 919 stereo control center would be where designers would turn to develop a true stereo serviceable disco-tech mixer.
The 919 stereo control center developed in house and with the German company CMA (Commercial Manufactured Audio) was right in front of everyone's eyes and was the logical unit to work with. It was modular, easy serviced, had the features clubs required, and was a true stereo mixer. All needed to package it was a new chassis and mainboard. Like anything else there were issues in the beginning for the early CMA 10-2DL mixers but most of those issues were physical corrections and including the confusion of the designated model D becoming D1 then corrected to DL on early units. The electronics were directly brought over from the 919 to the D1/DL with little modification and the mixer could be assembled in half the time as the short chassis D mixer with the 10-2 style interior components. The DL was easily serviced, offered all disco-tech requirements, could be upgraded in the field, and most importantly all the extensive electronic development was all ready done. The stereo DL format was and remained through out as 2 Phonos, 2 Auxiliaries, and 2 Microphones. Variations to the DL would evolve but the internals retained all the 919 electronics till the end of production. If you look at the part numbers on DL mixer internal cards you will see most include the 919 designation in their part number.
Now let's get back to how to identify the originals as we started out to begin with. The CMA 10-2DL production ran for 14 years out of Connecticut locations before the final unit was shipped and the Connecticut facility's ceased to exist. During this time variations to the DL were developed as demand dictated. The first and most noticeable change to the DL was the 2 Phono channel upgraded to 3 Phono channels, 2 Auxiliary channels and 1 Microphone channel. The Cue switch became 5 position instead of the standard 4 position making all sources excluding the microphone available at the front monitor jack. This upgrade was so popular in the field that it was quite obvious to the sales department that a 3 Phono factory version was inevitable. The CMA 10-2DLS was the first visible factory change to the original DL format and this early case the S designated special version being factory produced. The DL design foreseen this and had the change ability up to 4 Phono channels built in but it did not become popular. The first run had misprinted CUE positions on the faceplate but was corrected with its advertised release along with the CMA 10-2DLA. These 2 new mixers along with the original DL gave operators and installers the choice between the original format, a mixer with 3 Phonos, or in the case of the CMA 10-2DLA optional 4 Auxiliary inputs as the cd format was becoming popular. The next mixer to be added to the evolution was the CMA 10-2DLB. This is the same as the CMA 10-2DLA with 1 Microphone channel removed and a 3rd switchable Auxiliary in its place making 6 Line inputs available. All factory original mixers retained the same exact metal work with the only change to switch locations added above the Auxiliary channels on the CMA 10-2DLA, CMA 10-2DLB, and CMA 10-2DLC. Any plates diversifying from this metal configuration with more than 3 Auxiliary switch holes or functions removed and no hole exists in its place are not authenticate or original.
Finally the CMA 10-2DLC. This mixer is identical to the CMA 10-2DLB with the exclusion of the power switch and a Booth output control added. Bozak was adding the Booth output option in place of the power switch as early as 1977 on special order mixers. This option can be seen on many various models but only the CMA 10-2DLC has the actual numbers for gain level on the faceplate. All other models the factory added this option to only have the word Booth above the control. Faceplates from the factory exist with different lettering or function wording but all have the same metal work as mentioned earlier. HB and BOZAK USA plates existed between 1982-1988 during litigation but those are all story's of their own. Also a few CMA 10-2DLM (M for customers mixer factory modified) and CMA 10-2DLO (O for factory mixer with options) were custom built. I have seen mixers modified, re-worked, meters added etcetera to the original DL series and even new chassis with faceplates made up over the years. This is not to say any of these mixers are good or bad only that they were not Bozak factory originals.
I hope this has helped in identifying original USA built Bozak mixers or at least offered some enjoyable reading with facts.
Chronological order of development and availability 1971-1988
CMA 6-2S Factory Version old interior format
CMA 10-2D Long Chassis old interior format
CMA 6-2S1 Factory Version 10-2 interior format
CMA 10-2D Short Chassis 10-2 interior format
CMA 10-2DL 919 interior format
CMA 10-2DLS 919 interior format
CMA 10-2DLA 919 interior format
CMA 10-2DLB 919 interior format
CMA 10-2DLC 919 interior format
CMA 10-2DLM 919 modified format
CMA 10-2DLO 919 optional format
HB-1- 8A 919 modified format 1983 prototype
BOZAK USA 919 modified format 1993 prototype
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