• Bozak Cma 10 2dl Mixer

Not that anyone is interested but here is a small write up on this mixer. If it wasn't because of the Bozak CMA-10-2DL, DJing would have never been possible during the 70s. Bozak designed the very first high quality DJ mixer in mid 60's (the monoaural CMA-10-1 with 10 inputs) when the whole concept of mixing and 'discotheques' was a brand new thing. By the 70's, the stereo version CMA-10-2DL, had already reached quote of 'the standard club mixer' status and it was extremely expensive. In late 70's/early 80's, Rudy Bozak kicked the bucket and there was no longer a production of Bozak mixers - until Urei/JBL took advantage on 1982 and released a Bozak mixer clone, the Urei 1620. New mixers - including the Urei 1620 - are designed using IC chips, the Bozak mixer was the only faithful mixer that was built up from ground up using resistors, capacitors, and transistors.

Every component chosen carefully to be able to reach the best audio output possible. The potentiometers were made by Allen&Bradley. The sound of Bozak has a definite shape: the bass is reproduced at the lowest bottom end (great for the old LPs), high frequencies are rounded for a warm sound, and the mids are not screetchy or harsh sounding. A Bozak mixer does not distort or deteriorates the audio output in any way. The Bozak outperforms in construction quality, electronic design, and audio quality.

The biggest collection of Bozak manuals and schematics. All available for free download. CMA-10.2-DL: Owners manual English: Download.

1. The biggest collection of Bozak manuals and schematics. All available for free download. CMA-10.2-DL: Owners manual English: Download.
2. Bozak CMA-10-2DL Owners Manual and Schematics. CMA-10-2DL Owners Manual & Module Schematics 1.3M 632k More info on the Bozak CMA-10.

The mic preamps on the Bozak mixer offer quiet amplification and reproduction. The Bozak mixer is fully modular with fiberglass PCBs inserted vertically through expansion slots with pins on a major horizontal routing PCB. During maintenance or upgrading, the appropiate circuit element on a PCB can be retrived and serviced. The open expansion slots allows for sound technicians to make custom designs on the DJ mixer. The Bozak comes with 2 turntable inputs (upgradeable to 4), 1 balanced mic input, balanced XLR and unbalanced RCA outs. It also includes a FX loop in/out where any kind of effect or processor can be plug. Bozak quick links Bozac Pre amps HB-1-8A rare prototype CMA-10-2DL on factory version (A, B, BS e S) a CMA-10-2DL 'full optional' (radio version) the CMA-10-2DL with silver faceplate Manual of CMA-10-2DL More Bozak mixer information.

An e-mail from Chuck McGregor of EAW company Hi Mick, Happened across your web site and have a few things to add about the subject mixer. The ones made before about 1977-78 used Allen-Bradley not ALPS potentiometers (Type 'J' for the inputs rated at something like 1,000,000 rotations.) Also the connectors for the plug-in boards were split pin gold contacts unlike the white connectors shown in your silver version interior photo. Richard Long was responsible for the 'effects loop' which was added into the design at his request. CMA-10-2DL did not come into being until about 1970. The CMA-10-2D, a 10 input 2-channel output preceded it in the mid 60s. However each input was mono assignable to either or both outputs.

Alex Rosner had a hand in that design. Rudy did not 'kick the bucket' until I about 1983.

In any event, he sold the company about 1977, well before production ceased. 'Every component chosen carefully to be able to reach the best audio output possible' is not far from the truth. The QC on the mixers was thorough. Capacitors were hand selected for the tone control boards to ensure flat response at the 'center position'. Gain, noise, output levels, and distortion were checked on each unit, with appropriate component replacements made in units that failed these qualitative tests. I wish it could be said that every unit was 'listened' to but that was not the case. The components used were high quality throughout.

As to servicing, one CMA-10-2DL went through a fire and came back to Bozak with water/smoke and physical damage. It was a mess!!

However it worked perfectly on the test bench. Generally, few ever came back for service. Thought you might like to know the above information. It is authoritative (to the limit of my memory) as I worked there from 1974 to 1978 variously as electronics technician, customer service contact, and loudspeaker designer.

I knew Rudy Bozak, Richard Long, and Alex Rosner quite well. My 'personal' 10-2DL is still in service as the mixer/preamplifier in my Music Room system (live music, not home Hi-Fi). It was hand built by me for me in the factory about 1976 with a custom tape monitor function.

Cheers, Chuck McGregor - Technical Services Manager (EAW) Former Bozak engineer Buzzy Beck on modern DJ technology Dear Mick, I just spent most of the weekend cleaning out the warehouse and i came up with lots of old equipment that i will e-mail you about. I got to look at the tech web site you told me about (wave) and it looked like some people know what they are talking about, and others don't seem to know very much. Please forward this to your friend Scott, it should make him laugh. It is nice to see that someone realizes modern technology a lot of the time is just old ideas polished. Here are a couple of tidbits you can shock the modern world with. On my first radio station mobile rig built in 1958 for school record dances we had many little items that were not so available to the general public.

Bozak Cma 10 2dl Mixer

The unit was built out of 3/4 inch plywood and housed 2 altec stereo peamps, 1 garrard record changer ( 16/33/45/78 ) and 1 rec-o-kut turntable. Gee did i just invent the DJ coffin? Under the garrard changer was a 120 volt variac which was used to slow down and speed up a record.

The way it worked was if you had to slow a song down you would just drop the voltage on the vari-ac, but to speed a record up required a little more skill. In order to make a 45 rpm record go faster you would use the 78 rpm speed and slow it down. Gee did i invent the variable pitch control? Ithink i will sell this idea to technics. Oops too late, Dual 1019 from Germany came out in 1962 with this feature long before disco days. One other unique item we had in the middle of the unit was a big 3 inch knob that let you switch the sound from the left turntable to the right, and back to the left.

I think i just invented the crossfader. I will be sending you and mario some very old and interesting pictures soon. If i can locate the old rig (possibly still in my sons warehouse) Iwill send it to you and mario and you can ship it to the smithsonian (ha ha). Oh and by the way the HB on the bozak mixer stood for Hammarlund/Beck. As you know Rudy was long out off the picture at the point of it's creation.

As i told Mario, it was a money issue and it did not create enough interest. Anyway thanks for protecting the old ideas and keep the other bullshiters straight.

By the way not to toot my own horn but over the years i installed and maintain over 40 clubs and discos, and was a radio anouncer turned club DJ until my retirement in 2000. I started in the 50s and have seen and heard it all. A friend (not a glory grabber) Buzzy Beck.