Bozak CMA 10-1 Help needed please....

pandemic · Post by **pandemic** » Tue Jun 17, 2014 9:15 am

So I searched around and have not found much on the interwebs. I just acquired this mixer and I am hoping to make some use of it in the st-st-studio. I have not gotten beyond powering it on and watching the meter jump when I sing Phil Collins songs into channel 1. So does anyone have one of these...use one of these....have a schematic.....have wired direct outs.....etc. Any help would be appreciated. Thanks in advance.
The mixer is a 10 channel, input tranny per and I am assuming discrete on the inside...and badass looking on the outside.

pandemic · Post by **pandemic** » Thu Jun 19, 2014 10:42 am

I've been fiddling around with this thing all morning and I like the sound of it. There are defiantly some issues though. The output (from the 1/4 monitor out) is screaming....but not super quiet. not super noisy either. When everything is turned all the way up there is some noise but the signal coming out is way to hot to use anyway. Messing with the input and output control allows for a nice sweet spot and these pre's sound thick. I'm simply going into a computer soundcard and listening to playback (SM7b microphone). I really want to add direct outs to the channels so again, if anyone has a schematic I would be in your debt. [/img]

winky dinglehoffer · Post by **winky dinglehoffer** » Sun Jun 22, 2014 8:32 pm

I've messed with one. They're not really suited to direct outs--I tried. Schematics are out there somewhere--I may have them stashed on a hard drive if they're not still available online. I like the input transformers on this thing. I ended up pulling a couple & using them on a diy tube mic pre--I was very happy with the sound.

pandemic · Post by **pandemic** » Mon Jun 23, 2014 5:50 am

Hi Winky,
Schematics would be great...I have looked all over. Why do you think these are not suited to use as pre's? The sound that i got from them (granted it was buzzy and through the mix bus) was pretty neat in a big fat wooly sort of way and I kind of liked it.

Where did you tap the preamp cards for your direct outs....I was thinking of tying directly to the spade connector on each card that connects to the mix bus.

Again thanks for any help....

pandemic · Post by **pandemic** » Thu Jul 10, 2014 6:24 am

I have spent some more time with these pre's and I am liking what I hear. The aforementioned cable buzz was just that and a higher quality cable has taken a majority of the noise away. I wired 1 direct out, directly to the pre-amp card, and it seems to have a fixed gain to this point as the gain/volume knob does not alter the level coming off the card. Rod C sent me some info on his Bozak and I am wondering if the gain layout on his is different than mine. The volume knob does adjust what is going to the mix buss so I am guessing that it is a volume control post preamp. If that's the case I will need to add a trim pot before the gain stage. There is not a lot of real-estate on the Bozak itself so I am thinking of breaking everything out to a 2 space panel wired with mic inputs, a polarity switch, pad, input trim knob and a 1/4" out. Maybe bolt this to the face of the Bozak and then into the rack? Anyhoo....sounds good just a little wonky setup. The tone control on this thing is pretty cool. The hi freq is way up there and adds a nice sheen to the mix bus...

pandemic · Post by **pandemic** » Tue Aug 19, 2014 5:01 am

Just an update if anyone cares about this......
I opened the bottom panel and there is enough room for a switched jack to be installed between each of the gain (volume) knobs. I am going to add a 1/4" switched jack so that when a direct out is plugged in, that channel is removed from the mix bus. I fiddled a bit last night and these pre's are very thick at the volume stage,,,,maybe a little "wooly" but I bet they will sound amazing on certain things. There is no noise and I am excited about moving forward with the project. I never did get schematics but the wiring inside seems pretty straight forward. At some point I may want to add a trim to the front side of the pre.....that may be more difficult but as it stands, all the wiring to install a switched jack is right there.....I think it will be drill, snip, solder, solder, solder and I'll be in business.
Pics to come as I work on this.

pandemic · Post by **pandemic** » Tue Aug 19, 2014 5:01 am

Just an update if anyone cares about this......
I opened the bottom panel and there is enough room for a switched jack to be installed between each of the gain (volume) knobs. I am going to add a 1/4" switched jack so that when a direct out is plugged in, that channel is removed from the mix bus. I fiddled a bit last night and these pre's are very thick at the volume stage,,,,maybe a little "wooly" but I bet they will sound amazing on certain things. There is no noise and I am excited about moving forward with the project. I never did get schematics but the wiring inside seems pretty straight forward. At some point I may want to add a trim to the front side of the pre.....that may be more difficult but as it stands, all the wiring to install a switched jack is right there.....I think it will be drill, snip, solder, solder, solder and I'll be in business.
Pics to come as I work on this.

pandemic · Post by **pandemic** » Mon Aug 25, 2014 2:01 pm

1/4" switching jacks came today. New tip for the smoke gun and some hookup wire.....and a drill press......next.

pandemic · Post by **pandemic** » Thu May 21, 2015 6:10 am

.....This thing is still sitting on the shelf. If anyone has schemo's it would help a bunch. My current plan is to re-rack this mess in a better..more usable case, add switchable direct outs for each channel and a 20db (maybe 10db) pad at the input...
Thoughts?

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Bozak CMA 10-1 Help needed please....

Bozak CMA 10-1 Help needed please....

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