Gately (ProKit) SM-6 mixer and EQ schematic?

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hodad

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I'm glad these help (there is at least one article I remember from Audio Amateur that should help you as well.) As of now, jpegs are all I have from the SM6--still can't find the manual. If I get a chance, I'll scan the other 2 manuals.
 

rickc

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Aug 25, 2005
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seattle
give me an exact date for the audio amateur articles. save me from searching (which I won't do). I do have the article.
 

MidnightArrakis

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Sep 25, 2015
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Dang, I did not gather these when they were available. The World Radio History site was asked to take down their copies of Audio Amateur. You can still buy them on CD-ROM at
WELL.....Well.....well.......I received the "Audio Amateur" CD yesterday (7/17/21) and with an internal sense of hyper-excitement, I was..........greatly disappointed!!! I couldn't believe it!!!

In a 1973 issue of "Audio Amateur", there was a somewhat lengthy article detailing the SM-6 mixer, its operations, its circuitry and its philosophy of design. But, there were no schematics.

It wasn't until a 3-part article series in the 1977 issues that the schematics were presented. While on the one hand, I am gleeful that the schematics were there. But, on the other hand, they're essentially - useless - for two main reasons. First, perhaps due to the fact that the schematics were hand-drawn, all of the text of the Reference Designators, component values, etc. were done using a broad font style, that everything is next to impossible to read. Secondly, whoever drew the schematics (Ed Gately?), used a combined architectural and electronic drafting style. What this means is.....certain notations about specific parts and/or the placement of Reference Designators and/or component values may be placed somewhere else on the schematic and - not - next to a schematic symbol. Then, an "architectural-style" - arrow - is drawn from the text over to a particular symbol and -- RIGHT OVER -- any other schematic symbols and/or text items!!! So, visually.....the schematics kind of have this "over-busy" look to them, which then makes the schematics rather difficult to read!!!

THEN!!!.....on top of all of that, however these magazine articles were scanned or "Optically-Character Recognized" or however the process was done, that induced yet another level of "fuzziness" to the graphics that has all but rendered them to be unreadable!!! I can't even make out something as simple as a 100K resistor value on the SM-6 schematic. So, there goes 40-bucks down-the-drain!!! --- swirl --- swirl --- swirl --- ga-bloosh!!!

Tomorrow (7/19/21), I am supposed to receive an actual SM-6 mixer that was shipped to me a week ago from some guy on the West Coast. It looks as though my best bet will be to take apart this guy's SM-6 mixer, trace out the PCB, measure all of the component values with an LCR meter that I have and create my own schematic literally "from scratch" from the PCB itself!!! YIPPEE!!!

As I have mentioned before.....at least my schematic will be from an actual in-production product and not an "engineering" schematic that may have gone through several changes and/or updates before being released to production. So.....tomorrow I break-out my tools, test meters and "flashlight" (YEP!!! I use a flashlight to shine a light through the PCB from its "Solder-Side" as I make note of the component Reference Designators on the "Component Side" of the PCB as I draw the schematic using my CAD-system) and begin my "SM-6 schematic journey. This will be fun!!!

/
 

L´Andratté

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Jan 17, 2013
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Hamburg Germany
If you look at the Gately schematics that are available of other models, e-g- the link I posted above, you´ll see that everything is mostly minimalistic design a la API but with ICs.

Mic pre->transformer plus opamp, output driver->opamp plus discrete p/p transistors in the loop, etc. and all those building blocks are put together in simple manner.

I think if you look at your mixer yet to arrive it´s not a far shot that it will be in a similar vein, probably very easy to trace out.
 

rickc

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Aug 25, 2005
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seattle
I will look in my mixers folder. I believe I have an original, for what that's worth.
I also have the original magazine on paper. so, somewhere in 1977, eh?
 

rickc

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Aug 25, 2005
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101
Location
seattle
Ed Gately wrote a series of articles in Audio Amateur Magazine, from issue1 1976 to issue 4 1977. There were some gaps in the middle of the date span given. 3 of the articles covered mixer basics, and the last article presented the schematic of the ProKit mixer. The last 2 articles covered a modular-type design, that incorporated many of the ProKit features with other larger mixer features. He calls this the MicroMixer.

I grabbed the issues that had useful content and created a composite file that contains all of the articles.
 

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