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

[hodad]

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]

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]

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
https://cc-webshop.com/collections/.../products/the-audio-amateur-on-cd-rom-1970-79

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]

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]

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]

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.

 

[rickc]

btw, the prokit schematic is legible.

 

[uplinkal]

Well.....the originator of this thread hasn't responded, so maybe he's gone to "The Great Audio Equipment Warehouse In The Sky" after contracting this COVID-19 virus!!! Who knows??? In any case.....some guy on the West Coast is shipping me his aging GATELY SM-6 mixer, that he says has been just sitting in his garage forever, so I can "Reverse-Engineer" the circuit board and create a schematic of the unit myself. I remember the PCB being a "single-sided" board, so it shouldn't be too difficult to do. A few years ago I did a "Reverse-Engineer" project of a PCB that was originally designed in 1979 and was used in the control electronics for U.S. fighter jets, so I believe that I can handle a simple 6-Channel audio mixer project.

I also sincerely appreciate the Audio Amateur CD information that you posted. That may be worth purchasing just to have all of the great information that that publication used to offer. GOOD STUFF!!!

/

I am "some guy on the west coast" and am waiting for the return of my SM-6 after nearly 18 months being without it. I hope Jerry got the reverse-engineering done as I would like a copy of the schematic too (as well as my SM-6 mixer).

 

[uplinkal]

I am "some guy on the west coast" and am waiting for the return of my SM-6 after nearly 18 months being without it. I hope Jerry got the reverse-engineering done as I would like a copy of the schematic too (as well as my SM-6 mixer).

If anyone knows the whereabouts of Jerry Williams. who is supposed to be reverse-engineering the Gately SM-6 mixer I shipped to him back in July of 2021, I'd like to contact him to see what's happening. I have emailed him at his last known address and he has not responded. I hope he hasn't gone to "The Great Audio Equipment Warehouse In The Sky" either. I want my mixer back. Please email me if you know how to reach him at [email protected].

 

[uplinkal]

Still waiting for Jerry Williams to return my Gately SM-6 mixer. I shipped it in good faith, thinking he would "reverse engineer" it as he out it to create a schematic, but he has not returned it or even responded to my emails. I'd like to have the mixer back before I die. It's been a couple of years now!!

 

[uplinkal]

If anyone knows Jerry or his whereabouts, please let him know I've trying to seek him out. thanks.

 

[Disco Volante]

If you're looking for the guy that goes by MidnightArrakis here, he is still active on the forum?

 

[uplinkal]

I just bought this CD this evening in the hopes that it contains the one single piece of information that I am looking for!!! I can only hope!!!

Yesterday (7/12), a guy on the West Coast has shipped to me his GATELY SM-6 mixer so I can "Reverse-Engineer" it and derive a schematic from the PCB. That will certainly be lots of fun!!! Then, earlier today, he sent an e-mail asking me that since I am going to be taking his mixer apart anyway so I can "Reverse-Engineer" it, if I could then essentially - re-build it - by purchasing all new parts of everything and replace all of the capacitors, resistors, IC chips, switches, etc. WOW!!! I didn't see - THAT - coming!!! I could only respond by telling him that I will need to work up a Parts List and find out how much all new parts will cost, plus my labor, and see if he is willing to spend whatever number all of that comes to. What do you think about doing all of that???

Right now.....I am going to be interested in seeing how (if) the Audio Amateur CD schematic compares to the one that I "Reverse-Engineer" from the PCB. I can only hope and pray that they (somehow) end up being identical. However, should they end up being different, I'll go with my "Reverse-Engineered" schematic because it was obtained from an actual production unit and not a "piece of paper" that probably had changes to it before being finalized. What do you say???

/

Sorry if my "request" was too much for you to handle. After all, it was me who graciously sent you my Gately SM6 mixer for you to "tear apart" and reverse engineer, as you put it.
Right now, all I want is to get my mixer back, intact, before I die !!! Do your part and reciprocate.