24 channel mixer the "Stereotype"

[hakanai]

EDIT 1/23/24: Here are the MarkIV docs. They should work for most versions. Basically C2 and R9 were tweaked and added over the versions, along with the fader insert point. Make sure the C2 package diameter will fit the older versions and all should be fine. R9 should basically always be skipped and just use 0.1% resistors in R1 and R2. Remember to bridge the unused footprints of R9 and the fader point.

https://www.dropbox.com/scl/fo/ervj8rw7ptpgiywbub0wp/h?rlkey=ji9xs3qxn8z5f9amsjby452z7&dl=0

The power supply question:
https://groupdiy.com/index.php?topic=41430.msg737588#msg737588
The opamp question:
https://groupdiy.com/index.php?topic=41430.msg735402#msg735402
Sorry most picture links are broken at this point. Too many to fix really. If anyone is working on this or interested in it PM me and I can probably come up with whatever is no longer here. Thanks

Old Stuff~~~~~~~~~~~~~~~~~~~~

EDIT 9/24/13: So there is a new thread with the latest incarnation here: [Build] Stereotype Mark V Mixer (photo heavy)
I will continue to check this thread but I think most of the discussion will be over there. Thanks

EDIT 5/17/13: Ok so this project has evolved. I will try and post links here in the first post pointing to key sections of the thread so people can read the meat of the thread without wading through the full thread.

Page 16 has some good info and is where the project is currently at:
http://www.groupdiy.com/index.php?topic=41430.300
here is some discussion of the channel board:
http://www.groupdiy.com/index.php?topic=41430.msg656068#msg656068
~~~~Original Post~~~~
Hey, so i just finished (nearly) this mixer I have been building for myself. It uses GAR 2520 as dif line receivers and sums through the classic api 2 channel ACA board. The Pan switches are 7 position. It's currently wired up so i could get a quick listen. I still need to wire up the send and return to the booster correctly, pull the bottom metal to drill the mounting holes, and decide how i want to unbalance the return to the booster since i'm not putting a master fader in. but it works nicely so far!

~~~~~~~~~

EDIT: a limited run of boards are available for this project on page 3 of this thread
EDIT: schematic on page 4
EDIT: boards now shipping pics of new boards on page 4
EDIT: have a look at Zayance's build on page 6, it's really slick
EDIT: White Market thread here Stereotype Mark 4 boards available

Here are some pics of my build

Don

 

[hakanai]

here is a close up of the pans

 

[justanalogue]

Nice work!

Analogue.

 

[plumsolly]

That looks fantastic. Nice work, indeed. - Ben

 

[Ptownkid]

Holy hell, that's badass!

 

[Kingston]

Very very nice work. Top notch parts all around. Has no chance but to sound brilliant and deliver.

In that last (but awfully revealing) close up I see the copper shields of the pan pot wires dangling around in free air with no restriction of movement. You should put some shrink wrap around them. Now you're just asking for accidental shorts. It's only what, 3mm to a short with that resistor (and the one next to it! whoops). It will happen eventually.

PS. I wish I had camera and photography skills like that. That picture is as detailed as is gets.

 

[hakanai]

Thanks for all the kind words. Yeah, the first few pans i did look like that. After doing a few a figured out a nice technique for pulling the sheathing back while working and sliding it back up when it was done. Good point though, I'll have to address that.

It's only a few days old and i have already designed the markII haha

thanks
Don

 

[mrc]

KITS  ;D ?

 

[horvitz]

Really great stuff!  I build a summing mixer myself off of Jeff's board.  I love seeing how many different ways people use this thing.  Fantastic work  

It's funny, too.. I have had other projects come and go and be done and whatever, but I'm constantly thinking about this thing and how to make it better.  Been through a few revs already!  It may never be done, and I'm just fine with that.

  Brian

 

[jsteiger]

Nice looking bit of kit you have here Don. I love it. It's gotta sound great. I really prefer the all discrete path over something passive with make up. Really love the Grayhills.  ;D

And like Brian said, it is so fricking cool to see the many different ways the Inverting ACA and 2-ACA-Bo boards are used. From perking up Gary's old Tangent to something fresh and new like this bad-ass little discrete mixer!

Carry on! 

Best, Jeff

 

[pucho812]

Do I dare repeat what you already know? I dare... that looks great and I am sure sounds killer with the DOA's

 

[gar381]

Really nice looking work Don !!

Nice use of Jeff's ACA PCBs !!

Bet it sounds Killer !!!!

GARY

 

[SIXTYNINER]

"infinitely Porn!!!" 

how many $ in parts?

cheers

 

[hakanai]

Thanks again guys. I am working on an 8 channel version of the main PCB's. essentially the same exact thing as the picture but a smaller foot print and phoenix screw terminals for all signal connections (I hardwired everything on mine, huge PITA). Would anyone be interested in these boards?

Also here is the gerbers for the pan boards. I revised them to be a one layer design and have some labeling in copper, so you can do one layer with no mask or screen.

http://hakanai.com/mixerpics/GerberFiles%20Pan3.zip

Don

 

[Cosmonaut]

Awesome project!I would be interested in a 8 channel summing, but with the possibility of using a faderpack instead of fixed resistors...
what do you think?

 

[indigom]

Don,  very nice work, congrats!  How do you plan on powering this?    I've been working on a 16-chan DOA line mixer for many years, currently undergoing a revamp thanks to Jeff's Inv-ACA PCB work and powered by the Group 51x PSU.

Details will be posted in its own thread upon working arrival.  : )

I'd be in a an 8 channel version of the DOA PCB!

cheers man!
-J

 

[mrc]

Yes, please!

 

[horvitz]

Don, maybe with your 8 ch board mount the DB25 right on the PCB?  Helped me, anyway.. much easier to deal with the cabling and the grounds and all.

  Brian

 

[funkmuffin]

I'd be in for 3 of those 8 channel mainboards for sure.

 

[hakanai]

So one way or another I think at least one run of these boards will get done. Currently I am futzing with the markII. I am seeing how  incorporating a pcb mount db25 looks. I like the idea Brian, but it causes two things I loath to go head to head, soldering leads onto db25 connectors and aligning metal work on multiple parts. Neither is really that big a deal but it's the trade off, and I am inclined to think getting DIY metal right is more a PITA then soldering. Having said that however, I am kinda liking the pcb mount db25. Preferences out there?

The other change is maybe adding a point for an optional fader. We'll see on this one.

Don