Advice and ideas for a mixing console build

[efinque]

Sup GDIY,

I've been planning a mixing console build for a while now. I started putting the frame together just yesterday from leftover wood I had from various speaker builds.

I'd figure it needs at least mic preamps, low cut, mute and EQs per channel, direct in/out routing, aux buses and some sort of monitoring capabilities. I've been thinking of a buss compressor and a meter bridge too. Initially I've been looking at 12-16 channels with 2 or 4 aux. The frame dimensions are approx. 980mm/780mm/390mm (WxDxH)

So I'm asking for advice and ideas from experienced builders.. also ideas on sourcing components/kits etc, tips for wiring and making the build a bit easier are welcome.

Thanks in advance,

-ef

 

[efinque]

I think it's coming along nicely.. I made a prototype channel strip.

Now I need like 20 of these..

 

[efinque]

Here's the initial channel strip schematic..

..and the aux channel.

Any thoughts?

EDIT : added solo and some minor fixes

 

[ruffrecords]

Here's the initial channel strip schematic..

..and the aux channel.

Any thoughts?

EDIT : added solo and some minor fixes

You need to think carefully about switching. At the moment when you try to bypass the mic pre you actually connect the external input to the mic pre output. Also on the low shelf bypass the parallel capacitor remains connected.

Cheers

Ian

 

[efinque]

You need to think carefully about switching. At the moment when you try to bypass the mic pre you actually connect the external input to the mic pre output. Also on the low shelf bypass the parallel capacitor remains connected.

Cheers

Ian

I didn't think of the switching.. maybe a common ground somewhere would fix this?

Anyway, I wired a prototype today to get an idea how much stuff I can fit on a channel.

 

[pahstah]

HI,
don't do the same mistake a made in my first mixer: think about the master module's and control room module's  dimensions before committing, especially if you are going to use transformers in it! otherwise you may risk to find yourself out of space for components.

Paolo

 

[Holger]

I second that. Don't start with the frame. Collect all the necessary components and cards and decide later how to assemble the stuff.

 

[kooma]

This will be a huge project,
I would first try to complete something smaller.

 

[ruffrecords]

I didn't think of the switching.. maybe a common ground somewhere would fix this?

Anyway, I wired a prototype today to get an idea how much stuff I can fit on a channel.

Somewhere you are going to need to convert from balanced inputs to unbalanced for the internals of the mixer. Switching unbalanced signal is much simpler.

Cheers

Ian

 

[Monte McGuire]

This will be a huge project,
I would first try to complete something smaller.

I agree. Try building just one channel of your filter, use it. and see if it's something you want to use first. It's like you're writing up the sales order before you've even figured out the design - flip your process around and make component circuit prototypes, see that they do what you think they do, re-design them when they don't, put good modules together into a channel,  then package them into a housing.

Study existing gear - people have been recording with electricity for almost a century - check out what has already been done. The internet, which I did not have 40 years ago when I was trying to learn these things, can help you with this!

 

[JohnRoberts]

+1  maybe don't build the garage before you build the car...
+2 maybe look at what others have done... this is a very mature technology

Good luck, one thing is sure, before you finish you will know more than when you started.

JR

 

[efinque]

This will be a huge project,
I would first try to complete something smaller.

I've already built 2 dj mixers and serviced/modified a few..

Thanks everyone for the advice! I've been thinking whether it makes a noticeable difference when running the EQ shelves in series or parallel.

Another thing is whether to use ABS or aluminium for the channel strips and the fader section, I have a hunch that it's better to nail down the physical stuff first in order to stay organized (I ran out of space big time in my 3RU dj mixer build)

I've envisioned the fader section to be "fixed" with a strip of interlocking connectors instead of modular for the sake of saving the trouble of mounting bare fader modules. The master/monitoring section isn't much else than a bank of input selectors/switches.

Another thing that worries me is whether the stereo bus compressor modules fit in a single channel as the smallest one I found from ESP, project 67, was about the size of a postcard, another candidate is the DIYRE Colour VCA, an optocompressor (I've built one) is an overkill imo.. and the fact that this'll probably be a story of how I became poor (edit : I already am though)

EDIT : also, I'd imagine it needs depending on the configuration somewhere around 100-200m of wire.. but I think it's doable for a one-man project.

EDIT 2 : here's a block diagram I made some time ago (this is actually why I got the MCU in the first place, I was told on the Arduino forum that it doesn't have enough processing power though, however I could use one to drive LEDs)

 

[boji]

otherwise you may risk to find yourself out of space for components.

++1

I'm living this lesson presently.  I get that building the frame gets you motivated and on the path. It's what I did. However from PCB design to ergonomics to scope of functionality, all gets constrained or relaxed by the frame, and the frame of course does not care how many features or mistakes or blinky lights you discover are necessary or want to account for along the way. Therefore build the channel first, keeping spacing of components you'll be touching at the top of your decision making process. Once you've got a working channel with a black plane that fits well, with all the bells and whistles you want, wrap those beasts in a frame that fits the circuits.

 

[efinque]

++1

I'm living this lesson presently.  I get that building the frame gets you motivated and on the path. It's what I did. However from PCB design to ergonomics to scope of functionality, all gets constrained or relaxed by the frame, and the frame of course does not care how many features or mistakes or blinky lights you discover are necessary or want to account for along the way. Therefore build the channel first, keeping spacing of components you'll be touching at the top of your decision making process. Once you've got a working channel with a black plane that fits well, with all the bells and whistles you want, wrap those beasts in a frame that fits the circuits.

Atm I'm trying to approximate the BOM for a single channel and multiply that with the number of channels.. and hell no I'm not rolling all those caps, this isn't a sweat shop and they need an active stage to drive them.

 

[boji]

Ok let me be more...blunt.  Chop up and set fire to your wood frame.  Remember in your mind's eye the angles you find appealing but forget the space it occupies for now.  Let the features that you'll discover or modify along the way determine the final geometry.  If you don't you'll just have to take my word on it that it will cost you weeks, or in my case,  months of finding 'solutions' to problems you didn't know you didn't know you had in the first place. This includes assembly of all the channels.

 

[efinque]

Ok let me be more...blunt.  Chop up and set fire to your wood frame.  Remember in your mind's eye the angles you find appealing but forget the space it occupies for now.  Let the features that you'll discover or modify along the way determine the final geometry.  If you don't you'll just have to take my word on it that it will cost you weeks, or in my case,  months of finding 'solutions' to problems you didn't know you didn't know you had in the first place. This includes assembly of all the channels.

I've been thinking of rolling my own preamps too... I just tried breadboarding an LTV4N35 IC with 6/7,5V as an experiment.. no sound though.

 

[boji]

I wish you all the luck and tenacity you can muster up for your life-altering, time-devouring endeavor.   

It will either become an all-consuming project for much longer than you expect or it will haunt you the rest of your life...
 
  .^"-.._ '-(\__/)-' _..-"^.
                '-.' oo '.-'
                  '-, ,-'

 

[boji]

Also consider if making music with some golden electronic goose is what you're after, this is not the most efficient way to do it by far... Chances are, there's a product out there that will do what you want as good as or better than your concoction.  =D

Roots or ATB24 or a used Amek/Studer/Neve/API/SSL/Trident? If time is our most precious commodity, they are worth every single penny of their asking prices...

Edit: Forgot to include Ian's beauty-in-the-making.  ;D

 

[efinque]

Roots or ATB24 or a used Amek/Studer/Neve/API/SSL/Trident? If time is our most precious commodity, they are worth every single penny of their asking prices...

Well, time and energy are a factor. But I haven't been doing my recent DIY ventures to save either, or money as for that matter. Prototyping consumes all of the above and also means risk-taking.. but once one of those three resources is removed things get hard, however I think usually that's when inventions are made.

EDIT : I'll probably go with off-the-shelf kits for channel gain/mic pres.. I did have some plans for a NE553x based preamp about 10 years ago, too bad I've lost the papers. The one I just tested with the 4n35 had a DC blocking cap and a 10k resistor in the feedback loop... I think I heard a very quiet thud when I powered it. I could've wired it wrong though.

 

[boji]

I'll probably go with off-the-shelf kits for channel gain/mic pres.

I'm taking the same direction with pre's, mostly to option tx's in signal path.

Have you looked over the "green pre"?
https://groupdiy.com/index.php?topic=5839.880

Or poured through the THAT pages?
Pre:
http://www.thatcorp.com/datashts/dn140.pdf
Comp ideas:
http://www.thatcorp.com/Design_Notes.shtml

I assume you are wanting to keep things simple and avoid tx's.