24 channel mixer the "Stereotype"

[Fuccimain]

Right. Thanks for the clarification. I thought you meant it wasn't compatible circut wise but use the same pinouts.

Thanks for clearin that up for me.

A couple things I'm curious about with the new channel boards, they are going to have a fader but will it be a knob style or will we be able to use linear ones as well?

Also, you mentioned in addition to the fader, there would be a gain attenuator for controlling the gain of the channel DOA, correct?

Last thing, will it be possible to add an insert to the channel, after the DOA but before the fader ?

Thanks again for all the hard work on this don. It's pretty amazing.
Peace

Sean

 

[kante1603]

Hello Sean,

I'm sure the schematics will clear all these things up.
Most of your questions have been discussed here before,but having a schematic in hands will be easier to get the answers.
From what I remember (and asked for) you'll have a gain trim in circuit meaning you can boost or cut levels,usefull for aligning them e.g. to a faders zero position (or in other words "unity gain").
Remember this position is not the top end position of a fader,so you'll need a boost of +10 or +12(Api-style) dB to compensate the loss through it.
About the insert point:Why not use the mixers inputs for insert return? A perfect point for a pre-fader insert since you will have a line- level signal at matching input impedance here..... and it is balanced....?
A scenario could be a mic-preamp or an interface output ( from a daw) feeding the mixer input,so the insert point is already there.Having the i/o connections on a patchbay is most useful,you can easily insert your eqs or dynamics here.

Best regards,have a nice weekend and sweet dreams,

Udo.

 

[Fuccimain]

Hey udo,

Sorry I don recall this being fully answered,

Yeah, obviously adding a processor at the mixer input is an option, just not the one I am looking for.

I believe this question was asked by someone else earlier in the thread and someone also responded with the obvious answer about adding a processor pre-mixer I don't recall it being discussed further as a true insert.

I was hoping, as with my other question about adding a gain, to be able to boost or cut gain in the DoA and then insert a processor, after the DOA before the fader, hence askin about an insert, not a pre mixer patch.  I don't recall that being answered, my bad if it was.

Just thinking I guess the point on the circut that would be the send To the fader could be wired as an insert send and then have the return go to the fader input, but yeah, looking at the schematics will help. 

Again sorry if I missed the answer to this earlier in the thread, wanted to make sure want I wanted to do was possible and was unsure.

Peace

 

[kante1603]

Hi Sean,

I see what you mean and have thought about it often when this thread started.
Personally I don't see an advantage picking the insert point there because it will be unbalanced.
But it should be doable,there's some good stuff to read over at Jeff's mixer project which is a larger scale one.
Anyway,I think Don didn't change the input stage followed by the fader too much,so here's the schemo from his first 8 channel input board,maybe this gives you an idea:

http://www.hakanairecording.com/mixerpics/Stereotype%20mark%202.pdf

Hope to have helped,

Udo

 

[Fuccimain]

Hey UDo,

Cool thanks,

Yeah I thought about the whole unbalanced thing, I found a company sonewhere on the web that was making cheap little unbalanced to balanced pcb adapter boards for  racking console channel strips and bein able to use the inserts and aux/buss outputs without the consoles main bus master boards. Thought it was a pretty handy idea, instead of adding transformers to do this.

I'll see if I can find the site again, but I don't think it would be toooo difficult to get the design for that and make some  balancing pcb boards.

Thanks again!

Peace

 

[kante1603]

You're welcome.
There are lots of circuits around for this,especially ic based.E.g. look at all those chips like INA and DRv types from Burr-Brown,or even easier get some of Joe's nice and easy to build boards over at the JLM site.Here's one of them:

http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=118

Or this one:

http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=96

Lots of ways leading to rome,hahahaha.......although I still don't see an advantage.

But yes,why not do it......

Best,

Udo.

 

[Fuccimain]

Cool man thanks for them links.

Yeah I hear ya, I just have it in my head the way I'd like to ideally wire the mixer. Might make more sense to you once I've got it completed, I know that ideally I want to have the outs of the DA normaled to the is on the mixer.

I know the differences have been discussed in other threads, but I'm curious if anyone that has built this has any opinions of different DOAs in the main channel board or Jeff's inv-aca or his aca-booster..  Curious what people like about certain DOAs over others for whatever reason.

Peace all

 

[kante1603]

I know that ideally I want to have the outs of the DA normaled to the is on the mixer.

Same way I'm going to go.......and this already is my insert point for mixdown.
Maybe you can do a little drawing of your mixer as a block diagram or so?

I know the differences have been discussed in other threads, but I'm curious if anyone that has built this has any opinions of different DOAs in the main channel board or Jeff's inv-aca or his aca-booster..  Curious what people like about certain DOAs over others for whatever reason.

Not easy to answer,but in general all about "coloured" or "clean" or "wide open" or "superfast" or or or or...........hahaha..........
One should try them in different situations and builds.
Personally I really love the Gar2520s in some of my builds (VP28,LC53,Pultec) while I like an APP992 more on my 1176s and Sontecs.So I use the first mentioned more like being "musicians" and the others like "surgeons".A matter of taste.....best to have them all,no?
I highly recommend building some different ones and then swap them out in your builds....and give it a good listening.It also matters on how they behave in the complete signal chain.
E.g. I like this chain very much when tracking vox:VP28-LA500-LC53(sometimes)-AD on my FF800s.
This way the signal hits (if counting correct) nine DOAs and six transformers.....that is really one huge sounding channel strip!
Just an example.....

Cheers,

Udo.

 

[hakanai]

I'm hesitant to post this because of how amazing crappy it is, but I think something will be more helpful than nothing at this point. There are no values and I just realized the aux pot slugging resistors are not represented, but this does show what is happening. I'll try and get a real drawing together, but I have been endlessly busy lately.

don

 

[kante1603]

Hi Don,

thanks for sharing!

Best,

Udo.

 

[hakanai]

Ok as I wait for the last few parts to come in so I can stuff come channel boards, I am working on how to deal with the master section. I decided to tackle the simpler aux master first.
Originally I was going to draw a board that had 4 summing amps and 4 THAT 1646 balanced out puts. This would act as the aux master but could also simply act as a balanced out put for the direct outs. After throwing all the parts on a board in Eagle, I quickly realized it was going to be bigger than I wanted and more specialized than I wanted. So I added this to the queue of things that rattle around my brain in every spare second of the day. After imagining up a few different solutions that were either going to be a pain in the @ss to implement or more complicated than they needed to be, I remembered that Jeff doesn't make one summing board, he makes 2. The other ACA board he makes is traditionally used as a bucket sub-summing amp, but with 2 small trace slices it is 4 independent channels of summing amps. Perfect for our aux master summing. It still needs to get an output stage, and so do the direct outs. So this morning I drew what I like to call the THAT Backpack. it's a small one square inch board that hangs off of a neutrik NC3MAV with everything you need for a nice little 1646 balanced output. It has a standoff mounting point and 3 pin header output as well if for some reason you don't want to have it hang of the xlr (maybe a bunch feed a db25). it also has a power passthrough so you won't have a billion power lines running everywhere (I am thinking my mixer will end up with 20 or more of these). Also since this is the same size and shape as my grayhill boards I already know the pricing. It should work out to 4 for 12$ or 8 for 20$. I will need to confirm that, but it should be a safe guess.

The primary master section is still rattling around in my head, but I am thinking it will have some basic monitor control, meter pick up point, and all the necessary buss routing and solo control. I am debating a headphone amp.

things are moving along.
Don

EDIT: oops just saw the silk was labeled wrong on the power header

 

[hakanai]

HAHAHAHA! Sometimes I really get in my own head. I read the previous posts about an option for balancing the outputs the other day and I totally forgot to address that in my last post.

So yeah there are options out there for ic based balanced outputs, but they tend to be either big, expensive, or both. Now I mean this relatively speaking of course. The JLM kit is incredibly flexible and fairly priced for what it does, but because my board is going to be a more specialized thing it is going to be about half the size and half the price once stuffed, and that is huge when you are trying to stuff 20+ of these things on a back panel with a pile of other IO. It will also be a question of what you are into, the THAT chip or the JLM circuit.

as for an insert point, and where it would land in the circuit. The only reasons I could see wanting an insert point on a line mixer is if you want an unbalanced insert or if you wanted the pre-fade aux and direct out sends to be pre insert as well. Are these things what your after? What exactly are you trying to accomplish with the insert point? The idea of a pre-insert direct out has it's appeal for me but it would be a pain to implement, as it would essentially be an active split requiring another output and input stage per channel.

don

 

[fenchelteefee]

Hi Don,

I'm pretty interested in your project since the early Stereotype protos. So thumbs up and here're my mixing desk considerations. My goal is still a hybrid mixing solution with a bunch of outboard and 500 series for electronic music production in mind. A first class summing amp for going gracefully out of the box still capable for basic (line) tracking hardware synths and FX over AUX within the desk (not in DAW). This is important when jamming around with nice outboard and getting inspired, at least to me.

First of, I suggest to open a new thread with the first page summerizing all points of concept up-to-date. It's hard for me to follow up which features had already been discussed and what is finally getting considered by you, even in alpha-version. 

Generally:

1. - 24 Channels
1.1 - Section - 8 mono channels;
1.2 - Section - 8 stereo channels;
2. - Fader or poti option for volume.

3. - 2-4AUX for both, mono and stereo section (synths have stereo output);
4. - Subgroups - not critical, but maybe 2 or 4?;
5. - Inserts - one per mono (8), balanced. Pre-Post fader switch. It's comfortable to have some 500 series "audio bacon" switchable in at your fingertips. Yes, patchbays are nice but ...;
6. - User option to add hardwired (balanced) processing like EQ/comp per channel. Single channel no problem, but stereo (sorry if dumb question)?;
7. - User option for dip8 (yes, IC is not a dirty word).

Master section:

1. - Switchable A/B Monitor out;
2. - 2-Buss insert would be nice;
3. - Maybe smth relay/microcontrolled like Igor's CRM, just smaller and less features, futureproof and maintainable (Igors CRM is based on microcontroller that is outsold).

Headphone amp:

1. - This thread is raging over this h-phone amp. maybe worth to check out?;
2. - I remember this was successfully implemented to the early stereotype by somebody, here at gdiy.

 

[ruffrecords]

Isn't squared paper wonderful? I would be lost without it.

Cheers

Ian

 

[hakanai]

progress!

I partially stuffed 4 channel cards and 1 input board to confirm spacing and show you guys how the whole thing actually works.

don

 

[hakanai]

from the input board

 

[hakanai]

from the front. No pots yet, just switches.

 

[kante1603]

Wow,looking very nice Don!
A pretty compact build,love the "DOA-battery".
Keep up the good work!

Best,

Udo.

 

[Fuccimain]

Looks amazing Don.

As far as the insert, I wasn't really thinking along the lines of prefade direct out, but prefade aux could be cool, I just thought it could be cool to insert a processor after the signal has been effected/treated by the DOA, like if it was gained up really hot and then eq'd or compressed, as an example. But yeah, I can see how it would be a can of works adding another balanced in/ out to the circut.

Peace

 

[gar381]

Lookin Good Don

Keep up the good work.

Best

Gary