[BUILD]CAPI 2-ACA-Bo~Official Support Thread

I'm positive that some of Jeff's ACA buyers must be building summing boxes to be used with DAWs, etc., as opposed to being part of a larger mixing console.

I'd love to see any pics of your work. They don't have to be pretty, just have to use the ACA board(s). I'm looking for ideas.

I've already built the boards, and keep struggling with how to rack this up - I keep vacillating back & forth between a really simple L & R summing box with few or no controls (simple 2bus, separate L&R inputs) to a (Neve 8816-like) mixer with pan & level controls, etc. I plan to use buffered VU meters on the 2bus, whichever way I go.

Anyway - anybody want to share?

Thanks,
Frank @ Area8

Hello!

There is project on the board which uses the ACA-Bo.
Thread is here:
http://www.groupdiy.com/index.php?topic=41430.0

If you want to save some money i would build the input stages with IC-LineReciever like the ones from THAT.

If you want Volume, Pan and maybe a Solo/Mute-Function things get more time- and money consuming.
I build a small Mixer with that features based on the ACA but build my own PCB´s. It was a lot of time and not really cheap but i like it alot!!!!
Small thread can be found here:
http://www.groupdiy.com/index.php?topic=48128.0

kind regards,
Wolfgang

Wolfgang - thanks for the pointer, and I like your mixer - nice work.  Exactly the sort of thing I was hoping to see.

I've used the THAT 1200 series receivers before with very good results, and the price is right at Mouser, so your recommendation is a good one. I like the 2520 family DOAs as much as anyone and don't mind building them, but seems like a bit of overkill for the application, especially when you follow it with two or three stages of DOAs and iron, anyway. Another tempting input possibility is to take the Black Lion approach, and use a bunch of Edcor 10K/10K transformers for pretty cheap (~$12/ch) and really minimal work.

I already have a decent mixer (Malcolm Toft Trident-like thing), so I'm not ready to embark on something too full-blown, but it is tempting if the sonic results are worth the work. Actually, the ACA would be a much better summing bus for the Toft, but there isn't any room to mount it internally; I'd have to work out an outboard solution. My downfall is really metal work.

I kind of liked the use of simple LCR assignment switches to save money and panel real estate... I think one of the Dangerous boxes do that, don't they? On the other hand, it would be perfectly usable for my application to have dedicated R & L inputs, and do all my panning and levels in the DAW before the outboard summing. I'd likely also use the box to sum a bunch of old Ward Beck preamps I have, as well as some of Jeff's preamps. I sort of have a nasty mic pre fetish, and have far too many for my needs, including a bunch that I've done on perfboard and such over the years.

I'm torn about I/O connectors, though - I'm leaning toward XLRs, instead of going the DB25 route, although I guess I could just run DB25s from a patch panel and still have the same flexibility with the XLRs or TRS. I'll likely just prototype things with a stock XLR panel (like the ones from Middle Atlantic), without any metal work, and mount a power connector in one of the punchouts, instead of mouting a power supply inside.

I like Jeff's new VU meters - they are tempting to use for this, also.

Speaking of VUs, and only slightly off-topic: I'm trying to find which model VUs that Neve uses in their 8816 (I have a blank 8816 panel) - anyone have one you could peek at? I know that they are in a 27mm cutout, and that probably points toward Sifam (along with the fact that they are British and used elsewhere by Neve), but I haven't seen the same model as a stock offering.

Many thanks for the links.

Cheers, Frank

Hey Jeff, you still selling these boards...can't find them in your site anymore!
Cheers
Jay

JayDubrek said:

Hey Jeff, you still selling these boards...can't find them in your site anymore!
Cheers
Jay

Click to expand...

Yes I am. I ran out last week but have more coming in this Friday. For some reason, the item was "hidden" when the last one was purchased. I just changed that and updated the expected date.

Sorry for the confusion and thanks for pointing it out! 

Awesome! Still in the early stages of my console build and panicked I'd missed the boat on them!!
Cheers
Jay

Hello, i need some help to accomodate the Rf, and Cf, of my ACA-Bo in a vintage mixing desk ("Saje"). The bus resistors of the mixing desk are 22kohm. the mixer is 30 channels.

I'v dowloaded  the gaincharts.xls by bob Schwenkler. but i dont understand well all of this.

What must be the values of  Rf and Cf on the ACA, to not overdrive its input stage too early ?


regards,

With 22k bus R's, use 13k as the Rf and 100pF as the Cf.

Hey there,

i have an old 089 studer stereo chanel strip (line in, mic pre EQ) that i want to rack and searching for a line driver modul.

the output of the unit is unbalanced and if ive red the shamtics right @-10db. i want to have balanced output with studio level - so i think about an API solution because i like API

ive seen that the api chanel strips have an 325 line driver.

so what do you think about adding this driver to the studer unit?
may there be impedance problems?
and jeff do you still have those 325 PCBs (best in stereo) on sale?

kind regards
nico

Hello everybody,

I know this might sound boring but does anyone have a good working solution to get the insert return balanced pre fader?
I find it really important to be on the safe side and don't want to have special patchcords for it.
My setup will often change concerning gear to be inserted.
I read somewhere here that a transformer might be a solution.If so,what specs would you recommend?

Thank you in advance,

Udo.

What about a line reciever like the THAT 1246 or similar?
I find it a very transparent solution!

regards,
Wolfgang

wolfgang said:

What about a line reciever like the THAT 1246 or similar?
I find it a very transparent solution!

regards,
Wolfgang

Click to expand...

Thanks Wolfgang,

but I´d like to keep it all-discrete if possible.
If nothing else works (what I don´t believe) I can still do it like you recommend,have even thought about that as a last possible solution.

Best regards,

Udo.

In the modular console project, I am using my DTO5 as a receiver before the fader. Is a very simple circuit not to different from the input channels on the boards you just got.

Hi Jeff,

2ACA-Bo & Co. received here in germany.Top parts and pcb as always.
Thanks a lot for the L-brackets (EA2503),I totaly forgot to order them!
May I pay them with my next order?
Excellent service here!

Best regards,

Udo.

Hi Jeff,
finally getting around to putting those ACA boards to use that I've bought a few years back!. I am attempting to build a 16 channel summing mixer on steroids, with the provision of adding another 16 channels later. I am planning on adding an additional bus or four, and a few sends as well. They say a picture is worth a thousand words, so I'm wondering if the block diagram below would be correct for this configuration? I would need to order a few more boards from you, and want to be sure I know what i'm getting into here! Many thanks for your help, as always!

Hmm, just noticed that I don't need the two ACA boards for the effects return, as they can feed the master 2 bus directly.... oops!  I shouldn't do this at 2am i suppose!

Hi folks

I am joining the thread because I just bought this module and I am planning on building a 16 channels summing box.
I am planning on having 16 balanced inputs going to hard left / hard right, this module as the final master section, using its stereo insert if needeed and if possible a pair of nice VU meters.

I am taking any advice, starting with the resistors value... =)

Any help is welcome, and congrats for this cool thread

Thomas

edit:

By sneaking on the forum, I found this http://i52.tinypic.com/21dqvqc.png and I think this is what I am going to aim.
Do you think I can simply grab the stereo out and get into the API module? Do I need to match up the impedance? Or tweak some other value?

Thanks

Hello,

the schemo in your link above is just a passive summing network meant to drive a mic preamp.
Don't know if it can be tweaked to work correct with the aca part,at least the shunt resistors should be omitted.Also from what I have seen so far is that the aca is working with 47k bus resistors.

Cheers,

Udo.

Thomas

You will need to unbalance the outputs of your proceeding devices. It will be device dependent on whether you float the - side or shunt it to ground. The bus R's for the summing network should be 47k. Also the 237R shunts will not be needed.

Thanks for all those informations.
Do you think it is better to unbalance the signal right out of my soundcards, or after the summing and right before hitting the ACA module?

I like the 2nd option better because it gives me the opportunity to pretty easily turn my summing box into a passive one if needed.

When you say that the bus R's must be 47K, does this mean that the whole summing stuff must have a 47k impedance? Because this seems pretty hard if I have to put 10K resistors on each input...

I am a bit lost here...