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

[jsteiger]

Hello,

I'm using the CAPI ACA & Booster on my summing system. I'm having the ACA feed a patchbay and return into the Booster side, but with no master fader. I just want to be able to insert a buss compressor there. Do I have to change anything if I skip the master fader?

You can just put a 1k shunt R to ground where the fader would be.

 

[orangerec]

Thanks, Jeff.

Another question for the community? In the spirit of using some parts I already own, I have a bunch of new Jensen JT-112-LPC line output transformers. I was thinking of using them on the output of the right side of the card (ACA outs). This is feeding my patchbay to provide and insert point for stereo buss compression/processing. Here is a link to the specs:
https://www.yumpu.com/en/document/view/22838301/jt-112-lpc-jensen-transformers
These should work well. Or, can anyone see a potential problem with them? Thanks.

 

[jsteiger]

Looks like those should be fine. Give them a try and see!!

 

[Potato Cakes]

Hello, everyone.

I made another one of the 3:2 versions for IEM mixing for another monitor engineer friend of mine, except this time it was requested to have 2 channels with panning and a stereo pair feeding two sets of outputs. I used 4 differential input boards from DIYRE with INA137's. For the panned inputs, I took those to a DPDT switch so I could select between mono (bypass pan knob) or stereo pan. The poteniometer is a 10k linear with center detent that I got from Jeff. I would like to find a little beefier pot as this one has solder pins that require some care when handling. But that's what I had and the Bourns pots do feel nice. With the switch at mono position, it splits with the prescribed 47k bus resistors to sum with the stereo input. With the switch at the stereo pan position it feeds the pan knob with the signal split across two resistors as shown in the Orban panning schematic. The values I landed on are 10k to feed the wipers and 15k as the bus resistors that sum with the stereo input. I started off incorrectly as I misplaced in my head where the 10k resistors in the schematic were, and I didn't actually know this till I started typing this. Even so, it does work as expected.

Thanks!

Paul

 

[Potato Cakes]

And the unit itself.

 

[orangerec]

Hello,
I'm using CAPI's passive panner feeding my ACA card. I've wired the panner as per Jeff's recommendations off the CAPI site:
http://www.capi-gear.com/catalog/images/gallery/pots/BI/Passive-pan-pot-network.pdf
I'm using 2k2 resistors in the RS position. According to the notes, this should get me a -4.5dB pan law, but I'm getting an almost 7dB drop at center. If I change the RS resistors to 4k7 ohm, I get about a 6dB drop. Wracking my brain here.  Can anyone shed some light on this? Thank you.

 

[jsteiger]

It may have something to do with the value of Bus R's (if they are dif) or whatever you are feeding the pan network from. There will be some interaction so adjustments may need to be made. Its easy enough to try with no slug R's to verify and then just adjust the slug R until you get the pan law drop you want based on your exact circuit.

 

[orangerec]

Jeff,

I'm coming out of my pro tools interface (mytek 8x192) as a temp source. Feeding + into the pan, - and shield (ground) to the panner's ground. When you mention Slug R, are you referring to RS on your schematic? Currently, I'm using your pan pot,  RB = 47k, RL =3k3.

 

[jsteiger]

Jeff,

I'm coming out of my pro tools interface (mytek 8x192) as a temp source. Feeding + into the pan, - and shield (ground) to the panner's ground. When you mention Slug R, are you referring to RS on your schematic? Currently, I'm using your pan pot,  RB = 47k, RL =3k3.

Yes Slug R = RS. It may have something to do with unbalancing the Mytek outputs. I would not bank on this if you are changing the source. I saw "temp source".

 

[orangerec]

I have two Cinemag CT-2385 line output transformers.  They looks just like the output transformers from the CAPI store and fit on the Booster board. Can any of you pros have a look and see if the color code match between the Cinemag and the CAPI Booster output section? Thanks for the help.

 

[jsteiger]

I have two Cinemag CT-2385 line output transformers.  They looks just like the output transformers from the CAPI store and fit on the Booster board. Can any of you pros have a look and see if the color code match between the Cinemag and the CAPI Booster output section? Thanks for the help.

http://www.capi-gear.com/catalog/images/gallery/2503/2503-specs.pdf

 

[supafuzz99]

I have a 1974 Allen & Heath Mod 2 that has 8 output busses
that I mix into protools. I would like to be able to get more headroom by adding line amps with output transformers for each of the 8 busses the busses go into seperate channels of lynx aurora and get summed  in protools. This way I can compress each channel differently with outboard.

So what would I need to do this?
2 capi's?or 4
or do i just need booster amps?

I am electronically challenged so please bear with my confusion.

thanks

 

[jsteiger]

If you do not plan on replacing the summing amps in your board then it sounds like just a single stage line amp would work for you.

 

[madbeavis]

Hello all,

I am trying to re purpose the Classic 2-ACA-Bo Rev B.1 into a simplified 536 input module replacement. I read on this thread that several traces would need to be cut on the ACA side. The difference in the schematic is clear but im not sure if I should just leaving those thruholes unpopulated or actually cut the traces. From what I can tell this is only needed on the ACA side, the booster side appears to be similar to the 536 already. If anyone has attempted this before please let me know.

Thanks,

Chris

 

[Sinkia]

Hi everybody !

I just have finish my 2-ACA, and after several testing, it appears I do have one side with ground noise, and the same side is distording too..

It seems to be a grounding issue, but I don't really know where it could be wrong...

Any ideas..?

 

[jsteiger]

Hi everybody !

I just have finish my 2-ACA, and after several testing, it appears I do have one side with ground noise, and the same side is distording too..

It seems to be a grounding issue, but I don't really know where it could be wrong...

Any ideas..?

Have you ruled out opamps? You can swap left for right to see if the problem follows. You can also do the same for the wiring to and from the board to see if the fault is truly on the ACA card. You can next isolate if it is within the ACA section or the Booster section the same way.

 

[Sinkia]

Have you ruled out opamps? You can swap left for right to see if the problem follows. You can also do the same for the wiring to and from the board to see if the fault is truly on the ACA card. You can next isolate if it is within the ACA section or the Booster section the same way.

I already have swap the op amp in it, but still have the same issue.. I will keep looking on tomorrow... I'll come back here on tomorrow to let you know!
Many thanks for your help !!! Jsteiger

 

[Sinkia]

Atention - Weird -

So I made a couple test and here are my result :

The summing do not have any noise when nothing is plugged in. slightly a reaaaaaaally small noise like Voltage issue that we an ear.

Here is the main point : I have plus my mpc straight into the sub d input of the summing. no noise, no distortion, everything is smooth.

then  have plug my digi HD interface in it, and here it happen again.
I guess it all come from the 192... seems weird no? cause it do nt distort when I plug in other gears..

 

[Sinkia]

INVESTIGATION - PART 2 :  8)

So I'm checking the calibration of my 192, eveything is great. there's a slightly 0,5 db less on one output, but otherwse, everything works as it should be..

I arrive with different question now :

- How many 47k resistor h-should there be in the signal pass? I mean, when this s a line lvl conneced, everything is smooth and go as it should be, but when this is the otut of my interface.. BADABOOM

So here is my question :

IN 1-16 -> 47k bus resistor -> INPUT L/R ACA 

ORRRRRRRR

IN 1-16 -> 47k bus resistor -> 47k bus (L&R busses) -> INPUT L:R ACA?

My question seems stupid, but we doin't know.. what bother me is that everything works fine with the MPC...

 

[jsteiger]

It may be easier to understand a quick sketch rather than your circuit description.

Its possible that the 192 does not like being unbalanced? Maybe using an INA134 as a unity gain balanced to unbalanced receiver might be a better solution.