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

Hi to all!
I've just ended my Aca booster board with APP 992 Doa and need some help...
I want to use the Aca as alternative master for my Amek M2000 board ( 47k summing resistor as API console).
On Amek There are 2  - Summing board GL80C
I just nedd to patch the Aca Boster in same place of GL80C?
Thanks!!!

Yes it appears that way.

Sorry,  if I want to build a completely new master, where I can find some info about a possibly monitor section and aux input (some for Daw L/R Master )?
All the suggestions are welcome!
THANKS!!!

A question about the 2S-LA: how much gain can it be setup to give? I`m planning to use it as makeupgain for a couple of line-units.

fragletrollet said:

A question about the 2S-LA: how much gain can it be setup to give? I`m planning to use it as makeupgain for a couple of line-units.

Click to expand...

How much do you need? I have never experimented with max gain but it should be capable of an easy 40 if need be.

That is more than enough! I`m going to use them as makeup-gain for some boutique guitar-pedals I intend to inject into my modular synthesizer. So I was planning to use them without transformers, merely as line-boosters. No need of  balancing the signal. The guitar pedals have a line outputs, so I was planning to use the 2s-la without transformers, just for gain control. So I just wire it up with an attenuator in between the stages?

and what power is it expecting?

fragletrollet said:

...So I just wire it up with an attenuator in between the stages?

Click to expand...

Yes that should work. Just a pot or fader. The card uses 2520 style opamps so +/-16VDC.

Hi,
I've build and mounted the CAPI Mixbuss in my Yamaha m1516.

Now I need to decide how I am going to power it?

The Yamaha has +_ 25 vdc rails for audio.

What is the max safe operating voltages for the CAPI mixbus?

Do I just drop the +-25vdc through some diodes to the safe operating voltage of the 2520's, +- 20v dc??

10 diodes for each rail?

I would assume its depends on the opamps used. If you are using Yamaha NE80200 then you can supply the CAPI board with that voltage feed, provided you use 35v caps where appropriate.

Otherwise you should find the m1516 also supplies -+16v voltage from its PSU as well, as the EQ section of the m1516 are using DIP8 opamps. So use this voltage feed if you are using DOA's which are happier under -+20v...

Yes it mainly depends on the opamps used on the 2-ACA-Bo board. There is not much to gain by running 2520 style DOA's beyond 16V.

Keep in mind the voltage of the PSU caps used on the 2-ACA-Bo. IIRC, 47µf/25V are in the BOM. They should be ok for 24V use but if it were me, I would increase them to 35V parts.

....same , but different diy layout of original Api Summ "set" )
as in image?

r

r2d2 said:

....same , but different diy layout of original Api Summ "set" )
as in image?

Click to expand...

That is not DIY but products from API. They are discontinued now.

Hi all!

I am considering building up an ACA-BO and a 32 channel summer, and a way to get audio out of my DAW.. into the analog world, and back into the DAW.
There will be times when I will only used 4-8 sums, and most often none...  maybe a switch network to cut off unused inputs, with different resistor values switched in and out?

At this point, the summing will be secondary to having an analog stereo set coming out of the DAW, with some inserts, and a stereo fader to go back to a A/D converter, back into the DAW.

Has anyone done a table top set up with the ACA-BO using db 25 sum ins/outs as well as insert jacks, meters, and a fader, etc?

This will be used primarily for Mastering.

Any thoughts, or ideas welcome.  I would like to start this sooner, rather than later.


Peace,

Mike

Hi Jeff,

I have powered up for the first time. No smoke. But no audio. All I have is a high frequency oscillation, which the faders seem to modulate up and down a bit.

I ended up providing the +- 16v by making up a little board using two 16v zeners, some resisters and caps, as per the Yamaha m1516 schematic (for eq section).  I tested the power supply prior to connection to the API board.

I used the existing pair of 10K faders, I just de-soldered the existing wire and individually shrink wrapped them to prevent any shorts.

Also I broke the Buss jumpers on Master (Program 1 and 2) boards 1 and 2 so no signal is going to the old master section. I then took my LR feed from the Master board 1 (where the jumpers can be, but are not now) I did remove one ceramic cap from the old master section so as to use one of the pcb pin holes which goes to earth. This was my shield point for the feed to ACA input.

The outputs of the new booster amp I wired up directly to the existing xlr outputs for program 1 and 2 (Main buss). I made sure to remove the old connections and again shrink wrap them individually.

Finally I connected the mute input to an earth point on the API board (as advised on the schematic), I choose the shield input of T/B as it was available.

I have measured the DC voltages at the input DC on the CAPI board. That is wrong for sure. around +-7vdc, should be +-16vdc. I have measured the voltage feeding the zener board and it is as it should be at +-25vdc. I measured the output of the zener board as +-16vdc  (correct) before i attached the CAPI board. But now it is wrong.??

I have now disconnected the Zener +-16vdc board and tested the unloaded voltage. It is once again correct at +-16vdc. 

Schematic for Yamaha m1516:

http://elektrotanya.com/yamaha_m1516.pdf/download.html

Could someone please have a look at the resisters in the +- 16 zener distribution? Do I need to change these based on the current usage of the CAPI? I have 4 x GAR2520 installed.  An6522 x 1.5 vs Ga2520 x 4,  current difference?

Or should I build a separate +-16vdc power supply for the CAPI board? I have a build JLM ACDC, i just need a transformer and stick it in a box. Will this lead to hum issues?

Thanks

Sounds like a PSU issue. I couldn't see the zener schemo but can only imagine that the series R's would need to be adjusted for current draw. I don't know if this is the best solution for powering a master summing circuit.

Also, have you tested all of the opamps in something so you know they are working?

Good Idea Jeff.

I tested all 4 Gar2520 in my VP312, all working fine.

So If I go ahead now and build a dedicated power supply for the ACA-BO, are there any special earthing considerations?

Should I tie the ov to chassis of the console and do the same with the earth point on the ACA-BO?

stuartpre said:

Good Idea Jeff.

I tested all 4 Gar2520 in my VP312, all working fine.

So If I go ahead now and build a dedicated power supply for the ACA-BO, are there any special earthing considerations?

Should I tie the ov to chassis of the console and do the same with the earth point on the ACA-BO?

Click to expand...

I am not sure how the grounding scheme is carried out with your board. It may take some experimentation to get the most quiet grounding scheme with the 2nd PSU.

Well all modules have a fat green wire and/or an aluminum mounting bracket that run to an aluminum cross member. One member for the channels and one member for the master section. These alluminum members have a fat green wire running back to the rear panel and mount a screw located about one inch from the power distribution, a small 3 by 2 pcb that is mounted to the rear panel via a strip of angle copper. So if I earth my additional power supply at the same point and run a fat green wire from earth of the CAPI board to the same rear panel earth, then finger crossed?

stuartpre said:

Well all modules have a fat green wire and/or an aluminum mounting bracket that run to an aluminum cross member. One member for the channels and one member for the master section. These alluminum members have a fat green wire running back to the rear panel and mount a screw located about one inch from the power distribution, a small 3 by 2 pcb that is mounted to the rear panel via a strip of angle copper. So if I earth my additional power supply at the same point and run a fat green wire from earth of the CAPI board to the same rear panel earth, then finger crossed?

Click to expand...

You can start that way and see how it performs. You may want to connect the shield for the main bus feeds to the bus bar that the consoles master section uses.