andow

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #520 on: March 04, 2020, 12:51:36 AM »
Wow, just discovered this and am really interested! Anybody tried it in a Trident 80?

How many channels can be summed with this board? I guess there shouldn't be a limit, but I'm wondering why there is a cascaded summing in the block diagram?  ???


Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #521 on: April 16, 2020, 08:57:52 AM »
Hy

Can be used balanced inputs with this board?
Out of daw via RME fireface, to resistors board to capi 2-aca-bo stereo out balanced via RME in DAW.

thanks in advance

jsteiger

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #522 on: April 16, 2020, 12:14:00 PM »
Hy

Can be used balanced inputs with this board?
Out of daw via RME fireface, to resistors board to capi 2-aca-bo stereo out balanced via RME in DAW.

thanks in advance
Yes it can be done. I kinda depends on the interface. The cold leg will likely need to be grounded. Some electronic devices don't like this, some don't care.
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #523 on: April 16, 2020, 04:31:08 PM »
Ok thanks

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #524 on: April 18, 2020, 05:32:12 AM »
Hy
i have heard that signal from resistor board is too weak. After resistor board signal becomes a microphone signal and it is too weak for input in aca board. Is that correct?
If so I can put an input transformer in between to increase signal to correct input level for aca?
Is that correct.
For Chanel's inputs I will use passive summing resistor board van Ian.
This is idee rme out to passive summing resistor board out to 2 aca board

Thanks in advance

jsteiger

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #525 on: April 18, 2020, 12:59:43 PM »
Hy
i have heard that signal from resistor board is too weak. After resistor board signal becomes a microphone signal and it is too weak for input in aca board. Is that correct?
If so I can put an input transformer in between to increase signal to correct input level for aca?
Is that correct.
For Chanel's inputs I will use passive summing resistor board van Ian.
This is idee rme out to passive summing resistor board out to 2 aca board

Thanks in advance
I am not really sure what "resistor board" you are talking about. In a  typical application, 47k bus resistors are used and they are fine with the rest of the 2-ACA-Bo built as we suggest.
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #526 on: April 18, 2020, 02:10:20 PM »

Potato Cakes

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #527 on: April 18, 2020, 10:44:10 PM »
Hy
i have heard that signal from resistor board is too weak. After resistor board signal becomes a microphone signal and it is too weak for input in aca board. Is that correct?
If so I can put an input transformer in between to increase signal to correct input level for aca?
Is that correct.
For Chanel's inputs I will use passive summing resistor board van Ian.
This is idee rme out to passive summing resistor board out to 2 aca board

Thanks in advance

The first stage DOAs on the board do the make up gain for the signal loss after the summing network. The second set is for a fader insert.   The console I installed mine in uses 10k for bus resistors and there is no issue with gain. I've also built a unit using the recommended 47k resistors also with no issue. The only way I can see you having problems is if you are not feeding line level to the summing network.

There are several passive style summing contraptions such as DB25 to two (2) XLRs and the end user is usually instructed to plug it into a preferred preamp for the tone of their liking, but that probably has more to do with the fact that most consumers of pro audio gear won't have, want, or know how to build a dedicated gain circuit for summing.

In conclusion, build one and just follow the instructions. They're awesome.

Thanks!

Paul

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #528 on: April 19, 2020, 05:23:54 AM »
Thank you  for info

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #529 on: May 27, 2020, 06:20:38 AM »
Hi all,

I just realized my console PSU is unipolar and would need the -24 rail to power AM10 on the ACA board.
How would you guys do it? Should I use a separate PSU?

Thanks !

Fabien


Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #530 on: June 23, 2020, 02:15:19 PM »
Hello Jeff,

I've noticed that in your ACA schematic you list 47k feedback R, while in the ACA/BO, on the ACA side you list 28k.
I've built a summing mixer with 2520 receiver stages, 47k bus R's and following the ACA/BO schematic, 28K bus resistors in the ACA/BO (47k in booster with a 10k switch). What gain should I expect at the output of the 2503?

How would the gain change with 47k in the ACA?


Thanks and all the best,


jsteiger

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #531 on: June 23, 2020, 02:23:05 PM »
If built to the schematic it will be unity gain.
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

groselicain

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #532 on: October 14, 2020, 09:11:49 PM »
Wondering if anyone has had any problems from the fader connection between the ACA and Booster sections. I'm using a 1k pot with the 47.5k resistors and wired as the schematic shows. I even emailed Jeff and he confirmed it was correct. Both sides operate correctly when used individually, but there's something very wrong when they're joined by the fader.

To be more specific, the noise floor is untenable with the fader at minimum. As I raise it, the noise goes away but the signal is completely distorted. If I disconnect the ACA output negative, my noise issues are no longer as problematic but I lose gain, and of course I can't get by without the shield on the BO input side. Any ideas?
« Last Edit: October 14, 2020, 09:15:28 PM by groselicain »

boji

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #533 on: October 15, 2020, 08:14:57 PM »
Might help to draw out your connections.

I've only done some testing, but did not experience any noise issues using a 10k fader.
I used insulated standoffs to mount pcb to console frame. For ACA tx outs, cold legs were tied to console agnd and fader low.

Edit (just read your edit): I've tied both ACA and BO unbalanced input coms to agnd, chassis pins only for use as cable screen.
« Last Edit: October 15, 2020, 08:31:08 PM by boji »

groselicain

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #534 on: October 15, 2020, 09:10:26 PM »
Might help to draw out your connections...
I've tied both ACA and BO unbalanced input coms to agnd, chassis pins only for use as cable screen.

https://drive.google.com/file/d/1_11YdpihPsTDgYgHhCyLLN2ius4CJV8G/view?usp=sharing

Here's a picture of what I had. Couldn't get everything in the shot, but yellow and purple run to BO input positive and shield, respectively. When you say you tied BO input common to audio ground, are you saying you did it in addition to connecting the fader common to it? I apologize if I'm not following. Thanks Boji.

boji

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #535 on: October 16, 2020, 02:46:23 AM »
If all four units are working fine independently, then it's likely a connection issue.

Looks like you might be feeding Bo into ACA?!? (can't tell since picture is cropped).

Signal should go ACA 2520---> 2623---> Fader--->2520 booster---->2503

« Last Edit: October 16, 2020, 04:03:22 AM by boji »

groselicain

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #536 on: October 16, 2020, 09:34:37 AM »
If all four units are working fine independently, then it's likely a connection issue.

Looks like you might be feeding Bo into ACA?!? (can't tell since picture is cropped).

Signal should go ACA 2520---> 2623---> Fader--->2520 booster---->2503



Oh my goodness. Thank you so, so much. I sent these exact same pictures to Jeff and I guess he just never looked at them. With the outputs of each section for left and right being flipped on the board, I should've guessed that the signal flow would be flipped from right to left in the same way—but then again, I never looked at the damned silk screen either.

Thank you Boji, you just fixed everything. I owe you.

boji

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #537 on: October 16, 2020, 10:59:15 AM »
Rock on, it's a great sounding summing unit. Glad we found the issue.

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #538 on: October 18, 2020, 11:51:22 PM »
Can I substitute the 33uf PC caps for 47 uf?

Can I turn a Inverting Aca board into 4x fader boosters/output transformer drivers, by omitting c4 and jumping r4, and changing R2 to 47R .5W and use 2503 transfomer? What difference does the R2 (inv aca board) or R8 (ACA/BO board) play in the circuit, and could I use the 2623 instead (keeping 100R for R2?)


boji

Re: [BUILD]CAPI 2-ACA-Bo~Official Support Thread
« Reply #539 on: October 28, 2020, 05:15:04 PM »
Quote
Can I substitute the 33uf PC caps for 47 uf?
Going from memory, if the 47's are going to power pins you should be fine.

Quote
Can I turn a Inverting Aca board into 4x fader boosters/output transformer drivers
Yeah should be simple value swaps. Again going from memory, R2 sets gain giving +10db in-hand, whereas aca nfb value would be unity with 2623 providing a +3dB boost.

Edit: Jeff sells 1x4 PCB aca's that could be repurposed for make-up gain.


« Last Edit: October 28, 2020, 05:41:34 PM by boji »


 

Related Topics

  Subject / Started by Replies Last post
986 Replies
203797 Views
Last post June 19, 2020, 08:55:58 PM
by zonkola
143 Replies
44129 Views
Last post October 09, 2020, 05:21:52 AM
by Isax1984
372 Replies
82422 Views
Last post August 24, 2020, 11:06:24 AM
by jsteiger
22 Replies
7709 Views
Last post June 09, 2020, 10:04:37 AM
by jsteiger