modding a Behringer ADA8000?

[levlhed]

I've realized my optimum set up would be *anything* with an ADAT input and 8 DC-coupled outputs. Trolling around the interwebs I've seen people suggest that modifying an ADA8000 might be a fruitful venture.
Does anyone have some advice or ideas concerning this?

From what I've read it *should* just be a matter of bypassing a doodad or two on the outputs?

[justin3am]

It may just be a matter of shorting DC blocking capacitors at the outputs but I've found that some devices have those caps on the outputs because there is a DC offset present in the signal that would need to be compensated for.

[levlhed]

How would a guy with a screwdriver, a multimeter, and more ambition than sense go about determining this?

It would appear that a new ADA8000 can be had for under $200, used ones even less. If there was some way to make it work it'd be stupendous.
I was looking at the Alesis io 26 which appears to have the ADAT-in/DC-out covered but they can't be found new and I think now that word has got out that they'll work for SW/Volta their market price has gone up.

[ThePunkMonk]

they'll work for SW/Volta

Have you seen the new AC Encoder from Silent Way? They claim it lets you use their DC control plugins with any audio interface with or without DC coupled outputs.

http://www.expert-sleepers.co.uk/siwaacencoder.html

[levlhed]

Yes I have seen that. At first read there are too many caveats and the whole "cable modifying" part is a little on the beta side for me. If there was a definitive answer/parts list/etc then I suppose that'd be the more reasonable answer to using an ADA8000 than opening it up and hitting it with a soldering iron.
I think the idea of someone coming up with a "magic i/o box" that'd let you just stick it in between and sort the mods out would be pretty sweet too. An 8 i/o box between and ADA8000 and my analog juiceboxes, please!

Can anyone look at this ADA8000 schematic and say if the doodads just block or are there to offset as well?

http://www.gyraf.dk/schematics/Behringe ... alouge.PDF

[os]

I think the idea of someone coming up with a "magic i/o box" that'd let you just stick it in between and sort the mods out would be pretty sweet too.

Working on it.
http://www.muffwiggler.com/forum/viewtopic.php?t=14521

[levlhed]

cool! That seems to be the slickest way to use an AC interface in the end.

[mjohann]

AUTO-ADMIN: Non-MP3, WAV, OGG, SoundCloud, YouTube, Vimeo, Twitter and Facebook links in this post have been protected automatically. Once the member reaches 5 posts the links will function as normal.

Hello, I just registered here to contribute to this topic.

- Yes, there are DC offsets needed at input and present at the outputs of the ADC/DACs on the ADA8000;
- You cannot just short the coupling caps, not only because of the DC, but, at the outputs, because this messes up with the output filters (I tried at first);
- but it is possible to DC-couple it. Easier at the outputs, as the DAC has differential pins. All you need is an op-amp in differential configuration. You can make a small board, take the signals from the spots where the coupling caps were on, and route your outputs to wherever you want, or try to use the onboard output op-amps by doing some work with an airflow reworking station to change some resistors.

I am working with DC because of sound quality reasons, and I am focused on the inputs at this moment. You can check some information I just started to place at this page:

http://www.inf.ufrgs.br/~johann/ada8000/ (http://www.inf.ufrgs.br/~johann/ada8000/)

Regards,
Johann

[os]

Hi Johann - thanks for posting.

I wondered if you could do me a favour - on an unmodified (DC blocked) output, I'd love to know what sort of voltage the ADA8000 is capable of producing, using a simple rectifier/capacitor e.g. like this:


Thanks in advance.

[mjohann]

Hi Johann - thanks for posting.

I wondered if you could do me a favour - on an unmodified (DC blocked) output, I'd love to know what sort of voltage the ADA8000 is capable of producing, using a simple rectifier/capacitor e.g. like this:

Thanks in advance.

Sorry for the delay, I wasn't paying attention to this track.
I will try to check that for you later, but I'd say 2V peak, which is the DAC's swing.

I have another information regarding the inputs, in case anyone here is interested in getting DC values in. Although we can DC couple it to avoid the use of the coupling capacitors, we cannot get DC values recorded at the digital domain, as the AL1101 has a low cut digital filter that removes DC. I tested. We never get any DC in.

Johann

[os]

My results are here:
http://www.muffwiggler.com/forum/viewto ... 97&start=0

2V turns out to be about right.