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#1190487 - 01/11/13 06:09 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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 Originally Posted By: Ptr
....Any tricky parts required ?...


The ADAT CODEC interface is done with LSI ICs -- WAVEFRONT AL1401 and AL1402 ICs - I actually bought some off EBAY - to officially buy them you need to go through the manufacturer, and they actually demand you sign an NDA with them before they will even sell them to you.

EBAY is fine for a few

The OPTICAL transmitter and receiver jacks (I used TOTX178 and TORX179 on my breadboard) are also tricky to find - EBAY again is where I ended up - and had to order them from China!! But they arrived no problem.

The rest of the circuit is just some standard HC logic chips and some caps and resistors and an inductor. And a DB25 connector to connect to RBUS.

If you want the MIDI port, you need 2 DIN connectors and an opto-isolator IC.

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#1190492 - 01/11/13 06:19 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
 Originally Posted By: Ptr
....Any tricky parts required ?

...


A.k.a. Mystery parts,

... but no, serious, I was surprised this to be possible as easy as this breadboard looks, but I guess there's some specific programming going on in those chips, right ?

I've contacted Roland for a few Service Notes recently, I should ask them for those of the DIF-AT(24) as well. I assume you _didn't_ consult those docs on purpose, to keep the puzzle interesting perhaps ?

Bye
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#1190495 - 01/11/13 06:23 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
 Originally Posted By: Ptr
....Any tricky parts required ?...


The ADAT CODEC interface is done with LSI ICs -- WAVEFRONT AL1401 and AL1402 ICs - I actually bought some off EBAY - to officially buy them you need to go through the manufacturer, and they actually demand you sign an NDA with them before they will even sell them to you.

EBAY is fine for a few

The OPTICAL transmitter and receiver jacks (I used TOTX178 and TORX179 on my breadboard) are also tricky to find - EBAY again is where I ended up - and had to order them from China!! But they arrived no problem.

The rest of the circuit is just some standard HC logic chips and some caps and resistors and an inductor. And a DB25 connector to connect to RBUS.

If you want the MIDI port, you need 2 DIN connectors and an opto-isolator IC.


Now in reply to your full text:

I'm surprised to read that this is 'all it takes' (without wanting to downsize your work & investigations in any way!), but it sure sounds all good!

I mean, I'm curious how/where the RBUS-format is decoded ?

Regards
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#1190498 - 01/11/13 06:29 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
 Originally Posted By: Ptr
....Any tricky parts required ?...


The ADAT CODEC interface is done with LSI ICs -- WAVEFRONT AL1401 and AL1402 ICs -


FWIW, the Behringer ADA8000 uses those two ICs as well. For say a VSR-880 + ADA8000 combination, one might actually consider skipping the 1401 & 1402 & bypassing the ADAT-format part of this converter-box design & 'inject' right away into the ADA8000 ?!
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#1190501 - 01/11/13 06:36 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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 Originally Posted By: Ptr
... but I guess there's some specific programming going on in those chips, right ...
Bye


No programming at all. The RBUS format pretty much matches one of the modes the ADAT interface IC supports directly. Inverted, but that is easy...

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#1190502 - 01/11/13 06:39 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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If you removed the ADAT chip from the ADA8000, you could probably pretty much drive the DACs from the RBUS signals. It would take a few inverters and such.

Seems cleaner to me to just hook the two together with an optical cable though and not screw around modding the ADA8000

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#1190505 - 01/11/13 06:47 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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Hi,

I should read up on the RBUS-format, since for years I've thought it to be some 'special format' (different from 'the others').

But I just got pretty flabbergasted by the circuit in this link:

http://dc386.4shared.com/doc/a54WJbju/preview.html

Just as you described and to my surprise it turns out it's pretty straightforward indeed. Boy, the time looking for those DIF-AT(24)-boxes would have been way better spent by doing an alike thing as you did, heating up the soldering iron oneself !

I agree with you that it's best to leave the ADA8000 untouched & connect by an universal link (ADAT).

Thanks again for triggering all this, very nice thread!
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#1190507 - 01/11/13 06:49 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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 Originally Posted By: Ptr
...I'm curious how/where the RBUS-format is decoded...



It turns out RBUS is pretty simple -

There are 4 pins of audio (stereo on each pin for 8 each way) in each direction on the RBUS and 2 MIDI pins

2 clocks - LRCLK OUT and LRCLK IN - IN must always be supplied, even if it is being sourced from the LRCLK OUT

LRCLK runs at 44.1k or 48k or 96k (But the ADAT will only work with 44.1 and 48)

And 2 pins for MIDI in and out

Audio is encoded as 24bit left justified 2's complement with RIGHT channel on positive phase of LRCLK and LEFT channel on negative phase

Bitrate is at 64x LRCLK (which the ADAT IC internally supplies through it's own PLL - all you have to give it is LRCLK)

All signals on the RBUS are driven through 74HC14 inverting buffers so must be re-inverted to be used by the ADAT IC

Audio encoding is like this after inverting (LEFT JUSTIFIED 24)





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#1190508 - 01/11/13 06:56 PM Re: RBUS ADAT convertor [Re: bear]
bear Offline
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Wow a DIF-AT schematic... That would have made it less of a challenge...

Do you have a 2480 service manual? Email me if you do not, and I will send you one in pdf. That is what I was using to work off of...

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#1190509 - 01/11/13 06:57 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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Hello Bear,

Thanks for sharing this info, informative!

It's actually a bit amusing that RBUS has had such a "it's different" air around it, while it was actually pretty close to the rest! Not bad, selling those DIF-AT(24) converter-boxes for solving a problem they've created themselves. But OK, this is another discussion.

I guess I've always been thinking the audio as appearing on the RBUS-connectors was still coded in their propr. data-reduced fashion, but not so...

Thanks !
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#1190510 - 01/11/13 07:00 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
Wow a DIF-AT schematic... That would have made it less of a challenge...


I got the impression you deliberately didn't want to see this, to have a nice challenge ? ;-)

 Quote:
Do you have a 2480 service manual? Email me if you do not, and I will send you one in pdf. That is what I was using to work off of...


I'll send a PM, thanks !
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#1190513 - 01/11/13 07:04 PM Re: RBUS ADAT convertor [Re: Ptr]
Ptr Offline
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 Originally Posted By: Ptr
Hi,
But I just got pretty flabbergasted by the circuit in this link:

http://dc386.4shared.com/doc/a54WJbju/preview.html


It's possible to read, but still a preview. I'll see if I can get hold of the pdf.

Bye
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#1190515 - 01/11/13 07:19 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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BTW - I have gone ADAT crazy - I opened up my TD-20 DRUM brain awhile ago - it is going to be easy to add an ADAT out port to it to send 8 channels of drums over one optical cable...

I will have to solder a couple of wires to the PCB, but I see places where it will not be too difficult...

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#1190517 - 01/11/13 07:28 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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ADAT convenient indeed

Sounds like you bought a few more 140X for additional applications, sure handy!

The conversion to ADAT for the VSR-880 would pretty much bring it back in use again! (Now let's hope the conversion to SSD-drive starts working...)
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#1190518 - 01/11/13 07:29 PM Re: RBUS ADAT convertor [Re: Ptr]
Ptr Offline
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Looks like the DIF-AT24 could have been in a smaller box ;-)

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#1190525 - 01/11/13 08:17 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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Your email bounced as too big - download 2480 service manual here

https://www.yousendit.com/download/UW16S3d1d0FrYUJBSXNUQw

And just for fun - 1680 service manual here

https://www.yousendit.com/download/UW16S3d1d0F0QTE3czlVag

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#1190529 - 01/11/13 08:48 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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Hi,

Thanks for the uploads - files-by-email arrived OK (6 files), despite the warning message.


Thanks!

Peter
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#1190854 - 01/13/13 11:05 AM Re: RBUS ADAT convertor [Re: Ptr]
JazAddict Offline
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So can either of u build a dif-at24 and sell it to me?
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#1190889 - 01/13/13 03:11 PM Re: RBUS ADAT convertor [Re: JazAddict]
bear Offline
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Yes I can... WILL I is the question...
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#1190930 - 01/13/13 04:31 PM Re: RBUS ADAT convertor [Re: bear]
bear Offline
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OK - here is the schematic of what I would build if I was going to build it. This version includes MIDI and the option of external power for those RBUS devices which do not supply power.

Because of these additions (mostly the connectors involved) I think it would have to built as a standalone box hooked up to RBUS through a cable. Cable would be a normal D25 NOT a special RBUS cable - the schematic already crosses over the necessary wires on the RBUS port.

EMAIL me if you want a pdf version of schematic you can really read.




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#1191307 - 01/15/13 11:26 AM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
Cable would be a normal D25 NOT a special RBUS cable - the schematic already crosses over the necessary wires on the RBUS port.


That sounds good. Was wondering what normal DB25 cable does w.r.t. grounding/screening. Twisted pairs as well ? (without the crossing) Won't be too critical I guess, for shorter distance.

It remains tempting though to construct this as a plug-on (without cable) at the rear of the VSR-880 (that's all I own & will own VS-wise), there's nothing above the RBUS connector, so a little box less than 2RU would fit - not as universal, but good for my setup.

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#1191308 - 01/15/13 11:35 AM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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If it weren't for the need for MIDI jacks and the ext power connector (only a few RBUS devices do NOT supply power - the VSR880 supplies it just fine) I think you could build it in the form factor of a little dongle that plugs directly into the jack, no cable needed.

I would try to build it that way if the no MIDI configuration was OK.

You can get pretty good cables straight through with shields, but as you say probably not twisted pairs. I do not know how much it matters though - for my breadboard I was using a 8 foot D25 cable, and then a couple of feet of ribbon cable salvaged from a computer, and I didn't see any problem.

The signals involved are really not all that fast - even the 64x LRCLK bitrate is only 3mhz or so. In my world this is SLOW - my normal work is with circuits at 900mhz and 2400mhz and 5.8ghz.

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#1191356 - 01/15/13 04:31 PM Re: RBUS ADAT convertor [Re: bear]
dkfackler Offline
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 Originally Posted By: bear
...the form factor of a little dongle that plugs directly into the jack, no cable needed.


That's what I'd like.

DK

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#1191365 - 01/15/13 05:02 PM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
If it weren't for the need for MIDI jacks


If I'm not mistaken, for the VSR-880 the MIDI-I/O on the DIF-AT24 does not add anything that can't be done with the MIDI-I/O on the VSR itself (selection for MTC has to be made, so the internal MIDI-I/O will do).

So as you say, sounds indeed like the MIDI-I/O on the plug-on box can be skipped. Increases the chance that I'm finishing this little project soon ;-)

 Quote:
I think you could build it in the form factor of a little dongle that plugs directly into the jack, no cable needed.

I would try to build it that way if the no MIDI configuration was OK.


Sounds the most practical, skipping sourcing/wiring a cable. I don't have clear view though how I could connect a plug-on directly on the RBUS connector _and_ secure the conector-screws for added stability - the box would obstruct access to the screws I figure.


 Quote:
The signals involved are really not all that fast - even the 64x LRCLK bitrate is only 3mhz or so. In my world this is SLOW - my normal work is with circuits at 900mhz and 2400mhz and 5.8ghz.

I agree, many people would call that 3MHz 'almost DC' (about time to put that lame joke to rest ;-). It's been a while, let me think out loud, even if we had pretty sloppy connections & timing here, there still wouldn't be any opportunity for degradation because of jitter - since unless the timing-differences add up to really drastic amounts, everything is re-clocked - but please correct.
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#1191366 - 01/15/13 05:05 PM Re: RBUS ADAT convertor [Re: dkfackler]
Ptr Offline
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 Originally Posted By: dkfackler
 Originally Posted By: bear
...the form factor of a little dongle that plugs directly into the jack, no cable needed.


That's what I'd like.

DK


It sure would suit the VSR-880 (see the pic above), but no experience with the other VS-models. Maybe it doesn't fit too well there.
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#1191376 - 01/15/13 05:21 PM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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I think dongle sized would fit real well with the 24xx series recorders also, as long as the width was kept to the same as the actual D25... in fact most devices...

The only thing that threw me for a loop was trying it with my SI-24 and realizing the SI-24 does not supply power on PIN1 like the other devices do... having a connector to be able to supply ext DC for the adapter really throws a monkey wrench into making it dongle size.

And of course there is no way to provide 2 DIN5 connectors for MIDI on a dongle sized board - these things are HUGE comparatively speaking.... MAYBE you could make the MIDI connect on 3.5mm jacks, and just bring out an adapter cable to MIDI DIN5's if you wanted MIDI. There MIGHT be enough room for that in a dongle sized device.





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#1191382 - 01/15/13 05:42 PM Re: RBUS ADAT convertor [Re: bear]
dkfackler Offline
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I'm not concerned about MIDI on the RBUS. I'd use the standard MIDI connectors for that.

MIDI still uses only three of the five DIN5 pins(imagine that-- a standard that remains standard after several decades!), so it _could_ be adapted to a 3.5mm TRS if you _really_ needed it.

~DK

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#1191429 - 01/15/13 08:01 PM Re: RBUS ADAT convertor [Re: dkfackler]
Starliner Offline
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Quote:
"MAYBE you could make the MIDI connect on 3.5mm jacks, and just bring out an adapter cable to MIDI DIN5's if you wanted MIDI. There MIGHT be enough room for that in a dongle sized device."

That sounds like a viable solution.

Starliner
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#1191484 - 01/16/13 03:58 AM Re: RBUS ADAT convertor [Re: Starliner]
JazAddict Offline
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Dfackler...pretty sure midi only uses 2 of the 5pins.

Bear, how much to replicate that difat24 with midi?....do you have a bundle deal with a spirit 16 board ;\) ?

Edit.... Reread and basically i just want what u mentioned in options C... 2way audio and midi...... In ur spare time. ;\)


Edited by JazAddict (01/16/13 05:19 AM)
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#1191494 - 01/16/13 05:51 AM Re: RBUS ADAT convertor [Re: JazAddict]
dgh1952 Offline
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If I had one of these, what would be the easiest and least expensive way to get adat in to my laptop?
Dan

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#1191518 - 01/16/13 08:19 AM Re: RBUS ADAT convertor [Re: JazAddict]
dkfackler Offline
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 Originally Posted By: JazAddict
Dfackler...pretty sure midi only uses 2 of the 5pins.


Quite right-- the third is ground.

~DK

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#1191544 - 01/16/13 11:00 AM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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 Originally Posted By: bear
if you wanted MIDI.


Just wondering which VS-recorders do have RBUS, but no MIDI of their own ?
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#1191548 - 01/16/13 11:10 AM Re: RBUS ADAT convertor [Re: Ptr]
bear Offline
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 Originally Posted By: Ptr
 Originally Posted By: bear
if you wanted MIDI.


Just wondering which VS-recorders do have RBUS, but no MIDI of their own ?


I think all VS machines have MIDI... but the RPC1 card does not - with an RPC1 you can convert a PC or MAC into a ADAT interface and MIDI interface(that is actually what I have been mostly testing with).

And it just bugs me to have something so easily available and not provide to use it.

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#1191550 - 01/16/13 11:16 AM Re: RBUS ADAT convertor [Re: bear]
Ptr Offline
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Registered: 01/03/05
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 Originally Posted By: bear
 Originally Posted By: Ptr
 Originally Posted By: bear
if you wanted MIDI.


Just wondering which VS-recorders do have RBUS, but no MIDI of their own ?


I think all VS machines have MIDI... but the RPC1 card does not - with an RPC1 you can convert a PC or MAC into a ADAT interface and MIDI interface(that is actually what I have been mostly testing with).


Good to know, thanks. I'm still using trusty Terratec EWS88D's for ADAT-I/O, but who knows I run into the RPC1 sometime.

 Quote:
And it just bugs me to have something so easily available and not provide to use it.


+1 ;-)
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#1191551 - 01/16/13 11:18 AM Re: RBUS ADAT convertor [Re: dgh1952]
bear Offline
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 Originally Posted By: dgh1952
If I had one of these, what would be the easiest and least expensive way to get adat in to my laptop?
Dan



There are many USB and FIREWIRE interfaces that supply ADAT ports - FOCUSRITE, MOTU, RME, M-AUDIO.... depends on your price range, anywhere from a couple of hundred bucks to thousands...

Google it. Or look here

http://www.recordingreview.com/soundcard/soundcard_wizard.php

And of course FIREWIRE is getting scarce on laptops.

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