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#1244300 - 09/18/13 10:12 AM Re: RBUS ADAT convertor [Re: JC1]
JC1 Offline
Space Cadet


Registered: 09/03/13
Posts: 15
Aarrgh!
Got one of Bear's boards and a Beringher ADA8000. As soon as I attach the board, I get this "R-Bus Buffer Full" error, whether the ADA8000 is connected or not. Tried every combination of clocking, so maybe there IS something wrong with the mixer. Once in a while I can get the mixer to boot and it works, but it's so unreliable, I can't make use of it.
Loopback test still works perfect.

Bear, got any ideas?

Thanks,
JC

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#1244385 - 09/18/13 03:29 PM Re: RBUS ADAT convertor [Re: JC1]
JC1 Offline
Space Cadet


Registered: 09/03/13
Posts: 15
Ok, I think this is finally working (fingers crossed)
A few different troubleshooting procedures got me to this point.

I noticed if my hand was near the converter board to change the clock switch or check the ADAT cables, the error message would briefly clear. So I started suspecting noise on the data lines. ( body parts can affect impedances and suppress or induce noise)
Then I stumbled on a little tidbit of info that the "R-BUS Buffer Full" error can be triggered by a MIDI buffer overflow.

Looped the MIDI TX terminal to the RX terminal (as in the loopback test)and the system started working. Suspecting noise on the RX (MIDI in) line and not being too keen on keeping this loop in place, I pulled the RX terminal up to the +5v terminal. So far everything is working great. Even been able to use the preamp's ADAT signal as clock master, but startup is much more stable keeping the 3100 as master and slaving the pre-amp.
The last part of the solution was to set the 3100 to RPC-1 mode. In DIF-AT mode, I had to toggle the clock settings to get it going. I can even bang the rack on with the master power switch and it has locked every time (so far).
Acid test will be torture testing over the next few days and a live gig this weekend!

Why did I have so much trouble with this? Who knows? Maybe there's a problem with the RBUS buffer board inside the mixer. I have no need for the R-BUS MIDI, so as long as it works reliably this way, I'm good with it.

JC


Edited by JC1 (09/18/13 03:37 PM)

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#1244389 - 09/18/13 03:50 PM Re: RBUS ADAT convertor [Re: JC1]
bear Offline
Planeteer


Registered: 10/25/99
Posts: 6223
Loc: abq,nm,usa
Hmmm, looking at the schematic for the adapter - The midi buffer input is left floating - bad design on my part, I should have provided a weak pullup or pull down. There is a provision to tie it into the ADAT receiver IC, but that resistor is not loaded.

However no one else I know of has had any problem with it... I think pretty much everyone is using it with VS2480 type machines though - you may be the first to try it in depth with a VM3100...

When you say you added a pullup - I presume you mean right across the terminal block pins.. that should be no problem. I would probably do it through a 100k resistor or so... but it does not really matter, even a direct connection to the 5V (or ground) will keep it from chattering.

Anyway congrats on making it work - hope it does well for you.

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#1244472 - 09/19/13 12:15 AM Re: RBUS ADAT convertor [Re: bear]
JC1 Offline
Space Cadet


Registered: 09/03/13
Posts: 15
Yes, pulled up the MIDI RX terminal on the terminal block to the +5v terminal (how convenient). Used an 82k resistor that was within reach when I had the notion to try it, so I guess that puts me in the ball park.

JC

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#1244711 - 09/20/13 01:01 AM Re: RBUS ADAT convertor [Re: JC1]
JC1 Offline
Space Cadet


Registered: 09/03/13
Posts: 15
Hey Bear,
Now that I have this working, would it be possible to get a valid WC off the converter board to clock an external AD? ( i.e.-my Focusrite Octopre, which has WC in, but not ADAT in)
Why use a Beringher when I can use a Focusrite or at least have the option ( the 3100 does not have WC out)
I see WC running through the circuit, but is that the same WC that would show up on a BNC?

Thanks,
JC

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#1244736 - 09/20/13 04:10 AM Re: RBUS ADAT convertor [Re: JC1]
bear Offline
Planeteer


Registered: 10/25/99
Posts: 6223
Loc: abq,nm,usa
If you tapped into the LRCLOCK and buffered it so that it could drive a 75ohm terminated port I think it would work...

A simple emitter follower might work..

I am a little unsure of the voltage level required by a word clock in though..... but the frequency is just the sampling rate (which is LRCLOCK) for normal word clock - there is a variant on wordclock that runs much faster...16x or something. I think it is called super word clock or something...but normal word clock should work

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#1246772 - 09/28/13 10:59 PM Re: RBUS ADAT convertor [Re: bear]
JC1 Offline
Space Cadet


Registered: 09/03/13
Posts: 15
A few wrinkles I had to iron out.
Since this is used in a portable rack, I decided to mount the converter inside the mixer and wire the ADAT I/O to the rear panel optical ports. That all worked fine, but I discovered putting the VM3100 in RPC-1 mode routes MIDI through R-BUS and disables the rear panel MIDI jacks. It wasn't a show stopper, but not what I expected.
Sooo..., I wired the converter board MIDI terminals to the rear panel jacks and got MIDI I/O only to discover that MIDI output activity was causing clicks and pops on the ADAT in. Long story short, I found suppressing the MIDI out signal with a 100pf cap to ground solved the problem.
BTW- I did a quick test with the WC signal off the converter board and it seemed to work. External preamp locked right up. Not sure the quality of the clock, but I don't think it would be worse than the ADAT stream. I feel better with a secure BNC connection and the added advantage of being able to use different preamps/converters.

Bear, can I get a PDF or DWG copy of the schematic for the converter board from you? The printed copy that came with the board is difficult to read.
Thanks,
JC

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#1246789 - 09/29/13 02:45 AM Re: RBUS ADAT convertor [Re: JC1]
bear Offline
Planeteer


Registered: 10/25/99
Posts: 6223
Loc: abq,nm,usa
Sure - just send me an email and I will send you a pdf
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#1265993 - 12/17/13 01:31 PM Re: RBUS ADAT convertor [Re: bear]
mutetourettes Offline
Planeteer


Registered: 02/10/13
Posts: 37
ello - thinking about tdif... looking at the info on pages 12 and 17 of the following document do you think that is pretty similar to rbus?

Neve tdif/madi info

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#1266347 - 12/19/13 04:09 AM Re: RBUS ADAT convertor [Re: bear]
Frans Offline
Planeteer


Registered: 08/31/02
Posts: 190
Loc: netherlands
The RPC-1 works with the latest M-audio Delta driver under WIN7 64 bit and I am confident it will work under 8 64 bit too. Been working with that combo for a long long time.

My SI-24 does not do midi over the DELTA DRIVER I do use midi to a UM-880 for that.
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#1266348 - 12/19/13 04:10 AM Re: RBUS ADAT convertor [Re: Frans]
Frans Offline
Planeteer


Registered: 08/31/02
Posts: 190
Loc: netherlands
The EGOSYS AUDIOTERMINIAL 010 could do RBUS and TDIF over the same connector. It is my believe RBUS is TDIF but with differently twisted pairs. I have layouts of both...
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#1565845 - 03/13/18 10:57 AM Re: RBUS ADAT convertor [Re: Frans]
das_efg Offline
Space Cadet


Registered: 03/12/18
Posts: 2
Hello!

I'm new here, I'm Tilman and I just bought a VS-2400 to get away from the DAW. I guess I'm pretty late to the party;)

I'd like to connect the VS to a RME Digiface via ADAT to use some processing on the PC and to record stuff I'm doing on the PC with max/msp and pure data. Unfortunately the DIF-AT are pretty scarce here in Germany and when they show up on ebay or classified, they are horribly expensive.

I found this thread about the great efforts of bear to make a adapter DIY.
I'd say I'm able to etch a PCB for myself and solder the stuff, but to be honest I only got a limited understanding about digital circuitry, the levels and the logic stuff.

So: Does anybody got a schematic or even a layout, that he/she would share with me?

Thank you in advance!
Tilman

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#1566687 - 03/20/18 02:34 PM Re: RBUS ADAT convertor [Re: das_efg]
Starliner Offline
Planeteer


Registered: 05/19/09
Posts: 2600
Loc: Florida - Dunnellon
You might contact bear directly via PM. I don't know that he will build any future boards, as it is expensive and time-consuming to build just a few of them, without sufficient interest to sell a number of them.

They are all SMT boards, so you would need a microscope or very good magnification to place and solder the components on his design.

Starliner
_________________________
Half The Lies They Tell About Me Aren't True!

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#1566818 - 03/21/18 10:59 AM Re: RBUS ADAT convertor [Re: Starliner]
das_efg Offline
Space Cadet


Registered: 03/12/18
Posts: 2
Hi Starliner,

Thanks for your response.
I tried contacting bear, but he didn't answer yet, I guess he isn't reading here often, his last efforts with the USB-RBus adapter are dating back 2 years....

The SMT-soldering would be no problem for me, at least down to 0604 package. I think bears USB-RBus adapter is laid down in 0402, that's too small for soldering by hand, but I could do a layout with Eagle or Kicad in 0805.

The problem is that I don't have any formal education in EE, just practice in building analog Synths and Effects, so it's quite difficult for me to figure out the necessary logic and voltages for interfacing the V1401 and V1402 chips to the RBus.

I guess in his original attempt bear used some 74-logic to flip the polarity of the RBus-lines, which are basically I2S lines.
The other problem is the question of pull-up or -down resistors, I don't have any clue of them.

I think the layout isn't too critical, since we're dealing with not too high frequencies here, but for me 4MHz are like voodoo, whereas for someone with experience in HF this might be like DC.

Maybe someone around here has some clue of digital circuitry?


Tilman

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