Topic: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

I run a recording studio. We currently use an Antelope Orion 32 for conversion. We're considering an ADI-2 Pro FS to add higher quality DAC and ADC (4ch and 2ch, respectively) for mixing and mastering.

Some constructive criticism: the use of Phones 3/4 as a line output isn't addressed fully in the manual – it really deserves some commentary on using the High Power setting in conjunction with digital attenuation and external balancing. For people who don't need a headphone amp, a digital routing assignment that brings Output 3 to Phones 1/2 and Output 4 to Phones 3/4 would be a big selling point – it's basically the same as the current balanced phones option. Maybe this thread will help?

In my application, all inputs and outputs at the ADI must adhere to 0dBFS = +24dBu and be balanced. We have a balanced patchbay, the Orion is in it, and the ADI would need to sit about 25 cable-feet away from the patchbay. Thus the only digital methods that we can use to get from the Orion to the ADI are 110Ω XLR and ADAT. The Orion has multiple ADAT ins and outs, but only one S/PDIF in and out, all of which are currently unused.

From my reading of the ADI-2 Pro FS manual, my current understanding of AES/EBU to S/PDIF conversion, and my ability to DIY simple balancing circuits, here is a potential signal flow.  I'd appreciate any comments or corrections.

https://drive.google.com/open?id=1GYLOp … bI7u1yaiY6

There is an alternate version of this that uses the optical S/PDIF input and output of the ADI (set to ADAT) for analog output 1/2 and analog input 1/2, respectively, but I am unclear on whether Phones 3/4 can output signal from the AES/EBU input under this condition.

2

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

Your signal flow idea should work. As does the latter - Phones can be set to be fed from any input, independent from Output 1/2 source.

Regards
Matthias Carstens
RME

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

MC wrote:

Your signal flow idea should work. As does the latter - Phones can be set to be fed from any input, independent from Output 1/2 source.

Thanks for looking at that, Matthias!

Is it correct to say that on both input and output, Toslink/ADAT and coaxial S/PDIF can not be addressed separately – i.e. they are one input or output, you just get to choose the format?

Is there anything in the existing hardware that would prohibit a software assignment of DAC 3/4 to the two frontpanel phones jacks, each balanced? I don't see a difference between DAC 1/2 and 3/4 in this regard, but also I don't use balanced headphones so maybe there's something I'm missing.

4

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

1. No. Input is automatic (takes any), output is set manually in the menu to SPDIF or ADAT.

2. The hardware design does not allow that, sorry. Check the balanced chapters of the manual, balanced is done differently than usual.

Regards
Matthias Carstens
RME

5 (edited by KaiS 2020-02-19 13:40:35)

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

Jonah wrote:

I run a recording studio. We currently use an Antelope Orion 32 for conversion.
...
In my application, all inputs and outputs at the ADI must adhere to 0dBFS = +24dBu and be balanced. We have a balanced patchbay, the Orion is in it,

I have the Antelope Orion 32, mainly for 32 track live recording outside my studio, via USB into a laptop.

The Orion 32 does not have true balanced outputs, neither has it 24 dBu level.

Orion 32's outputs are pseudo-balanced, sometimes called "impedance balanced".

Only the hot side carries a signal, the cold side, instead of carrying the inverted signal, is connected to the ground through a 56 Ohm resistor that matches the impedance of the hot side.
There is nothing wrong with that approach, except it does not give the advantage of doubling the output voltage.

Orion 32's output level is 0dBfs=20dBu.
Even more important:
Orion 32 will not take 24dBu at it's input, which is equally limited to +20dBu.

That's the only point in your proposed setup that I won't agree with.


The Orion 32 is a great piece of gear that sounds good and works flawless here for it's purpose.
The ADI-2 Pro just replaced it here in my private setting (where it lives when it's not in studio use) as interface for headphones listening.

6 (edited by Jonah 2020-02-19 14:45:55)

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

KaiS wrote:
Jonah wrote:

I run a recording studio. We currently use an Antelope Orion 32 for conversion.
...
In my application, all inputs and outputs at the ADI must adhere to 0dBFS = +24dBu and be balanced. We have a balanced patchbay, the Orion is in it,

I have the Antelope Orion 32, mainly for 32 track live recording outside my studio, via USB into a laptop.

The Orion 32 does not have true balanced outputs, neither has it 24 dBu level.

Correct. And I have a note for guest engineers who use the space for primary tracking that 0dBVU = +4dBu = -16dBFS. But the entire 2-track path needs to be +24dBu = 0dBFS for headroom purposes and because the associated Dorrough metering is calibrated at that level.

It would be nice to have differential I/O on the Orion 32, but one can only expect so much from a 32-channel converter that's now dropped below $1K USD used. I have two.

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

Can the S/PDIF / ADAT output be assigned separately than the AES/EBU output when in AD/DA mode? For instance, if the AES/EBU output is assigned to the analog inputs, can the S/PDIF / ADAT output be assigned to the optical input?

Is there any way to split the digital outputs in this fashion without using a USB connection?

If not, would that be a feature that could theoretically be implemented in a firmware revision?

This is applicable if the AES/EBU outputs are already in use for analog input 1/2, and one wants to use an AES/EBU VU meter to monitor the signal entering via ADAT, as there are no stereo metering options for ADAT on the market. But S/PDIF to AES/EBU conversion is easy.

8

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

All modes are clearly described in the manual with easy to understand block diagrams. Digital outputs are always fed from the same source except for USB multi-channel mode, and that will not change, sorry. For such a flexible and multi-I/O application you should have a look at our other interfaces that come with TotalMix FX.

Regards
Matthias Carstens
RME

9 (edited by Jonah 2020-02-27 05:13:47)

Re: ADI-2 Pro FS – AD/DA – 4ch DAC – 2ch ADC – no phones

Dropping this here for anyone trying to do what I am in the future:

IF you have a console, you mix a lot, and master in both the analog and digital realm,
AND you have an RME ADI-2 Pro *, three digital Dorrough meters with XLR & BNC I/O, and an Antelope Orion 32 (or anything else with ADAT & S/PDIF but no AES/EBU),
AND you want the ADI close at hand, with its entire DAC  > ADC  > DAC chain available for analog mastering (i.e. Phones 3/4, Analog Input, Analog Output),
AND your patchbay is far enough away from the mix position in cable terms to discourage long S/PDIF runs,
AND your Orion is at that patchbay,
AND you might need to accommodate 192kHz files sometimes (even though the meters are 96kHz max and you normally work in 96kHz),
AND you're not trying to add any rackmount format converters but you can find a Kramer 466,
AND you can find or make a little unit that transparently balances the Phones 3/4 output with the requisite 6dB of gain (I'm using Sparkfun Outsmarts for example),


WELL THEN, Here's one way to get it done in AD/DA Mode (ADI in bold, Orion in italic, long cable underlined):

DAC: Orion ADAT Output >>>TOSLINK>>> Optical Input to Phones 3/4 > balancing unit >>>XLR>>> Patchbay

ADC: Patchbay >>>XLR>>> Analog 1/2 Input to AES/EBU Output > "INPUT" Dorrough >>>110Ω XLR>>> 110:75Ω trafo > 12dB attenuator > Orion S/PDIF Input

DAC: Orion S/PDIF Output > Kramer 466 >>>110Ω XLR>>> "OUTPUT" Dorrough > AES/EBU Input to Analog 1/2 Output >>>XLR>>> Patchbay


NOW, the third Dorrough is attached to the ADI's Coaxial Output, is labeled "MIX: INPUT SUM-DIFF // MASTER: OUTPUT 3-4," and performs those features in the two modes:

AD/DA Mode: Analog 1/2 Input to Coaxial Output (which is automatic), set for sum/diff function, so it's doing something useful when you're just mixing

USB Mode: Optical Input to Coaxial Output (via DAW routing), flip to levels function, so it's monitoring the level to the Phones 3/4 DAC when that is your mastering source


Feel free to correct this. The workarounds are tricky, so it makes sense to share. Never let a good DAC go to waste! So, uh, who's got a used ADI they want to sell or trade? ...cuz I didn't do all those mental calisthenics for nothin'!