Topic: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

I am trying, without success, to set up my ADI-2 Pro as an outboard AD/DA converter to bypass the converters in my very reliable, but aging FireFace 800, and use my outboard analog hardware chain to go back into the DAW and render the final mastered tracks.  I am definitely missing something in the setup as I can get the SPDIF coaxial from the FF800 into the ADI2P and out to the analog buss, but when I render the master mix track the analog buss processing is not there and is bypassed completely.

Here is my signal path using the ADI-2 Pro in AD/DA Converter mode (@96K) in 64 bit Reaper DAW.
Master Track VST Insert (ReaInsert) SPDIF L & R Send to...
>> FF800 SPDIF (coax) out.
>> ADI2P SPDIF (coax) in
>> ADI2P XLRs analog out
>> Input to Dangerous Music "Liaison" analog matrix switcher buss A in
>> Buss A&B have the analog gear matrix, (comps, eq's, M/S processor) buss A is daisy chained to buss B, then...
>> Liaison analog buss B output to...
>> ADI2P analog XLRs in
>> ADI2P ADAT optical (SPDIF) out
>> FF800 ADAT2 optical (SPDIF) input
>> Master Track VST insert Channels 1&2  Return
>> PSP Xenon VST limiter plug in
>> Channels 1&2 main speakers out.

I am monitoring this analog chain in several places using the Dangerous Music Monitor ST.  I can listen to analog pre buss A,  post-Buss B, and post limiter (PSP Xenon VST plugin) on the master track.
For some reason the post buss B signal with all the analog processing is not getting back into the DAW... 
I can hear that Buss B is not returning when I monitor the DAW master track and of course in the rendered track.

It all works fine up until buss B does not return to the DAW.  Also, if I just render using the FF800 going out to my analog chain and coming back into the DAW using this same VST plugin insert works fine and has for many years... The later version of that VST insert has been very reliable so I'm inclined to think it must be something else I am doing incorrectly with the ADI-2 Pro.
All the usual settings in the ADI2P AD/DA look OK; Clock, SRC, Source, ADAT locked, etc...
A very special thank you in advance to anyone that can offer suggestions to get me up and running with this setup.
Martin

2

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

The manual is fully clear that you cannot use SPDIF coax and optical at the same time. You switch between them. You have to use the AES input via a cable adapter instead of the SPDIF coax to be able to use that signal together with optical.

And is the unit set to Multi-channel mode?

Regards
Matthias Carstens
RME

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

MC wrote:

The manual is fully clear that you cannot use SPDIF coax and optical at the same time. You switch between them. You have to use the AES input via a cable adapter instead of the SPDIF coax to be able to use that signal together with optical.

And is the unit set to Multi-channel mode?

Yes, the unit is set to multi-channel mode, and you are correct; I had forgotten it was coax OR optical, not both, and was exactly my problem.  Thank you so much for pointing this out.  Somehow I missed that.

However, now that signals are routed properly there is a newly discovered issue that I now see happening.

There appears to be a low frequency oscillation occurring around 33Hz and about -32.8 dbfs.  At around 40Hz the oscillation stops and the trace falls all the way down to the noise floor around -145dbfs!  I can also see it as a vertical bar on the Analog Input RTA window and in the headphones RTA window.  On the lower frequency side of the oscillation, the tapering off is more gradual -- tapering down to about -75db or so at 10Hz.

When audio is playing above the level of -33db the ADI2P's RTA window hides this vertical bar until the audio stops and then the horizontal level indicator does not drop to zero, but stays at -33db showing the level is present as well as the vertical bar in the RTA window shows the same.
To me I first thought this must be a ground loop; but my input XLR's have the shield lifted on the male ends.  To confirm this I disconnected AC power to all the equipment busses in the studio, and disconnected all the inputs, outputs and Dsub9 from the ADI-2 Pro -- and the oscillation is still there, with nothing connected to the unit but the DC switching power supply.
I have photos of it and also the trace of it using Voxengo SPAN.

Aside from my SPDIF routing problem the only thing I have changed is upgrading to the firmware V.72 but I am sorry to say I do not know if this issue was also happening in the earlier version firmware because I was preoccupied with my SPDIF routing problem.
Do you have any suggestions I may try to help solve this issue?
Thank you very much,

Martin

4

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

Oscillation means feedback. You have to check the whole signal path, interrupt it from end to start in small steps until you find the stage where the feedback happens.

Regards
Matthias Carstens
RME

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

MC wrote:

Oscillation means feedback. You have to check the whole signal path, interrupt it from end to start in small steps until you find the stage where the feedback happens.

Thank you for your reply.  I am well aware of what oscillation is. I was fully clear in my email that the unit is oscillating on its own with absolutely nothing connected to it.
The RTA windows on the unit confirm this.  Surely you do not want me to get out  my oscilloscope and trace the actual stage inside the unit where this is occurring?

Please let me know how to proceed to get this fixed. Obviously the unit is brand-new.

Very best regards,

Martin Tryon
Tryon Mastering

6

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

If there is a real oscilllation with nothing connected then you could record that signal via USB and show its waveform (maybe you did that already, your description is a bit unclear to me). And then the unit would be considered defective.

But before you return it maybe you could try to reset it first (hold encoder 1 and VOL buttons pressed during power on). I would not rule out that you found a magic configuration setting that exposes a bug...

Regards
Matthias Carstens
RME

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

MC wrote:

If there is a real oscilllation with nothing connected then you could record that signal via USB and show its waveform (maybe you did that already, your description is a bit unclear to me). And then the unit would be considered defective.

But before you return it maybe you could try to reset it first (hold encoder 1 and VOL buttons pressed during power on). I would not rule out that you found a magic configuration setting that exposes a bug...


Yes, I did record the waveform using Voxengo SPAN.  If you would like to see the waveform photos and the RTA Windows photos let me know where to email them...

It is interesting to note that the Main Output 1/2 RTA window does NOT show the oscillation.
Perhaps the oscillation is only occurring in the Phones 3/4 DAC which I suspect is the case.

Thank you for your suggestion.  I will try the factory reset option and let you know if that cured the problem -- or not.

.... Just got back from doing a factory reset by holding down encoder 1 and the volume button on power-up.
The reset did not cure the problem.

Interesting that I did not notice this problem with the original factory firmware.   Only after I installed the V.72 firmware did I notice the problem -- and only on Analog Input and Phones Channels 3/4.  It is not on Main Output 1/2 which is a separate DAC.

Is there a link to reinstall the old firmware to test this?  Then we would know whether or not it is a firmware issue.

Thanks again for your help...

Martin

8

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

If the Analyzer shows the signal on An 1/2 then there is a problem with the ADC. Not checking your current config exactly I would say you do not send that signal to AN 1/2 out, only to AN 3/4 out.

Old firmware is available maybe tomorrow again.

Regards
Matthias Carstens
RME

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

Thank you for your assessment.  Yes, it looks as you say...
I look forward to being able to reload the older firmware.  I checked the downloads, but it is not there yet.
...MT

10

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

Sorry, might take another day as I am travelling with limited internet. It would be here in this thread, not on our website.

Regards
Matthias Carstens
RME

11

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

http://www.rme-audio.de/download/adi2pro_128_70_win.zip

http://www.rme-audio.de/download/adi2pro_128_70_mac.zip

Regards
Matthias Carstens
RME

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

Matthias,
Thank you very much for the download link.  I installed the V.70 firmware and that did not fix the problem.  It is still self-oscillating at 33Hz and -32.8 dbfs (with nothing attached to the unit except the switching power supply).  If I had a way to power it from a battery I would eliminate the switching supply as a possibility too, since the slope of this curve does taper off down towards DC at 10Hz but I cannot measure frequency any lower than that. 
Please let me know if you think the unit is for sure defective and I will find out how to ship it back. 
Thanks again,
Martin

13

Re: Questions Setting UP the ADI-2 Pro for Mastering Using Analog Gear

I am pretty sure the unit is defective. Simply exchange it.

Regards
Matthias Carstens
RME