Topic: ADI-2/4 Pro SE analog inputs protection questions

Hello everyone,

Can someone explain to me how analog input protection works?

Flowcharts and some logic behind would be even better.

Here's some explanation of the problem:
I feed some loopback and unity gain signals (pink / white noises) into the analog input of the ADI-2/4 Pro SE, taking into account the signal levels. Such signals are usually -6...-12 dB less than the reference settings in the analog inputs (+1 dBU, +7 dBU, +13 dBU, +19 dBU).

But from time to time it triggers some input protection circuits that block them from any signals until I reset the power.
I tried the manual reference input settings as well as the Auto mode. But it's still happening. Sometimes I hear the relay click and then it turns off the inputs. Another time, the right channel goes into what looks like a self-excitation of amplifier. The high frequency amplitude increases logarithmically until it reaches a certain limit and turns off the inputs.

2 (edited by johny_2000 2024-05-24 03:25:37)

Re: ADI-2/4 Pro SE analog inputs protection questions

The source of test signals is the 3/4 headphone outputs of the same ADI-2/4 Pro SE device.

Could this be a problem?
It is a kind of positive feedback for the amplifier, having a self-exciting effect.

3

Re: ADI-2/4 Pro SE analog inputs protection questions

There is no internal loopback unless you activated that manually. So it sounds more like a software based feedback.

A relay click would be the output muted, not the input. That could have a different reason - what does the unit show on the display in that moment?

Regards
Matthias Carstens
RME

Re: ADI-2/4 Pro SE analog inputs protection questions

Thank you, MC.

The cable is external. From one headphone output channel 3/4 to the analog input of the device. Somewhere with a direct connection (soundcard calibration), somewhere through a device with unity gain. All with unbalanced (1/4'' TS) connection. In the coming days I will repeat the measurements and show screenshots of those moments.

5

Re: ADI-2/4 Pro SE analog inputs protection questions

Also, in case you use higher sample rates, the unit might falsely be triggered into DoP (DSD) mode by random signals. In that case disable the automatic DSD detection (in Setup - Device mode / DSD).

Regards
Matthias Carstens
RME

6 (edited by johny_2000 2024-05-24 14:28:33)

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

Also, in case you use higher sample rates, the unit might falsely be triggered into DoP (DSD) mode by random signals. In that case disable the automatic DSD detection (in Setup - Device mode / DSD).

Ok, I will do it.  I don't use DSD anywhere, so turning off automatic DSD detection is not a problem for me.

Regarding the protection of analog inputs: do they have protection against signal levels exceeding reference levels?

Correction: This happens with SWEEP TONE signals. Not pink/white noise.

7

Re: ADI-2/4 Pro SE analog inputs protection questions

And again you did not mention the sample rate...

The analog inputs have no protection that switches them off.

Regards
Matthias Carstens
RME

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

And again you did not mention the sample rate...

Sorry, missed that.  I'm using a sampling rate of 192 kHz. I found that this is the maximum sample rate for Windows Recording.

9 (edited by johny_2000 2024-05-24 17:48:10)

Re: ADI-2/4 Pro SE analog inputs protection questions

Here's how it looks like for the Right input channel:
https://i.imgur.com/UeIT3ff.jpeg

Zoom in:
https://i.imgur.com/xi1VRlJ.jpeg

Input device: Analog (1+2) (2- RME ADI-2/4 PRO SE)
Input: LINE_IN (Master Volume)
Channel: Right
Output device: Analog (1+2) (2- RME ADI-2/4 PRO SE)
Output: Default Output
Input RMS target: -12.0 dB
Actual RMS at 1 kHz: -11.8 dB
Sample rate: 192000 Hz
Input volume: 1.000, Sweep level: -12.0 dB
20 Hz .. 20 kHz flatness: +1.5, -119.9 dB
-3 dB points: 7.3 Hz,  14.340 kHz

14.34 kHz is when I hear the relay click and then the signal (output? or input?) turns off.


For example, this is the result for the Left channel under a same test conditions:
https://i.imgur.com/BhOMy21.jpeg
Input device: Analog (1+2) (2- RME ADI-2/4 PRO SE)
Input: LINE_IN (Master Volume)
Channel: Left
Output device: Analog (1+2) (2- RME ADI-2/4 PRO SE)
Output: Default Output
Input RMS target: -12.0 dB
Actual RMS at 1 kHz: -11.8 dB
Sample rate: 192000 Hz
Input volume: 1.000, Sweep level: -12.0 dB
20 Hz .. 20 kHz flatness: +0.0, -0.6 dB
-3 dB points: 7.3 Hz,  91.971 kHz

There are no relay clicks or signal cuts on this channel.

10 (edited by johny_2000 2024-05-24 18:06:42)

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

A relay click would be the output muted, not the input. That could have a different reason - what does the unit show on the display in that moment?

Yes, your assumption was correct. This is the output that is muted under these conditions. Not the input.
For some reason, only on the Right Channel.

Also, this only happens with an external loopback cable from the 3/4 headphone output to the 1/4 TS input. When I do the same with the internal mode *PH 34 - Loopback pre FX to 1/2*, this does not happen.
https://i.imgur.com/LwPfZhx.jpeg

Input device: Analog (1+2) (2- RME ADI-2/4 PRO SE)
Input: LINE_IN (Master Volume)
Channel: Right
Output device: Analog (1+2) (2- RME ADI-2/4 PRO SE)
Output: Default Output
Input RMS target: -12.0 dB
Actual RMS at 1 kHz: -12.0 dB
Sample rate: 192000 Hz
Input volume: 1.000, Sweep level: -12.0 dB
20 Hz .. 20 kHz flatness: +0.0, -0.0 dB
-3 dB points: <0.4 Hz,  96.000 kHz

Re: ADI-2/4 Pro SE analog inputs protection questions

And at this moment there are no messages on the display.  In fact, when the outputs are muted, the graphical spectrum analyzer still shows the audio levels, but nothing comes out during this time.

Re: ADI-2/4 Pro SE analog inputs protection questions

Check if the same thing happens with output PH 1/2.

13

Re: ADI-2/4 Pro SE analog inputs protection questions

Is that a TRS to 2 x TS split cable? Does the mute happen when it is only unplugged at the input side? Does the same output channel mute when you plug TS L in R input and TS R in L input? Did you disable the DSD detection?

Regards
Matthias Carstens
RME

14 (edited by johny_2000 2024-05-27 07:26:14)

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

Check if the same thing happens with output PH 1/2.

Thank you.

I'll definitely do it soon.

Additionally, I have another DAC that I can use as a signal source to test these inputs.
This won't be a loopback test, but at least it will rule out a suspected problem with the analog inputs.

A little background:
At first I thought that the problem was with the analog input, which overloaded and went into protection mode. But then the MC suggested that this should be the output if the relay clicks. So I tested this hypothesis, and indeed, the right 3/4 output channel was muted with levels of -12dBFS...-6 dBFS on the sweep tone test. Resetting the power restores its functionality.

15 (edited by johny_2000 2024-05-27 07:30:24)

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

Is that a TRS to 2 x TS split cable?

Yes, it is.

MC wrote:

Does the mute happen when it is only unplugged at the input side?

Thank you, MC for the help.
I don't fully understand what you mean. Please draw a diagram/flowchart of the proposed test.

MC wrote:

Does the same output channel mute when you plug TS L in R input and TS R in L input?

I haven't tried it. So far, I have tested Output 3 (Left?) - Analog Input 1, Output 4 (Right?) - Analog Input 2.
I don't have a TS-TS cable, so I use a TRS (output) to 2xTS (input) splitter cable.
But I can flip the input side to simulate the Right output channel to the Left input channel, etc.

MC wrote:

Did you disable the DSD detection?

I did it now, but haven't tested the system after that yet.

16

Re: ADI-2/4 Pro SE analog inputs protection questions

johny_2000 wrote:
MC wrote:

Does the mute happen when it is only unplugged at the input side?

Thank you, MC for the help.
I don't fully understand what you mean. Please draw a diagram/flowchart of the proposed test.

You plug the TRS into PH3/4, but don't plug the 2 xTS anywhere. Make sure the two TS do not touch anything.

MC wrote:

Does the same output channel mute when you plug TS L in R input and TS R in L input?

johny_2000 wrote:

I haven't tried it. So far, I have tested Output 3 (Left?) - Analog Input 1, Output 4 (Right?) - Analog Input 2.

I don't have a TS-TS cable

What is that good for?

johny_2000 wrote:

But I can flip the input side to simulate the Right output channel to the Left input channel, etc.

You just exchange the TS plugs L/R by unplugging/replugging.

Regards
Matthias Carstens
RME

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

What is that good for?

This is called "Soundcard Calibration" to account for any device non-linearity when measuring other devices.

Re: ADI-2/4 Pro SE analog inputs protection questions

Thank you, MC and KaiS.

Okay, I've done all sorts of combinations of Outputs and Inputs. This only happens at Output 4 (Right) to any Inputs (L or R) and even when unplugged (no load). This never happens with Outputs 1/2 or Output 3 for any Inputs.

I now suspect that there is some kind of hardware issue that is causing the Output 4 amplifier to become unstable and essentially ringing on high frequency signals. Loaded or not.
https://i.imgur.com/FFSmvD4.jpeg

19 (edited by johny_2000 2024-05-28 04:52:55)

Re: ADI-2/4 Pro SE analog inputs protection questions

Is there a possibility that the Op Amp at Output 4 has a defect causing ringing at high frequencies?
Is this the case for RMA?

I also tested it with a different signal source (USB device) and found that there were no problems with either Input at any signal level.

DSD Detection is disabled. No difference.

20

Re: ADI-2/4 Pro SE analog inputs protection questions

johny_2000 wrote:

I also tested it with a different signal source (USB device) and found that there were no problems with either Input at any signal level..

What was the 'signal source' before? I did not read about that in any of your posts.

Also: which firmware version is this unit on?

Regards
Matthias Carstens
RME

21 (edited by johny_2000 2024-05-28 06:59:13)

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

What was the 'signal source' before? I did not read about that in any of your posts.

All other tests were conducted from the own headphone outputs (1/2 and 3/4) of the same ADI-2/4 Pro SE.
Loopback mode: Headphone Output 1 -> Analog Input 1 or 2; Headphone Output 2 -> Analog Input 1 or 2; Headphone Output 3 -> Analog Input 1 or 2; Headphone Output 4 -> Analog Input 1 or 2.

The only time I switched the output device to another was today, one time, to figure out the problem.

All tests were conducted in REW software (Soundcard Calibration, Sweep signal mode), if we were talking about a software signal source.

MC wrote:

Also: which firmware version is this unit on?

Latest available. FPGA 209, DSP 40.

22 (edited by johny_2000 2024-05-28 22:45:10)

Re: ADI-2/4 Pro SE analog inputs protection questions

What confuses me is this: why is only PH4 automatically muted under normal testing conditions?

And it is muted somehow invisible. There are no messages on the screen, the software continues to work, only the output is muted and is not restored until the power is reset.

PH1, PH2, PH3 pass the test normally at any dBFS level (up to 0). The PH4 fails the test at a minimum of -12 dBFS and above. In all cases, the reference is the IEM (+1 dBu).

23 (edited by johny_2000 2024-05-29 19:42:42)

Re: ADI-2/4 Pro SE analog inputs protection questions

Due to the silence on this particular case of mine, I decided to investigate further and switch the 3/4 outputs to the rear TRS outputs and perform the same loopback test with sweep tone. This will not be the same test since the linear drivers will be different, but still close.

I've thought about it, and it's likely something special about the load pattern is causing some ringing in the 4th channel of a headphone amplifier that was designed for a low impedance load (16-600 Ohms) connected to high impedance analog inputs (48 kOhms unbalanced).  I've never had any problems with real headphones connected to the PH3/4 and Pentaconn balanced outputs. So I decided to switch to line outputs, redirecting the same DAC 3/4 output signals there. In this case, the output is initially designed for a higher impedance load, and is possibly more stable under such operating conditions.

Now I need to make a 1/4'' TS to 1/4'' TS cable, and then try this idea.

24 (edited by johny_2000 2024-05-29 23:06:33)

Re: ADI-2/4 Pro SE analog inputs protection questions

Ok, I found a TRS-to-TRS patch cable and connected it to the Rear (Right) TRS output and Analog Input 2 (TRS).
Here are the results:
- When the “Rear TRS 3/4” is enabled, the same thing happens. Logarithmic increase in oscillation amplitude at high frequencies, cutoff at 7+ kHz, report of too high distortion values.
- When the “Line TRS” is enabled, everything works fine.

I assumed this wouldn't happen with the rear TRS outputs (in 3/4 mode), because they use different line drivers and the problem was only with the 3/4 headphone output. But the assumption was wrong.

I've drawn the output audio paths of all the tests and also put question marks on the following suspected components.
https://i.imgur.com/VyvKtpp.jpeg

25 (edited by KaiS 2024-05-30 07:16:34)

Re: ADI-2/4 Pro SE analog inputs protection questions

I tend to think your unit has a hardware fault.
Specifically as the problem is limited to the right channel of 3/4 signal path.

One final test:
Set: I/O / Phones 3/4 / Mono to “ON” and repeat the test from Rear TRS set to output 3/4.

This way you can make sure left and right output carry the exact same signal.


And full factory reset is always a good idea to exclude a software problem:

While powering up, push and hold the VOL button (NOT the VOLUME dial) and Encoder 1 and Encoder 2, until you see the message: “Reset done“.

All user Setups and EQ Presets are deleted.
Take notes before, or store them through the Remote App, if you want to keep some.

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

I tend to think your unit has a hardware fault.
Specifically as the problem is limited to the right channel of 3/4 signal path.

Thank you, KaiS. I thought so too. Why do the other three channels always pass the loopback test regardless of the conditions. And one (4th) fails, with some strange ringing or amplitude oscillation at higher frequencies. Either they all failed equally, or they all passed if they were equal.

It would be great if someone with an ADI-2/4 Pro SE could run the same loopback test for output channels 3/4 on their device.
In REW it calls "Soundcard Calibration" with Sweep tone, Level -12...-6 dBFS, Reference +1 dBU for Outputs and Inputs.

KaiS wrote:

One final test:
Set: I/O / Phones 3/4 / Mono to “ON” and repeat the test from Rear TRS set to output 3/4.
This way you can make sure left and right output carry the exact same signal.

I'll do this 'Mono test' tomorrow too, just to be in order. I'll report back.


KaiS wrote:

And full factory reset is always a good idea to exclude a software problem.

I'll do this too as a final step.

Re: ADI-2/4 Pro SE analog inputs protection questions

I double-checked this with KaiS's suggestions:
- in the 'Mono' mode of the PH3/4 outputs, this never happens for the 'Right' channel.
- this also does not happen when both PH3/4 outputs are turned on in the test ('L+R', not just 'R'), despite the fact that 'L' output is not connected anywhere.
- resetting to factory settings did not change anything.

28 (edited by KaiS 2024-05-31 00:17:42)

Re: ADI-2/4 Pro SE analog inputs protection questions

This result is unexpected.

Can you provoke the shutoff with a simple sine wave, e.g. 16 kHz, on channel 4?
Then I could try to reproduce it here.
And I kind of mistrust the REW sweep generator.

29 (edited by johny_2000 2024-05-31 00:51:45)

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

Can you provoke the shutoff with a simple sine wave, e.g. 16 kHz, on channel 4?

I have to try this. Thanks for the offer.

KaiS wrote:

And I kind of mistrust the REW sweep generator.

What makes you believe so?

I need to ask John Mulcahy(REW Author) what he thinks about my particular case.
Perhaps he also has some thoughts about this.

***************************************************************************************
Measurement Sweep

The Measurement Sweep signal is used by REW when measuring system response. It consists of a logarithmic sweep from half the start frequency to twice the end frequency (with an overall limit of half the interface sample rate) to provide accurate measurement over the selected range. If the start frequency is below 20Hz the signal begins with a linear sweep from DC to 10Hz, followed by a logarithmic sweep from there to the end frequency.

30 (edited by KaiS 2024-05-31 09:01:03)

Re: ADI-2/4 Pro SE analog inputs protection questions

johny_2000 wrote:
KaiS wrote:

And I kind of mistrust the REW sweep generator.

What makes you believe so?

I need to ask John Mulcahy(REW Author) what he thinks about my particular case.
Perhaps he also has some thoughts about

Just instinct from decades of beta-testing soft and hardware.

Before stirring up the mud, let‘s check something.
(I still suspect a hardware defect, but want to exclude anything else).


I/O / Phones Out 3/4 / Settings / Width: “–1.00”  reverses the channels inside ADI-2’s DSP?

Done so, is it still channel 4 that cuts out, and channel 3 still runs through with no problem?

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

I still suspect a hardware defect, but want to exclude anything else.

Well nothing is excluded. I recently heard from another owner that he had to return the device under warranty due to a defective op-amp.

32 (edited by KaiS 2024-05-31 10:59:17)

Re: ADI-2/4 Pro SE analog inputs protection questions

johny_2000 wrote:
KaiS wrote:

I still suspect a hardware defect, but want to exclude anything else.

Well nothing is excluded. I recently heard from another owner that he had to return the device under warranty due to a defective op-amp.

Yes, of course.

Everything has a certain failure rate.
The rate for electronics is the highest at the beginning, then stabilized over the course and increases towards the end for certain parts like electrolytic capacitors.
Usually this is well documented from the manufactures.

E.g. makers of expensive, big studio consoles even have burn-in processing for certain components to reduce the number of first phase mal happen events.
This, BTW, has nothing to do with “audiophile” sound burn-in.


If the problem sticks with channel 4 it’s certainly a hardware problem.
What speaks a little against that: both channels driven the error disappears, which is harder to explain on hardware level.
Of course we can’t know what’s going on inside the DAC chip.


At some point it’s time to send the unit to RME.
First let’s do the 16 kHz (and some other frequencies) sine wave test.

BTW: if you have access to another ADI-2/4 Pro SE (store ?) you could check that if you like to take the effort.

33 (edited by johny_2000 2024-05-31 17:38:26)

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

Can you provoke the shutoff with a simple sine wave, e.g. 16 kHz, on channel 4?

Actually yes. I can get it to shut off with a simple sine wave, but the problematic frequency range is >6370-7650< Hz.
Everything below 6370 Hz and above 7650 Hz is stable.
https://i.imgur.com/ek853iq.jpeg

https://i.imgur.com/skH42CD.jpeg

https://i.imgur.com/e1xBE3k.jpeg

I think this correlates with my post https://forum.rme-audio.de/viewtopic.ph … 07#p219207 where the sweep test is interrupted at about 7 kHz. The problem always gets worse with repeated tests (2nd, 3rd time).

Possibly because I switched to the Rear 3/4 ports, but the sweep test is now interrupted before it reaches 7 kHz.https://i.imgur.com/Q5qoyJc.jpeg

34 (edited by johny_2000 2024-05-31 18:13:56)

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

I/O / Phones Out 3/4 / Settings / Width: “–1.00”  reverses the channels inside ADI-2’s DSP?
Done so, is it still channel 4 that cuts out, and channel 3 still runs through with no problem?

Okay, I did it too. This action (Width "-1.00") swapped the L and R channel outputs. I had to switch the signal source to the L output (in software) to get a signal on the R physical channel output. And it failed the test. The problem was exactly the same.

I also tested channel #3 of the same DAC. To do this I had to use the R output in software to get a signal on the physical L output. It passed all tests perfectly. No problems at all.

It seems to me that digital channel reversing in the FPGA made no difference. It always fails at physical output #4.

And another discovery: when it turns off output #4, the way to turn it back on (without resetting the power) is to send any signal to channel #3 of the same DAC. Then channel #4 will work again. I think this explains why it always works in 'Mono' or 'L+R' modes. And also this never happens when actually playing music through channels 3/4, since the stereo output is played on both channels (L+R) together.

35 (edited by KaiS 2024-05-31 21:08:41)

Re: ADI-2/4 Pro SE analog inputs protection questions

Does the problem occur on 44.1 or 48 kHz sample rate too?

I lack a sine wave generator, app or online, with 192 kHz sample rate to test this here.
Playing 7 kHz @ 48 kHz sample rate on my ADI-2/4 Pro SE, firmware. V 35, did not reveal any problem.

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

Does the problem occur on 44.1 or 48 kHz sample rate too?

I'll check this out in the coming days.

By the way, John (REW) thinks this is a hardware problem.

Re: ADI-2/4 Pro SE analog inputs protection questions

In the coming days, I will conduct several more tests to double-check this problem with all the tips from this topic. As I said, the problem with the 4th output channel is fairly consistent and easy to reproduce under my test conditions.

In the meantime, if I decide to request a Return Authorization (RA) from my local dealer, what is the best way to describe the problem?

I think incoming units are subject to inspection and testing before replacement is made.
I want to make sure the problem is understandable to the recipient and also reproducible on their end.

Re: ADI-2/4 Pro SE analog inputs protection questions

In case the dealer isn‘t technically minded:
What if you just play music solely on channel 4?
Does it cut out?

Everyone could easily reproduce and understand that.

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

In case the dealer isn‘t technically minded:
What if you just play music solely on channel 4?
Does it cut out?

Everyone could easily reproduce and understand that.

Thanks for the idea, KaiS.

I have to try this too.

I think the easiest way to do this is to use the balance adjustment slider moved to the right for the PH34 outputs.
https://i.imgur.com/bFsbsSK.jpeg

Re: ADI-2/4 Pro SE analog inputs protection questions

Today I had time to test all the ideas from KaiS.

Here are the results:
- Sample rate does not matter. It cuts off at 44.1 kHz, 48 kHz, 88.2 kHz and 192 kHz. This is what I tested.
- Playing music exclusively on the Right channel (PH34) does cut off. But it must be loud (or dynamic) music with an RMS level of -6 dbFS and above. Then it only takes a few seconds of playback before it cuts off. Repeatability is 100% on multiple repeats.
- Moving the 'Balance' slider even by 2% for the Left ch, and 98% for the Right channel restores the functionality of the 4th channel output at all times.

Thanks for all these great ideas. They really helped to narrow down the range of problems and will simplify diagnostics as much as possible for an uninformed technician.

Re: ADI-2/4 Pro SE analog inputs protection questions

johny_2000 wrote:

- Playing music exclusively on the Right channel (PH34) does cut off. But it must be loud (or dynamic) music with an RMS level of -6 dbFS and above. Then it only takes a few seconds of playback before it cuts off. Repeatability is 100% on multiple repeats.

100% a hardware defect.

Re: ADI-2/4 Pro SE analog inputs protection questions

Thanks to everyone who helped!
I have requested a warranty Return Authorization from my RME dealer for this unit.

43 (edited by johny_2000 2024-07-02 20:19:46)

Re: ADI-2/4 Pro SE analog inputs protection questions

Just so everyone knows, I returned the device and received a new one in exchange. After a quick assessment, to my surprise, it does the same thing, only on the right channel (4th) and on the same frequencies. I think it's some kind of hardware "feature" and I'm leaving it as is. There's no point in doing anything about it anymore. Just remember to always use the L+R output configuration in all cases, not just R-ch.

Re: ADI-2/4 Pro SE analog inputs protection questions

Just checked again:
My ADI-2/4 Pro SE (hardware revision 1) doesn‘t do that on any of it’s 4 channels.

Is the effect reference-level dependent, I checked with setting ”IEM” to not break my ‘phones?

45 (edited by johny_2000 2024-07-02 23:27:12)

Re: ADI-2/4 Pro SE analog inputs protection questions

KaiS wrote:

Just checked again:
My ADI-2/4 Pro SE (hardware revision 1) doesn‘t do that on any of it’s 4 channels.

Is the effect reference-level dependent, I checked with setting ”IEM” to not break my ‘phones?

Thank you, KayS! Would you like to trade your unit? smile

Both of my RME ADI-2/4 Pro SE devices were detected by the Flash Update Tool as HW-Rev.7. And both had an older version of firmware (v. 3x, I don't remember the exact one) out of the box, and did not work with Remote 2.0 software until I flashed them to firmware v.40.

I believe this "feature" is independent of level. I did this with the "Low power" settings on the PH34. But I can double check this at the IEM level. More important is the digital playback level, which should be between -6...-0dBFS. And also the frequencies played should be 5~20 kHz.

After seeing this behavior on two brand new devices, I accepted it as a "feature" and not just a faulty device I got from the seller. So less worry now, and I get around this problem by turning on both 3+4 (L+R) output channels at the same time, even if I only need 4 (R).

46

Re: ADI-2/4 Pro SE analog inputs protection questions

With this latest information I was finally able to reproduce the issue. It has nothing to do with inputs, loopback, protection, Ref Levels...

It looks like the DAC chip 2 (aka channels 3/4) disables its output (aka mute) when channel 3 (aka left) does not carry any signal (aka digital zero) while channel 4 (aka right) gets a signal whose frequency reaches sr/2. Such an unusual state only happens in specific measurement situations like described in this thread, not in any other case - no wonder no one ever found it.

We will examine this further and expect to fix it via firmware update, but that might take some time.

Regards
Matthias Carstens
RME

47 (edited by johny_2000 2024-07-03 16:45:55)

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

With this latest information I was finally able to reproduce the issue. It has nothing to do with inputs, loopback, protection, Ref Levels...

It looks like the DAC chip 2 (aka channels 3/4) disables its output (aka mute) when channel 3 (aka left) does not carry any signal (aka digital zero) while channel 4 (aka right) gets a signal whose frequency reaches sr/2. Such an unusual state only happens in specific measurement situations like described in this thread, not in any other case - no wonder no one ever found it

Thank you, MC!

I am glad to hear that my contribution has led to the root cause of this unusual situation being found.  There is no rush to fix this as it is very specific and technically never happens in real life scenarios.

MC wrote:

We will examine this further and expect to fix it via firmware update, but that might take some time.

My faith in RME company and my choice of device has been rewarded with this customer support.  Sincerely!

48

Re: ADI-2/4 Pro SE analog inputs protection questions

You're welcome. And thanks for your patience through all this.

Regards
Matthias Carstens
RME

49

Re: ADI-2/4 Pro SE analog inputs protection questions

FPGA firmware 73 and 210 for the ADI-2/4 Pro SE should fix this issue - it does for us, so please try:

Windows:
https://www.rme-audio.de/downloads/fut_ … in_210.zip

Mac:
https://www.rme-audio.de/downloads/fut_ … ac_210.zip

Regards
Matthias Carstens
RME

Re: ADI-2/4 Pro SE analog inputs protection questions

MC wrote:

FPGA firmware 73 and 210 for the ADI-2/4 Pro SE should fix this issue - it does for us, so please try:

Windows:
https://www.rme-audio.de/downloads/fut_ … in_210.zip

Mac:
https://www.rme-audio.de/downloads/fut_ … ac_210.zip

It did it for me too! The problem is solved. Thanks for the quick response.