RME ADI-2 FS Version 2 DAC and Headphone Amp Review

[AudioExplorer]

I have a question on the max output voltage of the DAC from the XLR outputs (for the AKM4493 version). It seems that the DAC outputs 4.087V at a volume of -4.5 dB (first graph in review). This translates to close to the reported 6.9 V at 0 dB. But the DAC also seems to allow raising the volume to +6 dB. Does this mean that if the volume is raised to +6 dB, the DAC is capable of an output of 13.8 V at the +6 dB volume setting from the XLR outputs? Or am I misinterpreting something in the measurements and specifications?

 

[MC_RME]

As explained in the manual max output level is reached at +2.5 dB volume setting. Higher gain is there to compensate in case the source is low in level/volume.

 

[AudioExplorer]

As explained in the manual max output level is reached at +2.5 dB volume setting. Higher gain is there to compensate in case the source is low in level/volume.

Thanks very much for the clarification. Somehow, I couldn't find this information in the manual. So, just to make sure I understand correctly, 0 dBFS corresponds to a volume setting of +2.5 dB? That is, +19 dBu max output level as per the line excerpted below from the specification is achieved at a volume setting of 2.5 dB, correct?
"Output level switchable +19 dBu, +13 dBu, +7 dBu, +1 dBu @ 0 dBFS".

Or is it that the DAC can actually put out 21.5 dBu at the 2.5 dB volume setting and a volume setting of 0 dB corresponds to 0 dBFS? Thanks.

 

[MC_RME]

The latter: The ADI-2 Pro has two balanced analog Line outputs that can operate at levels up to +26.5 dBu (+24 dBu with Volume set to +2.5 dB).

 

[Atanasi]

The latter: The ADI-2 Pro has two balanced analog Line outputs that can operate at levels up to +26.5 dBu (+24 dBu with Volume set to +2.5 dB).

What about the SNR values in the specs, are they measured relative to 0 dB signal or +2.5 dB?

 

[MC_RME]

0 dB (all measurements). If you dial up Vol to +2.5 you get 2.5 dB more SNR (around 123 dB rms unweighted, 125.5 dBA).

 

[AudioExplorer]

The latter: The ADI-2 Pro has two balanced analog Line outputs that can operate at levels up to +26.5 dBu (+24 dBu with Volume set to +2.5 dB).

Thanks for the clarifications. I realize now why I wasn't able to find this info in the manual. I was asking about the RME ADI-2 DAC fs, not the ADI-2 pro. Nevertheless, I understand how it works now.

A minor follow up question. In the red bold part of the excerpt from the ADI-2 DAC fs manual below, should the volume setting be 1 dB and not 0 dB since setting hardware Ref Level to +7 dBu and 0 dB volume will output 7 dBu and not 8 dBu?

----------------------
Fixed Output Level – Lock Volume
The option Lock Volume in the I/O menu allows to lock the analog output level to a specific value, a change via the VOLUME knob is no longer possible. The Volume adjustment within the menu is used to set the 'fixed' output level.

For example when the analog output should operate like a typical HiFi unit @ 2 V output level (equals +8 dBu), set the hardware Ref Level to +7 dBu and 0 dB volume. More examples:
1 V (0 dBV, +2.2 dBu): Ref +7 dBu, Vol -5 dB
0.775 V (0 dBu, -2.2 dBV): Ref +1 dBu, Vol -1 dB
0.5 V (-3.8 dBu, -6 dBV): Ref +1 dBu, Vol -5 dB
0.315 V (-10 dBV, -7.8 dBu): Ref -5 dBu, Vol -3 dB
-------------------------

Just wanted to check if this is an error in the manual or if there is something else I am missing. Thanks.

 

[danadam]

In the red bold part of the excerpt from the ADI-2 DAC fs manual below, should the volume setting be 1 dB and not 0 dB

The manual available online says 1:

 

[Oklei]

A praise of auto-ref
Most dac measurements are made at or nearby 0dB. For users like me who use the internal preamp function it's more interesting how the dac-preamp-combo performs at everyday volume settings. This depends on your power-amp and speaker efficiency but in my case in most DACs -40dB is a normal volume setting.
I thought I compare the very well measured Okto stereo DAC (ES9028pro) with the RME ADI-2 DAC (ES9028q2m).
First look at the TD+N at full volume for a DIN IMD signal of the Okto DAC:

Clearly superb IMD TD+N is at -115,6dB. Let's see the RME Adi-DAC at the same level:

Great performance but TD+N is "only" -110,7 dB
Now volume setting is reduced to -40dB. First Okto:

We're at -81,9dB now. Now the ADI-2:

At the same level we're at -82,7dB TD+N due to the lowered noise floor. This is now slightly better than the Okto (because of autoref). In the end SINAD values at 0dB don't tell you everything if you plan to use your device at lower volume settings.
Both devices perform exceptionally well and this is nothing to be concerned of (or audible) but just a demonstration that dynamic reference levels can be as important as a few dB more sinad depending on the use case.

 

[AudioExplorer]

The manual available online says 1:
View attachment 213964

Thanks for noting this. It seems that on the RME site, there are two manuals, one for the "ADI-2 DAC" (manual version 1.8 from Sept. 2019) and one for the "ADI-2 DAC (new remote)" (manual version 3.1 from April 2022). The older manual says 0 dB for the volume setting and the newer one says 1 dB as you noted above. I had assumed that the older one is the one applicable to the DAC with the AKM4493 chip and was using that. I guess I should be using the new manual even though I have the older AKM chip.

 

[MC_RME]

This additional information had been added in manual 2.5 (AK4493, not old):

19.3 Line Out XLR
The ADI-2 DAC has two balanced analog outputs that can operate at levels up to +21.5 dBu (Ref Lev +19 dBu with Volume set to +2.5 dB).

Right now we are at version 3.1. The 'old' manual is for units with AK4490, which did not have +2.5 dB Volume ability. So '0' in there is correct. You won't notice that 1 dB mismatch.

 

[anewaccount]

Hopefully not the wrong thread to ask this.
Is there any info on an upcoming newer/revised version of the rme adi 2 dac fs?
Planning to get them in the coming months.
Thanks!

 

[MC_RME]

No change planned for the forseeable future.

 

[Grotti]

Hopefully not the wrong thread to ask this.
Is there any info on an upcoming newer/revised version of the rme adi 2 dac fs?
Planning to get them in the coming months.
Thanks!

Nothing to complain about the actual version of the device....in fact I appreciate that RME does not follow the trend to push a new DAC into the market every year!

 

[DonDish]

Nothing to complain about the actual version of the device....in fact I appreciate that RME does not follow the trend to push a new DAC into the market every year!

FW updates are free with RME. Got alot of new functionality since I bought my ADI-2 DAC.

 

[gmoney]

I think they might be announcing the successor to this soon.

 

[Trell]

I think they might be announcing the successor to this soon.

No, read the post just above you.

 

[Music1969]

Guys,

Thanks to gentle members, I (finally) got my hands on two ADI-2 DAC FS: one AKM (4493) and one ESS, in intend, of course, to measure both side by side. I started to work on it, so stay tuned...View attachment 212405

So is there an ESS IMD hump?

I expect that to be the only major measurement (not audible) difference.

But hoping RME engineering was able to tame the beast, like some other designers have done

 

[Oklei]

So is there an ESS IMD hump?

I expect that to be the only major measurement (not audible) difference.

But hoping RME engineering was able to tame the beast, like some other designers have done

Afaik there is no ESS IMD hump in the 9028 series (like 9028pro or 9028q2m). ESS 'invented' that with the 9038 series.
Nevertheless I measured IM TDN vs signal level for the ADI-2 ESS and no hump can be observed. I'm not at my laptop atm but can post the graphs later..

 

[Trell]

So is there an ESS IMD hump?

I expect that to be the only major measurement (not audible) difference.

But hoping RME engineering was able to tame the beast, like some other designers have done

We’re still waiting for his tests.