Hi
here are some measurement of the new RME ADI-2/4 Pro SE in RIAA (phono) mode
The RME ADI-24 Pro SE is RME's last addition to their ADI-2 converters range.
RME explains that SE means "Special Edition", and they advertise it as a Special, Limited edition, on top of the existing ADI-2 serie.
Externally, the family relation with the ADI-2 range can't be denied.
Here-above, from top to bottom,
RME ADI-2 Pro fs BE
RME ADI-2 Pro fs R BE
RME ADI-2/4 Pro SE
The most obvious difference with the ADI-2 Pro fs (R) is the presence of an additional 4.4mm Pentacon connector, to allow direct connection of balanced phones.
On the rear, there is also a Trigger output, to remotely switch on a power amplifier, as an example.
The new ADI-2/4 is also deeper than the ADI-2 pro (160mm vs 130mm) and it includes those large "HiFi look" silver feets instead of the small rubber feet of the Pro,
In fact, it shares more of the look of the Audiophile-targeted ADI-2 DAC fs.
For functionalities, it is of course closer to the Pro, with its 2 stereo DACs and the inclusion of a stereo ADC.
Another difference is the new Power Supply, which, while still an external 12V DC PS with a lockable connector, is now more powerfull and grounded.
Internally, we read that the DAC is using ESS chips, similar to the one used in the ADI-2 DAC
and a new ESS ADC (the previous Pro were all using AKM ADC) with improved performance.
Also, the selectable DAC and ADC ranges are modified:
The previous "Pro" allowed a selection between +4dBu / +13dBu / +19dBu /+24dBu ranges,
The new ADI-2/4 has now +1dBU / +7dBu / +13dBu / +19dBu / +24dBu
That's one more range.
On top of this, the ADI-2/4 has a new RIAA mode "for directly digitizing vinyl discs"
This is not really a Phono Preamp.
But given the low noise level of the ADC, RME seems to think that the performance of the RIAA mode could compete with some very good phono preamp.
Let's find out if this is true.
Measurements below were performed using the RME ADI-2/4 Pro SE as a generator, Behringer Monitor1 and Shure A15AS to attenuate the level, and Virtins Multi-Instrument 3.9.7 software.
RME ADI-2/4 Pro SE - RIAA Mode
The RIAA mode can be selected from the Analog Input Menu.
It then allows selecting an additional "Gain" and, of course, will activate RIAA equalization / correction.
Here are the specs, copied from the manual
To compare with other measurements here, I chose 5mV / +26dB
Here is what the SINAD / Noise Dashboard looks like at that level
RIAA Mode SINAD / Noise Dashboard 5mV
80.8dB SNR
(and we get the same figure for SINAD: distortion is way below, as it measures 23dB below the noise at that level)
This is a pretty respectable figure.
We have 15dB headroom above 5mV, which is probably more than enough.
Measuring the other "Gain" settings for their respective specificied sensitivity, I got this
This pretty well matches the Specifications.
We see the SNR decreasing with the test signal.
(This most probably is partly due to the noise in the test signal, as the level is lowered)
If I measure all settings at 5mV, I get this:
The SNR remains the same for +20dB up to +38dB.
That just means that the difference in "gain" is purely done in the digital domain.
But for +14dB, you see a lower figure.
There is a distinct relay-switching sound when you go from +14dB to +20dB mode (and none above)
This means that some analog level stage is modified between those 2 levels.
This is not just digital compensation.
And we see this in the measurements.
RIAA Mono Bass
RME includes a setting called "RIAA Mono Bass"
The idea is that, on a vinyl, bass is mono anyway.
Therefore, noise may be decreased without loss by just averaging both channels for low frequencies.
Indeed, we can even measure some benefit on the ADC side.
(NB: a much more dramatic benefit can be expected on the Vinyl noise itself)
RIAA Mode - Frequency response after RIAA correction
One of the most critical measurements is the RIAA correction accuracy.
To perform this one, I went back to the original RIAA correction formula
(Where t1=3180µs, t2=318µs, t3=75µs)
I then computed a compensation curve, including a point for each of the FFT bins, for Virtins Multi-Instrument.
I usually perform Frequency response measurements with REW generated Periodic noise at 192kHz tuned for 128k FFT.
I use the same +/-5dB scale that Amir is using.
This looks like text-book perfect to me.
But RIAA compensation the way it's done here may have a different accuracy for different Sampling rates.
So I compared the correction for each sampling rate (44.1kHz, 48kHz, 96kHz, 192kHz) and compared with the flat Frequency Response of the ADI-2/4 DAC+ADC with no RIAA correction at 192kHz - In black in the plot.
Now we see a very (VERY) small amount of difference around 50Hz between the sampling rates.
Let's zoom in a bit:
(Warning: This is a +/- 1dB scale - a microscope look)
We see that the 192kHz sampling is slightly more accurate.
OK, that was fun, but let's be serious: there is absolutely NO audible difference between those correction curves.
RIAA Mode - Distortion vs Frequency at 5mV (90kHz BW)
I added the input level (dashed blue), so you may understand why the distortion is higher in lower frequencies: that's because the level is.
NB: This is measured at a -relatively- high level of 5mV.
RIAA mode - Conclusion
When I first read about the addition of the RIAA correction, I thought it was kind of a marketing gadget.
Now after measurements, I have to say this is quite serious.
If you try to rank this with Amir's ranking, here is where it would be located versus the very top of the chart.
Black arrow is where the "standard RIAA" mode +26dB result of 80.8dB would land,
The red arrow shows the "RIAA Mono Bass" mode ranking.
On top of the very serious performances we see here, we also have the powerfull parametric EQ at hand to fine tune any cartridge-specific FR difficulties.
And the benefits of the "Mono bass" mode are probably much more dramatic on the reading noise of an actual vinyl.
So no, it's definitely NOT a gadget.
Well done !
EDIT August 2023:
RME just published a very informative video on how this works here.
Given the technical details they added, I thought it was worth adding the link here.
here are some measurement of the new RME ADI-2/4 Pro SE in RIAA (phono) mode
The RME ADI-24 Pro SE is RME's last addition to their ADI-2 converters range.
RME explains that SE means "Special Edition", and they advertise it as a Special, Limited edition, on top of the existing ADI-2 serie.
Externally, the family relation with the ADI-2 range can't be denied.
Here-above, from top to bottom,
RME ADI-2 Pro fs BE
RME ADI-2 Pro fs R BE
RME ADI-2/4 Pro SE
The most obvious difference with the ADI-2 Pro fs (R) is the presence of an additional 4.4mm Pentacon connector, to allow direct connection of balanced phones.
On the rear, there is also a Trigger output, to remotely switch on a power amplifier, as an example.
The new ADI-2/4 is also deeper than the ADI-2 pro (160mm vs 130mm) and it includes those large "HiFi look" silver feets instead of the small rubber feet of the Pro,
In fact, it shares more of the look of the Audiophile-targeted ADI-2 DAC fs.
For functionalities, it is of course closer to the Pro, with its 2 stereo DACs and the inclusion of a stereo ADC.
Another difference is the new Power Supply, which, while still an external 12V DC PS with a lockable connector, is now more powerfull and grounded.
Internally, we read that the DAC is using ESS chips, similar to the one used in the ADI-2 DAC
and a new ESS ADC (the previous Pro were all using AKM ADC) with improved performance.
Also, the selectable DAC and ADC ranges are modified:
The previous "Pro" allowed a selection between +4dBu / +13dBu / +19dBu /+24dBu ranges,
The new ADI-2/4 has now +1dBU / +7dBu / +13dBu / +19dBu / +24dBu
That's one more range.
On top of this, the ADI-2/4 has a new RIAA mode "for directly digitizing vinyl discs"
This is not really a Phono Preamp.
But given the low noise level of the ADC, RME seems to think that the performance of the RIAA mode could compete with some very good phono preamp.
Let's find out if this is true.
Measurements below were performed using the RME ADI-2/4 Pro SE as a generator, Behringer Monitor1 and Shure A15AS to attenuate the level, and Virtins Multi-Instrument 3.9.7 software.
RME ADI-2/4 Pro SE - RIAA Mode
The RIAA mode can be selected from the Analog Input Menu.
It then allows selecting an additional "Gain" and, of course, will activate RIAA equalization / correction.
Here are the specs, copied from the manual
To compare with other measurements here, I chose 5mV / +26dB
Here is what the SINAD / Noise Dashboard looks like at that level
RIAA Mode SINAD / Noise Dashboard 5mV
80.8dB SNR
(and we get the same figure for SINAD: distortion is way below, as it measures 23dB below the noise at that level)
This is a pretty respectable figure.
We have 15dB headroom above 5mV, which is probably more than enough.
Measuring the other "Gain" settings for their respective specificied sensitivity, I got this
This pretty well matches the Specifications.
We see the SNR decreasing with the test signal.
(This most probably is partly due to the noise in the test signal, as the level is lowered)
If I measure all settings at 5mV, I get this:
The SNR remains the same for +20dB up to +38dB.
That just means that the difference in "gain" is purely done in the digital domain.
But for +14dB, you see a lower figure.
There is a distinct relay-switching sound when you go from +14dB to +20dB mode (and none above)
This means that some analog level stage is modified between those 2 levels.
This is not just digital compensation.
And we see this in the measurements.
RIAA Mono Bass
RME includes a setting called "RIAA Mono Bass"
The idea is that, on a vinyl, bass is mono anyway.
Therefore, noise may be decreased without loss by just averaging both channels for low frequencies.
Indeed, we can even measure some benefit on the ADC side.
(NB: a much more dramatic benefit can be expected on the Vinyl noise itself)
RIAA Mode - Frequency response after RIAA correction
One of the most critical measurements is the RIAA correction accuracy.
To perform this one, I went back to the original RIAA correction formula
(Where t1=3180µs, t2=318µs, t3=75µs)
I then computed a compensation curve, including a point for each of the FFT bins, for Virtins Multi-Instrument.
I usually perform Frequency response measurements with REW generated Periodic noise at 192kHz tuned for 128k FFT.
I use the same +/-5dB scale that Amir is using.
This looks like text-book perfect to me.
But RIAA compensation the way it's done here may have a different accuracy for different Sampling rates.
So I compared the correction for each sampling rate (44.1kHz, 48kHz, 96kHz, 192kHz) and compared with the flat Frequency Response of the ADI-2/4 DAC+ADC with no RIAA correction at 192kHz - In black in the plot.
Now we see a very (VERY) small amount of difference around 50Hz between the sampling rates.
Let's zoom in a bit:
(Warning: This is a +/- 1dB scale - a microscope look)
We see that the 192kHz sampling is slightly more accurate.
OK, that was fun, but let's be serious: there is absolutely NO audible difference between those correction curves.
RIAA Mode - Distortion vs Frequency at 5mV (90kHz BW)
I added the input level (dashed blue), so you may understand why the distortion is higher in lower frequencies: that's because the level is.
NB: This is measured at a -relatively- high level of 5mV.
RIAA mode - Conclusion
When I first read about the addition of the RIAA correction, I thought it was kind of a marketing gadget.
Now after measurements, I have to say this is quite serious.
If you try to rank this with Amir's ranking, here is where it would be located versus the very top of the chart.
Black arrow is where the "standard RIAA" mode +26dB result of 80.8dB would land,
The red arrow shows the "RIAA Mono Bass" mode ranking.
On top of the very serious performances we see here, we also have the powerfull parametric EQ at hand to fine tune any cartridge-specific FR difficulties.
And the benefits of the "Mono bass" mode are probably much more dramatic on the reading noise of an actual vinyl.
So no, it's definitely NOT a gadget.
Well done !
EDIT August 2023:
RME just published a very informative video on how this works here.
Given the technical details they added, I thought it was worth adding the link here.
Last edited:
Any plan to measure the overall ADC performance against the COSMOS?
