RME ADI-2/4 Pro SE - RIAA mode measurements

[morillon]

thank you
;-)
v15/4 is a 4mv

have you had the opportunity to listen to some very heavily modulated records to try to check for hypothetical overload problems?
;-)

 

[LTig]

Listening to some LPs my wife came down in the living room and asked me what I did that the LPs sound so transparent now! She's not addicted to audio as I am, but she heard it straight away.

Did she listen from the kitchen?

 

[40th Anniversary]

Interesting read thus far. RME ADI-2 FS owner here with AHB2 amplifiers.
One feature which is not mentioned much in this thread is the new +12 volt trigger that is on offer!
Now if they could migrate "that" feature to the plain "Pro" version or the ADI-2 FS, I'd be a buyer in a New York minute.
I don't spin vinyl so I have no need for RIAA.
And just wow what they have packed into that device.

 

[DrCWO]

Did she listen from the kitchen?

She was not in the sweet spot if this is what you mean.
I'm also one of the few men who don't chain their wives in the kitchen.

 

[DrCWO]

thank you
;-)
v15/4 is a 4mv

have you had the opportunity to listen to some very heavily modulated records to try to check for hypothetical overload problems?
;-)

I have a trackability test record from Shure (TTR115) that I can play without issue.
Also tested with some loud LPs like Rumors of Fleetwood Mac. Also fine.

I don't have any single or EP which I think are even louder so I could not test. But until now I'm quite happy

 

[morillon]

I have a trackability test record from Shure (TTR115) that I can play without issue.
Also tested with some loud LPs like Rumors of Fleetwood Mac. Also fine.

I don't have any single or EP which I think are even louder so I could not test. But until now I'm quite happy

can be classic discs with strong contrasts of levels.. symphony orchestra or late 19th and 20th century opera type etc.
?
( otherwise there are discs of musical extracts (not only frequency test) over-modulated "by stages" but originally made for cartdrige traceability tests (era4? the old shure 101 sure).. detournable. ..
(in the good old days.. considering respecting a +15db was already a lot... and therefore the cells passing this value having a good margin in use)
(but these are discs that in fact wear out terribly.. are limited in their number of passages)
)
;-)

 

[levimax]

can be classic discs with strong contrasts of levels.. symphony orchestra or late 19th and 20th century opera type etc.
?
( otherwise there are discs of musical extracts (not only frequency test) over-modulated "by stages" but originally made for cartdrige traceability tests (era4? the old shure 101 sure).. detournable. ..
(in the good old days.. considering respecting a +15db was already a lot... and therefore the cells passing this value having a good margin in use)
(but these are discs that in fact wear out terribly.. are limited in their number of passages)
)
;-)

None of the " potential overload" issues being discussed have anything to do with music. The "potential" issues are in regards to playing back damaged LP's with loud pops and clicks which are far louder than the music. Whether 6 db, 15 dB, 20 dB, or 34 dB is "enough headroom" is the question and the answer is certainly not clear to me. I have been looking for my most damaged records and capturing the "pops" and I have yet to find a pop that is more than 6 dB louder than the peak music level. I am sure they exist but I would never play a record like that if I had one. To me it appears RME is on solid ground here.

 

[Gregg Hermetech]

I've played about 50 records since I hooked the TT up and all I notice is great sound.

 

[eliash]

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.

View attachment 249033

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

View attachment 249028

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

View attachment 249030

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

View attachment 249027

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:

View attachment 249026
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)

View attachment 249029


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

View attachment 249037
(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.

View attachment 249023

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.

View attachment 249025

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)

View attachment 249024

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.

View attachment 249040


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.

View attachment 249022


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 !

High quality digital Vinyl support is a clever move for a AD/DA unit which also partially aims at replacing traditional pre-amp components.

Personally, I would be attempted to buy one with a bit more dedication towards true vinyl input characteristics (47kOhms/<100pF) support.
On that basis, even high quality A/D conversion + digital signal processing w RIAA and room/frequency response correction (same as implemented today for digital inputs) + D/A conversion back driving analog main amps makes sense for me for life&direct listening experiences.
...would enable me to give up my full line analog setup for Vinyl and therefore could become a reasonable game changer!

 

[MC_RME]

Personally, I would be attempted to buy one with a bit more dedication towards true vinyl input characteristics (47kOhms/<100pF) support.

I expected a comment like this sooner or later. And all I can recommend is to buy an LCR meter and measure the real world values of various preamps and compare them to their data sheet, and then measure the cable that is used to connect the TT with the preamp. You are up to big surprises. I have one reference RIAA preamp from the old times that manages to have 100 pF only. But the simple truth is that design could not be built and sold today. The reason that value is so low is that the unit has zero (none, nada) EMI/RFI protection at its input. Those were the times...

That said our stated 45 kOhm and 150 pF are measured values. 45 or 47 kOhm makes no difference for the MM cart at all (and yes, I could have just written 47 kOhm into the manual. Would that have given you peace of mind?). The total capacity loading the cartridge is unpredictable. Not only because the value stated is often lower than when measured, but because of the cable between MM cart and preamp, which adds easily more than 50 pF.

 

[eliash]

I expected a comment like this sooner or later. And all I can recommend is to buy an LCR meter and measure the real world values of various preamps and compare them to their data sheet, and then measure the cable that is used to connect the TT with the preamp. You are up to big surprises. I have one reference RIAA preamp from the old times that manages to have 100 pF only. But the simple truth is that design could not be built and sold today. The reason that value is so low is that the unit has zero (none, nada) EMI/RFI protection at its input. Those were the times...

That said our stated 45 kOhm and 150 pF are measured values. 45 or 47 kOhm makes no difference for the MM cart at all (and yes, I could have just written 47 kOhm into the manual. Would that have given you peace of mind?). The total capacity loading the cartridge is unpredictable. Not only because the value stated is often lower than when measured, but because of the cable between MM cart and preamp, which adds easily more than 50 pF.

Thanks Matthias, that was quick...I agree with 45 to 47K and EMI precautions, but 150pF input capacitance are too high for many japanese carts.

...I had to tune my T+A preamp plus phono module by removing all RFI caps resulting in 45pF plus cable 50pF (mech. modified RG180 > lowest cap. shielded avail.) plus tonearm 15pF for a Nagaoka MP500, requiring as low as possible capacitance to cater for ~800mH of inductance to preserve high frequency response...

That´s why I wrote <100pF above...a valid question from my perspective would be to include a (removable) phono cable on a dedicated phono input to meet the EMI measurements at RME, 50p are easy to achieve and more can be added externally!?

Anyway, my main point was to show that all the benefits from high quality digital sound processing could become available for digital AND ANALOG sources in one unit when listening to a live (local) source. Which is of course a personal preference, i.e. operating a turntable for listening.
This would be the highlight for me...(btw. me being a grateful RME ADI-2 fs customer)

 

[morillon]

it is true that it would have been welcome for those who want to use mm from a much lower value (emi's problems are mostly with mc) ...
in many cases, for those who want to fine-tune, it will be necessary to use a wiring that is really not very low capacitive...
but for those who do ambitious mc-mc etc with an additional stage sut prepre.. it will be more of a subject...
;-)

 

[AnalogSteph]

I used this simple "Balanced Transmitter", the PCB version, https://sound-au.com/project87.htm and changed R102 to 47K. Loading for the cart is then right, you can have the transmitter close to the TT so easy to keep capacitance down, and the signal is transmitted to the ADC balanced. I found this to work very well ... ..especially no noise.

So Fig 3A? In this application I would suggest some further adaptations:
1. R103/R104 are a bit too high for a noise-critical application at modest levels... you can safely reduce these to 2k2 or even 1k5 without anyone breaking a sweat, for a noise reduction of 2-3 dB or so.
2. Protection against RF ingress at the input is minimal.

 

[levimax]

So Fig 3A? In this application I would suggest some further adaptations:
1. R103/R104 are a bit too high for a noise-critical application at modest levels... you can safely reduce these to 2k2 or even 1k5 without anyone breaking a sweat, for a noise reduction of 2-3 dB or so.
2. Protection against RF ingress at the input is minimal.

Yes Fig 3A. Thanks for the input. The reason I first went this way originally was because I lived in an apartment and my neighbor had a powerful wi-fi transmitter mounted on the other side of the wall right next to my TT and I picked up a lot of noise. I put the balanced transmitter right next to the TT to keep capacitance and RF pickup low and it worked well so RF ingress is OK for my use. Regarding R103/ R104 I don't notice any noise (I used OPA 2134 which are quieter than NE5532 I think) especially with vinyl playing but I may try lowering the resistance to see. Right now it is working so not very motivated to do anything Thanks again.

 

[LTig]

Regarding R103/ R104 I don't notice any noise (I used OPA 2134 which are quieter than NE5532 I think) especially with vinyl playing but I may try lowering the resistance to see. Right now it is working so not very motivated to do anything Thanks again.

OPA2134 has higher voltage noise but lower current noise than NE5532. So don't expect a significant reduction of noise with smaller resistances for R103/104.

 

[MC_RME]

Still I would have used 1k for both without even thinking. Standard to keep noise low. 10k is so yesterday...
Also it wouldn't have hurt to add a 100 pF (or 47 pF to satisfy the worrying MM enthusiasts) behind the 100 Ohms to ground (pin 3 of U1A).

 

[levimax]

Still I would have used 1k for both without even thinking. Standard to keep noise low. 10k is so yesterday...
Also it wouldn't have hurt to add a 100 pF (or 47 pF to satisfy the worrying MM enthusiasts) behind the 100 Ohms to ground (pins 3 of U1A).

Thanks.... I understand the trade off with higher resistance and higher noise.... is there any downside to lower resistance in this spot?

 

[MC_RME]

At high levels one has to be careful not to load the opamp output too much. But at the super low levels used here (a few mV) that absolutely doesn't matter.

 

[levimax]

At high levels one has to be careful not to load the opamp output too much. But at the super low levels used here (a few mV) that absolutely doesn't matter.

thanks, that makes sense as this was originally designed as a balanced line level transmitter not a phono level balanced transmitter.

 

[dlaloum]

I expected a comment like this sooner or later. And all I can recommend is to buy an LCR meter and measure the real world values of various preamps and compare them to their data sheet, and then measure the cable that is used to connect the TT with the preamp. You are up to big surprises. I have one reference RIAA preamp from the old times that manages to have 100 pF only. But the simple truth is that design could not be built and sold today. The reason that value is so low is that the unit has zero (none, nada) EMI/RFI protection at its input. Those were the times...

That said our stated 45 kOhm and 150 pF are measured values. 45 or 47 kOhm makes no difference for the MM cart at all (and yes, I could have just written 47 kOhm into the manual. Would that have given you peace of mind?). The total capacity loading the cartridge is unpredictable. Not only because the value stated is often lower than when measured, but because of the cable between MM cart and preamp, which adds easily more than 50 pF.

On decent vintage TT's from the period where they paid attention to these things.... the additional capacitance from arm and interconnect cabling is typically 100pf

With a low capacitance cable (such as BlueJeans) and a very short (and awkward!) cable run - I managed to get one TT down to 60pf
It would be very difficult to get the TT+cable capacitance down to 50pf, and even more so getting it below that figure!

I've measured some latter day TT's which with their interconnect, measured 300pf+

I have at least one RCA cable that measures over 500pf for a "quality" audiophile cable.