Topic: adi-2 dac fs specs vs adi-2 pro fs r be

the specs look largely the same but two questions:

1. why is channel separation 110db on Pro FS R BE yet 120db on DAC FS?

2. analog xlr out output level switchable:  i can i make the defaults for the Pro fs r be match the same defaults of dac fs if i want to use it for hi-fi?

2 (edited by KaiS 2021-02-13 02:44:50)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

The Pro’s XLR level is just 3 dB hotter than the DAC’s, both are well within what works for Hifi.


The I/O connectivity is where both are different, which one to choose depends on your needs.

The Pro, i.e., offers balanced headphones out and analog input, and two independent output channels.


The difference in channel crosstalk is pointless, 110 dB already is 60 dB (= 1000 times) beyond what’s audible.

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Thanks for your answers! 

Regarding the balanced headphones out on the Pro FS R BE, is my understanding correct that there are 2 balanced headphone outs, each independent with its own DAC?  And that there are 2 DACS in the Pro vs 1 in the ADI-2 DAC FS?

Also, since the headphones outs in front are for standard sized headphone jacks, similar to the single ended found on headphone amps, would my using a standard jack to XLR adapter to connect my headphones that use XLR cable create the equivalent of a balanced XLR port would?  or would it differ somehow?

Lastly, did the ADI-2 DAC FS experience a price increase to $1250 USD from $1150?  I see some retailers selling it for $1250 now.

Thanks in advance.

4 (edited by ramses 2021-02-13 10:00:21)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

The two phones outputs form 1 balanced phones output (in balanced mode).
Yes, the ADi-2 Pro * has two D/A converter built-in.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

5 (edited by KaiS 2021-02-13 11:02:07)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Zathrus1 wrote:

Regarding the balanced headphones out on the Pro FS R BE, is my understanding correct that there are 2 balanced headphone outs, each independent with its own DAC? ...

No, not exactly.

Zathrus1 wrote:

Also, since the headphones outs in front are for standard sized headphone jacks, similar to the single ended found on headphone amps, would my using a standard jack to XLR adapter to connect my headphones that use XLR cable create the equivalent of a balanced XLR port would?  or would it differ somehow?

As you correctly mentioned, the Pro has two (fully independent, each with it’s own DSP functionality and own DAC) unbalanced headphones outputs.


There is a special mode switchable that combines those into one single, balanced headphone output.

A special cable with two 6.3mm jacks is needed to use them, either as adapter into, i.e. 4-pin XLR, or as special cable directly to your headphones.

The connection scheme is in the manual page 43.

6 (edited by ning 2021-02-13 13:39:31)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

I have a question regarding the hp amp specs for a long time:

DAC FS (4490 version)
THD @ +18 dBu, 32 Ohm load, 1.2 Watt: -110 dB, 0.0003 %
THD+N @ + 18 dBu, 32 Ohm load: -107 dB, 0.00045 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %

DAC FS (4493 version)
THD @ +18 dBu, 32 ohm load, 1.2 watts: -120 dB, 0.0001 %
THD+N @ + 18 dBu, 32 Ohm Load: -114 dB, 0.0002 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %

Pro FS (4490 version)
THD @ +18 dBu, 32 Ohm load, 1.2 Watt: -110 dB, 0.0003 %
THD+N @ + 18 dBu, 32 Ohm load: -107 dB, 0.00045 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB

Pro FS R BE (4493 version)
THD @ +18 dBu, 32 Ohm load, 1.2 Watt: -110 dB, 0.0003 %
THD+N @ + 18 dBu, 32 Ohm load: -107 dB, 0.00045 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %

so when the dac chip upgrades from 4490 to 4493, the specs improve for DAC, but not the Pro.
This seems like an error for me. Reading the Pro FS R BE manual these two graphs
- page 87 Output Phones TRS +18 dBu output level @ 32 Ohm equal 1.2 W (per channel)
- page 89 Phones Distortion Comparison Phone out thd+n  @ 32 Ohm load
also clearly indicates at +18dbu and 32ohm, the thd+N should be lose to -114db rather than -110db for the Pro FS R BE.

Interestingly, the maximum thd+n for opa1688 for 32ohm load is -109.5db at 50mw (see specsheet page 26 and 27).
RME's -114db is 5 db better. it also generates 3 times more power (1.2watt vs 50mw*6) under the same load
The result achieved by RME is just amazing!

7 (edited by KaiS 2021-02-13 14:58:05)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

No pun intended, but I have the feel you‘re not familiar with electrotechnique, dB, Ohms Law and the like.

If this is true it’s pointless to closely inspect number by number, or try to discuss them in detail.


Just one: ADI-2 DAC / Pro use 6 OPA1688 paralleled per output, this explains the better specs than a single OPA1688’s datasheet figures.
6 times the current capability equals 6 times voltage.
Six times voltage squared equals 36 times power into the same resistor.
U=I * R
P=U^2 / R

Real value is less, because voltage is limited by Ub and current is limited by 47 Ohms summing resistors.


Let me rest-assured you that all of ADI-2’s figures are way beyond what is audible.
Let me even assure you that the output power with every headphone on the market is enough to either break the headphones or split your ears.



But- what really counts:
The ADI-2 Pro / DAC, combined with state of the art quality, offer unrivaled features and flexibility - that’s what divides them from the pack.

8 (edited by ning 2021-02-14 02:48:27)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

> If this is true it’s pointless to closely inspect number by number, or try to discuss them in detail.

I just want to point out the Pro FS R BE spec number might be wrong (under spec-ed).
It sees no improvements with updated DAC chip as the ADI-2 DAC does, and the number is different from other performance graphs.
I don't really care about those figures as they are beyond human hearing anyway.
But now that it is published it would better be right so those who are interested can compare how each generation gets better.

> Just one: ADI-2 DAC / Pro use 6 OPA1688 paralleled per output, this explains the better specs than a single OPA1688’s datasheet figures.

that's right. roughly speaking each channel will see the load as a 32*6ohm = 192ohm load. (depends on topology of course), so the opamp will clip at much higher voltages. (thus U^2/R will be larger).

>Let me even assure you that the output power with every headphone on the market is enough to either break the headphones or split your ears.

true. clipping point thd+n seldom gives useful insights. practically low voltage thd+n performance (such as at 10mv) is what really matters. seems manufacturers,  including RME, have yet to include those in the specs.
If the 6.5 inch jack is good enough MC would not include an IEM port into the DAC.

> The ADI-2 Pro / DAC, combined with state of the art quality, offer unrivaled features and flexibility - that’s what divides them from the pack.

right. the ADI-2 Pro or DAC is a different animal compared to a normal DAC+HP Amp combo. No other offering has comparable feature sets.

9 (edited by KaiS 2021-02-13 16:42:10)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

ning wrote:

>Let me even assure you that the output power with every headphone on the market is enough to either break the headphones or split your ears.

true. clipping point thd+n seldom gives useful insights. practically low power thd+n performance (such as at 10mw) is what really matters. seems manufacturers,  including RME, have yet to include those in the specs.
If the 6.5 inch jack is good enough MC would not include an IEM port into the DAC.

The reason for the IEM-out is:

There are extremely sensitive, read loud, IEMs that boots the faintest noise of an amplifier.
The only way to get the absolute noise down is to shift the gain of a combined DAC/Amp’s final stage to lower, that’s what the IEM out does.


The quality and dynamic range of both, the normal and the IEM outputs, are the same, just that the IEM output has shifted it’s dynamic range to a lower reference level that better fits to IEMs.

Re: adi-2 dac fs specs vs adi-2 pro fs r be

> The only way to get the absolute noise down is to shift the gain of a combined DAC/Amp’s final stage to lower, that’s what the IEM out does. The quality and dynamic range of both, the normal and the IEM outputs, are the same, just that the IEM output has shifted it’s dynamic range to a lower reference level that better fits to IEMs.

The dynamic range of both outputs is limited by the DAC chip as analog headphone amplifiers usually have a much lower noise level.
In adi-2's case, 6.5 inch jack's noise level is very low, but not low enough. so adding a lower gain switch in addition to the existing two gain settings will have lower SNR than the DAC chip. so a separate headphone amplifier based on a much better opamp (opa1622) is added. That's what you mean by shifting the output level to lower.

but it's not the only possible solution. It's entirely possible to design a headphone amp with even greater SNR that works for both scenarios, such as using nested feedback topology. In this case, you can get even lower noise than RME's IEM solution, while maintaining higher rail-to-rail voltage than the 6.5in hp amp for regular headphones. Not using such topology is just an engineering choice, not a technical limitation.

11 (edited by khronik 2021-06-23 13:31:40)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

I'm on the edge of purchasing the ADI-2 Pro FS R BE and also noticed the delta between the DAC and Pro FS R BE's headphone specs..

(as stated above)

DAC FS (4493 version)
THD @ +18 dBu, 32 ohm load, 1.2 watts: -120 dB, 0.0001 %
THD+N @ + 18 dBu, 32 Ohm Load: -114 dB, 0.0002 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %

Pro FS R BE (4493 version)
THD @ +18 dBu, 32 Ohm load, 1.2 Watt: -110 dB, 0.0003 %
THD+N @ + 18 dBu, 32 Ohm load: -107 dB, 0.00045 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %

While I understand the differences might be beyond perceivable when in use, there's is still a 10db THD, 7db THD+N and 10db channel separation spec advantage on the DAC FS model going by RME's stated specifications.

I'm guessing it might have to do with the different circuit design required to implement balanced HP output and/or dual DACs on the HP outs.

Any insight or clarification would definitely be appreciated!

12 (edited by KaiS 2021-06-23 15:08:29)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Might be a heat issue during measurement.
ADI-2 Pro cramps much more electronics into the same case than ADI-2 DAC and therefore heats up more.


The special designed high power headphones output stages, built around 6 OPA 1688 chips each, have a higher maximum output current limit when cold.

This means, in practice, with music, it performs even better than with a constant sinewave during measurement.
This might result in a slightly higher THD at the power limit.
Slightly below the maximum power, specs might be more similar.


A lot of “mights”, but I found during measurements that ADI-2 Pro performs much better short term (read: dynamic peaks like with music) than with continuous steady signals that don’t exist in music.


You even have to take into account that no headphones exist that can stand, without breaking, the long term power ADI-2 can deliver.

13 (edited by khronik 2021-06-23 18:45:07)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

My concern is the "PRO" having more THD and lower S/N than the less expensive "DAC" model when it comes to the headphone amp despite the pro nomenclature and increased price. If the performance is thermal limited, it would suggest even worse specs if put in a hotter environment.

I have the option to buy the DAC model instead of the Pro FS R BE since the A/D functionality is not 100% needed for me but would be nice to have, albeit not at a performance hit compared to a less expensive variant which appears to not suffer from a thermal design handicap.

14 (edited by KaiS 2021-06-23 20:03:58)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

khronik wrote:

My concern is the "PRO" having more THD and lower S/N than the less expensive "DAC" model when it comes to the headphone amp despite the pro nomenclature and increased price. If the performance is thermal limited, it would suggest even worse specs if put in a hotter environment.

I have the option to buy the DAC model instead of the Pro FS R BE since the A/D functionality is not 100% needed for me but would be nice to have, albeit not at a performance hit compared to a less expensive variant which appears to not suffer from a thermal design handicap.

You‘ve got me wrong, there is no “thermal design handicap”.

• My explanation is just an “educated guess”.

• With music it’s by no means possible to heat up ADI-2 Pro in the same way as can be done with sinewaves.
Even if you insist in becoming permanently deaf within minutes by sound levels louder than gunshots.
If you find headphones that can take that much power at all.
BTW: ADI-2 DAC would have the same limitation when forced into that much power.

• If you do amp power measurements very close to the maximum, the THD curve rises very steep.
If you do the same measurement at a few % lower level, the THD can be much lower.

• Anyway THD is NOT a sound quality factor, think Tubeamp with a THD of 3% at rated power

• Once you have the AD option you soon will find use for it, it makes the ADI-2 so much more versatile!

• Don’t forget about the balanced headphones option on ADI-2 Pro.

15 (edited by khronik 2021-06-23 21:36:58)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Best would be for someone with technical knowledge of the device to confirm rather than educated guesses but it's sounding like the performance delta is due to circuit design or implementation of features with the Pro rather than a typo in the manual. I was hoping for the latter.

While I would agree THD in itself is not an indicator of quality at these low levels, at this price range specs are significant (at this magnitude of difference) and if I can obtain a higher spec with a lesser model then it's important to understand before purchase.

As for the point replies..

• With music it’s by no means possible to heat up ADI-2 Pro in the same way as can be done with sinewaves.

The audio program should not dictate the thermal / audio performance of the unit. Last time I checked a sinewave is still audio as long as within the specified range supported by the device. I use it to monitor my synths which are very heavily sine / square / triangle based, I shouldn't have to worry about what I'm playing through the device.

• Anyway THD is NOT a sound quality factor, think Tubeamp with a THD of 3% at rated power

Quality is a subjective term. When using the device as a mastering / monitoring / measuring tool THD is a factor. If I'm casually listening to music on it, that's a whole different application. Regardless, the specs differ enough to warrant the question IMO.

Re: adi-2 dac fs specs vs adi-2 pro fs r be

The manual (spec) was just copied from the old version of ADI- Pro (ak4490 version) and is wrong. It can be easily confirmed in a loop back test (though it is not strict) with load. The manual has the power graph of the headphone amp, and the number on the graph is much better than the spec.

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Btw, if you are hesitating which one to choose, choose the dac version. Pro version is only for those who need ADC. For those who don’t use ADC, the DAC version is a lot cheaper, runs a lot cooler, and support DSP at higher sample rates, and has an IEM output.

18 (edited by KaiS 2021-06-24 07:04:57)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

As mentioned in the manual the AKM chip itself varies according distortions.
RME obviously did not cherry-pick a unit for measurement.

Look at the graphs in the manuals page 58 (DAC) and 87 (Pro).
The noise floor is even lower on the Pro, the distribution of THD products is different.
BTW: Noise (=dither) does reduce low level ADC and DAC distortions, so more noise = less distortions, and vice versa.


Maybe I underestimate myself with the term “educated guess”, I am such a person with “technical knowledge of the device”.
Without going into detail, I can assure you, a synth sound is by no means comparable to a sinewave for measurement.
No need to “worry” what kind of sounds to play.

Both ADI-2’s THD is magnitudes below what could be audible, and the ADI-2 Pro is better than most measurement devices, even the industry standard Audio Precision in it’s latest iteration:
https://www.admess.de/audioanalyzer/aud … px555.html

DAC or Pro is just a question of what features you need, and maybe your wallet.
E.g. if you’re in recording the “Pro” might come more handy.

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Kais is absolutely right. ask yourself what feature set you need. If you're deciding between the pro and the dac, probably ADC is not important to you. then you should probably go for the dac version.

The numbers don't really matter for RME products. They are all superb already.

20 (edited by ramses 2021-06-24 08:38:55)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

My latest blog article might give you an idea, whether to choose DAC or Pro.

E.g.: getting ADI-2 DAC and then adding ADI-2 FS at any time later for getting analog inputs makes no sense.
The price of the ADI-2 FS is close to the price difference of DAC and Pro and the Pro delivers more features in one unit.

https://www.tonstudio-forum.de/blog/ind … ses-EN-DE/

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

21 (edited by khronik 2021-06-24 15:46:24)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Appreciate the replies guys. So it's a error in the manual after all?

If its in-fact a copy paste error, they only did so for the headphone THD section since if you compare the SNR Headphone specs between the PRO FS & PRO FS BE in the manual they don't match. Odd that they would modify the specs for some parameters but copy paste the THD section.

Eg.

Pro FS:
Signal to Noise ratio (SNR) @ +22 dBu: 117 dB RMS unweighted, 120 dBA
Signal to Noise ratio (SNR) @ +7 dBu: 114 dB RMS unweighted, 118 dBA
THD @ +18 dBu, 32 Ohm load, 1.2 Watt: -110 dB, 0.0003 %
THD+N @ + 18 dBu, 32 Ohm load: -107 dB, 0.00045 %
THD @ +14 dBu, 16 Ohm load, 0.94 Watt: -110 dB, 0.0003 %

Pro FS R:
Signal to Noise ratio (SNR) @ +22dBu: 120dB RMS unweighted, 123dBA
Signal to Noise ratio (SNR) @ +7dBu: 118dB RMS unweighted,121dBA
THD@ +18 dBu, 32 Ohm load, 1.2 Watt: -110dB, 0.0003%
THD+N@ + 18 dBu, 32 Ohm load: -107dB, 0.00045%
THD@ +14 dBu, 16 Ohm load, 0.94 Watt: -110dB, 0.0003%

I currently use a RME Raydat, ARC USB & a Ferrofish Pulse 16 for 16x AD/DA so I'm not lacking inputs (or outputs).

The plan is to compliment it with reference grade monitoring & high quality headphone amp instead of going with discrete components like passive volume control, separate headphone amp etc. I think it's a great solution.

The choice between PRO and DAC isn't as easy as it seems as I'm able to get the PRO FS R BE for approx. $390 US more. I'm using the Pulse to perform AD but there could be applications in the future where the AD of the PRO can be used to mix down off an analog console's master section as it's much higher spec'd than the AD of the Pulse unit. Having AES/EBU inputs on the Pro also work better with the Raydat but it's not a must. It's a bit overkill though to have 16 AD's from the Pulse to then get another 2 on the PRO, but for the price it's not bad to have.

I've used the non Black Edition ADI-2 Pro FS that ended up having shorted headphone outs and displaying a short error on the display. It also got extremely hot after an hour or two, so I'm a little concerned about the Pro's thermal design though I've read people that had this issue got replacement units that didn't fail afterwards.

I currently have both PRO FS R BE and DAC at the moment, just deciding which to open smile

Re: adi-2 dac fs specs vs adi-2 pro fs r be

>I've used the non Black Edition ADI-2 Pro FS that ended up having shorted headphone outs and displaying a short error on the display. It also got extremely hot after an hour or two, so I'm a little concerned about the Pro's thermal design though I've read people that had this issue got replacement units that didn't fail afterwards.

usually this means the unit is broken. I had the same issue and a replacement solved the issue.

23 (edited by KaiS 2021-07-04 17:35:03)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Here you can find the reason for the different specs of DAC and PRO version:
https://forum.rme-audio.de/viewtopic.ph … 60#p172860


Latest ADI-2 DAC now uses ESS's ES9028Q2M Chip, while the current ADI-2 Pro FS R Black Edition still “features” the AKM AK4493.

Re: adi-2 dac fs specs vs adi-2 pro fs r be

> Here you can find the reason for the different specs of DAC and PRO version:


The spec has not been updated yet. at the time of this writing, both the manual and the spec are still the same as before (the 4493 version).

25 (edited by ramses 2021-07-04 18:25:18)

Re: adi-2 dac fs specs vs adi-2 pro fs r be

ning wrote:

> Here you can find the reason for the different specs of DAC and PRO version:


The spec has not been updated yet. at the time of this writing, both the manual and the spec are still the same as before (the 4493 version).

Yes for me it looked the same when looking at the timestamps of the pdf files (manuals). I am getting them by WinWGet.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Well I guess it's time to wait for the new DAC manual to be posted online --- probably MC will surprise us again!

27

Re: adi-2 dac fs specs vs adi-2 pro fs r be

Here you go:

http://www.rme-audio.de/downloads/adi2dacr_e.pdf

http://www.rme-audio.de/downloads/adi2dacr_d.pdf

Regards
Matthias Carstens
RME