You could try to calculate it like I did.
https://forum.rme-audio.de/viewtopic.ph … 24#p155724

Thanks for your suggestion. I followed the suggestion ramses' and  calculated the ref and volum level
.

> Ref Level 13dBu (+7dBu on XLR output)

I do not understand what you mean by " (+7dBu on XLR output)".
If you set the Ref Level to +13 dBu, then you have 13 dBu on the XLR outputs, when Volume is at 0.
On the Cinch outputs you have always 6 dB less, like described in the manual.

BTW, when doing the calculations, pls also read KaiS's comment:
https://forum.rme-audio.de/viewtopic.ph … 5#p157735:
"This way there are some few dB headroom for the amp's input electronics. Soundwise it's usually better not to drive electronics very close to clipping."

@KaiS: question: wondering whether a Ref Level of +7 dBu is maybe a little too low ?
The difference between 11,5 and 7 dBu (2,91 and 1,73Vrms) appears to me quite high.
Is such a high threshold really required ?

BTW .. the other similar thread is maybe also interesting for you
https://forum.rme-audio.de/viewtopic.php?id=31285

Hi SamdDark,

I think what he means is that if you are using XLR outputs from the RME DAC then it will automatically be +6 to whatever setting you have it on. For example, it will say +13dbu on your RME screen but in reality will be +19.

I've been playing around with my RME DAC using XLR output. I'm using it as a DAC only, not a preamp, but found that +7dbu and auto reference on gives me the best sound with the best dynamic range. It also lets me use the loudness feature which is very cool. The volume on the RME DAC seems to veer between -3 and -8, depending on the source. I tried using volume locked at 0 but found this decreased dynamic range on my system.

Once you've got these basics out of the way, I encourage you to start trying the EQ. I mostly use the SD SHARP filter but sometimes change to SD SLOW and, with the help of a forum, managed to change the EQ so the SD SLOW didn't have so much treble roll off. I'm very happy to have both sound options at my fingertips.

@ramses: some confusion here. If you set +13 dBu (visible in the display) you get +19 dBu at the XLR output. The DAC does not have a +19 dBu setting in the display. The RCA is not 6 dB less than this setting, the XLR is 6 dB +.

@Ramses:
You're right, the manual should more clearly state how the figures shown in the devices are connected to the real output levels.
Specially as the 6dB difference XLR to RCA (6.3mm on Pro) is handled different on both ADIs.

In general:
People here tend to determin their optimum levels from reading factory specs.

That's a mistake, as these specs aren't reliable (outside RME) and doing so based on theoretical values is prone to errors too, as we could see here.

How to reliably find the optimum level:

• Get youself a test signal, sinewave 400 or 1kHz, digital full scale "0 dBfs", from the internet, test CD, App or any other source, e.g.:

https://archiv.rme-audio.de/old/download/0_16.zip

• Run it to your system, dial up the ADI level until audible distortion appears.
Note down this clean reference level.

• Then dial back few dB's, as audio electronic likes a bit of headroom to work best.

Every other method is guesswork at best and no engineer in the world would skip that test.

With a sinewave the slightest bit of distortion caused by hard clipping becomes immediately obvious.

With music clipping distortions are covered by the music contained overtones.
Even worse, lots of contemporary masters are hard-clipped to stupidly squeeze out the last bit of loudness.

It is wide spread HiFi standard that everything relates to RCA, and the XLR just give 6 dB higher level. That's why we did that in the ADI-2 DAC as well.

It means you are feeding up to ~3.46 volts (RMS) or +13dBu via the XLR outs.

If you want to be sure you don't distort your amp with any music, you need to reduce that by ~1.5dBu.

A reference level of +7 (on the front of the ADI-2 DAC, which really means +13 balanced) needs to be at -1.5 dBr to stay below 3 volts.

To keep your amp's input happy (max 3 volts):

3 VRMS
3000 mVRMS
9.542425094393248 dBV
11.760912582051235 dBu
8.485281374238571 VPP

That's the maximum dBu you can feed it. You're giving it 13, so reducing it by 1.5 dBr gets you to 11.5 dBu or 2.9112240182327254 VRMS.

"Hervorragend". Many thanks @KaiS @Luckbad for your detailed answers. Now I get the relation between Ref Level and Volume level.

My next questions are about SNR.

From ADI-2 DAC Specs:

does this mean that the SNR is 120 dB if Ref Level for example @ +13dBu and volume @ 0dB?

If I set my Ref Level @ +13dBu and Volume@ -4.5dB, the effective SNR at XLR output should be 120 dB - 4.5 dB = 115.5 dB. Is this correct?

wouldn't the sound quality and dynamic range be better, if I'd set the Ref Level @ +7dBu and the volume @ 0 dB to get the highest SNR?

After reading all of your suggestions and explanations, especially the one from @KaiS, I came to the conclusion that I don't intend to overfeed my amp with voltage, but I want to have a better sound quality and less distortion.

There is another point which is not clear to me. I have noticed when I turn the auto ref on, the dac shows dBr instead of dB when i dial the volume knob. @Luckbad had mentioned this also in his post. What is this? dB relative to what?

From @Luckbad:

I look forward to hearing from you and learn further.

Many thanks in advance

The ADI-2 DAC is 24bit and has a resolution of 144dB.
So distortion is a non-issue.

If you don't hear noise, noise a non-issue too.

What remains are distortions at the upper end of the dynamic range from electronics struggling to squeeze out (literally, NFB does) the last dBs before clipping.
Not in the ADI-2, it's constructed with some headroom, but in the following amp.

In the studio, in favour of a cleaner sound, we tend to use a bit lower levels on critical signals like hihats, cymbals and other percussive instruments.

Classical orchestral music recordings are produced with a dynamic range (ppp to fff) of about 30dB at max.
Chamber music much less.
More is considered as unlistenable, as you either won't hear the ppp, or the fff will blow you out of your seat.
This is not a technical decision, but an artistic by the conductor's, BTW, and it's almost the same in the concert hall.

Comming back to your case, you can even go for Reference Level +1dBu and Volume 0dB.
You gain 1.5dB SNR relative to +7dBu/-4.5dB.

With Auto-Reference level the Vol. display's "dBr"-value is referenced to the max. possible undistorted level.
The value is the result of a calculation that even takes into account EQ and other DSP-funktions - clever, isn't it!?

Don't worry about the numbers, people are sometimes overly picky on these without gaining much, practically.

Out of the box ADI-2 is already configured to fit most setups automatically, plug and play.
There's some automatism built in, regarding input switching and levels.

Use the Cinch connection with the Feliks Elise, the XLR with the Topping A90.
Set both volumes to a middle position and let ADI-2 do the rest, listen to music.

Once you become more familiar with your ADI-2 you can dig deeper.
The manual is comprehensive.

Loudness, BTW, needs to be activated and adjusted to your listening level, see:
https://forum.rme-audio.de/viewtopic.ph … 83#p157883

Yes.
Might be you need to switch it on.

Many thanks @KaiS @ramses. You guys are great.  With your Info/explanations + the manual, I have decided to config ADI-2 DAC as follow:

Ref Level @ +7 dBu (+1 dBu for XLR Connection)
Volume Level @ 0 dB

This will feed 1.734v to my Headphone amp. If I want to hear my music louder, I should just turn the volume knob on my headphone amp. Next step is to play around with EQ.

I am enjoying the ADI-2 DAC and learning along.
RME Community rocks.

Best regards,
sam

@KaiS Thanks a lot !

Either does work.

Depending on the configuration I do use one or the other.

ADI-2 has such a high quality margin and clever construction that you can dial down the Volume Control by 30dB and more with no negative effects.

Using ADI-2's Volume Control to set the listening level is mandatory for the Loudness function.

BTW: If you use ADI-2's Volume Control for setting the listening level, leave the "Auto Reference Level" function on.
It automaticalliy optimizes ADI-2's dynamic range.

A little hint:
When I do use external amplifiers, while using ADI-2 to control the listening level, I set the ext. amp's volume dial to get the equal level like from ADI-2's headphones output.
Kind of a "Unity-Gain"- approach from studio work.

I can plug headphones in one or the other without changing the Vol setting.

You know the difference between preamp, power-amp, integrated amp, which contains preamp and power-amp ?

You can use the ADI-2 * to connect it either as DAC to a preamp or integrated amp or
you use it as a complete DAC/preamp in front of a power-amp.

Is this a question ? If yes, what question ?

Sorry, but this is easy to find out by simply reading a few product descriptions:

Topping A90 is a preamp for amplifier and phones.

Feliks elise seems to be a preamp for phones. BTW .. in one review I found this remark: Cons: Not very powerful, not suitable for planar-magnetic headphones, high output impedance

IMHO ... get the ADI-2 DAC and you do not need any of these two.

To make it simple, IMO, if somebody owns ADI-2 DAC, no other device is needed to enjoy the music. In my case, I owned my balanced amp, before I bought the ADI-2 DAC. Being some kind of headphone collector, I use my balanced amp only  for my balanced headphones, for all other headphones, I only use ADI-2 and nothing more. I am just blown away by how clean and joyful it sounds. The IEM input has surprised me the most. I recommend, if it's possible, pairing it with Beyerdynamic  dt 1990 pro. Just plug your headphone, turn the dac on and  enjoy your music.

Happy listening. It gave me a reason to go through my music collection again.

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