Topping D90 Balanced USB DAC Review

[wineandmusic]

If anyone has a D90 for sale please let me know. Oh, and it works well with a streamer such as the Allo?

Just curious, why not consider buying a Gustard A18 new for less? (on sale now for $505 and you can ask APOS.audio (us based company) to match price).

Many suggest that dacs that measure well will sound the same. The A18 is lowest price that measures well, has a linear ps, and balanced outputs....not sure you would be able to tell any difference between the a18 and d90 in an abx test.

 

[jtwrace]

Just curious, why not consider buying a Gustard A18 new for less? (on sale now for $505 and you can ask APOS.audio (us based company) to match price).

Many suggest that dacs that measure well will sound the same. The A18 is lowest price that measures well, has a linear ps, and balanced outputs....not sure you would be able to tell any difference between the a18 and d90 in an abx test.

I'll check it out...I don't keep up with every one. I have something pretty good so I've been content. Thanks for the recommendation!

 

[Cut-Throat]

How is it not a dac?

I never asked about a streamer...I asked specifically if the D90 would work with a Streamer such as the Allo.

Wait.... You said you never asked about a streamer...... Then you asked if the D90 would work with a Streamer like the Allo? Sounds to me like you asked about a Streamer....

So Obviously you are quite confused. --- It seems you have some kind of weird sub standard DAC..... Here is what you need to know... Any Good DAC such as the D90 will be able to process ANY Digital output from any Streamer, CD etc. --- without a problem.

 

[Pluto]

I've heard bad things about attenuators making the sound seem dull or "strangled" or damaging the frequency response.

Is that all nonsense from the snake oil peddlers?

The origin of those tales lies, almost certainly, in the fact that attenuators are employed to deal with overload situations (which is, of course, their primary purpose) and the result of removing an overload is a drastic reduction in all manner of distortion products that occur as a direct result of that overload.

Whether you prefer the sonic mess that an overload entails is yours to call, but that's the reasoning behind that particular old wives’ tale.

 

[Chippyboy]

The origin of those tales lies, almost certainly, in the fact that attenuators are employed to deal with overload situations (which is, of course, their primary purpose) and the result of removing an overload is a drastic reduction in all manner of distortion products that occur as a direct result of that overload.

Whether you prefer the sonic mess that an overload entails is yours to call, but that's the reasoning behind that particular old wives’ tale.

Thanks - I suspected as much.

I wonder if I am more missing something though? (I suspect I am not). All the tests on here seem to be done with an output voltage of circa 4v. Whilst the DAC is feeding a preamp or headphone amp with its own volume control that may be all well and good. But surely that's not the normal use-case? Won't most people will be using the DAC to drive their power amps or headphones directly - or else why would all these DACs have volume knobs and headphone outputs?

So the 4v test scenario is entirely unrepresentative of normal listening conditions. A DAC may achieve a very good SINAD measurement of say 110db but only at a volume setting which may never be used.

In real life, maximum (damned loud) volume might be a good 10 or 15 dB quieter and normal listening maybe another -15 dB quieter still. So the SINAD at normal listening levels could be perhaps more like 80 dB?

So a DAC such as the RME ADI-2 DAC with its adjustable reference output level, whilst not topping the charts at 4V output, could very well be significantly better than other DACs which need to be turned down by -30dB for normal listening?

What puzzles me is why is none of this mentioned in the reviews? And why do the other DAC manufacturers not incorporate similar output attenuators?

As I say, perhaps I am missing something?

 

[ReaderZ]

Thanks - I suspected as much.

I wonder if I am more missing something though? (I suspect I am not). All the tests on here seem to be done with an output voltage of circa 4v. Whilst the DAC is feeding a preamp or headphone amp with its own volume control that may be all well and good. But surely that's not the normal use-case? Won't most people will be using the DAC to drive their power amps or headphones directly - or else why would all these DACs have volume knobs and headphone outputs?

So the 4v test scenario is entirely unrepresentative of normal listening conditions. A DAC may achieve a very good SINAD measurement of say 110db but only at a volume setting which may never be used.

In real life, maximum (damned loud) volume might be a good 10 or 15 dB quieter and normal listening maybe another -15 dB quieter still. So the SINAD at normal listening levels could be perhaps more like 80 dB?

So a DAC such as the RME ADI-2 DAC with its adjustable reference output level, whilst not topping the charts at 4V output, could very well be significantly better than other DACs which need to be turned down by -30dB for normal listening?

What puzzles me is why is none of this mentioned in the reviews? And why do the other DAC manufacturers not incorporate similar output attenuators?

As I say, perhaps I am missing something?

How do you think RME adjust it's reference output level? It will be the same digital volume control. Also unless something really broken, SINAD won't go down to something like 80db more like 100-110, some of the reviews here has that information.

 

[Veri]

How do you think RME adjust it's reference output level? It will be the same digital volume control. Also unless something really broken, SINAD won't go down to something like 80db more like 100-110, some of the reviews here has that information.

RME does have a pretty unique approach though. It's not the same as digital volume.

 

[Chippyboy]

How do you think RME adjust it's reference output level? It will be the same digital volume control. Also unless something really broken, SINAD won't go down to something like 80db more like 100-110, some of the reviews here has that information.

You are mistaken about the RME ADI-2.

It has several attenuators which are switched in and out with relays, thereby maintaining the full DAC resolution even at reduced volume.

The benchmark DACs have similar with jumpered attenuators. And of course an analogue pot on the earlier HDR model.

Seems odd to me that two very highly respected manufacturers in the studio space would bother with this if there was no point.

Edit: And FYI my stupidly powerful amps (silly overkill on my part) have 27db of gain and sensivity of 2.95v. Rated power output is 1125w per channel of which I need perhaps 5w for normal listening. So that's -23.5 dB for a start. Add another 3dB or so for the input sensitivity being 2.95v and the DAC nominal maximum output of say 6v and there you have 27dB of SINAD down the pan.

I accept mine may be an outlier case caused by me buying stupidly powerful amps. But the point stands.

 

[VintageFlanker]

As I say, perhaps I am missing something?

Yes: Ref Levels.

RME does have a pretty unique approach though. It's not the same as digital volume.

What @Chippyboy said.
In fact, it's digital volume control + 4 analogue stages.

 

[ReaderZ]

RME does have a pretty unique approach though. It's not the same as digital volume.

I stand corrected then. But how? And how do we know that does not affect performance?

Edit: still want to know more detail about this analog control but on its website I found it does affect performance, at least for SNR.

 

[Veri]

I stand corrected then. But how? And how do we know that does not affect performance?

Edit: still want to know more detail about this analog control but on its website I found it does affect performance, at least for SNR.

See this post here for some measurements from MC_RME himself
https://www.audiosciencereview.com/...ac-and-headphone-amp-review.13379/post-401802

The benefits of this Auto Ref setting are quite clear when you compare On and Off. One could argue that it won't matter (audibly) at these high levels of performance but at the very least you can safely conclude it's definitely not hurting anything. On the contrary.. it's solid engineering.

 

[ReaderZ]

See this post here for some measurements from MC_RME himself
https://www.audiosciencereview.com/...ac-and-headphone-amp-review.13379/post-401802

The benefits of this Auto Ref setting are quite clear when you compare On and Off. One could argue that it won't matter (audibly) at these high levels of performance but at the very least you can safely conclude it's definitely not hurting anything. On the contrary.. it's solid engineering.

Thanks for the link. That's very nice indeed. Although I do like to rise that M400 hit the same number at 1V without this feature on XLR and 2V RCA is 118.5.

https://www.audiosciencereview.com/.../smsl-m400-balanced-usb-mqa-dac-review.13732/

 

[Veri]

Thanks for the link. That's very nice indeed. Although I do like to rise that M400 hit the same number at 1V without this feature on XLR and 2V RCA is 118.5.

https://www.audiosciencereview.com/.../smsl-m400-balanced-usb-mqa-dac-review.13732/

The positive on the RME is that you can lower/raise the output to whatever you need and the SINAD/distortion will essentially still be optimal, ~114 SINAD 1v, ~112 SINAD 0.5v etc. Quite impressive, especially AK4493/ If you use full output, yes, current output DAC like AK4499 at max output should measure quite favourably. The RME is first and foremost a production workhouse that can do all kinds of stuff w/ tons of features

 

[Pluto]

…about the RME ADI-2.

It has several attenuators which are switched in and out with relays, thereby maintaining the full DAC resolution even at reduced volume

And the difference between the above attenuators and the placement of in-line XLR attenuators in the output of a highly competent but cheaper unit is?

 

[Pluto]

Before anybody chimes in, I fully appreciate that having relays doing a lot of switching can assist in keeping whatever ‘damage’ a digital volume control might be doing, to an absolute minimum but if you are faced with a situation in which a power amp is clearly being fed with about 20dB too much wallop when the digital volume control is at a sensible position, then the obvious answer is to use an inline attenuator of -10dB to -20dB!

 

[AudioQuality777]

Why use XLR on ADI2 is unclear. It seems that there is no correct XLR output but a normal imitation! Actually, as it was written in the reviews, there is no difference in the sound quality between XLR & RCA on ADI2. Especially if you set the same volume on both outputs.

 

[Chippyboy]

And the difference between the above attenuators and the placement of in-line XLR attenuators in the output of a highly competent but cheaper unit is?

I dunno - that's why I asked ;-)

 

[Pluto]

I dunno - that's why I asked ;-)

Answer – nothing!

Well it's worth reading #1836 as it explains that there is possible merit in using a mixture of digital and analogue attenuation if the designer feels that the ‘damage’ caused by the digital attenuation is going to be unacceptable. At what level of attenuation does this occur? That's a tricky one; I would find yourself a DAC designer who uses this approach and ask him.

Despite the attractions of analogue attenuation, a good analogue knob is expensive and, even then, getting the two channels to track over more than half the range of the knob, within 1dB or better, is tricky. With digital attenuation this is simply not an issue. But the introduction of inline attenuators, made from high precision fixed resistors, the attenuation will match to within a very small amount without any of the practical problems associated with the use of potentiometers.

So to get back to your original point – if you have the straightforward problem that the DAC output is 10dB too hot for your power amp. (i.e. you are consistently on a knob setting below -30dB) either reduce the gain of the power amp or use a 10dB inline XLR attenuator.

 

[Chippyboy]

BTW, does anyone know if there is any physical difference between the D90 MQA and non-MQA versions? I am guessing the extra $100 is to cover the MQA license and that the units are otherwise identical? i.e. maybe you could flash the MQA version firmware on a non-MQA unit and save yourself a few quid? Might that work?

 

[Chippyboy]

Answer – nothing!

Well it's worth reading #1836 as it explains that there is possible merit in using a mixture of digital and analogue attenuation if the designer feels that the ‘damage’ caused by the digital attenuation is going to be unacceptable. At what level of attenuation does this occur? That's a tricky one; I would find yourself a DAC designer who uses this approach and ask him.

But to get back to your original point – if you have the straightforward problem that the DAC output is 10dB too hot for your power amp. (i.e. you are consistently on a knob setting below -30dB) either reduce the gain of the power amp or use a 10dB inline XLR attenuator.

To be clear, this a non-issue at the moment since my ADI-2 DAC handles it all perfectly. The question arises since I am considering swapping it to my office and replacing it in the living room with something else, like a D90. And I don't want the sound quality to be going backwards! And I don't want the D90 in the office because it has no ****ing volume knob! I cannot be fiddling around with buttons or trying to find the remote when the phone goes. It needs a volume knob!