• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

SMSL SU-8 Version 2 Balanced DAC

rajapruk

Senior Member
Forum Donor
Joined
Sep 22, 2018
Messages
472
Likes
489
Can someone explain why harmonic distortion sounds "warm" (if this is true)? Should it not sound brighter than without it? I mean distortions/sounds are added higher up in the frequency range so to speak, not lower down, right?
 

badyard

Member
Joined
Oct 18, 2018
Messages
84
Likes
75
Like? They emit noise/hum and "warm" the signal via harmonic distortion. that's it, nothing supra-scientific going on here....

If you were to say it's difficult to "map" this effect via digital processing, yes you might have a point. But trying the $199 TwinTube VST myself as an example, I have created presets that come VERY close, without any humming noise whatsoever, just the warm/gooey harmonics sound. I far prefer this approach, and don't have to spend $500-$1000 on a 'good' tube amp....
Yeah I also own TwinTube VST, but obviously we are not talking about that since that VST does something else to the sound under the hood in order to mimics tubes, we are talking about the DAC sound profiles which are just mere non-linear harmonics.
Twin Tube probably does distort these harmonics dynamically with the saturation knob and also sort of "multiband" compress the sound, im guessing..
 

Veri

Master Contributor
Joined
Feb 6, 2018
Messages
9,596
Likes
12,036
Can someone explain why harmonic distortion sounds "warm" (if this is true)? Should it not sound brighter than without it? I mean distortions/sounds are added higher up in the frequency range so to speak, not lower down, right?
A little of both. It adds distortion which can sound brighter/more fatiguing. It also can come with roll-off that can dampen some high frequency content.
 

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
4,600
Likes
3,065
Location
Zg, Cro
Can someone explain why harmonic distortion sounds "warm" (if this is true)? Should it not sound brighter than without it? I mean distortions/sounds are added higher up in the frequency range so to speak, not lower down, right?

It doesn't necessarily sound "warm". Folks usually describe it as "warm" when dominant added harmonics are even, like with tube equipment. With odd harmonics it is usually described as "harsh". And yes, generally it does sound brighter for the reason you stated.
 

badyard

Member
Joined
Oct 18, 2018
Messages
84
Likes
75
It doesn't necessarily sound "warm". Folks usually describe it as "warm" when dominant added harmonics are even, like with tube equipment. With odd harmonics it is usually described as "harsh". And yes, generally it does sound brighter for the reason you stated.
However is to mention that these sound profiles don't necessarily add the same amount of harmonics across the whole spectrum.
 
Last edited:

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
4,600
Likes
3,065
Location
Zg, Cro
However is to mention that these sound profiles don't necessarily add the same amount of harmonics across the whole spectrum.

So what? THD also isn't spread equally across the spectrum. Higher harminics are always of lower amplitude and eventually they got burried in the noise floor.
 

badyard

Member
Joined
Oct 18, 2018
Messages
84
Likes
75
So what? THD also isn't spread equally across the spectrum. Higher harminics are always of lower amplitude and eventually they got burried in the noise floor.
I mean they are subdivided in bands sort of in a multiband harmonic exciter fashion, if you take the time to test it with a spectrum analyzer you can see, some profiles are adding more harmonics to the low region of the spectrum etc.
 

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
4,600
Likes
3,065
Location
Zg, Cro
I mean they are subdivided in bands sort of in a multiband harmonic exciter fashion, if you take the time to test it with a spectrum analyzer you can see, some profiles are adding more harmonics to the low region of the spectrum etc.

Yes, we agree on that. :)
 

badyard

Member
Joined
Oct 18, 2018
Messages
84
Likes
75
Yes, we agree on that. :)
Actually I've tested them now, more carefully than last time, using a slow sine sweep they actually are adding the same amount of harmonics across the spectrum.
With the exception of "Crystal 1" and "Original" which they oddly don't seem to add much.
So yeah, I was wrong in the fact that they were acting in a multiband fashion! My apologies.
 

Nabobalis

Member
Joined
Feb 11, 2019
Messages
7
Likes
0
So in summary, it would be tube-like but if I wanted to see what a tube amp could do, I should get a tube amp?
 

Veri

Master Contributor
Joined
Feb 6, 2018
Messages
9,596
Likes
12,036
So in summary, it would be tube-like but if I wanted to see what a tube amp could do, I should get a tube amp?
If you want to buy one, regret and it sell it again :D

No I'm kidding but I do believe tubes only work with few select headphones..
 

Nabobalis

Member
Joined
Feb 11, 2019
Messages
7
Likes
0
If you want to buy one, regret and it sell it again :D

No I'm kidding but I do believe tubes only work with few select headphones..

Yeah the reason I ask is that I have a pair of HD 6XX and I heard they sound great with a tube amp.
But I have an atom amp on the way and thought why not see if I can find a DAC to change the sound profile.
 

Veri

Master Contributor
Joined
Feb 6, 2018
Messages
9,596
Likes
12,036
Yeah the reason I ask is that I have a pair of HD 6XX and I heard they sound great with a tube amp.
But I have an atom amp on the way and thought why not see if I can find a DAC to change the sound profile.

You could try one of the xDuoo or something like an SMSL T1, with line out to Atom. The Musical Paradice mp-301 is probably a 'little' too expensive :D
 

frogmeat69

Addicted to Fun and Learning
Forum Donor
Joined
Apr 25, 2018
Messages
951
Likes
1,710
Location
Western New York, USA
If you want to buy one, regret and it sell it again :D

No I'm kidding but I do believe tubes only work with few select headphones..
I have a Little Dot Mk III amp with some older Mullard tubes, it makes the Sennheiser HD700 cans tolerable, lol. The HD650 and 600 do seem to sound good through it, but I ain't saying it's fact, because I don't have your ears, only mine, :D.
 

Ultrasonic

Addicted to Fun and Learning
Joined
Dec 30, 2018
Messages
742
Likes
593
Location
UK
So in summary, it would be tube-like but if I wanted to see what a tube amp could do, I should get a tube amp?

Given that headphones are inherently portable, can you not take them to a shop somewhere with a tube amp to try?

I've never never owned any tubes myself, although I have heard some at shows and once at someone else's home. Consequently I've not looked into them much but I wonder if a distinction should be made between tube pre-amps and power amps? Or in your case pre-amps vs amps driving headphones. Just a thought.

A different thought: I've not looked but I'd guess there are software implementations of adding the sort of harmonic distortion that the SU-8 does? If there are you could have a play with this instead, for free I'd expect. Ultimately I'd go back to taking your headphones to a tube amp though.
 

yapst38

Member
Joined
Feb 17, 2019
Messages
12
Likes
2
Hi all owners of smsl su8. Would appreciate if anyone can recommend any good place to buy this unit with the latest version. Tks.
 

richpjr

Member
Joined
Dec 29, 2018
Messages
67
Likes
47
Hi all owners of smsl su8. Would appreciate if anyone can recommend any good place to buy this unit with the latest version. Tks.

I bought it on Amazon a couple of weeks ago and got the latest version.
 

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
4,600
Likes
3,065
Location
Zg, Cro
So in summary, it would be tube-like but if I wanted to see what a tube amp could do, I should get a tube amp?

Don't bother, I have pretty decent tube amp (50W in class A) and can tell it apart from my Rotel amp only if I switch amps very quickly. The difference I hear is not that tube amp sounds "warmer" but that Rotel sounds brighter probably because of its more linear HF response.

Ok, maybe it does sound a little "warmer" after I let it to heat up for at least 45 min but the difference is really subtle. :p
 

Pulkass

Active Member
Joined
Feb 17, 2019
Messages
275
Likes
59
This is an update to my previous review of SMSL SU-8. At a retail price of USD $212 on Amazon and balanced outputs, the SU-8 could provide a very compelling proposition. Unfortunately the performance of the balanced output in my first review sample was disappointing, showing significant switching noise. SMSL was kind enough to send me a second unit recently and I put it to test.

There is no functionality difference so see the previous review for details of that. Briefly here, you get a nice looking unit with a tiny display and remote control:

[the 44.1 kHz on the display is not showing all the way due to my camera shutter not being in sync with its refresh rate.]

Let's get into measurements and see how she performs.

Measurements
Let's start with our unbalanced dashboard:
View attachment 18140

This is some 8 dB improvement in SINAD/distortion relative to original review sample! Let's see how our previously problematic balanced output performs:
View attachment 18134

Nice! As I show in the inset, SINAD used to be just 87 dB but now is a whopping 110 on average! This puts the unit in the upper echelon of DACs tested: [click on chart for larger size]
View attachment 18135


We can clearly see the reason in sweep of distortion versus frequency:

View attachment 18136

Good news translates into intermodulation distortion too:
View attachment 18137

There is no saturation as the levels go up to maximum as we had before.

Jitter was good before but we still see some improvements:

View attachment 18138

Low level linearity remains the same though:
View attachment 18139

Balanced (red) is near excellent. Unbalanced especially in one channel falls short though (still transparent though for CD rate music).

Conclusions
I must say, I did not have any expectation of improvements and I was pleasantly surprised. Looks like SMSL went on hunting for sources of distortion and noise and annihilated just about all of them! This is proof that better design can be had without any cost premium. The unit sells for even less now than it did then, yet its performance -- especially in balanced mode -- has massively improved. It has gone from "nearly broken" to "nearly state-of-the-art."

I am a big fan of balanced interconnects to break nasty ground loops that can be hard to deal with when you string a PC, DAC and amp together. If you look at the balanced dashboard and compare it to unbalance, you see complete absence of any mains leakage/tones. This is the power of balanced. With advent of high-performance balanced headphone amps like the Massdrop THX AAA 789, there is even more of a requirement in my mind for balanced output DACs. And here we have one great option.

Needless to say, I am happy to recommend the SMSL SU-8 for both its functionality and performance. Great to see them focus on performance clean up the design of previous version.

I understand there is a sale going on on Massdrop for a couple of days more. I would jump on it if you are in the market for such a DAC.
Has it got 2 Dac chips??? Ess 9038 ? True Balanced circuitry?? Thanks
 
Top Bottom