SMSL SU-9 Balanced DAC Review

[Gradius]

Thank you for your help, but I can read, no need to add bold characters.

You said "I guess.". It was just to clarify. Nothing more, nothing less.

But since you insist on the subject, my opinion is that 256 levels is just a peeing contest that is detrimental to user experience. Same as 5V output when everybody does 4V.

By NO means 4V is reference. Who say that?!

 

[Gradius]

It's the pro world. Everybody use 4V levels for XLR and 2V for RCA. The effect of a 5V output instead of 4V is that the volume control is 1/5th less accurate when wired to 99% of the amplifiers. Second effect is 1.5 dB better sinad at full volume. Which one of these two effects will be noticed by the user?

That's pretty wrong.

In real PRO World, balanced can go as far as +24 dBu which is 12.28 Vrms.

RCA interfaces operate at a maximum signal level of +8.2 dBu which is 2 Vrms.

24 - 8.2 = 15.8 dB higher (on the professional-grade balanced interface).

"If the noise is the same on both interfaces, the balanced interface will provide almost a 16 dB improvement in the interface SNR. But, balanced interfaces always require dual output buffers and dual input receivers. These additional active devices contribute some noise and this tends to reduce the SNR improvement by about 3 dB. Taking this into consideration, the interface SNR of a professional balanced interface is still about 13 dB better than that of an unbalanced consumer interface."

"Many high-end consumer products have balanced interfaces, but they operate at a maximum level of 4 Vrms which is +14.2 dBu (note: many = not all of them). This is 10 dB lower than the level used in professional interfaces. This means that the 13 dB advantage provided by a +24 dBu balanced interface is reduced to just 3 dB when operating at a maximum level of +14.2 dBu. Consumer-grade balanced interfaces are definitely a step better than unbalanced interfaces, but the signal levels are too low for use in very high perfomance systems."

"Many D/A converters are equipped with professional-grade +24 dBu outputs. These outputs have 10 dB passive pads that can be engaged in order to drive consumer-grade 4V balanced inputs. If you find you need these pads, it is a good indication that the downstream device is limiting the SNR performance of your system. Likewise, some AMPs has a gain setting that supports inputs from 4 Vrms consumer-grade balanced outputs. Again, these consumer-grade devices will be the weak link in the system."

As another example, the DAC 2.7 preamp from bel canto has 4.4Vrms for XLR, and 2.2Vrms for RCA:
http://belcantodesign.com/home/eone/dac-2-7/specs/

Source:
https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces

More infos:
https://en.wikipedia.org/wiki/Line_level

 

[JohnYang1997]

This does not seem to be as powerful (in terms of output) as Topping A90. Which one from among these would @JohnYang1997 recommend from among Topping A90 and SMSL SH-9?

SH-9 has ten times higher noise than A90.

 

[Gradius]

SH-9 has ten times higher noise than A90.

Well...

SH-9: $290
A90: $500

That means something too.

 

[JohnYang1997]

Well...

SH-9: $290
A90: $500

That means something too.

It's also 10 times higher than L30 and A50s. So.

 

[Gradius]

It's also 10 times higher than L30 and A50s. So.

L30: no XLR inputs, no 4.4mm XLR, etc, etc.

A50: same, no XLRs, etc.

So?

 

[JohnYang1997]

L30: no XLR inputs, no 4.4mm XLR, etc, etc.

A50: same, no XLRs, etc.

So?

So what? I was talking about noise performance. He didn't even mention price. What's your problem? A50s is true balanced out SH-9 isn't. So? And both are way cheaper.

 

[boXem]

That's pretty wrong.

Oviously it's wrong since you edited my message to make it wrong.
Me:

Yes, pro gear has much higher output levels. But pro amplifiers also have much higher input levels. It's the pro world.
Smsl gear is for home usage. Everybody use 4V levels for XLR and 2V for RCA.

You:

It's the pro world. Everybody use 4V levels for XLR and 2V for RCA.

How much time did you spend doing your research to prove how wrong I was? Was somebody paying you during this time?
Don't reply, I want to keep these mysteries intact.
This is beyond ridiculous. But thanks for the good laugh! I needed one this morning.

 

[Gradius]

Oviously it's wrong since you edited my message to make it wrong.

What you are even talking about? Are you for real? Show me where I did that.

No, I didn't spent not even 2 seconds, as I already knew the answer... thank you.

 

[Gradius]

So what? I was talking about noise performance. He didn't even mention price. What's your problem? A50s is true balanced out SH-9 isn't. So? And both are way cheaper.

You didn't got it.

What I mean is you need to do some sacrifice if you want quality.

Either you cut some features, input/output, or go pricely.

 

[boXem]

Show me where I did that.

I already did it. You obviously cant't read. I will let you win the internet, have a nice day!

 

[Gradius]

I already did it. You obviously cant't read. I will let you win the internet, have a nice day!

Yeah, sure, whatever you say.

 

[bgtip]

So what? I was talking about noise performance. He didn't even mention price. What's your problem? A50s is true balanced out SH-9 isn't. So? And both are way cheaper.

Thank you for your remark. You saved me from a huge blunder. I was about to preorder SH-9 to stack with my SU-9, but then I saw SH-9 is not true balanced, and this is a deal breaker for me. It seems a little misleading from SMSL to advertise SH-9 as 'Balanced Headphone Amplifier'.

 

[Gradius]

Thank you for your remark. You saved me from a huge blunder. I was about to preorder SH-9 to stack with my SU-9, but then I saw SH-9 is not true balanced, and this is a deal breaker for me. It seems a little misleading from SMSL to advertise SH-9 as 'Balanced Headphone Amplifier'.

That decision was probably made to keep the costs down.

Pretty dumb (IMHO), having SU-9 balanced out, while the matching pair (SH-9), not.

 

[ZgSTar]

Hey Guys, after lots of thinking I decided it's time I spend more money...

I currently have an RME ADI-2 DAC v2 with my AHB2 to B&W 702s2 and I am extremely happy however I have a second setup at home (yes, my primary setup is in the office where I also have the room treated nicely) which currently has a Chord Hugo2 (this was before ASR times...) going into an Audiophonics Purify S400ET off to some PMC Twenty5.23.

I still like the Hugo2 but I am using it purely as a desktop amp since I bought an e1da 9038s v3 (which I use with great satisfaction mainly with Etymotic er2xr), so I will most likely sell it shortly (from Europe).

In both cases, I am not using any preamp which is where I would like a bit of advice. I am thinking of moving the RME at home to pair it with the purify and enjoy also the very good headphone out and buying another DAC for the main setup in the office. The SU-9 seems like a very interesting solution (also looking at the M500 v2 or today's newly reviewed Gustard X16) however I am a bit puzzled about the output voltages and what is the best option because of output voltage and amplifier gain settings.

I am able to listen to loud volumes with the AHB2 on low gain and RME ADI-2 DAC on auto ref which should always maximize sinad and I am afraid that with the SU-9 I will be forced to go to medium gain settings thus losing a few DBS.

I realize that I can put a preamp in the mix and always feed the AHB2 (or the purify in opamp bypass mode) with 9V but isn't the preamp going to have a negative influence on the overall SINAD anyways?

All of this to ask the following within context: 1. Preamp between SU-9 and AHB2 yes or no? 2. I've read somewhere on the forum (but can't find anymore) that the DAC should always be at least a certain number of DBs better than the amplifier to get max performances, this is the main driver in this switch, do you remember this number and maybe have a link to a post with the explanation?

Of course, I do realize that we are talking at minimal, and most likely inaudible, differences but in my audiophile journey, I learned that what measures better, do sound better to my hears so why sacrifice even 2 or 3 DBS when you can avoid it?

Yes, I know... I should stop the nonsense and just enjoy the music but I am a geek with a strong tech background, nothing can save me.

Last but not least, if you believe my logic is flawed and that I a missing some background knowledge I would be really glad if you can point me in the right direction so that I can study and fill my knowledge gaps. Any comments on the above are really welcome.

Thank you very much for the time you spent reading this. Truly appreciate it.
Z.

 

[Gradius]

Hi ZgSTar,

A little long post, so I will not make a quote of it.

I'll comment the preamp part, AFAIK you don't need to add a preamp on today's DACs, as they already have volume control.

More:

Worth noting:
https://audiophilereview.com/amps/to-preamp-or-not-preamp-that-is-the-question/
https://audiophilestyle.com/forums/topic/58263-differences-in-sound-dac-vs-dac-pre-amplifier/

As for DAC, either SU-9/M500v2/X-16 alternative would be more than enough.

Keep in mind adding preamp will add the costs too, as it needs to be of good quality.

 

[Gradius]

Another video worth watching:

 

[ZgSTar]

Thank you Gradius. I really appreciate the effort. My question was more specific to input voltages and understanding what would be the best path to maximize every dB an ahb2 had to offer. As per the Ps audio posts and videos, I have seen the videos and enjoyed them, this is exactly the stuff that would have got me extremely excited pre-asr times. I am pretty sure that tube preamp is well done and will have an impact on the sound which is likely to be very enjoyable but by introducing distortions and removing information that might make things sound more 'natural'.

My philosophy of hifi is that I am where I want to be when I hear exactly what the audio engineer who has mixed and mastered heard when thought: yes, this is the final version.
I do however now want a good tube pre to spice things up when I feel like it.

Going back to my original question I am trying to understand if putting a good pre that would take the 4v and Amplify it to 9v before it enters the ahb2 so that I can be kept at low gain is going to give me a few more DBs of 'transparency'. I am doubtful however because the opamps internally are likely to be doing this in a cleaner way.

 

[Juan Francisco]

Not a stupid question.

If it’s the same as my SU-8 v2, then “fixed” is just “Max” volume, which is actually 38.. I run mine balanced into a Classe CAP-151 integrated with great results. Volume control and balance is controlled by the integrated.

What a coincidence! I have the same equipment as you: SU-8 v2 attached to a Classé CAP-151 (balanced, just the reason why I bought the Classé) ... And wondering the same: whether upgrade or not to a SU-9

 

[Gkhercules]

I have the project pre box s2 digital DAC, is the su-9 a big upgrade. Thinking about purchasing this the M400 or topping D90 but not sure the extra cash is worth it. Looking to move toma balanced DAC. Any advice is much appreciated. Thanks.