Review and Measurements of SMSL SU-8 DAC

[FalFung]

Hi @Toku ! I also owned an SU-8. To my knowledge, the "fade-in" effect happens when the steaming format (PCM change to DSD, or vise versa) or sampling rate (44.1 KHz to 192 KHz ) changes.

Thank you @amirm for the detailed review! I definitely love this tiny silver box a lot. It does sound good!

I am interested in what the volume setting on this DAC (min,1 - 37, max) would match about -7.5 dB gain level. I want to do this for the balance output. It would also be great if we could know the RMS level on balanced output in -7.5 dB gain level. I know @amirm you do not have a unit on hand. Is there a way to calculate the RMS level on balanced output in -7.5 dB level mathematically?

For me personally, I cannot hear the output stage saturating (clipping) even in 0 dB gain level in my normal usage. I use it to feed in my Stax Driver and SR-L700 headphone. So I am interested: in theory, for the saturating level from measurement, how obvious should the saturation be like? Is there any way I can hear/sense its effect?

 

[amirm]

Hi there. Welcome to the forum and thanks for the kind words. As to your question, the volume steps are not standardized so I don't know how we can compute anything based on that. If you have an RMS reading multimeter, you could play a low frequency tone and measure it. And then use the online calculators to convert that into dBu, dBv, etc.

 

[FalFung]

Hi there. Welcome to the forum and thanks for the kind words. As to your question, the volume steps are not standardized so I don't know how we can compute anything based on that. If you have an RMS reading multimeter, you could play a low frequency tone and measure it. And then use the online calculators to convert that into dBu, dBv, etc.

Thank you @amirm for your quick answer! I shall look into measuring it in the future.

 

[andreasmaaan]

For me personally, I cannot hear the output stage saturating (clipping) even in 0 dB gain level in my normal usage. I use it to feed in my Stax Driver and SR-L700 headphone. So I am interested: in theory, for the saturating level from measurement, how obvious should the saturation be like? Is there any way I can hear/sense its effect?

I don't think it's surprising that you can't hear the saturation even when playing music at 0dBfs. The measurements show that the saturation only begins at -6dBfs, and many recordings (those that are not extremely heavily compressed) will only contain the loudest peaks at that level and above.

Moreover, the saturation distortion is still only less than 0.01%, which is very unlikely to be audible when it affects only loud transients.

Finally, the saturation distortion does not appear to affect the bass frequencies, which is where the loudest peaks are likely to be present.

In short, I'd be more surprised if this were a phenomenon you actually could hear

If you really want to hear the effect, the best way would be to play a 0dBfs sinewave at maybe 1 or 2KHz. (But obviously don't do this, it will put your hearing in danger)

 

[FalFung]

I don't think it's surprising that you can't hear the saturation even when playing music at 0dBfs. The measurements show that the saturation only begins at -6dBfs, and many recordings (those that are not extremely heavily compressed) will only contain the loudest peaks at that level and above.

Moreover, the saturation distortion is still only less than 0.01%, which is very unlikely to be audible when it affects only loud transients.

Finally, the saturation distortion does not appear to affect the bass frequencies, which is where the loudest peaks are likely to be present.

In short, I'd be more surprised if this were a phenomenon you actually could hear

If you really want to hear the effect, the best way would be to play a 0dBfs sinewave at maybe 1 or 2KHz. (But obviously don't do this, it will put your hearing in danger)

Thank you @andreasmaaan for your detailed explain! Now I see the reason behind. Feeling easier to sleep tonight

Before you recommend me not to do, I already did listen to 1 KHz sine ware tone ... in a moderate volume level, a few days before. Still, feeling my brain being scrambled like eggs even after a few minutes at that time. Cannot really say I hear anything, but I do "feel" some interesting tone in high frequency. Or maybe its just my hurt ear and brain ringing.

 

[andreasmaaan]

Thank you @andreasmaaan for your detailed explain! Now I see the reason behind. Feeling easier to sleep tonight

Before you recommend me not to do, I already did listen to 1 KHz sine ware tone ... in a moderate volume level, a few days before. Still, feeling my brain being scrambled like eggs even after a few minutes at that time. Cannot really say I hear anything, but I do "feel" some interesting tone in high frequency. Or maybe its just my hurt ear and brain ringing.

Haha very possible Your auditory system produces its own distortion when hit with high SPL sounds.

 

[Toku]

This is my simple doubt.

I think SMSL SU-8 is a very mysterious product.
why? Although the date have passed considerably since the launch of this product, SMSL's homepage has no postings other than the driver's download. Why? Is not SU-8 an official product of SMSL?

 

[amirm]

This is my simple doubt.

I think SMSL SU-8 is a very mysterious product.
why? Although the date have passed considerably since the launch of this product, SMSL's homepage has no postings other than the driver's download. Why? Is not SU-8 an official product of SMSL?

It is indeed strange that it doesn't show up on their product page even though it is being sold on Amazon, etc.

I thought the little display was common to their other devices though.

 

[jsmiller58]

This is my simple doubt.

I think SMSL SU-8 is a very mysterious product.
why? Although the date have passed considerably since the launch of this product, SMSL's homepage has no postings other than the driver's download. Why? Is not SU-8 an official product of SMSL?

Discontinued maybe?

 

[gvl]

Discontinued maybe?

Maybe. Am I the only one who thinks it was listed on the website a couple of weeks back but now is gone?

 

[frogmeat69]

Maybe. Am I the only one who thinks it was listed on the website a couple of weeks back but now is gone?

As far as I know, it was never on their website. First time I remember seeing it was on Massdrop, then Amazon. Pretty sure I was the first to buy one on Massdrop.

 

[jsmiller58]

As far as I know, it was never on their website. First time I remember seeing it was on Massdrop, then Amazon. Pretty sure I was the first to buy one on Massdrop.

It is also back on Massdrop... it is a mystery!

 

[Atrox]

Hi! Seeing that the toppind D50 performs better then the SMSL SU-8 I wonder if you will actually be able to tell a difference sound wise considering they use the same dac chips? Not sure if I wanna buy the Topping D50 and pair it with my Atrox V2 or buy the SMSL SU-8 and use it in balanced and pai it with the Schiit Jotunheim.

 

[frogmeat69]

Hi! Seeing that the toppind D50 performs better then the SMSL SU-8 I wonder if you will actually be able to tell a difference sound wise considering they use the same dac chips? Not sure if I wanna buy the Topping D50 and pair it with my Atrox V2 or buy the SMSL SU-8 and use it in balanced and pai it with the Schiit Jotunheim.

I didn't hear any difference between them, and they both sound good.

 

[FalFung]

Hi @amirm ! I am growing more interested in the balanced output of SMSL SU-8. In my understanding, output stage saturating could show 2 symptom (both are saying, for instance, under -10 dB to 0 dB, 1 KHz or 2 KHz sine wave signal): 1). After certain point, even pushing the level higher, the sound from the balanced output does not increase anymore; 2), After some point, pushing up the level makes some obvious/nasty distortion audible. My question is: I connect my SU-8 to both my headphone amps using balanced and listen from my headphones (a recent STAX model and FOCAL Elear, should be low distortion models, relatively speaking). I conduct the previous mentioned test. The result is: from -10dB to 0 dB, I can hear 1) clear continuous increment of volume from my headphone; 2) no obvious distortion or strange noise. Could I reach to a conclusion that: a). not generalize to all SU-8 model, only on my set, there is no output stage saturation; or b) on my set, the output stage saturation is low enough to an ignorable level?

 

[amirm]

After certain point, even pushing the level higher, the sound from the balanced output does not increase anymore; 2), After some point, pushing up the level makes some obvious/nasty distortion audible.

Hi there. What are you driving with SU-8? Balanced or unbalanced input on the amp?

 

[FalFung]

Hi there. What are you driving with SU-8? Balanced or unbalanced input on the amp?

Hi @amirm ! I connect my SU-8's balanced output to both of my headphone amps' balanced input (of course, tried on one amp, then tried on another amp).

 

[amirm]

OK, despite reading your post a couple of times I still don't understand it. WHen you say pushing the level, where are you changing the level? In SU-8? Or the amp?

 

[FalFung]

Hi @amirm ! So sorry that I did not mention it clearly I keep the headphone amp volume level the same, only change SU-8 's level. The maximum volume level of SU-8 using the remote control is 38. On listening test, when SU-8's volume level is set to 31 from the remote control, it is the same as I only set the gain level to -7.5 dB from my computer (cannot hear too big difference). I start a little bit lower than 31, from 29 on SU-8, letting the computer plays 0 dB sine wave, then increase the volume level to maximum level 38 on SU-8 stepwise. On each step, I stayed for a few second to get use to the volume, then increase by 1. I can hear clear volume increment on each step. Also, no obvious distortion is heard on maximum level 38.

 

[amirm]

I don't have the unit anymore as it was on loan but I think observed the same thing. I am not sure though.

SMSL is going to send me another SU-8. Let's circle back when I get that unit.