SMSL SU-1 Stereo DAC Review

[staticV3]

You can use an impedance transformer to feed the SU-1 an AES/EBU signal without risking damage: https://www.neutrik.com/en/neutrik/products/accessories/aes-ebu-impedance-transformers

 

[Roland68]

Anyone tried feeding the SU-1 coaxial input with AES/EBU signal?

AES/EBU can have Voltage up to 7 Vpp while normally SPDIF input is supposed to get about 0.5Vpp. Would I fry coax input on SU-1 with 7Volt signal or it does not care?

Before you spend so much money on an adapter/converter, you could just buy the balanced SU-2 DAC with AES/EBU input instead of the SU-1. It also has a built-in input transformer, and you get better measurements for free.

There are cases where this has worked, but those were SPDIF inputs with transformers. The SU-1's SPDIF input is much simpler, so I wouldn't bother. It wouldn't offer any advantage over coaxial or TOSLINK anyway.

 

[SDX-LV]

Before you spend so much money on an adapter/converter, you could just buy the balanced SU-2 DAC with AES/EBU input instead of the SU-1. It also has a built-in input transformer, and you get better measurements for free.

There are cases where this has worked, but those were SPDIF inputs with transformers. The SU-1's SPDIF input is much simpler, so I wouldn't bother. It wouldn't offer any advantage over coaxial or TOSLINK anyway.

Thanks. I have a very weird case where I am looking for the most compact, decent DAC with SPDIF/AES/Toslink input and powered by DC voltage (USB).
So SU-2 is a great alternative to to most people, except me...

I saw all sorts of information on the subject, including this: https://www.ranecommercial.com/legacy/pdf/ranenotes/Interfacing_AES3_&_SPDIF.pdf So I guess I can send a couple of Volts at least instead of the nominla 0.5Vpp for SPDIF without burning anything in the SU-1? I will have to risk it.

 

[modus2000]

friends, I see that SU-1 has only one clock generator with 24 herz.
Does it mean that it can perfectly play only music which coded multiple 24 herz - 48 / 96 / 192
And all CD music 44.1 will be resampled to 48 herz with reduce of quality ?

 

[RandomEar]

friends, I see that SU-1 has only one clock generator with 24 herz.
Does it mean that it can perfectly play only music which coded multiple 24 herz - 48 / 96 / 192
And all CD music 44.1 will be resampled to 48 herz with reduce of quality ?

No. Look at the dashboard from the review:

It is captured at 44.1 kHz and looks pretty much perfect. Please don't overanalyze the interals of devices or get hung up on irrelevant details. What counts is the performance the device delivers on the outputs, not the individual components.

 

[modus2000]

Что имеет значение, так это производительность, которую устройство обеспечивает на выходах, а не на отдельных компонентах.

If SU-1 really resamples 44.1->48 it means it not bit-perfect. I think this is very big disadvantage.
As I understood when I using Toslink the clock is going from Toslink signal with bit-perfect 44.1 ?

I even don't hear the difference between DAC's but I want to be sure that my music is bit-perfect )

 

[RandomEar]

If SU-1 really resamples 44.1->48 it means it not bit-perfect. I think this is very big disadvantage.
As I understood when I using Toslink the clock is going from Toslink signal with bit-perfect 44.1 ?

I even don't hear the difference between DAC's but I want to be sure that my music is bit-perfect )

The 24 Mhz crystal is next to the XMOS XU316 chip and is precisely the required clock speed for that. The AK4493 DAC chip requires three different external clocks (MCLK, BICK and LRC) which are not round numbers, but something like 16.3840 MHz. They are probably supplied using one or both of the other crystals on the board (I see three in total) and/or with the help of a clock generator chip. Since SMSL has lasered most chips on the PCB, it's difficult to tell how it is done exactly - at least for me.

The end result is this: The 44.1 kHz signal is accepted by the device, hence it is capable of playing that sampling rate. Internally, the 44.1 kHz is upsampled anyway, probably around 16x. The output signal is clean and free of distortion (<-120 dB). It is as "perfect" as it will get for 80$ and audibly transparent.

 

[modus2000]

Oh, 24 Mega hz... Ok, thank you for explanation. Let think there is no stupid resempling 44.1 -> 48 -> 44.1

 

[NoxPlague]

Just wanted to add to this thread as a happy user of the SMSL SU-1 for 2 years.

I've used the TOSLINK from my Windows 11 PC and Thunderbolt 3 Dock for my Mac & iPad without issues. I did set Windows sound settings output to 24 bit 96Khz, so my understanding is that Windows is resampling any audio I play to 96Khz and that my chain is not "bit-perfect".

I power the unit with a usb-c cable plugged into battery backup. I never turn it off or on, it has just sat plugged in for 2 years. I use it pretty much any day I'm home.

I run the output into various headphone amplifiers, currently the Schiit Midgard.

I think the SU-1 makes for a great, compact desktop audio solution and currently at $85 on Amazon it is hard to beat the performance.

 

[MBWORLDZ]

I got mine yesterday and there is one big problem I can't really find a way to fix it.
When I played music through tidal from my ROSE RS250. Pretty much most of the songs I click on , it has a short drop out at beginning of the song. The first half second. This is very annoying. I am not sure if the SMSL U-1 itself need more time buffering or determine is the song is MQA...or what frequency to use....etc. I really don't want to disbale any features that will degrade the sound quality just becuase to fix that issue. I rather return the unit.

Overall it sounds great without a doubt but just that "short drop out at beginning of the song" not acceptable.
I remember 5 years ago when I bought the Cambridge Audio DacMagic 200M, it had the same problem when it switched to MQA itself.

I am not sure if you guys experience the same like me or the one I bought is defective.