SMSL DO100 Review (Stereo DAC)

[Mike123]

What modernization did you do?

Replacing the two OPA1612 I/U operational amplifiers with an OPA1656. When I disassembled the DAC and looked at the circuit, I saw that the I/U op-amps operate in current modes close to the limiting ones. They are loaded with two DAC current channels, an RCA adder and an XLR load. Since the E1DA Kosmos ADC used for measurements has a low input impedance, the maximum output I/U currents were close to 20 mA. The maximum output current of OPA1612 is 30mA. My DAC THD measurements were -126/124 dB, third harmonic -129/125 dB. It seemed excessive to me. After replacing the I/U with an OPA1656 whose maximum output current is 100 mA, my DAC's THD is -129/132 dB, third harmonic -139/138 dB. SINAD has not changed and is 119 dB. It's a good change imo .

 

[ishmeister]

Well that's it folks, the USB and BT inputs are now completely dead. Optical works but my display is blinking between sample rate and three dashes. So it looks like it's going to have to go back to SMSL and my faithful old Topping D10 will be filling in.

 

[ishmeister]

I recently received my replacement DO100. It was from new stock. However, I'm having a new issue with this one. I get quite a loud pop just before audio starts to play and then a few seconds after I stop playing audio.

 

[staticV3]

I recently received my replacement DO100. It was from new stock. However, I'm having a new issue with this one. I get quite a loud pop just before audio starts to play and then a few seconds after I stop playing audio.

If you're on Windows, then you can give this workaround a try:

XMOS driver settings for no cutoff/delay

I was contemplating on creating a "tutorial" of sorts for all XMOS drivers on devices that have a cutoff -- latency between the start of a sound and the dac "reacting" and actually playing said sound... So here it is: XMOS drivers use a control panel not unlike this: Usually the "Options"...

www.audiosciencereview.com

 

[ishmeister]

If you're on Windows, then you can give this workaround a try:

XMOS driver settings for no cutoff/delay

I was contemplating on creating a "tutorial" of sorts for all XMOS drivers on devices that have a cutoff -- latency between the start of a sound and the dac "reacting" and actually playing said sound... So here it is: XMOS drivers use a control panel not unlike this: Usually the "Options"...

www.audiosciencereview.com

Interesting, thanks. I've emailed SMSL about it first, so let's see what they say.

 

[Mike123]

One of the two secret chips has been identified. This is
10 pin programmable clock generator Skyworks Si5351A.

 

[jindy30]

Would this power some 8Ohme speakers? Cambridge audio sx-50 to be precise. I am looking for a cobo DAC/AMP

Recomendations, and advice on small laptop to speaker set up, using USB-C

Hi Folks, so i have been using the headphone output of my laptop (into old receivers and speakers) to edit and mix some music. Recently I bought some cambridge audio sx-50 speakers (8Ohms) that i would like to use and I need an amp, $100-300 is my budget. Any rec's? SX-50 KEY FEATURES 135mm...

www.audiosciencereview.com

Thanks Jonathan

 

[staticV3]

Would this power some 8Ohme speakers? Cambridge audio sx-50 to be precise. I am looking for a cobo DAC/AMP

Recomendations, and advice on small laptop to speaker set up, using USB-C

Hi Folks, so i have been using the headphone output of my laptop (into old receivers and speakers) to edit and mix some music. Recently I bought some cambridge audio sx-50 speakers (8Ohms) that i would like to use and I need an amp, $100-300 is my budget. Any rec's? SX-50 KEY FEATURES 135mm...

www.audiosciencereview.com

Thanks Jonathan

The DO100 is a pure DAC.
It does not power anything, so needs to be used with an external Amp.

 

[jindy30]

The supplied USB cable is 115cm. I think this DAC would be fine (or even perfect) for pretty much

Mine just arrived. I plugged it into my Mac and it's showing a max sample rate of 96 kHz. I purchased this expecting 768 kHz support. Does anybody know how to enable higher sample rates? Am I SOL?

Please understand that for my purpose (testing some audio software) I actually need the higher sample rates.

P.S. This product would be much better if it could run off usb-c power too. Needing the power chord is annoying and the one that comes with it is short.

Interesting so no power through the usb_c

 

[jindy30]

Yes. I connected it to two separate amps and used a two way amplifier receiver. Both the XLR and SE outputs were simultaneously active. Similar to the Schiit Modius

DAC at max volume gives the cleanest signal and so does Amp at min gain.

Can you say what the signal level is, in dbu, or volts and how it compares to output line levels on professional audio equipment.

 

[staticV3]

Can you say what the signal level is, in dbu, or volts and how it compares to output line levels on professional audio equipment.

The first graph in Amir's review shows the DAC's maximum output voltage.

You can use online tools like this to convert Vrms to dBu etc.

 

[jindy30]

Wow, the same thing just happened to me and I came here and saw your post. I have exactly the same issues, but i'm running a Mac. I also tried my Windows laptop and had the same problems. It sounds fine in optical or in USB 1.1, it sounds great once it stops popping, but it pops every single time I start or stop playback. My setup: Mac Mini 2018 (Intel), SMSL DO100 plugged directly in with USB-C cable, XLR to RTS cables, Topping PA3s in balanced mode, Polk S-15 speakers.

Such a bummer since I got this to replace an SMSL C200 that had a problem with static charges stopping audio playback.

And some context: I also have a Topping D10 Balanced and it plays back in the same system perfectly. I wanted something with a volume control that had balanced output. I also have an SMSL D-6 balanced in another system that plays perfectly as well. Guess I'm going to have to stick with the D-6 units.

No analog input? Did you mean that? I use this with a ncore amp as a DAC and preamp. Controlling volume with DACs volume

This is what I am trying to wrap my head around. After the digital signal has been converted to analogue what is its "level?.of the source material? Is this signal being amplified in the unit? Yes by the volume knob.

Therefore I question Whether this is named correctly, and is even necessary. As it has been pointed out it should be set.to the highest level so not altered depending on listen volume

Yes it alters the loudness tou hear but it also lowers the level going into you specially engineered amp.

 

[jindy30]

The first graph in Amir's review shows the DAC's maximum output voltage.

You can use online tools like this to convert Vrms to dBu etc.

This?
1 VRMS
1000 mVRMS
0 dBV
2.218487487657987 dBu
2.8284271247461903 VPP

Test revealed, Max was.6V, and 4.0Vrms

Math was never my strong point...but here goes, 4Vrms ( x 2.2) = 8.8dbu

Thanks

Jonathan

 

[jindy30]

only digital volume attenuation

What is this "digital volume attenuator". Are we reinventing the wheel here?

 

[jindy30]

My DO100 arrived today, connecting to vintage Yamaha P-2100 professional series amplifier that has been rewired/updated and RCA inputs added, also has XLR inputs (unbalanced). I’ve never had gear with XLR options or a power amp. DO100 specs show output 2.0Vrms RCA , 4.0Vrms XLR.
Two question if anyone has feedback:
1. should I use rca output since this shows higher than listed input for amp? (1.3)
2.Yamaha Amp has L&R volume attenuators. do I run D0100 at full volume as preamp and adjust with amp controls?


View attachment 280576

Hi, did it work out? I am starting look at the output of this unit for when I connect it to a.power.amp, and also figuring out if it has pre amp it. Also why it has a variable amp, aka volume knob at all.

I am not sure which one is the best output, I guess.you just have to try them both, at low volume at first.and see. I find it curious but maybe helpful that they are different.levels. i would have imagined they would be the same coming from the same source, the DAC.

Also, the test was done at max "volume" and it was said to leave it that way. Although I do think the outputs are " hot" as.in too high. I could be totally wrong on that last comment but optimon line level is +4dbV for pro stuff and -10dbu for consumer equipment.

Thanks jonathan

 

[staticV3]

This?
1 VRMS
1000 mVRMS
0 dBV
2.218487487657987 dBu
2.8284271247461903 VPP

Test revealed, Max was.6V, and 4.0Vrms

Math was never my strong point...but here goes, 4Vrms ( x 2.2) = 8.8dbu

Thanks

Jonathan

Mate you just have to enter the voltage in the online tool:

4Vrms=14.25dBu

 

[jindy30]

My DO100 arrived today, connecting to vintage Yamaha P-2100 professional series amplifier that has been rewired/updated and RCA inputs added, also has XLR inputs (unbalanced). I’ve never had gear with XLR options or a power amp. DO100 specs show output 2.0Vrms RCA , 4.0Vrms XLR.
Two question if anyone has feedback:
1. should I use rca output since this shows higher than listed input for amp? (1.3)
2.Yamaha Amp has L&R volume attenuators. do I run D0100 at full volume as preamp and adjust with amp controls?


View attachment 280576

Mate you just have to enter the voltage in the online tool:
View attachment 343457
4Vrms=14.25dBu

i see, thanks. can you also answer a question. What is the difference between a Digital Volume Attenuator and a pre amp, and which oine does this have. cheers Jonathan

 

[staticV3]

What is the difference between a Digital Volume Attenuator and a pre amp, and which oine does this have. cheers Jonathan

Digital attenuation happens before the D->A conversion, analog after.

Analog attenuation preserves SNR, while digital attenuation does not (minus 1dB SNR for every minus 1dB volume).

In practice, modern DACs have so little noise that this difference is basically inconsequential.
In 99% of cases, the bottleneck is your playback environment.

Since digital attenuation is controlled by software/firmware, there is a chance for that firmware to bug out, suddenly increasing the volume.
I've read about such a bug exactly once, so it's not something that you have to worry about usually.

The DO100, like almost every desktop DAC, uses digital attenuation.

 

[Atanasi]

Analog attenuation preserves SNR, while digital attenuation does not (minus 1dB SNR for every minus 1dB volume).

Analog amplifiers have their own noise floor, and attenuating signal beyond the analog noise floor sacrifices SNR. However, state-of-the-art amps have lower noise floors than state-of-the-art DACs, so there is more SNR-preserving attenuation there.

 

[bpcf]

Novice here, on my DO100 I am getting rapid, loud, startling popping noises if I drag around the volume slider in windows with nothing else playing... it's kind of like the transient popping you get if you turn off the source before the amp except there's several in a row at regular intervals and rapid like a quick burst of semi-auto gunfire. It's actually enough that my speaker drivers visibly move a few mm each pop. It's consistently reproduceable in USB2.0 mode but in USB1.1 mode it rarely and seemingly more randomly happens. The volume level on the DAC has no bearing on the popping volume, and changing USB ports did not seem to do anything either. The popping doesn't happen when using RCA out. It happens on both XLR channels, i.e. it occurs on both at the same time, and if I unplug one the plugged one will still have it.

My setup is a bit janky, as this is thru XLR to my cheap amp to speakers. But I am using a monoprice XLR to RCA along the way to the amp as the amp only has RCA inputs (and the DO100 RCA output is in use by a sub). Is it possibly related to going from balanced to unbalanced? Not very knowledgeable about balanced cables at all, though it did not sound like the typical hum/noise. I do have an amp on the way with balanced inputs but I'm wary of directly trying it out as the amp does not have preamp/volume control and I would like to not blow out my drivers. Anybody experience this issue or know what it is? Thanks

edit: I did see a few mentions of popping elsewhere in this thread, but at least as described seemed to be happening under a bit different circumstances, and no definitive explanations on the cause.