SMSL D1 - ROHM DAC for everyone

[Evgenliman]

The DAC originally had this op amp.
SMSL deliberately erased the name from the chip.
The repairman replaced it with an NE5532.

 

[conuss]

The DAC originally had this op amp.
SMSL deliberately erased the name from the chip.
The repairman replaced it with an NE5532.
View attachment 500728

A clear photo, NOTHING more.

 

[sabih]

can you share the picture?
And why did you do this?

 

[jareinertson]

So the D1 came and its working as it should. The uC connector is so lose that the stock cable just dangles inside but SPDIF is so god damn tight that i barely could unplug the cable. The power button does absolutely nothing. After installing the SMSL driver it only works if i use an OTG cable for some reason. When i connect external power nothing happens at all. ASIO doesn't work at all. As for the sound, the bass distortion is finally gone but now the treble is way more annoying. I had to lower to volume on the amp by 6dB to get the same loudness as the old dac.
MQA labelled as DSD LUL. The SU-1 got MELF resistors but this one doesn't considering both goes for the same price. The FW comes with Always ON as default and FW version is v55.15.
Here are some pcb pics, not the best quality.
EDIT: I dont know what happened. Had a brownout and now the secondary usb for power and the power button works all of a sudden. After trying out a few driver versions ASIO started working.
View attachment 457171View attachment 457172View attachment 457173View attachment 457174View attachment 457175View attachment 457176View attachment 457177
View attachment 457178

Some not so nice looking solder work…

 

[sabih]

SMSL has tuned this DAC to sound a little Dull, dark or warm sound.
You can change the opamp to get different flavor. But you are saying something which I have never heard to place an extra pair of caps. I don't understand your logic

 

[JSmith]

SMSL has tuned this DAC to sound a little Dull, dark or warm sound.

Compared to what, controls used, level matched?

You can change the opamp to get different flavor.

Uh huh.

I don't understand your logic

There is logic happening here?


JSmith

 

[kazuviking]

Still debating which method to take for the balanced output. Make a separate LPF and buffer for it but that can asymetrically load the dac chip causing unknown issues. Tap after the LPF right on the SE converter opamp inputs but then it can backfeed emi/dc triggering the mute ic. Slap a DRV134 after the SE converter and call it day albeit with worse SNR. The pentaconn plug would be a tight fit in place of the COAX considering the chungus RCAs.

 

[Roland68]

Still debating which method to take for the balanced output. Make a separate LPF and buffer for it but that can asymetrically load the dac chip causing unknown issues. Tap after the LPF right on the SE converter opamp inputs but then it can backfeed emi/dc triggering the mute ic. Slap a DRV134 after the SE converter and call it day albeit with worse SNR. The pentaconn plug would be a tight fit in place of the COAX considering the chungus RCAs.

Do you still need the single-ended output?

Assuming the D1 uses the standard I/V stage/output circuit from the datasheet (you'd have to check this), I would use it unchanged.
Then you would tap the balanced signal directly from the I/V op-amps.
This was done exactly the same way in the D300, without a buffer stage. Don't forget the coupling capacitors for the outputs, though.

If you want to add a buffer stage, keep in mind that the DC/DC converter's power supply might not be sufficient. There are alternative 2- and 3-watt DC/DC converters available; you can find information about them in the SU-1 thread.
Again, don't forget the coupling capacitors for the outputs.

 

[kazuviking]

Do you still need the single-ended output?

Yep, the SE output will feed the VU meter and the balanced one the HP amp. Yes i tried splitting the RCA and it created an even worse ground loop due to the cheap VU driver.

Assuming the D1 uses the standard I/V stage/output circuit from the datasheet (you'd have to check this), I would use it unchanged.

SMSL didn't follow the datasheet as they did not use any recommended coupling caps. From the looks of it i can just wire the balanced out directly without any buffers as my hp amp have opamps on the input.

 

[truth_soldier]

How to spruce up the boring looking but good sounding SMSL D1, SU-1 (and possibly other small DACs) in 10 minutes for $5...
It also has the practical purpose of increasing the weight a little, helping w/cable pull issues, and equal or better airflow around the case.

• Cut a bamboo drink/cup coaster in half and silicon glue to the sides.
• screw on four chromed-metal glass pane supports with 6mm mouth/opening - aka glass shelf supports.
• Affix rubber/poly pads to the bottom of the metal feet (not shown in pics)
  
  Instead of adding rubber pads to the metal feet, you could instead screw the feet down to some other large surface to remove any cable/movement issues.
  
  
  

 

[valions]

Looking to see if anyone else has experienced this. I have an SMSL D1, purchased in August 2025. Current setup FiiO DM13 > SMSL D1 (Coax) > Vintage Stereo AUX jack. Starting last week, the audio is extremely low, to the point that it's just a whisper even at 90% stereo volume. At first, I thought it was the AUX jack. I did the following tests to narrow down the issue:

CD → DAC → AUX / Tape 1 / Tape 2 → extremely faint

CD → DAC → Phono 2 → audible (of course not recommended)

Turntable → Phono 1 → normal

CD → AUX (no DAC) → normal

All RCA cables remained the same, so that's ruled out. I changed power cables and outlets, too. I also tested the DAC on a PC and encountered the same volume issue using powered speakers. Also tested OptIn, same issue with output. I reached out to SMSL, and they said to contact the seller. I reached out to the shop on AliExpress, and it's been hard to get a straight answer from them. They eventually gave me an address to ship it to, but since it's past the 90-day AliExpress return window, I cannot use the return/refund feature.

Has this happened to anyone else, or do you know what else I could try? Honestly, the cost to ship it to China from Canada probably isn't worth it, and I might open it to test it.

 

[JSmith]

Hey @valions and welcome to ASR.

tested the DAC

You don't all the correct troubleshooting steps and it seems fairly clear it's the DAC, maybe output stage failing.

I reached out to the shop on AliExpress, and it's been hard to get a straight answer from them.

Unfortunate, but not unexpected... sorry to say.

Maybe best to buy a new DAC from a local seller or a platform with better return policies like Amazon/eBay. Sometimes it can be worth paying a little extra for that peace of mind for when things fail.

@SMSL-Mandy


JSmith

 

[valions]

Maybe best to buy a new DAC from a local seller or a platform with better return policies like Amazon/eBay. Sometimes it can be worth paying a little extra for that peace of mind for when things fail.

Thanks for the information. At the time, AliExpress was the only way I could order the D1, as it was sold out on Amazon.ca. Definitely a lesson learned. I'm going to ask for a partial refund as a last-ditch effort. I really enjoyed this little DAC. I'll start the search in the meantime for another one. If I hit a wall with the seller, I'll just crack this one open and see if I can find the issue.

 

[Roland68]

Thanks for the information. At the time, AliExpress was the only way I could order the D1, as it was sold out on Amazon.ca. Definitely a lesson learned. I'm going to ask for a partial refund as a last-ditch effort. I really enjoyed this little DAC. I'll start the search in the meantime for another one. If I hit a wall with the seller, I'll just crack this one open and see if I can find the issue.

It could be the same problem/defect as occurs with the SU-1.
It's possible that the DC/DC converter (5V to +/-12V) in your D1 is defective. You can easily test this with a multimeter.
You can find information about spare parts in the SU-1 thread.

However, I would also contact SMSL again and point out that the dealer isn't making any effort to find a solution.

 

[valions]

It could be the same problem/defect as occurs with the SU-1.
It's possible that the DC/DC converter (5V to +/-12V) in your D1 is defective. You can easily test this with a multimeter.
You can find information about spare parts in the SU-1 thread.

However, I would also contact SMSL again and point out that the dealer isn't making any effort to find a solution.

Thanks for this information, it's very helpful. I might go ahead and test the converter myself or have my neighbour give it a go since electronics is his profession. I have a multimeter, but I definitely don't want to short anything. I reached out to SMSL again to see what they say about the seller. Honestly, at this point, I'd take a partial refund and then ask my nieghbour to replace the coverter (if that's the issue), though after reading the SU-1 thread, it sounds like it.

 

[Roland68]

Thanks for this information, it's very helpful. I might go ahead and test the converter myself or have my neighbour give it a go since electronics is his profession. I have a multimeter, but I definitely don't want to short anything. I reached out to SMSL again to see what they say about the seller. Honestly, at this point, I'd take a partial refund and then ask my nieghbour to replace the coverter (if that's the issue), though after reading the SU-1 thread, it sounds like it.

This can be measured relatively easily on the underside of the circuit board. The two connected pins are 5 volts and ground. The three pins are +/- 12 volts and ground.

If you order a DC/DC converter, please get one from a reputable brand, preferably one rated at 2 or 3 watts; they last longer.

 

[solderdude]

You can measure the +/- 12V without taking the PCB out.
You just need to take the top off.
Black lead to RCA ground.

Red lead to -12V test point (the little via) should read somewhere between -11 and -12.5V
Change red lead to +12V and that should read somewhere between -11.8 and -12.2V

Note that there are many different 5V to +/-12V converters with different pin arrangements.
Look in the datasheet what the correct pinning should be.

 

[Roland68]

You can measure the +/- 12V without taking the PCB out.
You just need to take the top off.
Black lead to RCA ground.
View attachment 506390
Red lead to -12V test point (the little via) should read somewhere between -11 and -12.5V
Change red lead to +12V and that should read somewhere between -11.8 and -12.2V

Note that there are many different 5V to +/-12V converters with different pin arrangements.
Look in the datasheet what the correct pinning should be.

There's no removable cover; you have to pull the circuit board out, but that's not a problem.
Thanks for the tip about the test points; that should make things easier for inexperienced DIYers. I always measure directly at the component leads—it's an old habit.

 

[solderdude]

There's no removable cover; you have to pull the circuit board out, but that's not a problem.

Ah...

 

[valions]

This can be measured relatively easily on the underside of the circuit board. The two connected pins are 5 volts and ground. The three pins are +/- 12 volts and ground.

If you order a DC/DC converter, please get one from a reputable brand, preferably one rated at 2 or 3 watts; they last longer.

I used the pins under the board as well as the +/- 12V on the top. For the -12V, I get 0.58V, and 0 for the rest. Sounds like the converter needs replacing.