• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

SMSL DO400 Fully Balanced Audio Decoder & Headphone Amplifier

I flashed the latest firmware and it seemed to me that they fixed the filter labeling. Fast filters were fast (roll off before 0.55 Fs) and slow filters were slow (~0.8 Fs) but I was unable to get proper impulse responses measured to verify if minimum/linear phase was correctly labeled.

EDIT: per datasheet looks like at least filter off, linear fast, linear slow, minimum slow and apodizing are correctly labeled. Can't really tell minimum phase/minimum fast or minimum slow/minimum phase low dispersion apart.
 
Last edited:
I flashed the latest firmware and it seemed to me that they fixed the filter labeling. Fast filters were fast (roll off before 0.55 Fs) and slow filters were slow (~0.8 Fs) but I was unable to get proper impulse responses measured to verify if minimum/linear phase was correctly labeled.
 

Attachments

  • smsl1.png
    smsl1.png
    383.3 KB · Views: 80
I flashed the latest firmware and it seemed to me that they fixed the filter labeling. Fast filters were fast (roll off before 0.55 Fs) and slow filters were slow (~0.8 Fs) but I was unable to get proper impulse responses measured to verify if minimum/linear phase was correctly labeled.

EDIT: per datasheet looks like at least filter off, linear fast, linear slow, minimum slow and apodizing are correctly labeled. Can't really tell minimum phase/minimum fast or minimum slow/minimum phase low dispersion apart.

The filters all seem labeled correctly apart from Filter 4 which is Linear phase fast roll-off low ripple (ESS #4) not Linear phase fast roll-off (ESS #3).
 
I keep getting the "Disconnected" message in the programmer. I have the USB cable connected since device manager shows the DO400 as a USB device and have the input selected to USB.

What am I doing wrong?
 
I flashed the latest firmware and it seemed to me that they fixed the filter labeling. Fast filters were fast (roll off before 0.55 Fs) and slow filters were slow (~0.8 Fs) but I was unable to get proper impulse responses measured to verify if minimum/linear phase was correctly labeled.

EDIT: per datasheet looks like at least filter off, linear fast, linear slow, minimum slow and apodizing are correctly labeled. Can't really tell minimum phase/minimum fast or minimum slow/minimum phase low dispersion apart.
When you say latest firmware do you mean version 1V0A6? And which PCM filter and DSD filter would you recommend on this firmware version? Many thanks!
 
When you say latest firmware do you mean version 1V0A6? And which PCM filter and DSD filter would you recommend on this firmware version? Many thanks!
Yes, I meant version 1V0A6. I would recommend minimum phase for PCM, or you can choose apodizing if you want full attenuation at the Nyquist frequency. I'm actually not sure about DSD as the 9039 datasheet does not mention 47K/50K/60K/70K for `iir_bw`. On the signal path there is a "DSD FIR" but is not otherwise elaborated.

Controls the IIR bandwidth in the digital datapath.
• 3'd0: Reserved
• 3'd1: BW * 8
• 3'd2: BW * 4
• 3'd3: BW * 2
• 3'd4: BW (default)
• 3'd5: BW / 2
• 3'd6: BW / 4
• 3'd7: BW / 8

9038 datasheet states
Note: 47.44k filter should only be used for PCM data. Recommended settings for DSD data are 50k, 60k or 70k.

Topping does not have DSD filter settings for their 9039 DACs (D90 III/D50 III/D70 PRO SABRE), while they did have DSD filter settings on their 9038 DACs. I don't think the DSD filter selection will do anything on the SMSL 9039 DACs, as the DSD FIR does not seem to be configurable.
 
Yes, I meant version 1V0A6. I would recommend minimum phase for PCM, or you can choose apodizing if you want full attenuation at the Nyquist frequency. I'm actually not sure about DSD as the 9039 datasheet does not mention 47K/50K/60K/70K for `iir_bw`. On the signal path there is a "DSD FIR" but is not otherwise elaborated.




9038 datasheet states


Topping does not have DSD filter settings for their 9039 DACs (D90 III/D50 III/D70 PRO SABRE), while they did have DSD filter settings on their 9038 DACs. I don't think the DSD filter selection will do anything on the SMSL 9039 DACs, as the DSD FIR does not seem to be configurable.
appreciate it!
 
You'll likely need the CH341 drivers, which can be downloaded from Microsoft here: https://catalog.s.download.windowsu..._9ca4570386a1dc29d482f64e8d4b402c95d61b10.cab

Extract and right click on the INF file to install.
Thanks ... did as suggested and now Ch341 comes up as COM3 serial port. When I start the program(ISPV2.4), I have no way to select COM3 in the program. Attempting to program without this selection ability leads to the same Disconnect Error.
 
Thanks ... did as suggested and now Ch341 comes up as COM3 serial port. When I start the program(ISPV2.4), I have no way to select COM3 in the program. Attempting to program without this selection ability leads to the same Disconnect Error.
Have you tried clicking on the connect button?

- open drop-down menu "Options -> Connect"
 
Have you tried clicking on the connect button?

- open drop-down menu "Options -> Connect"
1728183606002.png


Alll is good now...It was the turning off the dac, the pressing and holding the knob thing is what I skipped!
Thanks!
 
I flashed the latest firmware and it seemed to me that they fixed the filter labeling. Fast filters were fast (roll off before 0.55 Fs) and slow filters were slow (~0.8 Fs) but I was unable to get proper impulse responses measured to verify if minimum/linear phase was correctly labeled.

EDIT: per datasheet looks like at least filter off, linear fast, linear slow, minimum slow and apodizing are correctly labeled. Can't really tell minimum phase/minimum fast or minimum slow/minimum phase low dispersion apart.
BTW, is anyone able to confidently tell these filters apart from listening tests?
 
Look at me ... I even had to look up what DFU meant:)!
And I had just read DFÜ (in German the abbreviation for remote data transmission), after all it has something to do with sounds. :facepalm:
 
Let's just wait a few months before these are obsolete as well :)
Feels like Amirn just reviewed the obsolete units not long ago and there is already a replacement now.

But for 500 bucks that's really impressive what the DO400 offers.

Saving up money now for a RME instead.
what RME can offer with much more expensive price tag ?
 
what RME can offer with much more expensive price tag ?
Some things
- Working firmware updates
- Functionality
- EQ
- Excellently developed and fully developed product
- Impeccable and tested firmware without problems or errors
- Reliable volume control that can also be trusted with large power amplifiers
- Real guarantee where the manufacturer takes care of the device and the customer
- Service, support and repairs even after the guarantee for many years
- Reliability and durability
I'm sure I've forgotten a few points.

The DO400 is definitely not a bad device for the price.
I have to say, however, that I am in no way dependent on the DO400, I can carry out many repairs and modifications myself, and I have durable and reliable devices from reputable German manufacturers here.
If the DO400 is defective outside of Amazon's warranty/return period, it will simply be sold as defective without me giving it a second thought.
 
Last edited:
Some things
- Working firmware updates
- Functionality
- EQ
- Excellently developed and fully developed product
- Impeccable and tested firmware without problems or errors
- Reliable volume control that can also be trusted with large power amplifiers
- Real guarantee where the manufacturer takes care of the device and the customer
- Service, support and repairs even after the guarantee for many years
- Reliability and durability
I'm sure I've forgotten a few points.

The DO400 is definitely not a bad device for the price.
I have to say, however, that I am in no way dependent on the DO400, I can carry out many repairs and modifications myself, and I have durable and reliable devices from reputable German manufacturers here.
If the DO400 is defective outside of Amazon's warranty/return period, it will simply be sold as defective without me giving it a second thought.
Thanks for the reply. DAC is not something easy to be defective, if you got a bad unit just return to amazon. I don;t expect to use same device for decades. All I care is sound quality , low noise and I don;t see much advantage of RME out of the spec. Some people claim that RME sounds better than topping and smsl DAC regardless the measurement number, but I don't really believe that.
 
Thanks for the reply. DAC is not something easy to be defective, if you got a bad unit just return to amazon. I don;t expect to use same device for decades. All I care is sound quality , low noise and I don;t see much advantage of RME out of the spec. Some people claim that RME sounds better than topping and smsl DAC regardless the measurement number, but I don't really believe that.
The Loxjie D40 Pro and D60 are identical devices, so you have some choice in terms of design.
There are currently good deals on returns/warehouse for the Loxjie D40 Pro on Amazon. Even with used/acceptable items, I couldn't see any major signs of use.
 
Back
Top Bottom