SMSL D-6s Balanced DAC Review

[somebodyelse]

OK, thanks. So ground loops can be easily created using this DAC.

Yes, just like any other system using single ended interconnects.

So it might be reasonable to use an USB isolator if used with a source in electrical class I.
And also using a preamplifier/amplifier in electrical class I could be also a problem with unbalanced interconnection.

Yes, if removing the USB connection solves the ground noise issue. Ground related noise issues are always a possibility when using unbalanced interconnects, or when using poorly implemented balanced interconnects.

 

[miero]

All DACS can form part of a ground loop (as can any other component in the chain) unless they include galvanic isolation. I am not aware of any that do.

I know some boutique European DACs (CustomWorks, gredAudio, SPaudio), which used optoisolators on I2S bus (between XMOS and DAC chip). And also there were some DIY modules from Twisted Pear Audio and Ackolabs which had a similar solution before USB isolators were available.

 

[antcollinet]

which used optoisolators on I2S bus (between XMOS and DAC chip)

But did those isolators work between galvanically isolated circuits with separate ground? Also with two galvanically isolated power systems for the two sides of the circuit.

 

[pma]

Sure.

 

[nanook]

or when using poorly implemented balanced interconnects.

Indeed. For quite some time the pin 1 of the XLR connection has been misunderstood.
Finally Bruno Putzeys has written a nice paper about this. As usual this paper is just great :

http://www.troelsgravesen.dk/FUSION-BI-AMP/AN_Legacy_pin_1_problems.pdf

 

[Bwaslo]

Indeed. For quite some time the pin 1 of the XLR connection has been misunderstood.
Finally Bruno Putzeys has written a nice paper about this. As usual this paper is just great :

http://www.troelsgravesen.dk/FUSION-BI-AMP/AN_Legacy_pin_1_problems.pdf

Bruno's paper is as aways a good one.
Though an exception is with phantom powered microphones -- those won't work at all without a pin 1 connection to the supply in the mic. (Bruno does cover that indirectly by mentioning that the ground problem is only for boxes with both an input and an output).

 

[somebodyelse]

Indeed. For quite some time the pin 1 of the XLR connection has been misunderstood.
Finally Bruno Putzeys has written a nice paper about this. As usual this paper is just great :

http://www.troelsgravesen.dk/FUSION-BI-AMP/AN_Legacy_pin_1_problems.pdf

The only down side of the old paper is the now-broken links at the end. Current versions are:
https://www.ranecommercial.com/legacy/note110.html
https://www.ranecommercial.com/legacy/pdf/whitlock.pdf
https://www.jensen-transformers.com/application-notes/

 

[nanook]

Though an exception is with phantom powered microphones -- those won't work at all without a pin 1 connection to the supply in the mic.

Absolutely true
For phantom powered microphones pin 1 should be wired to the enclosure of the mic as direct (short, broad -> low inductance) as possible. The connection to the mics internal ground should be picked elsewhere from the enclosure such that ground-loop (or EMI) currents may still cause a voltage drop but it won't find a way into the signal for audio frequencies (acting as an antenna it still can for RF).
This is nicely illustrated in Fig. 6 in the Rane AN165: https://www.ranecommercial.com/legacy/note165.html

Sorry for getting off- topic.

 

[Lyricman]

Has anybody tried to upgrade to ver 1.1 of the firmware?
I downloaded it and followed the instructions but failed 3 times. Unfortunately the program is in Chinese so don't know what the errors are.

SMSL Audio Official -Professional audio product manufacturer

Foshan ShuangMuSanLin electronics Co., LTD. founded in 2009 which located in Shenzhen, China. And our branch company VMV Technology(HK) Company Limited registered in HK in 2013. Our company is specialized in the audio DAC, stereo headphone amplifier, power amplifier, and with own R&D...

www.smsl-audio.com

 

[Esprit]

What should the new firmware do?

 

[Grael]

Has anybody tried to upgrade to ver 1.1 of the firmware?
I downloaded it and followed the instructions but failed 3 times. Unfortunately the program is in Chinese so don't know what the errors are.

SMSL Audio Official -Professional audio product manufacturer

Foshan ShuangMuSanLin electronics Co., LTD. founded in 2009 which located in Shenzhen, China. And our branch company VMV Technology(HK) Company Limited registered in HK in 2013. Our company is specialized in the audio DAC, stereo headphone amplifier, power amplifier, and with own R&D...

www.smsl-audio.com

Like the DL200, you need to be fast to plug the power cable after clicking start... Like 3s max

SMSL DL200 the best ever value DAC/AMP?

Have you experienced sync-problems? My point: The firmware development of these Chinese manufacturers has not been very reliable. I would apply a firmware update only if I absolutely have to and if it is solving a problem I am having. No, but I'm not sure what it fixes exactly but I tend to...

www.audiosciencereview.com

 

[Esprit]

Can I update the firmware with a Mac?

 

[Lyricman]

Can I update the firmware with a Mac?

The upgrade exe is windows only

 

[somebodyelse]

Can I update the firmware with a Mac?

You can probably use a virtual machine with USB passthrough, like VirtualBox, and a Windows developer image (free, time limited). Start the virtual machine, install the driver, enable USB passthrough for the DAC (effectively like plugging it into the Windows 'machine'), then update the firmware. Once that's complete you can shut down the virtual machine and use the DAC on the Mac again. This is the approach I've used for the Hypex DLCP when I only have linux. I don't have a Mac or a D6s so can't be sure it'll work, or that it won't brick your D6s for that matter.

 

[Esprit]

The upgrade exe is windows only

Then I won't update...

 

[nanook]

Did anyone perform the update successfully?
Any clue what SMSL changed?

Regarding the filter "labelling": For the D-6s a manual change would have been sufficient, which SMSL did not update. They likely re-use the same firmware code blocks for different products using the same DAC chip, so the assignment of filters to the number displayed may have changed in the same way as for other products.
Just speculation...

Anyone who experiences the "pops": has this been improved?

 

[JIW]

Did anyone perform the update successfully?
Any clue what SMSL changed?

Regarding the filter "labelling": For the D-6s a manual change would have been sufficient, which SMSL did not update. They likely re-use the same firmware code blocks for different products using the same DAC chip, so the assignment of filters to the number displayed may have changed in the same way as for other products.
Just speculation...

Anyone who experiences the "pops": has this been improved?

Edit: See correction in next post.

I just checked and it has been updated and is correct. This is the filter page now:

 

[JIW]

I just checked and it has been updated and is correct. This is the filter page now:

View attachment 399756

This is still incorrect. Filter 1 (dark blue) is a slow minimum phase filter hiding behind filter 7 (black), i.e. filter 1 is ESS #7 or #8 not #1 minimum phase. Filters 2-6 are correctly labeled though.

 

[Lyricman]

Decided to give the upgrade another go and with Graels advice selected the USB serial port and with power unplugged click the start and plug power supply in within 3 secs and it kicked off and upgraded. Don't know what has changed renumbered filters ???? it defaults back to FL2.

 

[JIW]

Decided to give the upgrade another go and with Graels advice selected the USB serial port and with power unplugged click the start and plug power supply in within 3 secs and it kicked off and upgraded. Don't know what has changed renumbered filters ???? it defaults back to FL2.

Filter selection and order has changed. Filters 2-6 are now labeled correctly whereas 1 is incorrect and 7 is unclear. See my above posts.

Since the ESS default filter is omitted, it may select the next in ESS' ordering which is filter 2 or it is programmed to select filter 2 by default and the assignment is done elsewhere in the code.