[hsg120]

I've no idea if anyone else is interested, but I recently tried to buy a Singxer SDA-6 DAC from Linsoul and just wanted to share--

Hello there,

This is Linsoul Audio, thanks for your order and support.

Sorry that the Singxer SDA-6 you ordered has been discontinued.

We have received feedback from the manufacturer that there will be a new model (SDA-6PRO2), priced the same as the Singxer SDA-6.

It didn't seem as though the SDA-6 ever got really popular, which never made sense to me. So, I'm glad to see Singxer is releasing a new model soon.

While the SDA-6 was not an inexpensive DAC, so many DACs today seem like carbon copies. What other competitors at its price point offer neat features like an oven-controlled clock, o-core transformer, USB galvanic isolation, etc?

 

[hsg120]

I just found an update on this--https://www.stereocheck.com/news/hifi/singxer-sda-6-pro2-balanced-dac-based-on-ak4499ex/

Singxer SDA-6 PRO2 , the second version of SDA-6 PRO, is a high-precision balanced DAC. It has many improvements compared to the first version:

• For digital-to-analog conversion, the SDA-6 PRO2 uses two AKM AK4499EX DAC chips combined with an AK4191 digital filter.
• The USB interface crystal oscillator uses a femtosecond oscillator coupled with an internal constant temperature system to improve stability.
• The USB interface has been upgraded to the XMOS XU-316 third generation USB interface, supporting 32-bit 768 kHz PCM and DSD512.
• The power supply has also been upgraded to an ultra-low noise system that reduces low-frequency distortion
• Digital preamp supports volume control, analog gain up/down, screen brightness adjustment and screen-free playback

In short, looks like they updated the DAC to the latest flagship from AKM, digital filtering is now handled on a discrete chip, and upgraded to a 3rd-gen XMOS USB interface. Otherwise it appears largely unchanged, which maybe a good thing, idk.

Only price I could find so far is from MagnaHiFi and shows €982.64 https://magnahifi.com/singxer-sda-6-pro2-balanced-akm-dac/

I just contacted Linsoul to see how soon I can get one.

 

[hsg120]

Just placed an order for the PRO2.

I saw this on Shenzhenaudio's product page--

"Upgraded with specially optimized ultra-low noise power supply system, completely solved the problem of large low-frequency distortion of AKM DAC"

Does anyone know what that is all about? I've never heard of this before, and a quick google search didn't yield anything either.

 

[Feischmaker]

Just placed an order for the PRO2.

When the product arrived, can you kindly help check whether direct DSD works? Thank you in advance

 

[hsg120]

When the product arrived, can you kindly help check whether direct DSD works? Thank you in advance

Hello!

I actually decided to go in a completely different direction and actually just canceled my order yesterday. So I'm sorry I will not be able to comment on your question.

I still believe on paper that it is the best DAC for the money, but the analog output voltage was not going to be sufficient for my new setup...

 

[Feischmaker]

I still believe on paper that it is the best DAC for the money, but the analog output voltage was not going to be sufficient for my new setup...

Quite surprised to hear that the output voltage is not going to be enough for your setup.
I thought that what it has (2.6v unbal 4.6v bal) is average.

If i may know, what is your setup going to be and what DAC you are now aiming for?

 

[hsg120]

Quite surprised to hear that the output voltage is not going to be enough for your setup.
I thought that what it has (2.6v unbal 4.6v bal) is average.

If i may know, what is your setup going to be and what DAC you are now aiming for?

Of course! Happy to share =)

Preface--I currently use a Topping A90D amp and Topping E50 DAC with a balanced connection. Amplification on the A90D amp on high gain is 15.3dB...

The setup that I decided to switch to is...unusual, and one could reasonably argue that it's totally unnecessary for my particular setup. But I like playing around with different equipment and wanted to give it a try...

My favorite headphones are TH900s and not coincidentally, I like bass. They also have 20Ω nominal impedance, which is low for headphones. And the voicecoil is capable of 1.5 Tesla, which is high for headphones. Considering that the bass will be limited most by power (or more specifically, by amplifier current) I wanted to see how they sounded with a really good speaker amp, which presumably won't be current limited in this application. Like, ever. So, I recently bought a Topping LA90D, along with a balanced XLR headphone adapter.

While reviewing the LA90D specs one night, I noticed that the input sensitivity on the LA90 in low gain was up to 7-volts with an amplification of 9.4dB. Since the amplification with the LA90D was much lower than my current headphone amp I decided to switch to a DAC that had enough voltage to drive the LA90D amp right up until its limit in low gain. I just wanted to make absolultely sure I had enough amplification.

So, I decided to switch to an RME ADI-2. That'll do up to 7-volts via XLR, and also does the neat thing with its pre-out where it varies voltage and also the digital signal to optimize both noise and dynamic range.

 

[roderickvd]

It didn't seem as though the SDA-6 ever got really popular, which never made sense to me. So, I'm glad to see Singxer is releasing a new model soon.

While the SDA-6 was not an inexpensive DAC, so many DACs today seem like carbon copies. What other competitors at its price point offer neat features like an oven-controlled clock, o-core transformer, USB galvanic isolation, etc?

Could not agree more. Was measured great by L7Audiolab too, for those who care about that. Only reason I can think of is that they missed the hype train when it was released around the same time as maybe Denafrips units.

I imagined it wasn't a big commercial success and would be a one-off. Glad to see that apparently wasn't the case. Who knows, as Singxer is big in the OEM world, maybe this SDA-6 is more about marketing (luring in OEM sales) than making volume sales with customers.

Just placed an order for the PRO2.

Awesome! Do you have an original PRO to compare it to? Looking forward to hearing your impressions.

"Upgraded with specially optimized ultra-low noise power supply system, completely solved the problem of large low-frequency distortion of AKM DAC"

Maybe distortion from translation https://www.diyaudio.com/community/threads/improving-ak4490-thd-n-figures.332319/ has something about increased distortion at lower levels (not lower frequencies), which indeed improved by tuning the power supply.

When the product arrived, can you kindly help check whether direct DSD works? Thank you in advance

DSD direct should still be supported, according to the marketing blurb. However realise that this work a bit differently between the AK4191+AK4499EX on the PRO2 and the AK4499EQ on the original PRO:

• On the original AK44199EQ, the DSD stream will indeed go directly to the switched resistor array at the output stage of the AK4499EQ.
• On the PRO2, the AK4191 in DSD direct mode will also bypass the volume control, but, different from the AK4499EQ, still apply a DSD filter and then convert to multibit before sending off to the AK4499EX. It does skip the sigma-delta modulator, so the conversion from 1-bit DSD to multibit data should otherwise be lossless.

The filter that the AK4191 applies in DSD direct mode is significantly higher in frequency than the normal filter. So it's like direct but not completely direct. If you'd ever be able to hear the difference, I don't know, but I just thought I'd share what's happening behind the scenes.

 

[bogi]

DSD direct should still be supported

With AK4191EQ&AK4499EX combo DSD direct works only at DSD128 or DSD256, since that's the rate of the multibit interface between the chips. It would require a menu item to switch this mode on/off. Most DAC producers ignore the direct DSD possibility with this AKM combo since it does not work on all DSD rates. It is not easy for DAC manufacturers to correctly configure this chip combo and that results to bugs of most of existing implementation. Direct DSD with this AKM chip combo currently works on Gustard A26 and R26 and Audalytic AH90 but that's happened only after Jussi Laako of Signalyst contacted Gustard. It does not work correctly on SMSL DACs despite they have the menu item to turn it on/off present. Jussi mentioned in November that SMSL DL300 may get firmware update to fix current buggy behavior.

So ... with this chip combo it does not look so easy for fans of direct DSD. The formulation from magnahfi "DSD, on the other hand, embraces the native direct solution technology, supporting resolutions up to DSD512." is very vague and I do not trust this marketing materiual, which mixes words 'native' (only USB relevant, as opposite to DoP) and 'direct' as synonymum to direct DSD path - that are 2 different thisngs - and by mentioning DSD512 it looks that they consider 'direct' and 'native' to be the same - about USB interface and not about direct DSD path.

I am waiting for further information and confirmations in this regard.

 

[roderickvd]

Appreciate you chiming in! I don't own any of the ones you mention, and fully take the word of Jussi, others and yourself on these implementations. Could there be an error in the AK4191 datasheet? According to tables 14 and 15, the AK4191 supports DSD512 and DSD1024 streams, so 22/45 MHz DCLK even when the base MCLK is 11 MHz! And according to table 24, DSDD ("DSD direct") can be set up to and including DSD512. Either this must be in error, or by using a PLL. In any case, I agree with you, it's a misnomer to call it "direct".

 

[bogi]

AK4191 supports DSD512 and DSD1024 streams, so 22/45 MHz DCLK even when the base MCLK is 11 MHz! And according to table 24, DSDD ("DSD direct") can be set up to and including DSD512

AK4191 supports DSD1024 only in indirect mode (it involves downsampling to 22.6 or 11.3M with format conversion from 1bit unary to 5-7 bit binary weighted representation and then re-modulation). Lower DSD rates can work also in this indirect mode.

Regarding direct DSD path, the interface between the chips operates at 5.6 or 11.3 M, so it cannot process DSD512 in really direct way, although according to the datasheet it is possible to skip volume control and delta sigma modulator of AK4191EQ with DSD512 too. If that's true, it would require to perform some kind of downsampling from DSD512 rate to fit the interface between the chips. I am very curious how the chip does that. Every downsampling requires also anti alias filtering. In any case, that's not direct DSD how we were used to understand this term. Gustard and Audalytic don't support direct DSD at DSD512 rate. I currently don't know about DAC with this AKM combo which would support that. Marketing materials are not a reliable source of information regarding direct DSD (except of manufacturers which specifically care about DSD, like Holo, T+A and few others).

 

[leaves]

I would like to ask those who have purchased the SDA-6 PRO2 or SDA-6 PRO or SDA-6, is the 5V power wire on the USB cable necessary for device recognition?
I would like to know if the above DAC can be used with a USB cable that eliminates only the 5V line or with a USB card that does not output 5V power (such as the JCAT USB CARD XE with the jumper pins removed).

 

[roderickvd]

AK4191 supports DSD1024 only in indirect mode (it involves downsampling to 22 or 11M with format conversion from 1bit unary to 5-7 bit binary weighted representation and then re-modulation). Lower DSD rates can work also in this indirect mode.

Regarding direct DSD path, the interface between the chips operates at 11 or 22 M, so it cannot process DSD512 in really direct way, although according to the datasheet it is possible to skip volume control and delta sigma modulator of AK4191EQ with DSD512 too. If that's true, it would require to perform some kind of downsampling from DSD512 rate to fit the interface between the chips. I am very curious how the chip does that. Every downsampling requires also anti alias filtering. In any case, that's not direct DSD how we were used to understand this term. Gustard and Audalytic don't support direct DSD at DSD512 rate. I currently don't know about DAC with this AKM combo which would support that. Marketing materials are not a reliable source of information regarding direct DSD (except of manufacturers which specifically care about DSD, like Holo, T+A and few others).

I've been changing my mind about upgrading my PRO to a PRO2 because of this. Loving HQPlayer DSD output directly to the AK4499EQ of my original PRO... not so sure anymore if the AK4191EQ + AK4499EX combo is going to improve on that. If listening to PCM, probably, DSD, I now doubt it.

 

[bogi]

I've been changing my mind about upgrading my PRO to a PRO2 because of this. Loving HQPlayer DSD output directly to the AK4499EQ of my original PRO... not so sure anymore if the AK4191EQ + AK4499EX combo is going to improve on that. If listening to PCM, probably, DSD, I now doubt it.

Splitting DAC functionality to two chips has its advantages and disadvantages. The advantage is separation of noisy DSP circuits from D/A stage. Within one chip their distance is maybe 1mm with all negative impacts of EMI. That's then lowering reachable DR and SNR numbers of the D/A stage.

Disadvantage of the discussed AKM chipset, affecting direct DSD mode, is design of the rate restricted interface between chips. It was not designed for direct DSD to work optimally. Clearly direct DSD was not considered to be a higher design priority. But, at least at DSD256 rate, it may work like direct DSD and it may bring better DR and SNR numbers than the previous single chip solution.

Newer devices in similar price range where direct DSD works as really direct at higher rates than DSD256 are for example ROHM chip based VMV D2R (DSD512) and Holo Audio Cyan 2 (DSD1024) with discrete D/A stage implementation and galvanic isolation of USB input.

 

[TheRealDz]

Still no purchasers? I am eager to hear how this one sounds...