Sunday, June 30, 2019

Singxer SU-6 USB Digital Interface


The SU-6 is an updated model to the very popular SU-1 Digital Interface from Singxer. The SU-6 is more than 1.5x the price of the SU-1, but is still modestly priced for a high performance USB Digital Interface.

The burning question though for most people would be why the need for this product ? USB inputs on DACs are ubiquitous and having an off-board solution is practically speaking not required. Apart from the expense of an additional box, you also have to budget for an additional digital cable, rack space and other accessories like a power cord and footers.

My personal experience is that most DACs do benefit from being paired with high quality USB converters, often sounding significantly better compared to a direct connection to the DAC's USB input. In the case of the SU-6 (and also the SU-1 for that matter), it also brings I2S output to the table for compatible DACs. 


The SU-6 is a compact metal black box, with three indicator lights on it's front panel. The rear panel reveals the flexibility of the SU-6, with a DC jack for it's supplied external power supply (you can use any 7.5 - 9 V DC power supply with a 3A current rating), a USB input, and no less than 7 digital outputs, and a word clock output. Not bad for a product that carries a three figure price tag. 

The digital outputs consist of two SPDIF jacks (one coaxial and one BNC), AES / EBU, Toslink, and three I2S outputs (two HDMI sockets, and RJ-45). Since there is no industry standard for I2S, Singxer thoughtfully includes a bottom panel cutout with a variety of DIP switches to configure the I2S output. I did not get to test this, although I tried the SU-1's I2S output over HDMI with the Holo Spring and Denafrips Pontus DAC.

A word about the power supply - the SU-6 uses a 7.5 F (7.5 million uF) supercapacitor    power supply, the supplied switched mode power supply is used to charge up the internal power supply. 

The SU-6 utilises two Crystek CCHD low phase noise Femto second clocks. These clocks are contained in a metal enclosure for temperature stability. 

All common sampling frequencies are supported, including the ability to handle 32 bit data. DSD sampling rates cover DSD 64, 128, 256 and 512. 32 bit data is only available over I2S as the SPDIF standard supports up to 24 bit data only. 

The key differences between the SU-1 and SU-6 are set out below :-
                             SU-1                                                 SU-6
Power Supply       Onboard linear power supply           SMPS + Ultracapacitor power supply
Femtoclocks         One                                                  Two (Temperature controlled)
I2S                        HDMI                                                HDMI and RJ45
DSD Support        64, 128 and 256                               64, 128, 256, 512
Digital Outputs     AES, 2 x SPDIF, 1 x I2S (HDMI)       AES, 2 x SPDIF, Toslink, 3 x I2S (HDMI / RJ45)
Customised I2S   Yes                                                    Yes
Power Switch       Yes                                                    No

Sound Quality

The proof of the pudding is in the eating. In the case of the SU-6, it offers a sweeter taste with less astringency and a fuller and more refined mouth-feel compared the SU-1. I would also like to point out that my SU-1 has been modified to accept and external power supply. I use mine with an Sounds Affairs Plixir Elite Balanced DC power supply. 

Modified SU-1 pudding performs at a much higher level than stock pudding, so I can assure owners of stock SU-1 units, that the SU-6 performs at a much higher level. That leaves the comparison then between the modified SU-1 and stock SU-6. Price wise, the SU-6 commands only a small premium, after you take into account the cost of modifying the SU-1 backplate, and an aftermarket power supply.

The SU-6 offers a high level of information retrieval, with a silky and refined top-end and  controlled bass with the right amount of tightness and bloom. Midrange is more laidback and richer compared to the SU-1, but is still detailed and textured. You do not get the feeling of information being smoothed over, but yet music is at all times very well behaved.

I would argue that the SU-1 is tonally more neutral, but without the refinement and fine resolving power of the SU-6. The SU-1 also comes across sounding as somewhat clinical and dry, especially through the SPDIF outputs. This required careful cable matching to balance out the tone. In this respect, the SU-6 is more cable agnostic. You are also able to tune the SU-6 through choice of power supply. 

To be continued ...

Saturday, April 27, 2019

Acrolink 8N-PC8100 Performante Power Cable


Just worked yourself to the bone saving your precious pennies for the flagship Acrolink 7N-PC9700 power cable ? The bad news is that Acrolink has launched a limited edition model, the 8N-PC8100 Performante Cable. I certainly didn't see this coming, especially so soon after the launch of the 7N-PC9700 ! Such is life, and we can only see whether this new model (limited to only 99 pieces in the world)  will dethrone the King of the castle.


Acrolink has somehow managed to retrieve enough stressfree 8N copper material from it's secret vault to launch this limited edition series (the current lineup uses 7N DUCC conductors). Technically, the PC8100 is closer to the PC6700, with both using 50 strands of 0.37 mm diameter copper conductors for neutral and live conductors, as well as polyolefin, tungsten and amorphous powder as filler (the PC9700 included carbon powder). The shield is different, with the use of copper foil tape and silver plated copper braid, instead of carbon tape and enameled copper braid on the PC9700.

Visually and handling wise, the PC8100 and PC9700 are similar, with identical plugs, and flexibility (or lack thereof).

Pricing will depend on your market, but be assured that the PC8100 will cost significantly more than the PC9700. In Singapore, the local dealer X-Audio is offering this cable for S$ 5,500 (or about slightly more than US$ 4,000).

Sound Quality

Admirers of the Acrolink Mexcel house sound will not encounter any surprises - the PC8100 treats it's audience to extended and silky highs, with a refined presentation that is precise and quiet.

A concise way to describe the PC8100 is that this is the progeny of a union of the PC9500 and PC9700, with a well-struck balance that highlights the strengths of both Mama and Papa cable. The PC8100 has the well-defined strength and muscularity of a bodybuilder, and the speed, elegance and grace of a ballerina ! Click on these links to see my previous reviews of the PC9500 and PC9700.  

But stopping short at this description would be doing the PC8100 a disservice - it is able to do everything slightly better than the PC9700, with a slight edge in resolution, micro-detail and background quietness. Throw in the low frequency authority and dynamics of the PC9500, and you have it all - at a price (financially). 

Your choice of poison really depends on taste. The PC9500 has the most powerful sound, albeit with a more raw edge to it - perfect for the rockers. The PC9700 has the most laidback and sweet tone - perfect for small scale jazz and classical works, or vocals. The PC8100 takes the middle road, which is great if you listen to both ends of the spectrum, but an audition is a must - it may be too polite for the headbangers and too forceful for the pipe and slippers crowd. The level of improvement compared to the PC9700 is more evolutionary than revolutionary, and the PC9700 owners should be able to sleep soundly at night. For the prospective Mexcel purchasers sitting on the fence though, this cable is really the one to have in my view.


The PC8100 demonstrates Acrolink's commitment to pushing the envelope of what is possible from power cords. If you move fast, you just could be one of the lucky owners of this limited edition flagship cable. A big thanks goes out to the guys at X-Audio for making this review possible.

Acrolink 8N-PC8100 Performante Power Cord
Price : S$ 5,500 

X-Audio Pte Ltd
Bukit Timah Plaza. 
1 Jalan Anak Bukit, #01-01S
Singapore 588996
6466 2642 

Sunday, April 21, 2019

SB Acoustics Ara Beryllium Speaker Kit


Welcome to Part II of the SB Acoustics Ara Speaker Kit review. This article covers the assembly process of the speaker kit, an upgrade to the Beryllium tweeter, and our very first episode of "Pimp my Speaker" !


A short walk back to the initial article of the SB Acoustics Ara Speaker Kit review would be useful to understand the speaker in depth. For now, let's have a look at the assembly and tweaking process.

Assembly of the speaker kit is quite easy for anyone with some DIY experience. I would not however recommend it for first timers as decent soldering experience is required, and the speaker driver units are quite expensive - one slip of your screwdriver is all it takes to destroy them.


My kit came with fully assembled cabinets and crossover boards. The crossover board is wired with their leads terminated in push-on clips for the drivers, and tinned leads for the binding posts. 

The most tedious part of the assembly would be the cutting of the fiberfill pads to size, and pushing / gluing everything into place. The crossover board can be a bit tricky to install though, as you need a short stubby cross head screwdriver to attach the board to the base of the cabinet. In my case, one of the cabinets did not have any pre-drilled guide holes and I had to hammer the screws into the cabinet to make my own guide holes.

The rest of the hook-up process is quite idiot-proof. The push on clips are sized to match the terminals of the speaker drive units, so you can't install them in reversed polarity. I also liked the fact that the holes for the binding post plate and both drivers had metal thread inserts - no more stripped MDF, and you can torque the bolts with confidence (but not gorilla strength please !). The length of the supplied cables were generous and you do not need to be a contortionist or Octopus to attach the wires to either the binding post or the speaker drivers. The binding post leads do need to be soldered though - the only time your soldering iron will get any action. A glue gun is also required to seal the guide holes where the crossover board wires connect to the binding posts, or you could use your imagination to seal them in any other way you deem fit.

Pimp My Speaker

Good Audiophiles like to milk every ounce of performance out of their gear and DIY equipment are a great way to express and showcase your creativity and talent. I installed the crossover board on top of the speaker, and extended the leads using Belden wire and terminals blocks. The speakers were given about 10 hours of run-in time in between each stage of modification unless otherwise indicated.  

Part 1 - Replace the sandcast resistors with Ohmite and Mills resistors

Nothing fancy used here - just wirewound Ohmite and Mills MRA-12 resistors. The latter have non-inductive windings. Despite their specified tolerances, all of the resistors measured very closely, within +/- 0.1 ohms of their stated values.  

The stock resistors are "thoughtfully" glued into place. Brute force is required here to detach the resistors from the board. 

There is a slight but noticeable improvement here, with an uplift in clarity and reduction in grain. 

Part 2 - Replace the plastic capacitors with Auricap XO film capacitors

The stock Jantzen Cross Caps supplied are quite decent, but the Auricaps are well worth the expense. The Auricaps improve clarity and lend an extra level of dimensionality and detail to the speakers. In comparison, the Jantzen sound flatter and drier. 

Stock crossover board in the middle of surgery

All complete except for the wires

Part 3 - Replace the speaker drive unit leads with Neotech OCC cables, and the binding posts with Furutech.

I used 20 AWG Neotech Pure Silver solid core OCC wire for the tweeters, and 16 AWG multi strand copper OCC cable for the woofers. I am not really found of push on terminals, and soldered the cables directly to the drive unit terminals.

The initial impressions were quite negative, with the speaker losing both drive and vitality. These cables use Teflon insulation, which have a reputation for long run-in time -  I put in 48 hours of run-in here. Post run-in, the cabling provided a higher level of refinement and micro-detail. The stock wiring has a more forward and incisive sound, but in terms of layering and staging, the Neotech is noticeably better. The Furutech FP-803B(G) binding posts just happened to be lying around - the stock posts would do just fine.  

I would rate the capacitor upgrade as the most effective, followed by the internal wiring upgrade. The resistors and binding posts could be left alone, unless you are the sort that leaves no stone unturned. Actually even with the stock crossover board, the performance level is already very high. 


The Beryllium tweeter is well worth the upgrade in my opinion. In my earlier article, I pointed at a slight discontinuity between the two drive units, and a prominence to the tweeter that called a bit of attention to itself. There were no such issues with my personal build (the version I heard used the silk dome crossover board with some modifications). I would only recommend the fabric dome version if budget is tight, or you have a dislike for extended high-frequencies.

If you felt that the base level kit was great value, this premium version will have the competition running scared - it's that good !