[dellafago]

Hi, I am planning to purchase usa (110 volt) version of x20pro through amazon usa when I will be there next month. Hence I kindly ask what should I do to use it when a go back to my home country having 220v/50 hz country electricty. In addition to sliding the ac voltage switch at the back of the unit from 110 volt to 220 volt, should I also need to change the fuse (and can it be simply replaced from the back of the unit without opening the unit box). And, if fuse must also be replaced, I kindly wonder if anyone knows such fuse's specs to be suitable for 220v/50 hz and I would also like to know wherher I need to go through an additional modification for the intended voltage conversion like a capacitor change etc. which will probably change my plan to buy it from usa. Thanks in advance, regards.

 

[markk02474]

   
Would you please let us whether it is easy to take the board out and whether it is easy desolder those M4s? Also, what is the model number of the Fred diodes you put in? 

I didn't take the board out, just the front panel by removing some Torx screws, gently pulling out the ZIF cable for the front panel, and unplugging the connector on the DAC/output board. Unsoldering the M4 diodes was fairly easy using an iron and Solder Wick.
 
So, I used VS-HFA004TB60-N3 TO-220 package diodes with leads trimmed a bit, some face up and others face down so Cathodes matched originals. When cool, I just bent them up, but probably not needed for clearance. I must say I'm impressed with the circuit board in that PC traces don't peel up easily like most other consumer audio gear.
 
However, after seeing 8 more M4 diodes on the edges of the board down near the buffering and output circuitry, I ordered some surface mount Vishay Fred Pt parts for there, VS-3EMU06-M3/5AT. These are about 1/3 the price and should fit exactly in place of the original diodes, so much cleaner too. I will report on results after using them to replace those other diodes. Not sure if I will bother replacing the freds I already put in. This time I will need to remove the board from the chassis.
 
You could also try SS34 surface mount Schottky diodes as used on the clock/input board and front panel. These have a smaller voltage drop and are supposedly also soft recovery. Price is similar to Fred surface mounts, around 30-40 cents (US, depending on quantity) each compared to under 1 cent for M4 diodes.

 

[wwmhf]

Many thanks for sharing your experiences. Now, I need time ...

 

[markk02474]

I just did another upgrade. My ifi SPDIF iPurifier ($149.99) came. Took maybe 2 seconds to hear the improvement using my Oppo BD83se as a CD transport. Veils removed, soundstage opened yet more, sound yet further to the sides, behind and above speakers. Doubles as a coax<->toslink converter, though I still preferred coax.

 

[MLGrado]

  I just did another upgrade. My ifi SPDIF iPurifier ($149.99) came. Took maybe 2 seconds to hear the improvement using my Oppo BD83se as a CD transport. Veils removed, soundstage opened yet more, sound yet further to the sides, behind and above speakers. Doubles as a coax<->toslink converter, though I still preferred coax.

 
Yup.  Am amazing product.  
 
 
I have had similar results with the USB iPurifier2 in combo with the original iUSB 2.0 Micro and the two head Gemini cable, and the iPower PSU.  
 
Just incredible.  The REGEN and LPS I was using is now stuffed in a drawer somewhere.  

 

[markk02474]

I ordered an iSilencer and plan to buy a 15v. iPower for my Universal Audio Apollo Twin interface (Thunderbolt, not USB version)
 
By the way, I just bought a 16 foot QVS USB3.0 active extender cable. It has a built in USB re-generator that seems like those used in much more expensive audio products. At Provantage.com for example its only $10.76. Its not like an audio tweak company had an integrated circuit designed and made for audiophiles!

 

[allhifi]

"Chip doesn't actually matters so much." One hears this all the time. Let's get real --and smart. The "chip" type and sophistication matters a great deal.
 
Why do company's test and audition chip-after-chip, if its impact is small/negligible?  
And how is tat that every new-generation DAC is typically better than its predecessor ?
 
Is it that these companies are just "learning" about sophisticated power supply design, grounding schemes etc.
No, they know of such considerations (hopefully) in electronic circuit school !
 
Indeed, as a product (DAC) evolves, more research into circuit board type, layout, grounding may be evaluated --and implemented.
 
Yet, the heavy-lifting is the DAC itself --if it's messed-up, no P/S, or output-stage will save it --from sounding like crud.
 
So, finally, for all, please refrain from suggesting DAC chip type/gen. has little influence.
 
pj 

 

[allhifi]

The ESS 9028-PRO chip is a direct drop-in replacement  (for the 9018). Not so for the 9038 --circuit design changes required.
Possibly a price differential as well?
 
If better, the 9038 will likely be in the next-gen. X-20 --or successor. A price increase likely --due to further R&D (with the X-20PRO/9038).
 
pj 

 

[allhifi]

 
Hi, No reason to panic. Shenzen will reply to your email. I got the A20H last week and Susie wrote back after a day or so. There is no battery in the remote, because that is not allowed in the shipping. They cost a few $ on Amazon. Shenzen is a huge company and they will resolve the issue with the X20pro, which may simply be DOA, so that you need a new one.

Hi Everyone: I'm strongly considering purchasing the new X-20PRO DAC. 
 
The "DOA" and other issues are a bit disconcerting however. 
 
Shenzhen Audio is who I'm considering to order from. Any other recommendations --or advice?
Thanks,
 
 pj

 

[mishoristov]

Can I get this somewhere in Europe?
m.

 

[rafabro]

Look for on ebay. Some time ago I've seen seller from Germany.

 

[Maru10]

O can recommend that particular german seller. I got full refund on x20pro (quality issue - one channel not working). Customer service was immaculate.

 

[Peleg]

New to posting here. I may have missed it but does the x20 Pro have op amps in it that can be changed to something like Burson discrete op amps? Thanks.

 

[rafabro]

No, doesn't have any.

 

[markk02474]

  New to posting here. I may have missed it but does the x20 Pro have op amps in it that can be changed to something like Burson discrete op amps? Thanks.

There are two surface mount ADA4898-1 ultra low-noise op amps per channel, used for converting the ES9028pro differential current outputs to voltage output. They are not easily replaced. They are very, very good, so not sure you would want to replace them. These are like the famous AD797, but half the price at about $2.29 each, and much higher speed, which is what you want for low distortion DAC current to voltage conversion. The price for the much faster speed is -110 db THD versus about -120db THD for the AD797. I doubt any other op amp or discrete amp could better Gustard's choice.
 
If you want to swap op amps, there is another ES9028pro DAC which may interest you when they work out the bugs of the current firmware. I bought one a few weeks ago and its version 1.0 firmware only worked for USB input, not coax or optical inputs! The output stage is reference standard ESS. There is a dual op amp on each channel for balanced outs, and then a second single to convert those to single-ended outs. All but a couple parts are through-hole, so they too can be more easily upgraded. This seller stopped responding to me after I asked a couple times about getting firmware that works. Meanwhile Gustard support from topsales has been first rate.
 
The version I bought was a premium version with Noratel toroidal transformers, Muses 8920 op amps for I/V conversion, and AD797 for the balanced to single output conversion. There are two 4.7k SMT resistors right before the first op amps. Capacitors are all high grade: WIMA, Nichicon audio caps, and Oscon for digital sections. My Amero USB to I2S board uses the miniature, and probably higher jitter oscillators. The circuit board is labeled: Heart ESS9018 V1.1 2015-5-12.
 
http://www.chinaaudiostore.com/274-latest-es9028-es9028pro-premium-32bit-384k-dsd-dac-da-converteroptional-asynchronous-usb-input.html#/11-color-black/35-usb_input-amanero_italy
 
Compared to the x20pro, the above "designed by

Weiliang"​

"Breeze Audio" dac is smaller, has half the size (25w) transformers, no remote, no phase reverse, no +6 and +12 levels, no discrete output buffers, no AES input, a single shared noisier regulated (LM 317/LM337) power supply shared by both output channels, and just one dac chip. What is better than Gustard is a low jitter 100MHz clock right next to the dac chip, and low noise diodes everywhere, while the Gustard only has them on the input/clock and display boards. Baffling why Gustard didn't use soft recovery diodes on the output board (topped out budget?). Stock, I think the Breeze sounds slightly better than Gustard, but after some minor mods to the Gustard, its better and with more potential. Oh, and the Breeze costs less than half as much. I've not tried upgrading the Breeze op amps yet, but likely will try ones from Sparkos after I get a firmware fix. Other opportunities are DC-coupling the balanced outputs, upgrading the 3 terminal voltage regulators with discrete replacements, and upgrading the resistors and capacitors in the outputs.
 
The DC-blocking caps in the signal path are little green Nichicon 10uf/25v electrolytics bypassed with Wima films. I am not sure if they are genuine Wima caps as there is no indication if they are MKP or other dielectric. I'm no expert in detecting Chinese fake parts or what genuine Wima caps should look like. They are red, boxes that say Wima for sure. Another strange thing is the ESS dac chip appears like someone tried to remove the markings with acetone/sanding, as is sometimes done to protect intellectual property in electronics.
 
My criteria for "better" is a more relaxed and musical sound and bigger, more 3 dimensional soundstage through speakers - not sure you'd appreciate it as much on headphones.
 
Meanwhile, Oppo seems to have delayed their ES9038pro DAC yet again, saying "early 2017" availability.
 
So, again, DON'T buy the above DAC if it has ES9028 V1.0 firmware. Wait for them to fix it so coax and optical toslink work. I got the Amero USB board, though XMOS is available too. Oh, one other problem with it: the female RCA jacks are just ever so slightly too big in diameter. My cables plugged in fine, but my ifi TOSLINK iPurifier wouldn't fit, which is a problem because it really improves SQ. Well, when they get coax SPIDIF working, that is.