[MINORISUKE]

  Gustard DAC-X20
http://item.taobao.com/item.htm?spm=a230r.1.14.35.1TBYRG&id=520159383364&ns=1&abbucket=14#detail
I found this on Taobao.  It seems that Gustard is going to control its selling price: USD 799 (without USB input); USD 866 (with USB input)
ES9018 dual mono

The optional USB-I2S/DSD board seems to use a connector with several large pins, which means MX-U8 I2S/DSD output can be fed to DAC-X20 easily, I assume.

 

[b0bb]

  Gustard DAC-X20
http://item.taobao.com/item.htm?spm=a230r.1.14.35.1TBYRG&id=520159383364&ns=1&abbucket=14#detail
I found this on Taobao.  It seems that Gustard is going to control its selling price: USD 799 (without USB input); USD 866 (with USB input)
ES9018 dual mono

$870 the USB input version of the X20
http://www.ebay.com/itm/GUSTARD-DAC-X20-Super-Ultimate-HIFI-DAC-2xES9018-XMOS-USB-384KHZ-DSD64-128-/111708547958

 

[rb2013]

 
$870 the USB input version of the X20
http://www.ebay.com/itm/GUSTARD-DAC-X20-Super-Ultimate-HIFI-DAC-2xES9018-XMOS-USB-384KHZ-DSD64-128-/111708547958

I'm inclined to the more tonally rich R2R DAC's especially with a true tubed output.  The Lite DAC60 in stock form is pretty amazing - with some mods it's killer good.  Smooth, musical, rich natural tone, detailed and transparent.
 
$650 shipped with buyer protection.
http://www.ebay.com/itm/Lite-DAC-60-Hi-Fi-D-A-Convertor-Tube-Output-Brand-New-/321461674743?pt=LH_DefaultDomain_0&hash=item4ad89be2f7
 
With some mods and great tubes - rivals and in some ways exceeds my APL DAC that cost 6 times as much.
 
What you don't get is I2S and native DSD - but so what.  If the SPDIF sounds great who cares (especially with all the issue surrounding hdmi/rj45 i2s).  And how many real DSD files are available (versus DSD conversion of PCM files) and those can be played with a DSD to PCM Foobar converter.  What you get is sumptuous musicality, extended bass and excellent detail and holographic sound staging.
 
The link to the mods I did to get it to world class.
http://www.head-fi.org/t/740362/lite-dac60-pcm1704-r2r-tubed-dac-mod-project
 
Some info on the pluses and minuses on different DAC designs (The ESS Sabre have been know to be 'hard' sounding).
 
Here are some great articles that explains resistor ladder DACs vs the sigma-delta and multi-bit newer designs.  All have issues.  The R2R's are very expensive and difficult to make, the S-D have major filtering issues and the Multi-bits have on silicon opamps.

http://www.mother-of-tone.com/conversion.htm
http://funwithaudio.blogspot.com/2012/01/today-in-electronics-everything-is-made.html

Some of the very best DAC's use R2R ladder DACs - like Audio Note, Total DAC, MSB, Audio-gd (Master 7 - uses the same PCM1704 but twice as many), Zanden, etc...

 

[jodokus]

I'm waiting for the Elfidelity AXF100 Pro USB card to clean up the USB bus, but also read some positive comments about the Audioquest Jitterbug. Do you guys think the Jitterbug does mostly
the same as the Elfidelity card? Or would they be a good team together?
 

 

[rb2013]

Anybody try the Hydra Z?  It looks outstanding Crystek 950/957 clocks, excellent PS filtering and USB isolation.
 
http://audiobyte.net/products/hydra-z
 

  MORE FLEXIBLE The Hydra Z can be powered in 3 (three) ways :

1. Directly from USB
2. From an external, fixed 5Vdc/0.5-1A power supply
3. From the dedicated Hydra ZPM (Z-Power Module)

Furthermore features:

1. Extended number/type of outputs
2. Adjustable I2S output clock polarity, to match all HDMI/I2S/LVDS dacs available
3. Adjustable masterclock output on I2S (512xfs or 1024xfs)
4. Firmware upgrade over usb
5. DSD native / DoP / hi-quality PCM converted (selectable)
6. DXD native (I2S out) / 192k or 176.4k (spdif, aes, bnc out)

TECHNICAL IMPROVEMENTS Hydra Z benefits from all the qualities of the X+, and even more. New clocking scheme allows shutting down one of the two main oscillators when not in use. By reducing the mutual interference between clocks, better phase noise performance can be obtained. The power supply section was moved to a different chassis for best results.

WORDCLOCK and MASTERCLOCK OUTPUT The Hydra Z can be additionally used as a wordclock or masterclock generator through its dedicated BNC output. In total there are available 6 (six) outputs, including the low-jitter wordclock/masterclock output for direct synchronizing external d/a converters. The output wordclock is the sample clock (44.1KHz - 384 KHz) or 512xfs (22.5792 MHz or 24.576 MHz). The other 5(five) are : SPDIF Coaxial, SPDIF BNC, AES/EBU, I2S, TOSLINK.

IMPROVED CHASSIS The new Hydra has a full aluminium chassis, with a 10 mm thick front panel. All connectors are conveniently placed on the back panel.

ISOLATION A 5KV isolation barrier is used to prevent any leakage of the noise from PC to your sensitive audio system. The USB isolation for audio devices is nothing but tricky. If you choose to use USB isolators, then sample rate will become limited, which is not an option. If you choose to isolate the output, you are adding significant amounts of jitter to the signal. By using a clever circuit topology, the Hydra design avoids these two bottlenecks. The isolation is placed between the ARM processor and the FPGA audio core, therefore not limiting the bandwidth. Being before the clocks, its jitter contribution becomes irrelevant.

ARM PROCESSING All USB audio transactions are made through a powerful ARM3 processor. Therefore Hydra Z supports any sample rate available (384k PCM, DSD128) while being future-proof for any extension.

FPGA TECHNOLOGY As all AUDIOBYTE digital products, the Hydra Z uses cutting edge, custom digital processing developed into a Xilinx Spartan6 field-programmable gate array. The fpga is the “heart” of the Hydra. This advanced programmable circuit is offering a bit-transparent processing and signal conditioning to all outputs. It also gives the ability of the Hydra to output raw dsd audio streams.

AUDIO GRADE CLOCKS Unlike other products which only specify "low jitter clocks", here is exactly what you will find inside : 2xCCHD-950/957 type from Crystek. These are real audio grade clocks. You can check real graphs for them here. These clocks are system masters. In order to remove any jitter induced by the FPGA circuit itself, special retiming is applied just before the Hydra Z outputs.

COMPONENTS AND LAYOUT Careful PCB layout is often neglected in the rush of getting a product quickly into the market. The Hydra Z design time took lots of work until everything came into the right place, until the shortest routing paths, the best decoupling places, the less interference and crosstalk placement for the components are found. Selected quality components (active and passive) are used for guaranteed long-time performance.

EXTERNAL POWER SUPPLY For best results you can use the Hydra Z with the dedicated Hydra ZPMpower supply.

DSD

1. 2.8 MHz (DSD64) - DoP, native
2. 5.6 MHz (DSD128) - DoP, native
3. 11.2 MHz (DSD256) - native (via ASIO)
4. 22.5 MHz (DSD512) - native (via ASIO)

PCM

1. 44.1 KHz
2. 48 KHz
3. 88.2 KHz
4. 96 KHz
5. 176.4 KHz
6. 192 KHz
7. 352.8 KHz
8. 384 KHz

 

1. Native MacOS 10.6 and later
2. Native Linux with UAC2 compliant kernel
3. ASIO, WASAPI, KS, DS drivers for Win XP to W8 32/64 bit
4. Recommended players : Foobar2000, Audirvana Plus, Jriver etc.

 

 

[bballas]

Chinese brand usb interface ,with XILINX FPGA，and CRYSTEK oscillator.
 
Half price than hidra z.
 

 

[m0reilly]

but not THE crystek. link to the device?

 

[m0reilly]

yep, a tanly. still like a purchase link for us in the usa...the hydra for me would be around $300 more or less. no mods needed on the face of it...

 

[prot]

Anybody try the Hydra Z?  It looks outstanding Crystek 950/957 clocks, excellent PS filtering and USB isolation.

http://audiobyte.net/products/hydra-z

Did not try the HydraZ but here's some (hopefully) useful info.
AFAIK, the company behind audiobyte is a MSB partner .. they write the MSB software and also sell a MSB-like DAC under some other brand (rockna?).

Judging by that, the Hydra should be a TOTL device ... and for people in the EU it's prolly cheaper than Tanly (no extra VAT, customs tax and less shipping costs) .. plus a reliable EU warranty. May even be cheaper from the US cause you normally get the EU VAT (~22%) back.

You may wanna contact user dan.gheorghe or check his review site .. he seems to know the people behind audiobyte

 

[rb2013]

 
Chinese brand usb interface ,with XILINX FPGA，and CRYSTEK oscillator.
 
Half price than hidra z.
 

I know all about the Tanly - it's been discussed here for months. It's not half the price, it's slightly less costly when all the costs (like German middlemen addons) are concerned.  That is with no guarantee at all - even if it arrives DOA.  You can buy a Hydra Z right now for $700 here on Headfi check the classifieds.
 
I suggest you do some research  first before posting rehashed and/or false information

 

[rb2013]

Did not try the HydraZ but here's some (hopefully) useful info.
AFAIK, the company behind audiobyte is a MSB partner .. they write the MSB software and also sell a MSB-like DAC under some other brand (rockna?).

Judging by that, the Hydra should be a TOTL device ... and for people in the EU it's prolly cheaper than Tanly (no extra VAT, customs tax and less shipping costs) .. plus a reliable EU warranty. May even be cheaper from the US cause you normally get the EU VAT (~22%) back.

You may wanna contact user @dan.gheorghe or check his review site .. he seems to know the people behind audiobyte

Yes the parent company is called Rockna.  The technology in Audiobyte is a trickle down from Rockna.
 
Here is a excellent review of their Wavedream.  The Hydra X+ is discussed in the review and very favorably.  It was the model before the Z, those can be bought used for less then $500.
 
http://www.6moons.com/audioreviews2/rockna/1.html
 
Interesting quoted from the article:

Whilst the current PCM/DSD debate gets more confusing with each passing day—experts disagree, manufacturers disagree, digital converter and recording equipment specs disagree on whether 'pure' DSD and PCM even exists on the recording never mind playback side—there's far more consensus about the ideal way to decode PCM. In theory. Say hello to multi-bit ladder-type aka R2R converters (click here for some tech talk on the subject). But why are so few actually doing it in practice today? Because such silicon has fallen out of popularity with the chip manufacturers whilst remaining NOS inventories are being depleted. Curiously the same is true for bona-fide 1-bit DSD converter chips. They've vanished for good. It's peculiar that given the current format debate moving briskly through the audiophile specialty press, purpose-engineered conversion silicon for either format is no longer being made. (Which isn't 100% true. Cees Ruijtenberg of Metrum Acoustics for example keeps building R2R DACs with currently made silicon, albeit from the non-audio industrial sector to remain unidentified.) 

 For those not wishing to spend their own years and discretionary funds in R&D of the same, MSB's discrete converter modules are available for OEM (we've previously encountered them in the Bulgarian Thrax Maximinus) just as are Andreas Koch's FPGA-driven DSD algorithms. With the mention of MSB and OEM—the latter bidirectional—we now arrive at today's subject. Welcome the Romanian Rockna Audio WaveDream DAC. Whether single-ended or balanced, in Reference or Signature guise, it gets two or four 2nd-gen modules sourced from MSB "capable of a sustained maximum sample rate of 3MHz". Beyond that designer Nicolae Jitariu pursues his own paths just as past their custom ceramic Koch board Nagra do with their HD DAC. Interestingly Nicolae has provided his own OEM/ODM assistance to Audio Mirror, Acoustic Precision, Fase, Jadis, Nonsolomusica, PS Audio (PerfectWave transport), Wadia, Goldmund and, yes, MSB. Though his name might still be news—Rockna Audio have been around for 15 years—you could already be familiar with his work.

As though to underscore his engineering credentials, Nicolae's €699 Hydra X+ under his second lower-tier brand Audiobyte performs its battery-powered USB bridge functions with a custom-coded Xilinx Spartan 6 as another FPGA custom job. To it he adds premium Crystek clocks and I²S output via HDMI. The Hydra X1 is thus direct competition for Audiophilleo and SOtM. Obviously the upscale WaveDream DAC gets the same proprietary USB solution, not a generic M2Tech, XMOS, Amanero & Co module. But our DAC get a lot more that's not off the rack. This includes selectable digital filters written by Jitariu's team. Those exploit 15 GMACS of processing power from 58 DSP blocks and "avoid standard Nyquist rate filters" in favour of "an advanced 2000-tap convolution filter created from a Parks-McClellan equiripple combined with a raised cosine type". Even his Femtovox clocking scheme is different*. The linear power supplies get three transformers and 20 linear regulators "designed from scratch for low impedance and ultra-low noise". 

"The heart of the WaveDream clocking system is a digitally programmable low-jitter clock. Its precision is set by a 38-bit control word which gives an accuracy of <1ppb (parts per billion). This clock generation creates a very low jitter of 0.3ps or 300fs on any input sample rate. In absolute terms there are claims of lower jitter figures on the market which can be obtained only by using oven-controlled crystals at single frequencies. With sample rates varying from 44.1 to 384kHz, it’s unlikely that a DAC can work with a single master-clock frequency unless it uses an ASRC with its own set of problems. Our digitally controlled clock allows bit-transparent operation without the smearing caused by an ASRC block. But the master-clock generation technique isn’t all. To properly adjust the digitally controlled oscillator frequency, our system measures the incoming sample rate with high accuracy. Whilst that could simply program the DCO, we use a complex algorithm that takes care of the real frequency that's written in real-time to the DCO. The algorithm keeps frequency variations to a minimum to yield a fixed frequency in the short term and to track source frequency deviations over the long term. The resulting loop corner frequency of the system is as low as 0.5Hz." 

They really have a unique solution and it looks to be superior to the off the shelf implementation of the XMOS in the Tanly.
 
Other advanatages of the Z - word clock output to possibly feed a DAC.
 
His take on the Hydra X+:

Hydra X+ retailers by the way report good workings of its I²S output into the equivalent port of Wyred4Sound's DAC2se-DSD converter (alas not without small ticks for DSD). Sonore and PS Audio also support I²S over HDMI. Such parallel-data ports can thus be used not only from a spinning transport like Paul McGowan's PerfectWave but also with this USB bridge (hence such devices are also known as CATs or computer audio transports). Whether that expense including a short HDMI leash will be worth the sonic uptick over going with a DAC's own USB solution should depend on your DAC and the overall resolution of your system.

Here we see Nicolae's block diagram for USB isolation and why he believes his is superior to the two standard types. The next diagram shows his TI silicon dioxide isolators which he prefers to common opto-couplers. From their application notes we learn that "these devices have a logic input and output buffer separated by TI’s SiO2 isolation barrier providing galvanic isolation of up to 4000 VPK. Used in conjunction with isolated power supplies, these devices block high voltage, isolate grounds and prevent noise currents on a data bus or other circuits from entering the local ground and interfering with or damaging sensitive circuitry. A binary input signal is conditioned, translated to a balanced signal then differentiated by the capacitive isolation barrier.

 
Excellent PS design and much attention to USB isolation

 

"Across the isolation barrier a differential comparator receives the logic transition information, then sets/resets a flip-flop and the output circuit accordingly. A periodic update pulse sent across the barrier ensures proper DC level of the output. If this DC refresh pulse is not received every 4µs, the input is assumed to be unpowered or not being actively driven and the failsafe circuit drives the output to a logic high state. The small capacitance and resulting time constant provide fast operation with signaling rates available from 0-150Mbps. The A-, B- and C-option devices have TTL input thresholds and a noise filter at the input that prevents transient pulses from being passed to the output of the device."

As these photos show, the '+' version Hydra has the clearly bigger battery over the original.

It now piggybacks above the main board on its own bed with standoffs. With this battery upgrade and attendant altered power management, play time of the Hydra X+ is over 40 hours. That's 4 times longer than the original. A full recharge now takes 9 hours i.e. overnight.

Sound quality:

Sonically my $1'350 two-box SOtM ride with super-clock feature had no definitive advantage. If there were any differences (depending on track I felt quite uncertain), they operated solely in the domains of relative soundstage depth and subjective speed. Sometimes the Hydra X+ seemed to have me more aware of a bit of added stage depth. At other times and obviously without any change in pitch, I thought the SOtM was the more relaxed to play it marginally slower. Because these observations were so subtle, ambivalent and as such unreliable, I decided to write them off. For all practical intents and purposes, these components were ideally matched equivalents and as such perfect stand-ins. Given the price offset, for many Rockna would be the obvious choice. It also passes 32/384. For those who hate black, sideways cable routing and don't do anything above 24/192, SOtM would swing the vote despite the added cost. 

Compared to Metrum Hex direct as the type of comparison potential buyers would find most relevant, the Hydra X+ improved what I thought of as timing. This manifested most notably on transients as the initial rise of sounds from silence being better defined. During complex passages this led to greater definition. It directly assisted better separation as the ability to follow many overlaid intertwined lines without suffering shadowing effects of partial obscuration. Lastly, minor tendencies for image bloat disappeared. This action is a very subtle shrinkage or firming up that comes from reduced micro blur. Very attack-driven crisp music makes it easiest to first hear the improved leading-edge definition. Think percussion and plucked strings. Gentle legato-rich recordings or those where microphones stood at a distance to capture more mixed-in reflections take steps back from this quality. It still applies of course but less overtly so.
 
The same goes for programmatic complexity. Girl+guitar fare is so non-challenging on complexity that you won't benefit from improved separation unless you started out very poorly indeed. In short, depending on how good the USB transceiver of your DAC is, an add-on external USB bridge will make less and less to no difference. In my financial comfort zone, I've simply not come across a DAC yet which couldn't be at least subtly improved by the best USB bridges à la Audiophilleo or SOtM. Now the Rockna Audio Hydra X+ adds itself to that list. To quantify the level of improvement I experience with adding a superior outboard USB bridge to DACs of Metrum Hex, AURALiC Vega or Eximus DP-1 caliber, I'd call it rather smaller than swapping complete cable looms as I did for recent reviews of Absolue Créations and Arkana Physical Research. Complete swaps of cable sets (interconnects, speaker cables, power cords) can affect tone and colour density, dynamics, body, bass weight and shift the transient/bloom/decay balance. Except for the last, in my context those qualities don't really apply for today's type of device. If you began on a lower tier of converter quality, I'd imagine that to become more inclusive.


Having their particular range of address be narrower and more focused doesn't invalidate an external USB bridge at all. But it's also fair to say that more than many others, it relies on the rest of your equipment for magnification. Here time-confused big multi-way speakers with poor impulse response would seem handicapped by design. The same could apply to slow cuddly valve amps of limited bandwidth, heavy THD and inherent treble phase shift. With systems dialled for speed and lucidity, upgraded USB converters come more fully into their own and now are well worth investigating. Given expected deltas of performance, I'd simply attend to a proper cable loom first. If you've heard what a well-engineered equipment rack can do, that's more the general type or flavour difference you'll obtain from an external USB-to-S/PDIF box. The remaining qualifier is obvious. What's built into your current DAC must leave sufficient room for improvement to be relevant. Against that proviso the Hydra X+ strikes me as a sensibly priced high-performance option for DACs up to €4'000. Of course you have to figure on a quality digital cable and whatever its cost might be to complete this proposition.

 
Now the Z improves further on this design - with all cables running in the back of the unit.  Seperate chassis for PS.

 

The previous model of Hydra, the X+, has built its reputation based on excellent sound quality. From our perspective, it is time to move on, and offer a new interface, that we named usb audio playback bridge.

While raising the bar even more in sound quality and keeping the existing set of features precedently available, the new Hydra Z comes with a list of improvements that we’re happy to share. Among the changes are a complete redesign of the digital board, changes in the way the Hydra is powered, new output configuration, new chassis and many other refinements – please see below.
MORE FLEXIBLE The Hydra Z can be powered in 3 (three) ways :

1. Directly from USB
2. From an external, fixed 5Vdc/0.5-1A power supply
3. From the dedicated Hydra ZPM (Z-Power Module)

Furthermore features:

1. Extended number/type of outputs
2. Adjustable I2S output clock polarity, to match all HDMI/I2S/LVDS dacs available
3. Adjustable masterclock output on I2S (512xfs or 1024xfs)
4. Firmware upgrade over usb
5. DSD native / DoP / hi-quality PCM converted (selectable)
6. DXD native (I2S out) / 192k or 176.4k (spdif, aes, bnc out)

TECHNICAL IMPROVEMENTS Hydra Z benefits from all the qualities of the X+, and even more. New clocking scheme allows shutting down one of the two main oscillators when not in use. By reducing the mutual interference between clocks, better phase noise performance can be obtained. The power supply section was moved to a different chassis for best results.

 

[prot]

rb2013
I think we've read the same 6moons reviews . Those audiobyte/rockna guys sound like a serious bunch, not your regular audio-mill. If you get one of their devices I'd be very interested to hear about it. Meantime, looks like that Dan guy already has a review with nice pics (including inner side) http://headmania.org/2015/04/23/audiobyte-hydra-z-review/

 

[riffer]

The one thing I can't find out about the Hydra-Z is what the pinout is for the I2s over HDMI;  just"Adjustable I2S output clock polarity, to match all HDMI/I2S/LVDS dacs available" and some additional info in the manual.  No diagrams or anything to explain in greater detail.

 

[rb2013]

@rb2013
I think we've read the same 6moons reviews

. Those audiobyte/rockna guys sound like a serious bunch, not your regular audio-mill. If you get one of their devices I'd be very interested to hear about it. Meantime, looks like that Dan guy already has a review with nice pics (including inner side) http://headmania.org/2015/04/23/audiobyte-hydra-z-review/

That's an excellent review - I wonder how much a sound difference there is between the X+ and the Z.  The Z shut down the unused clock - and as they say this does reduce phase noise.
 
Also this was interesting:

If you choose to use USB isolators, then sample rate will become limited, which is not an option.  If you choose to isolate the output, you are adding significant amounts of jitter to the signal. By using a clever circuit topology, the Hydra design avoids these two bottlenecks. The isolation is placed between the ARM processor and the FPGA audio core, therefore not limiting the bandwidth. Being before the clocks, its jitter contribution becomes irrelevant.

The approach for the U12 and MXU8 is having the isolating the outputs - one for the SPDIF and one for the AES outputs on the MX-U8 you can see the Muratas right next to the output connectors.

 
On the U12 Gustard uses the Pulse transformers

 
So does this mean they are adding jitter?  If so by how much?  What if they are eliminated?
 
The Tanly uses a FPGA solution like the Hydra's.
 
But is it implemented with the same type of design? What kind of 'special retiming is applied just before the outputs"?

 Unlike other products which only specify “low jitter clocks”, here is exactly what you will find inside : 2xCCHD-950/957 type from Crystek. These are real audio grade clocks. You can check real graphs for them here. These clocks are system masters. In order to remove any jitter induced by the FPGA circuit itself, special retiming is applied just before the Hydra Z outputs.

 
On the PS side - I guess the Z stock is non-battery fed.  Only with the ZPM is it using the super capacitors for power.
 
So the X+ has a plus in it's column as the LiPo battery is built in at no extra charge.  I imagine these can be had used for $300-$400 depending on condition.
 
Speaking of power supplies this was the comment on the ZPM:

I was very curious to see how the new linear power supply affected the sound, and  it wasn’t disappointing at all. It had an impressive impact on the sound quality as it brought better transparency, bigger soundstage, better instrument separation and layering, faster and more powerful transients, better textures on instruments and voices, and of course better bass control and punch.  So, as you can see, everything was better with it, taking the quality to a whole new level. 

The advantage of the 5VDC input is there many excellent - and relatively inexpensive high quality PS available - aside from the ZPM.
 
And an interesting side note link to this article discussing the Forza Hyrid Series Twin USB Cable
http://headmania.org/2014/11/27/forza-claire-hybrid-twin-usb-cable-review/
 
I will have to get one of those for a listen...for the U12 it would be very interesting to hear (using the linear PS to power the relay).
http://forzaaudioworks.com/en/product.php?id_product=46

 

[bballas]

Hydra z suckers!!!This is Gustard topic!!!!!!!!!!!