OMG! OMG! I'm excited ...
Apr 2, 2006 at 12:27 AM Thread Starter Post #1 of 62

Cronstead

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... for my new balanced DAC !!


Before went to the sound, first, the schematic ....
1794preview-1.jpg


I/V stage with OPA627BM and 0.1% precision resistors on signal path ....
dac1794-01.jpg


Analog power regulator with AD797 (showing half of the section for one channel) ...
dac1794-02.jpg


Analog power regulator with Elna Silmic & Cerafine caps (per channel) ...
dac1794-03.jpg


Can be switched between Voltage ...
dac1794-04.jpg


The overall view ...
dac1794-06.jpg


DAC1794 amongst Accuphase (DP-85, C-2800 Preamp, P-1000 Power amp, and PS-1200 power supply) and Tannoy Kingdom 12 speakers (sadly, none is mine).
cd_dacingingarry.jpg


Back panel I/O:
- Balanced analog XLR
- Unbalanced analog RCA
- External clock
- I2s digital input
- AES/EBU digital input
- SPDI/F digital input

Front panel:
- Power switch
- Reset/mute switch
- Digital input selector
- External clock switch

Some specs:
- Input sample rate: 32K, 44.1K, 48K, 88.2K or 96K
- 24.576MHz internal oscillator
- CS8414 for digital receiver
- SRC4192 for resample
- DF1706 for digital filter
- 2 x PCM1794 (1 per channel)
- 4 x OPA627 for I/V stage (2 per channel)
- 4 x BUF634P (2 per channel) - optional
- Output voltage:
--> 4 - 4.5 V on unbalanced RCA
--> 8 - 9 V on balanced XLR
- Total of 14 power regulators with:
--> 2 x transformer ((18V - 0 - 18V x 1.5A) x 1 + (0 - 9V x 1A) x 1) (1 per channel)
--> 1 x transformer ((0-9V x 1A ) x 8 ) for digital only.
----> 1st group: +5V for OSC
----> 2nd group: +5V for CS8414
----> 3rd group: +3.3V for SRC4192
----> 4th group: +3.3V for PCM1794
----> 5th group: +3.3V for PCM1794
----> 6th group: +3.3V for DF1706
----> 7th group: +5V for Re-Data
----> 8th group: +5V for line and the switch part
- dimensions: 430 x 310 x 65mm
- weight: ~10kg (incl. packaging)

Some random facts:
- Total component used is ~500, where ~100 of them are resistors (some are Vishay S-102k and Phillips MPR24 0.1%), ~80 of them are EPCOS/RIFA 0.1u, ~90 are capacitors (some are Sanyo OS-CON, BlackGate, Elna silmic&cerafines, Phillips, and Matsu****a).
- The DAC was in planning and completion phase from late 2004 until 17/05/2005.
- v2.1 simplified schematic: http://novas.myweb.hinet.net/project...94/dac1794.jpg
- Digital chips are on the back side of the PCB, to avoid interferences.
- True balanced design that utilises 1 PCM1794 (running on mono/balanced mode) for each channel.
- Can be ordered as DIY kit, which can be just the PCB board + 5 main digital parts or as complete kit that includes the case.


Now the most famous question of all ... how does it sound??

http://www6.head-fi.org/forums/showp...2&postcount=41
Quote:

Originally Posted by Cronstead
Sorry for the delayed, I've been enjoying the system too much.
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This is what I found so far:

It's very detailed, HF are very refined - no sibilance nor edginess, the bass is also very good - goes deep down and impactfull, soundstage goes wide and deep - not just on x and y axis but fills gaps between x and y axis as well, and sound separation is darn good.

For example, listening to Dadawa's Sister Drum, in particular the tifas and "Tibetians' trumpet", will literally shake your head with very low bass (the trumpet) or very impat bass (the tifas)!
basshead.gif

While listening to The Corrs, the instruments are located and separated nicely. It seems very accurate to me (I know it because the audio was demuxed from the DVD - The Corrs MTV Unplugged). The strings (guitars, violins), vocals, percusions are nicely defined and sound very real to me.

Overall, it is a very musical product, and well balanced through out the frequencies.

But please don't take it as final judgement yet, as the RCA that I'm using between DAC and my amp is Furutech SA-162, which I believe it's the bottleneck in the system. And since all this stuffs are very subjective (as we all know), so please take it with grain, and salt and remember YMMV!
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Btw, the system is: Emu 1212m->DAC1794->GS1->HD650 with Blue Dragon V2/K701.



RMAA (24bit 48KHz - single ended): http://www.users.on.net/~ehendriks/d.../DAC1794-3.htm
 
Apr 2, 2006 at 9:48 PM Post #7 of 62

Cronstead

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1 transformer for digital only ((0-9V x 1A ) x 8 )
1 transformer for analog left channel only ((18V - 0 - 18V x 1.5A) x 1 + (0 - 9V x 1A) x 1)
1 transformer for analog right channel only ((18V - 0 - 18V x 1.5A) x 1 + (0 - 9V x 1A) x 1)
very_evil_smiley.gif



The name is "The DAC1794".
 
Apr 2, 2006 at 10:23 PM Post #8 of 62

TigzStudio

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soo.. how bout you tell us what DAC it is????

share the goodness!

never mind i found it... it is called just a "DAC 1794"

everywhere you search only showing in chinese , cant find any reliable place to learn about it.

where can we buy one?!?!
 
Apr 3, 2006 at 4:00 AM Post #12 of 62

BrianS

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holy capacitors batman

those are capacitors right
 
Apr 3, 2006 at 4:25 AM Post #13 of 62

saturnine

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Looks nice! Be sure to let us know how it sounds.

Quote:

Originally Posted by TigzStudio
everywhere you search only showing in chinese


Anyone know of a site in English with any info??

<-- Also a member of team overbuilt DAC
smily_headphones1.gif


p30600517yg.jpg
 

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