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-   -   AD1865 vs PCM1704 (http://www.diyaudio.com/forums/digital-source/5702-ad1865-vs-pcm1704.html)

steve jones 3rd September 2002 01:42 AM

AD1865 vs PCM1704
 
I'd be interested in hearing the opinions of anyone who has compared AD1865 and PCM1704 DAC chips in a non-oversampling circuit.

Which did you prefer.

TIA,
Steve

Peter Daniel 4th September 2002 01:18 PM

Not too many people experiment, aren't they?;)

I just want to keep the thread alive, because I'm curious myself.

jwb 4th September 2002 04:37 PM

At $33/ea for one DAC chip, and hundreds of dollars in parts for a complete DAC, it is slightly painful to experiment with different parts or designs. What's really needed is a DIYAudio pow-wow where we can all huddle together and listen to our creations comparatively!

Elso Kwak 4th September 2002 05:34 PM

AD1865 vs PCM1704
 
Hi Steve,
The problem with the PCM1704 is that it is a 24 bit DAC.
The AD1865 is a 18 bit DAC but the CS8412 or 8414 can be put in 18 bit output mode. It are not really 18 bits but 16 bits plus two "stuffed" zero's. Consequently you have to stuff six zero's for the PCM1704. This can be accomplished with a shift register but will require this extra glue logic.:(
Some time ago I did compare AD1851, AD1865N; AD1865N-K and TDA1541AS1. I stepped on quite sensitive toes with my conclusions:D
The PCM1704 is resting in my famous shoebox for a with a sample rateconverter and DAC experiment (non-oversampling)
As I am quite happy with the AD1865N-K especially in conjunction with my asynchronous reclocker, the PCM1704 may rest in peace forever....:RIP:

steve jones 4th September 2002 09:33 PM

Stayin' alive
 
Thanks for the replies. I guess I'm the one that's going to have to experiment. :D

I was trying to map out a strategy for doing a non-oversampling DAC board that I could add to an inexpensive DVD player and nixing a SPDIF connection. I'd use a Kwak Clock to help lower source jitter even more.

Figured that I could remove the existing DAC in the DVD player, and tap the internal MCLK, BCLK, LATCH, and SDATA (more than likely 24 bit Japanese/Sony/BB format and not I2S) traces to feed the new DAC board.

With the PCM1704, there would be minimal glue logic to attend to. As the 1704 can input 24 bit word length, a similar (but not identical, no need to shift the LATCH to mate with LSB in converting from I2S) logic scheme (gating BCLK to one channel) as the one detailed in AN-207 would work.

But those 1704-Ks are $39 each. Ouch.

The AD1865 sounded great 1X oversampled in my Audio Note DAC 1.2.

The problem in using the AD1865 in the DVD player application is it's 18 bit input. Guess I'll have to try a 6 bit shift register to align the down-going LATCH to the 18th bit of the 24 bit SDATA stream. But in doing so, any 96K/24 bit DVD or DAD data would be trunicated, and I know how bad that sounds at the 16 bit level. Would this matter ta 18 bit resolution? I dunno.

But I've got 4 pairs of stereo AD1865N-Ks. Differential/paralleling them all might bring its own rewards (like what Kondo did in the M100 Hibari DAC).

Gotta split for now. Thanks folks!

Steve

Peter Daniel 5th September 2002 02:16 PM

You wouldn't have a schematic or more info on that Hibari DAC maybe?;)

Cobra2 5th September 2002 04:13 PM

DAC vs DAC...
 
Hi!
I might be on the edge of this thread...but I do not find the DAC-chip so important, as the implementation.

I just had my modified QED Digit Dac tested with my "favorite" Hi-Fi-pusher, he even tried it in his own home system. And he concluded that it played like a U.S.$ 1400-1500,- CD-player, but was beaten by a $ 2500,- one....

Arne K
NORWAY

steve jones 6th September 2002 05:05 PM

Hibari info
 
Here's a few links to the Audio Note Japan website:

http://www.audionote.co.jp/digital/content.htm

http://www.audionote.co.jp/digital/essay.htm

There was another webpage that showed the guts of the DAC, but it has been pulled. Might have shown too much.

And here's a mention of the Hibari in an article by Thorsten Loesch (warning: lotsa pop-ups!):

http://www.fortunecity.com/rivendell...io/Adagio.html

Kondo uses sixteen BB 16 bit PCM56s per channel (in parallel) with a passive I/V section, and vacuum tube output stage. There are a couple of advantages to doing it this way. THD+N will be -3dB for every doubling of DAC chips (but no CMR for paralleling). And a far lower resistance value to ground that the DAC's current output sees (closer to the ideal zero ohm..).

Or he just may like the idea of a single DAC for each of the 16 bits. ;)

BTW, I do believe that different DAC chips DO sound different. Even with proper implementation, I wouldn't want to listen to a MASH DAC. :D

Peter Daniel 18th October 2002 05:20 PM

Quote:

Originally posted by jwb
At $33/ea for one DAC chip, and hundreds of dollars in parts for a complete DAC, it is slightly painful to experiment with different parts or designs. What's really needed is a DIYAudio pow-wow where we can all huddle together and listen to our creations comparatively!
To compare DAC chips, the circuit doesn't have to be complicated at all. Even PCM 1704 can be implemented in non oversampling mode.

http://home.triad.rr.com/scottnixon/dac.htm

steve jones 18th October 2002 07:17 PM

I don't have the link handy, but a fellow on the Digital Asylum sold his Audio Note DAC 4.1X (non-oversampled AD1865) for a Zanden (non-oversampled PCM1704). Both have tube outputs.

This might not be a true (apples to apples) comparison, as the Zanden compensates for Sin(x)/Sin high frequency roll off with a peaking analog filter (the AN doesn't) , but the guy rates the Zanden highly.

I think he wrote the Zanden was a "10, with the AN a "7", and the 47 Lab Shingari a "3".

FWIW.

When I get back to work I might get a $175 Pioneer DV656 CD/DVD/DVD-A player (uses a BB DAC), and yank out the DAC, and use the SDATA, LRCLK, and WCLK (should be 24 bit Sony/BB/Japanese format) directly to 74VHC74 buffer and then to a standalone pair PCM1704s.

But until then.....so much time, so little money. :(


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