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 Post subject: any opinions on FN1242 ?
PostPosted: Wed Jul 02, 2014 3:08 pm 
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Cow

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Hi all..

putting together some ideas for my first DIY DAC... native DSD playback a must, have considered the usual suspects, but one I have not heard a lot about is the NS FN1242 fluency dac? I believe it acts in a similar way to TI DSD17xx when it comes to DSD...

Any thoughts/opinions on this piece of silicon?

Thanks

Andrew


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PostPosted: Mon Jul 07, 2014 5:57 pm 
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Muriel
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Hi,

ball3901 wrote:
I have not heard a lot about is the NS FN1242 fluency dac? I believe it acts in a similar way to TI DSD17xx when it comes to DSD...

Any thoughts/opinions on this piece of silicon?


Tried it for the iDSD line. Not bad. Was a strong contender. Then it turned out Niigata Seimitsu had not been treated kindly by the recession and was no longer making semiconductors (no money to be made) so even they may be still around,the only place to get the chip are "obsolete semi" scalpers that charge 10 times what it is worth including rarity value and 100 times original cost. And if you ask them for a 10KU price they sputter and it turns out they do not even have full reel.

With better analogue stages it may be able to pull a little past your iDSD nano. Maybe.

DIY?

What is wrong with:

1) ES9018 (everyone else does it)

2) Brüno the Putz's DSD DAC with a decent LC filter Bank (I may hate the guy's guts and philosophy, but for pure DSD his solution with passive filter is hard to beat - maybe a fair draw against your iDSD nano on DSD, if you really push the boat out on the analogue side, may be better?

3) Signalew the Lewsamplers DAC, it may be grossly incompetent digital, analogue and power supply design, but "no magic black boxes" (and no PSRR whatsoever as single ended) and "kill all magic" 317 Chip Regulators, but it has "33 Bit Multi Level conversation" (pun intended)...

4) TDA1541A no oversampling (CD/PCM only) - people who like "good sound" been on this gig for nearly 2 decades, it sounds so good on CD, DSD sounds broken next to a good one... Convert DSD to 176.4 PCM with a relaxed filter (best non - just remap timedomain to amplitude domain) and you won't mind the lack of "native DSD".

Well, there are always "magic black boxes" that totally sound so rad.

As long as you have this magic black box, everything sound great, even 92KB VBR internet radio... Oh, I believe that magic black box was the one I like if not Philips multibit.

F.C.U.K. ING Loblox (as the say on Lapnet Garamina)...

And they wonder why Roman "Romy the Cat" Besnov is so abrasive.

You should meet his Cat Koshka... Very scratchy and bitey. Stay out of claw/teeth range. Bloody smart Kat. Invented this:

Attachment:
Model_AD1.gif


Still my #1 FX Box.

AND you should see my FX Rack, almost up to my ex GF's Rack... Very nice rack.

I reviewed it against the Rane PI-14 Pseudoacoustic Infector and wrote:

"While the "This" and "That" controls on the pi14 are nice enough, you reach true nirvana with the AD-1's Presents control.

And I love how I can just turn up the "Quality" control on the AD-1 when picky opinionated audiophiles come around and I can tell them: "This system now has 150% quality, it is 50% better than real while your poxy systems do not even manage 100%, so there!".

Plus, the AD-1 is stereo of course, so no pesky dual mono controls...

Really, buy the AD-1 and all your dreams come true. It makes it so real, when my girlfriend stands between the speakers and sings karaoke, it is like she is really standing between the speakers! And when she does it sitting on my lap, it sounds really as if she is sitting on my lap.

Like, totally awesome, dude."

I have nothing to add....

Ciao T


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PostPosted: Mon Jul 07, 2014 6:21 pm 
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Cow

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Location: Knoxville, Tn
Kuei Yang Wang wrote:
Hi,

With better analogue stages it may be able to pull a little past your iDSD nano. Maybe.

DIY?

What is wrong with:




Well, soon to be iDSD Micro.. :)

And, well, I was wanting to do something different that the usual. Maybe that is a bad idea, since, it may lead to more initial headaches. But, just want to try something outside the box a little...


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PostPosted: Mon Jul 07, 2014 6:27 pm 
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Cow

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Also, I am not really all that drawn to that 33 level delta sigma wonder.

I think the 8 tap filter in my iDSD does just fine. So I only have 9 level Delta Sigma, I think. Seems to work okay :)


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PostPosted: Tue Jul 08, 2014 1:38 am 
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Benjamin
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Kuei Yang Wang wrote:
Really, buy the AD-1 and all your dreams come true.


No, you have it wrong...............

Image


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PostPosted: Tue Jul 08, 2014 2:53 pm 
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Muriel
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Hi,

ball3901 wrote:
And, well, I was wanting to do something different that the usual.


Not sure if taking a fairly ordinary DAC Chip is that unusual. It has an unusual digital filter,but that is only interesting for PCM.

I think making a pure single stage DSD only DAC with LC Filter banks to kill the ultrasonic noise and giving it real horrorshow low noise supplies and so on could be fun and different.

Because every other chip is multi level delta sigma with more or less processing between that and the DSD stream.

I think doing a passive LC 3rd order 50KHz Bessel filter would be nice and can be done balanced easily, for more rejection of noise near the audio band we could do extra LC traps for an elliptical filter. This can get better impulse response and less noise feed-through than the filter originally shown in BP'z paper:

http://www.grimmaudio.com/site/assets/files/1088/discrete_ad_converter.pdf

There could be no analogue stage at all if you use really modern, high drive Flip Flops. Go directly out from the LC Filter at maybe 150 Ohm or so, with a differential Flip-flop on 5V rails you get around 3.3V RMS out at 100% modulation, so 1.65V RMS at DSD "0dB" as balanced signal.

To me this would be a very interesting piece of DIY and one that stands a chance to be not just different, but genuinely better...

Ciao T

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PostPosted: Mon Jul 14, 2014 7:26 pm 
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Goat

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If you go the logic gate route, I'd use a dual flip-flop with the 2nd flip-flop outputting an inverted signal, followed by a differential filter.

I've used logic gates for a few different 'non-logic' applications, such as driving 10MHz clocks into cables and such. I find there's still a fair bit of asymmetry between N and P - rise/fall times are different, voltage drop at a given current is different, etc.


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PostPosted: Tue Jul 15, 2014 6:11 pm 
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Muriel
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Hi,

gmarsh wrote:
If you go the logic gate route, I'd use a dual flip-flop with the 2nd flip-flop outputting an inverted signal, followed by a differential filter.

I've used logic gates for a few different 'non-logic' applications, such as driving 10MHz clocks into cables and such. I find there's still a fair bit of asymmetry between N and P - rise/fall times are different, voltage drop at a given current is different, etc.


The really interesting stuff (SMD only of course, very small) which is very high speed and very high drive seems to be more symmetrical.

That said, Brüno's article is quite good in setting out additional reasons why to do that.

If you add all the PSU Shenanigans making the system not just differential but double differential seems like a jolly (or was that Joly) decent idea.

Ciao T

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