[Anaxilus]

Quote:

Me or the OP?
 
If me, for self defense of an idea, if the OP because he doesn't know:
The random noise of paralleled devices is reduced by a factor of sqrt(n) where n is the number of devices...
Distortion depends on the circuits. Id bet for improvements most of the time. 

Quoting you.  Replying OP.
 

 

[khaos974]

For all of those saying using multiple DACs and saying it's audiophoolery, there's a very logical reason to do so, the same thing is done when using more than two channels to decode a stereo signal (with the ESS9018 for example).

Suppose that you convert the same digital stream to analog through n independent DACs, we are assuming that noise is random.
Basic signal theory tell us that the signal to noise ratio is improved by a sqrt(n) factor.

So using multiple DACs is a means to improve the signal/noise ratio and has a sound logic behind it. Of course, this also assumes that the implementation is correct and that the improvement can be heard. I'll let you decide whether this is a useful or a useless improvement.

 

[Koolpep]

So,

we now established that there are benefits of having multiple DACs if the design is done right. The DAC chip producers themselves offer proof in their spec sheet. You could of course answer that it is in their best interest to sell more chips though...

We also provided proof that cars with 55hp can very well drive faster than 120kph except some drag coefficient stuff that makes it impossible according to one of our friends. 55hp are more than enough to reach 120. I have fond memories of Fiat Unos as well (sigh)

Anyhow, the last thing to proof now is that dogs can ride bikes faster because they have 4 legs instead of the lousy 2 we humans have:

http://www.youtube.com/watch?v=eOO4Q1T069Y

Done! (well I must admit, he is kind of slow. But when you imagine with a bit of training....)

Cheers,
K

 

[keanex]

He has training wheels on, void.

 

[Koolpep]

Damn, you noticed.

 

[keanex]

I got keen vision =)

 

[Shike]

Quote:

Another gem!  Time to update the thread.
 
I guess 4xTDA1543s in parallel is quadroaudiofoolery?  Don't answer, I re-read the previous posts and it helped me figure it all out.  

 

While you can reduce the THD+N by doing so, is it really worth bothering with such a circuit by today's standards?  I guess if you really need to scrap the bottom of the barrel or need to maximize profit . . .
 
Quote:

 

Keep telling yourself that. Someday you too can own a system that measures great and sounds like poop. 

Sounds like a personal problem to me.

 

[Albedo]

Depends on what's most important for your enjoyment of music...
http://www.computeraudiophile.com/content/Why-does-vinyl-still-exist#comment-13231
 
These quad monolithic DACs do sound nice with monolithic op-amps, preferably four LM6181.

 

[Willakan]

 
Quote:

Depends on what's most important for your enjoyment of music...
http://www.computeraudiophile.com/content/Why-does-vinyl-still-exist#comment-13231
 
These quad monolithic DACs do sound nice with monolithic op-amps, preferably four LM6181.

Large numbers of people on that thread are so full of BS as to stink from several miles off. Anyone who genuinely believes that the reason they prefer the sound of vinyl is because it is more accurate a reproduction of sound than digital, as opposed to adding pleasant distortion in the vein of tube amps, is, quite frankly, a moron. Not sure how else to put it. The "vinyl is true analog" argument is borne from a total lack of understanding of both mediums.
 

 

[Albedo]

I didn't mention vinyl or tubes, I was talking about square wave and monolithic NOS DAC.. as one can see by the last picture the result of a phase linear Bessel filter.
More about OS vs. NOS -> http://www.phasure.com/index.php?topic=642.msg4672#msg4672 just saying that I like my arpeggios bumpy and uneven.
 
Guess I'm just a screwed up individual thinking that's normal, but hey.. some of the music I like others consider anti-music.

 

[Willakan]

Sorry, I thought you were bringing it in as an example of stuff that seems to go against what is said by the measurements - didn't see the scope measurements later in the thread. 
 
Regarding square wave reproduction, square waves very, very rarely occur in music, and "My DAC produces a great square wave" is often an attempt to distract from the fact that many other measurements are terrible, as in the case of rather a lot of NOS DACs, IMO. 
 
Besides, looking at that graph of showing how the DAC produces a dodgy square wave at 10khz - at 10khz a square wave and an equivalent sine wave are completely perceptually indistinguishable if memory serves. To summarise, people are worrying about how their DAC can produce a waveform that almost never occurs in music - and if it does and is delivered in a way that looks horribly distorted on an oscilloscope it'll be indistinguishable from the original to our ears anyway.
 
NOS and most esoteric DAC designs sound nice because they add distortion or otherwise modify the sound in a pleasurable way. Square wave reproduction is a bit of a red herring.
 

 

[Anaxilus]

Quote:

While you can reduce the THD+N by doing so, is it really worth bothering with such a circuit by today's standards? 

The TDA1543 NOS DAC is an old chip from yesterday's standards, that's the point.  I know, I know, get an 8741.  Problem solved.  

 

[Albedo]

A saxophone is already very close to a square wave, as for the reed of a church organ -> http://www.skepticforum.com/viewtopic.php?f=65&t=85&start=40#p9653
 
Edit: The taste of the red herring are perhaps euphonic distortions, but somehow I seem to prefer it.

 

[High_Q]

I think the differential amps have two amps with 180 phase difference, amp the signals and outputs the difference which would cancel out the DC offset.  You would need two amps per channel to do so.  I think it is a solution to having lower output impedance at the DAC end.  

 

 

[anetode]

Stacking DACs improves the SNR, to a certain limit. The TDA1543 is seriously old and the performance benefits of using four of them are minute and unlikely to be audible.
 
Any high spec is great for marketing purposes. The ESS ES9018, for instance, is an 8-channel DAC perfect for something like a 7.1 setup, but it is also marketed as a 4 per each stereo channel DAC. The stacking rates at 129db vs. 135 db. Generally, if you double the # of DACs per channel you gain roughly 3db performance, mainly because of noise shaping. Still, you can only polish a turd so much, so stacking a bunch of ancient DACs makes little economic or practical sense. Modern DAC chips can handle both channels quite well.