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Using Two DACs?

post #1 of 42
6/17/11 at 11:20am
Thread Starter 

I recently found out there are some products that offer two DACs. How much audiophile bullcrap is this? After the first DAC converts the signal from digital to analog, the second one can't possibly do anything else, so what is the point?

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post #2 of 42
6/17/11 at 11:57am

No senor, they use one for each channel.

 

One DAC is purely converting the digital information for left, one for right. this creates supposedly a better separation and whatnot...

 

 

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post #3 of 42
6/17/11 at 12:02pm
Thread Starter 

So basically it's audiophile foolery, thanks.

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post #4 of 42
6/17/11 at 12:03pm

sometimes called "dual mono".

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post #5 of 42
6/17/11 at 12:28pm

Honestly, no idea if it's foolery, if it makes sense or not.

 

From the description of my NuForce icon HDP: 

The DAC chip consists of four internal 24/192kHz DACs that provide a fully differential and balanced output. The differential signal's DC offset operates without a need for decoupling caps.

 

DAC chips are expensive. I don't think anyone would just put redundant chips into a device if the same sound quality could be achieved with one. 

 

The top speed of the cars in my household is 250 kph / 155mph and the other one is 272kph / 169mph the legal speed limit in the country I live in is 120kph. That is the same "over-engineering" :-) but believe me, even getting to 120 with the former car is pure fun. 55horsepower would probably be enough and the same speed of 120kph would be achieved with 3 cylinders but it SOUNDS better with 6 or 8, especially when they are arranged flat ;-)

 

Maybe my future car has no cylinders and drives electric, but the point I tried to make is: you can achieve something in different ways. There might be a 4 cylinder 2 liter twin-turbo with the same horsepower than a 5.7 liter V8. So maybe 4 DACs of one kind result in the same sound quality than 1 super-turbo one, LOL or maybe they are just show and really make no difference. Somehow it seems the producers are not really keen on coming up with a standard measurement to compare this kind of "performance"...

 

Cheers,

K

 

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post #6 of 42
6/17/11 at 12:42pm
Quote:

Originally Posted by Koolpep View Post

55horsepower would probably be enough and the same speed of 120kph would be achieved with 3 cylinders but it SOUNDS better with 6 or 8, especially when they are arranged flat ;-)

 



That all depends on your drag coefficient, but any car that has 55HP with a 3 cylinder engine has a pretty high drag coefficient and this would not be enough to get up to 120kph.

 

Back on topic.  Using two DAC's is stupid.

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post #7 of 42
6/17/11 at 12:53pm
Thread Starter 
Quote:
Originally Posted by Koolpep View Post

DAC chips are expensive. I don't think anyone would just put redundant chips into a device if the same sound quality could be achieved with one. 

 

 



I know they would. The audio world has a lot of expensive things aimed at sound quality with absolutely 0 scientifical backing, but people believe it. A DAC is more than able to decode the max audio output, 1,411 kbps, into proper channels.

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post #8 of 42
6/17/11 at 12:54pm

 

Quote:
Originally Posted by Koolpep View Post

No senor, they use one for each channel.

 

One DAC is purely converting the digital information for left, one for right. this creates supposedly a better separation and whatnot...

 


This.

 

Ignoring separation (which can be good enough on a stereo DAC chip to be meaningless) there are some DAC chips that only come with 1 channel on a chip. 

 

Quote:
Originally Posted by keanex View Post

So basically it's audiophile foolery, thanks.


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

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post #9 of 42
6/17/11 at 12:57pm

Fact:

GM 1.0 litre ecotec engine, 3 cylinders, 55hp top speed 132kph, I drove plenty of cars in europe with 45-55 hp (oh yes, everybody starts small). They all had no problem exceeding 120 kph with relative ease. Don't know how you calculated the drag coefficient, but you are wrong, Sir.  

 

Using just one puny DAC is stupid.

 

 

Now, seriously, why is it stupid to have 2? I mean, I really don't know. Maybe it's hokus pokus, but if you state that it doesn't make sense or is stupid, could you elaborate why?

 

I couldn't care less if my DAC has half a chip, 2 or 16 chips, if it sounds good. 


Edited by Koolpep - 6/17/11 at 1:12pm
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post #10 of 42
6/17/11 at 2:18pm

Some DACs are based on a differential design i.e for each channel (or both) the signal is decoded independently twice by different chips and the two signals are compared, if there is a difference it does something or other - my old Rotel had two sets of differential chips - I have no idea if it made any difference at all !

 

My second car in 1986 was a 1984 (A Reg) Fiat UNO 55S (1.1 L, 55hp) and I could cruise at 90MPH or about 144KPH - the spec'd top speed was 93MPH but I never managed to get that, possibly the prior owner had thrashed it a bit.....


Edited by nick_charles - 6/17/11 at 2:19pm
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post #11 of 42
6/17/11 at 2:23pm
Thread Starter 
Quote:
Originally Posted by nikongod View Post

 


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



lol typical audiophile, though you should probably re-read this. Typical audiophile makes no sense as well. Great job!

 

By the way the car analogies couldn't be a worse comparison. How about another terrible one though:

 

If I can ride my bike at 20mph with 2 legs, a dog must be able to go 40mph since he has 4 legs!

 

LOL Typical audiofoolery analogy.


Edited by keanex - 6/17/11 at 2:24pm
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post #12 of 42
6/17/11 at 5:09pm

 

What about designs that use paralleled DACs in an effort to improve performance?

 

Quote:
Originally Posted by keanex View Post

lol typical audiophile, though you should probably re-read this. Typical audiophile makes no sense as well. Great job!

 


Could you elaborate on that?

 

I have re-read, but from your first post it sounded like you have more to say than to ask. 

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post #13 of 42
6/17/11 at 5:50pm
Quote:
Originally Posted by nikongod View Post

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


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.  rolleyes.gif

 


Edited by Anaxilus - 6/17/11 at 6:46pm
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post #14 of 42
6/17/11 at 6:29pm

Depending on the DAC, it will have higher SNR when used in mono than stereo. Having one for each channal makes sence in this type of installation because it gives the device an overall lower noise floor. Anything other than that reason alone is marketing foolery.

 

This is taken from the specs of a Wolfson 8741 DAC:

 

128dB SNR (‘A’-weighted mono @ 48kHz)
125dB SNR (‘A’-weighted stereo @ 48kHz)

 

 

Source: http://www.wolfsonmicro.com/products/dacs/WM8741/ 
 

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post #15 of 42
6/17/11 at 7:56pm

 

Quote:
Originally Posted by Anaxilus View Post

I guess 4xTDA1543s in parallel is quadroaudiofoolery?  Don't answer, I re-read the previous posts and it helped me figure it all out.  rolleyes.gif

 


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. 

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