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Old 4th January 2012, 03:02 PM   #21
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Quote:
Originally Posted by abraxalito View Post
I've moved on to balanced I/V stages now for which the AD605 is more suitable:

http://www.analog.com/static/importe...eets/AD605.pdf

Owing to the limited (5V) supply voltage it can't deliver the standard CD 2VRMS in unbalanced.
Thanks, for the device tip, brax.
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Old 4th January 2012, 04:02 PM   #22
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Originally Posted by Ken Newton
My experience is that increasingly lower THD measurements alone often do not correlate with improvements in perceived sound quality. In fact, there often seems to be a negative correlation between perceived sound quality and vanishingly low THD.
Yes, lots of people report something similar. Two possible explanations (both might be part of the truth):
1. Optimising one thing (low THD) can lead to a designer missing other important things or introducing new problems.
2. Some people actually prefer a little low order distortion (there is some experimental evidence to support this, as well as the anecdotal evidence of the popularity of 'tube buffers' etc. - I believe there is even some evidence that some prefer 2nd and others prefer 3rd)

My view is that low THD can mean low IMD, which must be a good thing provided other problems are not created in the process. Low order harmonics below a few percent are generally not audible, and below what the speakers will be producing anyway. So straining for extra zeroes after the decimal point is silly, but carelessly including unnecessary distortion through poor design or adjustment is equally daft.
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Old 4th January 2012, 04:19 PM   #23
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Originally Posted by olmeister View Post
Hey, i'm new to audio electronics in a sense, i'm currently studying I-V Converters for my first DAC which employs a PCM2707 and PCM1704, similar to that of many designs i've seen around here. I know I could buy someone elses PCB and simply solder the components, but I rather build it from scratch.
The PCM2707 is not a current output DAC so no I/V converter is required for that one.

The PCM1704 is a current output DAC and does need an I/V converter.

Which one are you talking about?
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Old 4th January 2012, 04:41 PM   #24
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Originally Posted by DF96 View Post
Yes, lots of people report something similar. Two possible explanations (both might be part of the truth):
1. Optimising one thing (low THD) can lead to a designer missing other important things or introducing new problems.
2. Some people actually prefer a little low order distortion (there is some experimental evidence to support this, as well as the anecdotal evidence of the popularity of 'tube buffers' etc. - I believe there is even some evidence that some prefer 2nd and others prefer 3rd)

My view is that low THD can mean low IMD, which must be a good thing provided other problems are not created in the process. Low order harmonics below a few percent are generally not audible, and below what the speakers will be producing anyway. So straining for extra zeroes after the decimal point is silly, but carelessly including unnecessary distortion through poor design or adjustment is equally daft.
I pretty much share those suppositions.
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Last edited by Ken Newton; 4th January 2012 at 04:47 PM.
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Old 4th January 2012, 06:03 PM   #25
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Originally Posted by DF96 View Post
So straining for extra zeroes after the decimal point is silly, but carelessly including unnecessary distortion through poor design or adjustment is equally daft.
You assume that what happend in '70's is still happening. Any low THD decent device today will have low intermodulation products too. The lessons from the deceiving ads from '70's where learned by all manufacturers that matter.
On the other hand, poor THD always sounds bad. Coloration of a musical program might be "desirable" only if is linear (like tone controls). That means maintaining the low harmonics.

Sure, there are people like to stick a sub in the car trunk and crank it up to 1000W with all the car panels rattling. And they say "it sounds goood". But that doesn't make them right.

Also, your argument that you don't have to be better than the speaker THD. So, in this thread that is about I/V stage of a DAC, you recommend DAC's with THD around 1%? So... 7 bits of data (0.8%) are enough?

Last edited by SoNic_real_one; 4th January 2012 at 06:07 PM.
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Old 4th January 2012, 06:07 PM   #26
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Originally Posted by SoNic_real_one View Post
You assume that what happend in '70's is still happening. Any low THD decent device today will have low intermodulation products too. The lessons from the deceiving ads from '70's where learned by all manufacturers that matter.
On the other hand, poor THD always sounds bad. Coloration of a musical program might be "desirable" only if is linear (like tone controls). That means maintaining the low harmonics.

Sure, there are people like to stick a sub in the car trunk and crank it up to 1000W with all the car panels rattling. And they say "it sounds goood". But that doesn't make them right.
Some people prefer Russian caviar, some people prefer French fois gras. Who's correct?
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Old 4th January 2012, 06:10 PM   #27
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No, that would be different genres of music.
There we are talking about same food - one fresh and one rottnen. If anybody preffers rotten food, it's fine, just don't tell the others, that prefer the food fresh, exactly how it was made, that they are wrong.
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Old 4th January 2012, 06:38 PM   #28
DF96 is online now DF96  England
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Originally Posted by SoNic_real_one
You assume that what happend in '70's is still happening. Any low THD decent device today will have low intermodulation products too. The lessons from the deceiving ads from '70's where learned by all manufacturers that matter.
Sorry, I don't understand your point. Exactly what of all that happened in the 1970's am I supposed to be assuming?

Quote:
That means maintaining the low harmonics.
Are you talking about frequency response (maintaining what is already there in the signal) or distortion (adding new harmonics)? I thought we were talking about distortion, but then you introduce the new topic of maintaining harmonics.

Quote:
Also, your argument that you don't have to be better than the speaker THD. So, in this thread that is about I/V stage of a DAC, you recommend DAC's with THD around 1%? So... 7 bits of data (0.8%) are enough?
I think from the context of my remarks it is clear that I am talking about low order distortion. Low bit DACs don't just produce low order, but lots of high order too. So for DACs some zeroes after the decimal point are needed, except perhaps for low order distortion introduced by the analogue circuitry. The DAC chip itself needs to be as linear as possible; the following circuitry can sometimes be less accurate.
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Old 4th January 2012, 09:04 PM   #29
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Originally Posted by SoNic_real_one View Post
No, that would be different genres of music.
There we are talking about same food - one fresh and one rottnen. If anybody preffers rotten food, it's fine, just don't tell the others, that prefer the food fresh, exactly how it was made, that they are wrong.
Amplifiers, DAC's, preamps, and loudspeakers all have different flavors as well. Everyone's entitled to their choice of flavors.
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Old 4th January 2012, 09:05 PM   #30
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Originally Posted by SoNic_real_one View Post
Sure, there are people like to stick a sub in the car trunk and crank it up to 1000W with all the car panels rattling. And they say "it sounds goood". But that doesn't make them right.
There is no right or wrong when it comes to what someone likes.
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