You may have noticed the till teorema: the more THD the more audiophile. Using a chip like that will prevend me from spending hundreds of hours searching for a little more of 7th harmonic by swapping resistors, expensive electrolytics, or adding ferrite or maybe even real pearls in the digital grounding....
I never did and will no do. I have a problem concerning what we call "Produktästhetik" with commercial elektronics. The only products of the consumer range of electronic/electric devices i buy are tools : Hilti, Fein, Flex/porter cable... and of corse computer parts if absolutely necessary.
btw: i would suspect the specs of commercial gear are very good. Same as compare gainclone THD to aleph THD...
Back to serious for those who are interested
Todays work so far:
Tested 5 chips like a, b, c, d, e, f (only one channel).
Then tested 6 combinations of two chips parallel, like a&b, c&f, b&d ...
Distortion is random, everything is possible.
The result of throwing two chips together is unpredictable.
If the two chips have values -50 & -54, the result could be:
-48, -50, -52, -54, or -56, but mostly it will be in the middle like -52.
In my test it was better than each single chip 9x, like the better chip 2x, in the middle 17x, like the inferior chip 3x, worse than each single chip 5x.
With lots of chips, good combinations can be found.
Todays work so far:
Tested 5 chips like a, b, c, d, e, f (only one channel).
Then tested 6 combinations of two chips parallel, like a&b, c&f, b&d ...
Distortion is random, everything is possible.
The result of throwing two chips together is unpredictable.
If the two chips have values -50 & -54, the result could be:
-48, -50, -52, -54, or -56, but mostly it will be in the middle like -52.
In my test it was better than each single chip 9x, like the better chip 2x, in the middle 17x, like the inferior chip 3x, worse than each single chip 5x.
With lots of chips, good combinations can be found.
Bricolo said:
The analyzer can only see down to it's noise floor of -75dB.
With full scale signal it will not see much, because THD of the TDA is very low, like -90.
With the -60dB signal THD of the TDA goes up, to -40.
So it gets visible for the analyzer.
Philips used -60dB signal for selection too.
Bricolo said:But why do you test them with a -60dB signal? Wouldn't full scale, or at least half scale, be more appropriate?
For the chip, it wasn't written made in taiwan but only taiwan, do france would also be enough
Not much harmonics to see with a 0dB signal. Just some garbage.
Bricolo said:That's what I was fearing
That's what is called amplitude modulation
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