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Old 19 October 2016, 09:53   #119
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Join Date: Nov 2007
Location: Lyon (France)
Age: 43
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Originally Posted by pandy71 View Post
Nope - anti-aliasing is a problem of AD conversion and later can't be removed from signal - DAC doesn't require anti-aliasing filter - DAC require reconstruction filter (sometimes it must be also anti-imaging filter).
There are some techniques to deal with problems, temporal averaging to remove uncorrelated with signal noise is one of them. And also we note measuring particular sample values (albeit it possible and it is used with some DAC calibration techniques).
Whatever you call it, there is still some kind of filtering that will make the output level differ from the numeric input.

Originally Posted by pandy71 View Post
Obviously not as you arguing using arguments common for some audiophiles - once again i never heard on equipment that has bad objective (measurements) results but anyway has amazing sound - behind good sound reproduction there is lot of scientific knowledge.
Wise people not say f**k theory - i live long enough to experience situation when good theory perfectly match real life.
A theory is only valid when all of the data it needs is known...

Originally Posted by pandy71 View Post
Nope, practically all audio PC cards using delta sigma AD converters - they are free from aliasing problem also AA filter is not a limitation as due way how DS works those filter are quite gentle and they are stable in phase domain.
Oscilloscope will be highly unsuitable for this as very limited dynamics present in typical oscilloscope - they usually use not more than 8 bit AD converters and with typical sample rates around 100MHz efficient number of bits is usually somewhere around 6 or less - definitely very bad for 14 bit audio.
Ok but there is probably better hardware than mere pc to do that kind of measurement.

Originally Posted by pandy71 View Post
Nope - emulator is not interesting as we testing idealistic not real system that functionally is close to Amiga but completely different.

I have A1200 and A3000 (CPU capable to run 68020 code) - in 3 -4 weeks i should e able to use A1200 (need to buy IDE>SD adapter and restore system disk), A3000 is slightly more challenging as i need to rework some problems on MB and buy a keyboard - as you can imagine it is impossible to buy A3000 keyboard nowadays.
The A1200 seems to be the best bet.

Originally Posted by pandy71 View Post
We not talking about high fancy amp - i know what I've heard on some Amiga's mentioned A600 is disaster not only due leaking caps.
The machine i tried was internally labeled A300, but i don't remember other details.
I had two A1200 and none made any hearable noise.
I could, however, hear a significant quality loss when using the calibration file of one machine on the other.
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