from PRR:
> My eye fell on the 2*10 Ohm resistors
Look at the 22uFd caps. They have much more impedance over most of the audio band.
Thanks, I still keep getting fooled by that too many times :wink: :evil:
But I was asking myself: there where the Hertzes accumulate (so where 'sqrt(BW) really boosts the noisy-density', so @ the right side of freq-plot) the cap-impedance is low, so couldn't it be that the 10 Ohm still results in a noticable higher noisefloor ?
Well, it doesn't really since the rest will be overwhelming it, but from what I got from some toying around, for a noiseless surrounding circuit,
the integrated noise over 20kHz-BW seemed some 9 dB higher (2.6uV vs 0.9 uV).
But please don't pinpoint me on my method to arrive there; I just based it on the 10 Ohm and 1/(2*pi*capvalue) and as such, I don't know if thats a completely valid approach.
Stuff like this matters much more in theory than in practice.
Fully agreed.
I have the feeling that in much of our efforts around here a lot of measures are taken just because:
* they could be done,
* would in principle be better,
* should improve things,
* was cheap to overengineer,
* was not that cheap to overengineer but might be important (if someone likes to replace the comparators in a LED-bar by 2520's, then why not ?),
* is fun to address now we understand what's potentially going to be a problem but might really never become a noticable influence etc etc.
That's at least how I feel it and it's all OK - maybe they help just a little bit,
but all those extra's will pay themselves back I think.
Whether it's economical/really noticable is another thing, but that's not really why we're into DIY.
Well, enough for now - too many words on an insignificant 10 Ohm resistor. :wink:
Regards,
Peter