I think it's a roll off of 9db from 1khz to 20khz, there is a specific circuit with inductors apparently. Might be cool.
Unless I am much mistaken it is a time constant of 25uS. Certainly no inductors necessary, just RC.
This is why they stopped doing preemphasis. Nobody got it right.
Two time-constants 50μS and 15μS. Ends up near -10.46dB
http://pspatialaudio.com/cd_deemp.htm
A lazy web-search turns up https://offset.skew.org/wiki/User:Mjb/Time-constant-based_EQ which leads to https://www.radonmaster.de/robernd/tAFILTER.html which seems to be an exact implementation. However the loss is non-zero and the impedance is high, so I re-scaled it.
To be fair any CD player that doesn't implement the red book standard in this regard is by definition faulty - not sure I've ever experienced this situation (de-emphasis being needed and not applied). There's another good discussion of the issue here: https://wiki.hydrogenaud.io/index.php?title=Pre-emphasis
My understanding is that most cd players made in the last 20 years are "faulty" in that respect, because they stopped making 14 bit cds 30 years ago.
You could try fishbone's truth and soul, or the dorchester variant of black sabbath's paranoid. They're not 14 bit that I know of, but they do have pre emphasis.
You could try fishbone's truth and soul, or the dorchester variant of black sabbath's paranoid. They're not 14 bit that I know of, but they do have pre emphasis.
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Why not look at some old service manuals to see how it was implemented. You could model (simulate) the circuit and then design your own to match if you wish. The inductors you mention may well be part of the early 'brickwall' filters that early players used to provide a steep cut beyond 20kHz.
This is from a CDP101 which should have it absolutely correct.
This is from a CDP101 which should have it absolutely correct.
