|
Hmm...from a user of the Prodigy Pro DIY forum:
"Replacing these with LED's will drastically change the behaviour of the non-linear time-constant.
In a steady-state condition, the timing capacitor is a combination of the physical cap C41 (10uF) that goes from pin 6 of the RMS to pin 6 of the LF353 (inverting input) and the virtual capacitance resulting from the active capacitance multiplier Ceq = C41/C45 . C47 = 10u/47n x 220n = 47u. Resulting in a total of 57uF.
Under large signal variations, the output of U9 swings and the diodes dynamic resistance is very low, reducing U9's gain to 0. The only capacitor left is C41 + C47 = 10.22uF. That means that the circuit is 6 times faster under large variations than at steady-state.
The difference of threshold between LED's and signal diodes makes the detector stay in its slower behaviour for much longer, making it less responsive to attacks. Is that really what you want? That's why dbx, in their great wisdom, have modified ALL the components around the circuit when they went for LED's instead of Si diodes."
Jim, have you found this to be the case?
|