http://www.diyaudio.com/forums/showthread.php?s=&threadid=13497
I have tried to get info about the very special Frequency Dependent Negative Resistor.... filter but noone here seems to have come close to it, except for a very few.
Some day I thought it would be fun to make a killer active filter. I have no personal need for it but I'm more interested in it in a technical sense.
Specifications (only at idea stage):
Input buffer
1 Mono subchannel, 10-50 Hz, 1st-4th order
2 Bass stereo, 50-250 Hz, 1st-4th order
3 Mid stereo 250-3000 Hz, 1st-4th order
4 Treble, 3000 Hz, 1st-4th order
All filter sections fed via an individual Jung Regulator
All highpass filters with simulated inductors as generalized impedance converters
All lowpass filters with FDNR's
All filters with adjustable gain
All filters configurable as 0-4 th order and all kinds, like Bessel, Butterworth etc.
All filters will have place for 2 resistors in parallel and the caps will also have options for different kinds and sizes.
The pcb will look as my pcb's usually look like, with groundplane and all.
The whole filter will be made of holemounted parts except for opamps which will have a SO08 option.
Time schedule if someone is interested is sometime in 2005.
This first post are the specification and may be changed anytime.
Feel free to comment.
Sounds like a rather complicated project! I have no need for a killer active filter right now.
Maybe some comments from me can be useful anyway.
Make space for a "killer" audiophile components such as large polyprop capcitors, Caddock MK132/Vishay S102 resistors (smaller footprint than normal hole mounted resistors). Especially those in the signal path!
But also for the regulators/power supply bypass components.
Just my 2 cents,
Sigurd
Sorry, but I have no intention to make room for huge audiofilic caps. The pcb will be rather large as it is. I plan to use "normal" polyprop's.
If you want to make the PCB smaller,
I suggest you use the Caddock MK132/Vishay S102 resistors as their footrprints are smaller than normal resistors' footprints :D
Sigurd
Quote from: perandersSorry, but I have no intention to make room for huge audiofilic caps. The pcb will be rather large as it is. I plan to use "normal" polyprop's.