Dr. Quacky, I Presume??

[RDV]

I built Nurse Quacky tonight on perf, but I added the J-Fet buffer from Dr. Quack. Works really good with practically no de-bugging. But it has an identity crisis, as well as gender confusion. Is it a Dr.?, or a Nurse?, or worse yet, both.

Regards, and thanks again Runoff Groove & Jack Orman

RDV

[Mark Hammer]

It is a FHP or "Filter Health Professional".  :wink:

On the other hand, I heard rumours that the original Dr. got his/her doctorate from an internet (mail-order n those days) divinity school....so maybe it's a different sort of doctor.

[RDV]

Disclaimer:

This thread is in no intended to imply that all Dr.s are male, nor that all nurses are female. PC rules!  Just thought I'd throw that in just in case peeps think I'm some sort of neanderthal. :wink:

Regards

RDV

[Mark Hammer]

When it comes to E-H effects, PC went out the window ages ago.  Between the topless babes in the old Guitar Player ads for the Freedom Amp, or the name of their most popular distortion (Muff Pi?), I think the only music gear manufacturer that ever outdid them on the chix-n-gear front was Dean Guitars, or these days The Tube Store.

If you can, double up on the filter section for some serious fun.  Just build the same filter section again, with transistor to ground and stick it in series with the first.  See the Baseballs for how to gang both transistors to the same envelope follower.

[RDV]

When it comes to E-H effects, PC went out the window ages ago.  Between the topless babes in the old Guitar Player ads for the Freedom Amp, or the name of their most popular distortion (Muff Pi?), I think the only music gear manufacturer that ever outdid them on the chix-n-gear front was Dean Guitars, or these days The Tube Store.

If you can, double up on the filter section for some serious fun.  Just build the same filter section again, with transistor to ground and stick it in series with the first.  See the Baseballs for how to gang both transistors to the same envelope follower.

I used Runoff Grooves' perf layout, and added AMZ's input buffer to it, so the Radio Shack board is like, packed. Does the series filter section cause a deeper sweep?, or something wackier perhaps?

Regards

RDV

[Mark Hammer]

Cascading filter sections, especially those that are already high-Q, results in a sharper slope, and by consequence, a very focussed and more emphatic-sounding filtering, with a touch of ringing-like distortion to it.

Actually, if one does use cascaded bandpass filter sections of the DQ type, it may be wiser to reduce the gain a bit by dropping down the 470k feedback resistor in the filter to maybe 390k or even 330k.  It's not so much the action at the middle of the frequency range we're interested in as the action at the rolloff.

One of the nice things about steeper slopes is that it doesn't take as much sweep to produce a noticeable change in the character of the sound.  With a shallower slope, bandpass filters have to sweep higher to produce a big change in bass content, and lower to produce a change in treble content.  A more selective filter means that even small sweep movement changes both bass and treble content more.