power switching via output jack

[m_charles]

Hi there.
I read an article from either RG or Jack Orman that gave an alternative way to wire up the batt power and bypass switch that helped reduce "pop" when the standard pull down resistors weren't enough to get rid of it.
It involved using a transistor Collector-Base junction and putting the stereo jack on the output jack instead of the input when used to turn on the 9v when the plug is plugged in.
Problem is, I forgot to bookmark it, and I'm going batty trying to find it online.
Can anyone point me to it?
BTW, it's not on the "Tech of bypassing" or the other standard switching pages from these gurus  .
Any help appreciated.
Thanks so much!
-charles

[davent]

http://www.geofex.com/FX_images/PNP_power_switching.pdf

Earlier version in here.

http://www.geofex.com/circuits/+9_to_-9.htm

[m_charles]

thx so much! that's perfect!

[italianguy63]

Question--  Let's say you wanted to power your LED from this circuit.  What would be the optimum place to grab the +V from (anode with resistor) ?  Collector, emitter, or even base?  Would it screw things up (using the base)?  I am guessing to keep any noise out, the emitter leg, and the LED cathode back to chassis ground?  MC

[R.G.]

Question--  Let's say you wanted to power your LED from this circuit.  What would be the optimum place to grab the +V from (anode with resistor) ?  Collector, emitter, or even base?

Collector

Would it screw things up (using the base)? 

Probably. The base is the control pin for power. An LED uses a lot of current, and switching the LED current through the base is likely to be difficulty to do quietly.

I am guessing to keep any noise out, the emitter leg, and the LED cathode back to chassis ground? 

It depends on how you switch the LED on and off for indication. It's best if the current for the LED never enters the pedal board, so I would start with connecting the LED circuit + side to the collector, through the switching, and with the switching minus side going all the way back to the power entry. That way the LED current transients share less of the power wiring resistance.

[italianguy63]

(I meant collector.. been using only PNPs too long)  Got turned around.
Thanks again.. learn a little more each day!