Hey Sean-
I am guessing you're refering to the 2nd diagram. A far as I can tell, the 20K resistor gives the preceding circuits a moderate dc-grounded load to drive, in case the next stage has a high-impedance and/or capacitive input. Without this, a high-impedance input stage can sometimes create enough mismatch to have an uneven frequency response, along with increased noise. Simply, it helps decrease hum and noise.
Hope this helps. Of course, I'm open to corrections on this.
-Bruce D.
From: Sean <fourtytwominds@yahoo.com>
To: newmellotrongroup@yahoogroups.com
Sent: Thursday, January 12, 2012 1:47 PM
Subject: [newmellotrongroup] OT again: summing box question
To: newmellotrongroup@yahoogroups.com
Sent: Thursday, January 12, 2012 1:47 PM
Subject: [newmellotrongroup] OT again: summing box question
I'm building my own mono-summing box as I'm tired of "smoking" on the signal of my clonewheel.
http://www.rane.com/note109.html
Simple, straightforward, except...
Scroll down to the "stereo-to-mono summing box."
What on earth is that 20Kohm resistor doing bridging hot and signal ground? I just don't understand why I'm to put that there. To my (limited) knowledge, the box should work as expected without it.
-Sean
http://www.rane.com/note109.html
Simple, straightforward, except...
Scroll down to the "stereo-to-mono summing box."
What on earth is that 20Kohm resistor doing bridging hot and signal ground? I just don't understand why I'm to put that there. To my (limited) knowledge, the box should work as expected without it.
-Sean