This circuit is a modified version of the MXR Noise Gate circuit. It mutes the output when the input signal is below a threshold set by a potentiometer, removing noise when not playing. Additional pads have been added to allow more control over the circuit. Modifications are not verified and off-board components except for potentiometers are not shown. Trademarks are owned by their respective companies.

1. Callate Gate 2 Rev.1.Feb.20.2004
This circuit is based on the MXR Noise Gate, it will mute the output when the input is below the
threshold level set by the potentiometer, removing noise while not playing. This is Tonepad’s modified
version which includes pads for experimentation that will allow for more control. Mods are not verified.
Layout is populated as stock circuit. Off board components except for the potentiometers are not
shown on the layout. Trademarks are property of their owners.
500k
3 2 1
10uF
SENSITIVITY +9V
1½
+
1k
0.047 22k D1 3002 PF
1uF
1uF
10k
+
1uF
0.047
47pF
100 OUT
0.01
+
680
IC 1
IC 1
1M
1M
100k
1M 1
1M 1M
22k 0.01 Q3 1M
GND
G
22k ATTENUATION
E F +
+
100k
IN Q1
1uF ½
10uF
1M
+
+
0.047
470k
1uFNP 2ETALLAC
2M2
22k
1k
Ra
10uF
Q2
+
A B C D
0
RELEASE
ATTACK
LAYOUT
Parts List 0 ½ 1 1½ 2
Layout and presentation© by Francisco Peña 2001 - 2004®.
Resistors Capacitors Pots NOTES:
7 - 1M 3 - 10µF 1 - 500k Log.
All rights reserved. Authorization for personal use only,
Mods require replacing jumpers with pots.
1 - 470k 3 - 1µF Attack:
Permission refused for posting from other sites.
1 - 150k (Ra)* 1 - 1µF / NP Diodes Use a 5k or 10k linear pot. (larger
resistance=longer attack time)
Permission for posting/serving limited to
2 - 100k 3 - 0.047 µF 1 - 5.1v Zener Release:
4 - 22k 2 - 0.01 µF
any commercial use is forbidden.
Use a 250k or 500k linear pot. (larger
1 - 10k Transistors &ICs resistance=longer release time) Lower Ra’s
2 - 1k 2 - 2N3904 (2N5088 will also work) value to allow faster than stock release.
http://www.tonepad.com
1 - 680 1 - 2N5952 (2N5485 will also work) Attenuation:
Use a 50k or 100k linear pot. (larger
2 - 100 IC1 - 4558 (TL072 will also work) resistance=less attenuation)
Schematic (attack, release and attenuation controls added) +9v
AC 22k 1M
ADAPTOR .01
5 8 OUTPUT
Vb 1uF 100
7
IC1b
10uF 10uF 5.1 1M
6 4
1M .047 10k
22k
100k
10uF
Vb
+
+9v 1M Q3
9v .01
1M
3 Vb 3
2 3 2
500k ATTENUATION
INPUT 1 2
1k .047 1 IC1a 1
1 3
Q1
2
1M Vb ATTACK
1M 150k(Ra) 100
.047 100k
1k 680 Q2
3
2
2M2 470k 22k 22k 1uF/NP RELEASE 1uF MOM.
1uF 1
Vb Vb Vb