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Copyright © 2014 by modkitsdiy.com

Use these instructions to learn:

How to build a tube preamp pedal

The Persuader uses a gain boost circuit driving a 12AX7 preamp tube operating in starved plate mode to go 
from clean, warm tone to smooth, real tube overdrive.  

THE PERSUADER (K-930)

Signal Input

(From Guitar)

Unplug when not in use 

to save battery life.

9 VDC

CENTER (-) 

ADAPTER

Signal Output
(To Amplifier)

Warning:  This circuit was designed for use with a 9 VDC power supply only.

Summary of Contents for K-930

Page 1: ...ircuit driving a 12AX7 preamp tube operating in starved plate mode to go from clean warm tone to smooth real tube overdrive THE PERSUADER K 930 Signal Input From Guitar Unplug when not in use to save...

Page 2: ...ion 6 Wiring Connections in the Vacuum Tube Section 10 Section 7 Mounting Components in the Vacuum Tube Section 11 Section 8 Wire the Output Jack and Footswitch Connections 12 Section 9 Finishing Up 1...

Page 3: ...rs 250KA and 5KL R V38 250KA 1 Terminal Strips with 5 Terminals P 0501H01 1 Terminal Strip with 8 Terminals P 0802H 1 6 Screws 3 8 long S HS632 38 4 6 Nuts S HHN632 4 Stranded Wire 22 AWG Blue K PUL15...

Page 4: ...or W orange orange orange gold 33K brown black green gold 1M R A1M 3 1M Resistor W R A5D1K 1 5 1K Resistor W green brown red gold 5 1K R A68K 1 68K Resistor W blue gray orange gold 68K 1 2 3 4 5 6 7 8...

Page 5: ...drawing as you make your way through each step of the instructions Before you make a new connection at a particular terminal or solder lug notice how many other connections will be made at that termi...

Page 6: ...e a good solder joint Take your time with each connection and make sure that all components are connected and will remain connected if your project is bumped or shaken Bend the component lead or wire...

Page 7: ...d lower portion of the terminal lower holes 3 1 5 Terminals 1 3 Anode to terminal 1 Cathode to terminal 3 1 Mount the diodes to the lower set of holes but do not solder Terminals 3 5 Anode to terminal...

Page 8: ...nt footswitch in hole Large nylon washer goes under mounting nut on outside of box Lock washer mounts on inside of box between the box surface and the other nut Make sure that the footswitch solder lu...

Page 9: ...mounting holes of the tube shield base and into the two 1 8 chassis holes ENCLOSURE BOUNDARY Use the 4 screws and nuts to mount the tube socket and shield as shown below Mount the socket with the lar...

Page 10: ...7 SECTION 6 Wiring Connections in the Vacuum Tube Section Terminals 5 12 1 Strip and tin a 2 piece of wire and connect Suggestion Connect to the lower hole of terminal 12 to make it easier when connec...

Page 11: ...f wire and connect Terminal 7 Terminal 10 SECTION 7 Mounting Components in the Vacuum Tube Section Please refer to DRAWING 8 Terminals 5 17 1 Mount the 1K resistor to Terminals 16 Tube pin 7 Do not so...

Page 12: ...two potentiometer shafts Install 9 volt battery close cover using screws provided Plug guitar into input jack on right This turns unit on Plug cable into output jack and plug into your amplifier Batte...

Page 13: ...Output Jack Input Jack DRAWING 1 DRAWING 2 RIGHT SIDE LEFT SIDE TOP BOTTOM INSIDE VIEW OF THE ENCLOSURE 3 8 3 8 3 8 3 8 9 64 104K BS170 D S G 1M 1M 5 1K 10 F 50V 1 8 5 220 F 50V 1 8 3 4 1 8 13...

Page 14: ...G 3 DRAWING 4 Output Jack Input Jack BS170 D S G 1M 1M 5 1K 10 F 50V 1 8 5 220 F 50V 1 2 3 1 2 3 5KL 250KA 104K BS170 D S G 1M 1M 5 1K 10 F 50V 1 8 5 220 F 50V 1 2 3 1 2 3 5KL 250KA 1 2 3 4 5 6 7 8 9...

Page 15: ...When the instructions mention a terminal __ this drawing illustrates the terminal numbering convention used for all three terminal strips Terminal Numbering Convention 1 8 5 1 2 3 4 5 6 7 8 9 9 13 14...

Page 16: ...DRAWING 7 104K BS170 1M 1M 5 1K 10 F 50V 5 220 F 50V 5KL 250KA 1 2 3 4 5 6 7 8 9 220 F 50V 13 1 9 18 14 1 DRAWING 8 5 1 2 3 4 5 6 7 8 9 14 10 11 12 15 16 17 68K 4 7K 1 K 1 M 104K 473K 3 3 K 1 5 K 16...

Page 17: ...DRAWING 9 104K BS170 1M 1M 5 1K 10 F 50V 220 F 50V 5KL 250KA 1 2 3 4 5 6 7 8 9 220 F 50V 2 68K 4 7K 1 K 1 M 104K 473K 33 K 1 5 K 3 Output Jack Input Jack 17 1 4 6 5 2 3...

Page 18: ...C 9 2 VDC 8 8 VDC 8 3 VDC 8 3 VDC 7 8 VDC 7 0 VDC 6 7 VDC 0 VDC 0 VDC 0 VDC 0 VDC 1 6 VDC 0 VDC 3 4 VDC 1 9 VDC 7 1 VDC 4 0 VDC Using a volt meter connect the ground side lead of the meter to any grou...

Page 19: ...V 220 F 50V 5KL 250KA 1 2 3 4 5 6 7 8 9 220 F 50V 68K 4 7K 1 K 1 M 104K 473K 33 K 1 5 K 1 4 6 5 2 A B C D E F G H I GROUND DC Voltage Test Points Guitar cable must be plugged into the input jack while...

Page 20: ...Voltage Signal Test Points 1 2 2 5 8 10 11 12 Turn all the way up Turn all the way up 9 7 4 3 3 6 Connect your guitar to the input jack and take AC voltage measurements at each test point with both co...

Page 21: ...ect the MOSFET from static and accidental reverse polarity 9 2V 9 2V 8 3V 8 8V 0V 0V 1 9V 3 4V 0V 1 6V 4 0V 7 1V 7 8V 8 3V 0V 0V 6 7V 7 0V 0V 0V 0V 0V 1 2 3 H 4 I 5 6 E 7 C 8 F 9 D 10 11 12 A B G AC s...

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