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Plexi SE PCB Valve Junior Conversion
Version 2
Build Manual
23 August 2009
4 of 34
Table of Contents
1.
Introduction ............................................................................................................................. 2
2.
Electrical Shock Warning ........................................................................................................ 3
3.
Disclaimer of Liability .............................................................................................................. 3
4.
Project Overview..................................................................................................................... 5
4.1
Here’s what you’ll need: ................................................................................................. 5
4.1.1
Parts: ..................................................................................................................... 5
4.1.2
Tools: ..................................................................................................................... 5
4.1.3
Supplies: ................................................................................................................ 5
5.
Let’s get started…................................................................................................................... 6
5.1
Remove the EVJ chassis ............................................................................................... 6
5.2
Remove the EVJ’s Stock Components .......................................................................... 7
5.2.1
Remove the Tubes and Tube Retainers ............................................................... 7
5.2.2
Remove the Output Transformer from the Chassis .............................................. 7
5.2.3
Clean Up the Power Transformer.......................................................................... 8
5.2.4
Remove the Volume Potentiometer ...................................................................... 9
5.2.5
Remove the Stock EVJ Circuit Board.................................................................... 9
6.
Prepare the Chassis ............................................................................................................. 11
6.1
Layout and Drill ............................................................................................................ 11
6.1.1
Layout the Plexi SE PCB for Drilling ................................................................... 11
6.1.2
Layout the Faceplate for drilling .......................................................................... 12
6.1.3
Drilling the Chassis.............................................................................................. 13
7.
Plexi SE PCB ........................................................................................................................ 13
7.1
Assemble the Plexi SE PCB ........................................................................................ 13
7.1.1
PCB Standoffs ..................................................................................................... 14
7.1.2
Tube Sockets....................................................................................................... 14
7.1.3
Spade Connectors............................................................................................... 15
7.1.4
Diodes.................................................................................................................. 16
7.1.5
The “Plexi Preamp”.............................................................................................. 17
7.1.6
The “Cascade Preamp” ....................................................................................... 18
7.1.7
Wiring the Heaters............................................................................................... 19
7.1.8
Filter Capacitors .................................................................................................. 21
7.1.9
Bypass Capacitors............................................................................................... 22
7.1.10
Install the Remaining Components ..................................................................... 23
7.1.11
Input Jack ............................................................................................................ 24
7.1.12
Control Leads ...................................................................................................... 25
8.
Putting it All Together............................................................................................................ 26
8.1
Install the New Components ........................................................................................ 26
8.1.1
Hookup the Plexi SE PCB ................................................................................... 26
9.
Turn on the Power ................................................................................................................ 29
9.1
Check Your Work ......................................................................................................... 29
9.1.1
Take a Break ....................................................................................................... 29
9.1.2
Visual Inspection ................................................................................................. 29
9.2
Power Up without Tubes .............................................................................................. 30
9.2.1
The First Power Up.............................................................................................. 30
9.3
Power Up with Tubes ................................................................................................... 32
9.3.1
The Real Test ...................................................................................................... 32
10.
Finish Things Up............................................................................................................... 34
10.1
Re-Assemble the Amp ................................................................................................. 34
