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Table of Contents
Table of Contents ................................................................................................................ 2
Table of Figures .................................................................................................................. 2
Section 1: About This Manual ............................................................................................ 4
Who Should Attempt these Projects? ............................................................................. 4
Tools and Supplies You’ll Need ..................................................................................... 4
Recommended Solder ..................................................................................................... 5
Project Overview ............................................................................................................ 5
Important Safety Notes ................................................................................................... 5
Section 2: About the Phono Preamp Upgrade .................................................................... 6
Effects of the Modification ......................................................................................... 6
Prerequisites ................................................................................................................ 6
Building the PAT4PPR Circuit Boards....................................................................... 6
Component Order............................................................................................................ 7
Install the Resistors ......................................................................................................... 7
Prepare and Add Shielded Cables to the Inputs ........................................................ 10
Install the Mounting Brackets ................................................................................... 10
Preparing to Install the Assembled PAT4PPR Circuit Board ................................... 11
Drilling Mounting Holes in the PAT-4 Chassis ........................................................ 11
Connect the RCA Jacks ............................................................................................ 11
Move Power Wires ................................................................................................... 12
Move Selector Switch Wires .................................................................................... 13
Converting to Accept 5 high level inputs and 1 phono input ................................... 14
Inspection and Preliminary Reassembly ................................................................... 16
Final Sanity Checks .................................................................................................. 16
Prepare to Reconnect your PAT-4 to your Music System ........................................ 16
Record Playing Reminders ........................................................................................... 16
Gain Tweaks ................................................................................................................. 17
More Tweaks ................................................................................................................ 17
Schematics .................................................................................................................... 18
Specifications ................................................................................................................ 20
Appendix 1: The Toothpick Trick ................................................................................ 21
Appendix 2 - Preparing a Shielded Cable End ............................................................. 22
Appendix 3 - Resistor Color Code ................................................................................ 24
Table of Figures
Figure 1-Component side of the phono preamp PCB before loading ................................. 6
Figure 2-Installing resistors ................................................................................................ 7
Figure 3-Shielded cable installation (right channel shown here)...................................... 10
Figure 4-Use 6-32x1/4" screws to attach mounting brackets ........................................... 10
Figure 5-Locating the mounting holes .............................................................................. 11
Figure 6-locating the two added 9/64" mounting holes .................................................... 11
Figure 7-Connecting Left Channel input jack and 0.01 µF capacitor .............................. 12
Figure 8-Selector Switch wire identification .................................................................... 13
Figure 9-Back Panel Re-wiring ........................................................................................ 15