Page 3 of 52
Testing the Power Supply ............................................................................................. 38
Final Amplifier Wiring ................................................................................................. 39
Wiring Amplifier Power ........................................................................................... 39
Fasten the Power Supply to the Chassis ................................................................... 39
Install the Wall and Fasten the Transformer Down .................................................. 40
Visual Inspection ...................................................................................................... 41
Section 5: Testing It Out and Installing the Top ............................................................... 41
Power-Off Tests ............................................................................................................ 42
Power-On Tests ............................................................................................................. 42
Install the Top ........................................................................................................... 42
Section 6: Using the GT-102 ............................................................................................ 42
Section 7: Specifications and Schematics ......................................................................... 43
Section 8: Theory of Operation ......................................................................................... 47
Power Supply ................................................................................................................ 47
Bulk DC Supply ........................................................................................................ 47
Pass Transistor .......................................................................................................... 47
Regulator Control Circuits and their Power Supply ................................................. 47
Current Limiting ....................................................................................................... 47
Start-up Circuits ........................................................................................................ 48
Amplifier Modules ........................................................................................................ 48
Reference Voltage Generator .................................................................................... 49
Gain Setting Circuits ................................................................................................. 49
Relay Control Circuit .................................................................................................... 49
Appendix 1 - Resistor Color Code .................................................................................... 50
Appendix 2 - Preparing a Shielded Cable End ................................................................. 51
Table of Figures
Figure 1-Component side of power supply PCB before loading ........................................ 7
Figure 2-Installing resistors ................................................................................................ 8
Figure 3-R11 location (PCB's are missing the silk screen for R11) ................................... 9
Figure 4-Form the cathodes of D4-D7 as shown (banded end denotes cathode) ............. 11
Figure 5-Pinout of U1, viewed from the top ..................................................................... 12
Figure 6-Note the rounded brackets used for the power supply heatsink and PCB ......... 13
Figure 7-Placing thermal compound on Q5 ...................................................................... 14
Figure 8-Installing Q5 on the heatsink and to the PCB .................................................... 14
Figure 9-Remember to solder Q5's leads .......................................................................... 14
Figure 10-Assembled Power supply mounted on heat sink .............................................. 15
Figure 11-Component location guide for amplifier PCB's ............................................... 16
Figure 12-Empty the amplifier components into a soup bowl .......................................... 16
Figure 13-Close-up of Amplifier board prior to U1, K1, and L1 installation .................. 17
Figure 14-Four of the same value resistors are installed, leads bent on the back side, then
soldered and clipped. ........................................................................................................ 18
Figure 15-showing LED cathode orientation .................................................................... 20
Figure 16-Starting to wind the output inductor................................................................. 22
Figure 17-finishing step for the output inductor ............................................................... 23
Figure 18-Mounting assembled PCB to heat sink ............................................................ 24