AkitikA PAT-4 Assembly Manual Download Page 3

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Figure 10-Phono Preamp Schematic Page 1 ..................................................................... 18

Figure 11-Phono Preamp Schematic Page 2 ..................................................................... 19

Figure 12- Shield wire end prep completed (right channel) ............................................. 23

Figure 13-demonstrating the resistor color code .............................................................. 24

Summary of Contents for PAT-4

Page 2: ...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 Rem...

Page 3: ...3 of 24 Figure 10 Phono Preamp Schematic Page 1 18 Figure 11 Phono Preamp Schematic Page 2 19 Figure 12 Shield wire end prep completed right channel 23 Figure 13 demonstrating the resistor color code...

Page 4: ...nd order lowpass filter that makes it much less likely to pick up external signals like switching transients and radio stations The PAT4PPR is installed much farther from the power supply so picks up...

Page 5: ...the phono preamp section of the original preamp circuit boards to the new phono preamp 4 Fastening the new phono preamp in place and performing a few sanity checks 5 Reassembling the preamp Important...

Page 6: ...rrect loading impedance The original PAT 4 design used a form of feedback biasing that made its input impedance look inductive falling to 10K ohms or less at low frequencies This kit presents an input...

Page 7: ...e Resistors In general you install the resistors by placing the body on silk screen side of the board and the leads through the indicated holes Bend the leads over on the back of the board to keep the...

Page 8: ...e Marking Done R4 158 Brown green white black brown R17 158 Brown green white black brown R2 1k Brown black black brown brown R3 1k Brown black black brown brown R10 1k Brown black black brown brown R...

Page 9: ...3 C22 3 3 F 3 3k63 The following capacitors are electrolytic capacitors The polarity is important Be sure to look at the polarity as marked on the silk screen and make it agree with the capacitor mark...

Page 10: ...lete installation of the input wiring Figure 3 Shielded cable installation right channel shown here Connect the wires as follows 1 Right channel signal wire red to the eyelet labeled INRIGHT 2 Right c...

Page 11: ...ift off the mark Figure 5 Locating the mounting holes Locate the drill holes near the selector switch as follows 1 The front mounting hole should be on a line with the front hole that holds the cover...

Page 12: ...pictured Figure 7 Connecting Left Channel input jack and 0 01 F capacitor Move Power Wires At this point 17 5 V 17 5 Volt power and ground wires run from the PAT4PWR board to the phono section of the...

Page 13: ...onnected to eyelet 5 of the front preamp PCB 2 Re attach the end of that wire to the OUTRIGHT eyelet of the new PCB Cut it to a reasonable length Insert the wire from the solder side and solder it on...

Page 14: ...s refer to Figure 8 Done Identify the wire that connects to terminal 5F of the front deck of the selector switch De solder its far end it will typically be connected to eyelet 1 of the front PC 16 Ide...

Page 15: ...Page 15 of 24 Figure 9 Back Panel Re wiring...

Page 16: ...f the new phono preamp should measure between 17 and 18 Volts DC with respect to ground The voltage on eyelet 12 of both original preamp PCB s should measure between 36 and 40 volts DC with respect to...

Page 17: ...d the cartridge body in one hand o Rotate the push on connectors around the input pin using needle nose pliers This will clean the crud and also let you tell if the connections are so loose as to also...

Page 18: ...Page 18 of 24 Schematics Figure 10 Phono Preamp Schematic Page 1...

Page 19: ...Page 19 of 24 Figure 11 Phono Preamp Schematic Page 2...

Page 20: ...Pass Filter with respect to 1 kHz 0 5 dB at 20 kHz 4 4 dB at 100 kHz 10 dB at 500 kHz 22 dB at 1 MHz Gain at 1 kHz 33 4 dB Distortion 5 mV rms input at 1 kHz produces 230 mV RMS with only 2nd harmoni...

Page 21: ...of the hole that you re trying to clear Heat the solder land on the component side of the board until the solder flows Insert the toothpick from the component side of the board while pushing and twis...

Page 22: ...le 3 4 back from the end Hold the blade perpendicular to the cable and draw it across the cable lightly as you rotate the cable along its long dimension This creates a scored line through the plastic...

Page 23: ...ed wire for RIGHT channel signals 8 To make a shielded cable for a LEFT channel application pull the red wire out of the shielded cable and leave the black wire for LEFT channel signals 9 Remove 1 4 o...

Page 24: ...bers Color Number Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Gray 8 White 9 The color band positions have the following meaning Position Meaning 1 Left most Digit e g most signifi...