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GT-102 STEREO
AUDIO POWER AMPLIFIER
ASSEMBLY MANUAL
© 2017 AkitikA LLC
All rights reserved
Revision 1p14
May 13, 2017
Page 1: ...Page 1 of 52 GT 102 STEREO AUDIO POWER AMPLIFIER ASSEMBLY MANUAL 2017 AkitikA LLC All rights reserved Revision 1p14 May 13 2017...
Page 2: ...ly Final Assembly 13 Section 3 Assembling the Amplifier Circuit Boards 16 Install the Resistors 17 Install the Small Capacitors and the Diodes 19 Last Capacitors and the Transistors 20 Winding the Out...
Page 3: ...e 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...
Page 4: ...installed into chassis 31 Figure 32 Installing power wires on the switch 32 Figure 33 spread thermal compound on the wide edge 32 Figure 34 Installing RCA jacks 33 Figure 35 Install both left and righ...
Page 5: ...l Need You ll need the following tools 1 Phillips screwdriver 1 and 2 2 pliers or nut drivers suitable for 6 hardware 5 16 nut driver or hex wrench Note that the 5 16 nut driver is also the correct si...
Page 6: ...t you to the hospital About Components We reserve the right to make design and or component changes at any time without prior notification Recommended Solder The kit must be assembled with 60 40 Rosin...
Page 7: ...3 Install the capacitors 4 Install the integrated circuits 5 Install the transistors 6 Install the pass transistor Q5 as you mount the PCB to the heat sink Component Order You ll notice that the compo...
Page 8: ...ne R2 1K Brown Black Black Brown Brown R3 1K Brown Black Black Brown Brown R4 1K Brown Black Black Brown Brown R6 10K Brown Black Black Red Brown R26 10K Brown Black Black Red Brown R27 10K Brown Blac...
Page 9: ...should help you identify the diodes Identifying the glass body diodes The glass body diodes have the following identifying marks If your vision is like mine you may need good light and a magnifying g...
Page 10: ...iode D2 BZX79 B10 DO 35 10 Volt 2 zener diode D8 1N4148 DO 35 0 2 A 100 PIV switching diode D9 1N4148 DO 35 0 2 A 100 PIV switching diode D10 1N4148 DO 35 0 2 A 100 PIV switching diode D11 1N4148 DO 3...
Page 11: ...5 resistor Designation Value Marking Done R12 0 1 0 1 Install the Small Capacitors Now install the small capacitors C1 C2 and C3 are polarized showing a minus sign on the negative end of the capacitor...
Page 12: ...om too much heat during the soldering operation Designation Type Description Done Q2 2N3904 TO 92 60 V NPN bipolar transistor Q3 2N3904 TO 92 60 V NPN bipolar transistor Q4 2N3904 TO 92 60 V NPN bipol...
Page 13: ...sinks that are black in color These black anodized heat sinks are used for the amplifier modules Figure 6 Note the rounded brackets used for the power supply heatsink and PCB 1 Use two 6 32x3 8 screws...
Page 14: ...nd on Q5 Figure 8 Installing Q5 on the heatsink and to the PCB Figure 9 Remember to solder Q5 s leads 5 Line up the PCB brackets and Q5 so everything is square and fits comfortably then tighten the 5...
Page 15: ...the board and clip the leads Inspect your work from both the top and the bottom of the board to make sure there are no solder bridges between the leads Once the power supply heat sink module is compl...
Page 16: ...2 Amplifier Module into a broad soup bowl as shown in Figure 12 In general you ll start with the components that lay closest to the board working your way toward the taller components You will 1 Insta...
Page 17: ...oles Bend the leads over on the back of the board to keep the resistors from falling out until your solder them in place Try to bend the leads in a direction that won t lead to solder bridges between...
Page 18: ...uild the second channel Designation Value Color Code Done 1 Done 2 R26 100 Brown Black Black Black Brown R8 133K Brown Orange Orange Orange Brown R3 100K Brown Black Black Orange Brown R5 100K Brown B...
Page 19: ...caps look like not to scale Next we install all the diodes except for the LED which is installed a bit later Be careful Diodes have a polarity Make sure the band on the diode aligns with the banded e...
Page 20: ...alue Package Done1 Done2 D7 LED T1 LED package Figure 15 showing LED cathode orientation Last Capacitors and the Transistors Now install the medium tall polarized electrolytic capacitors C1 C6 C7 and...
Page 21: ...Install the transistors Spread the outside leads a bit to make it easier to insert them into the board Double check their marking before you install them Orient the transistor so its body shape matche...
Page 22: ...carefully measure and cut the wire 2 Strip back 3 8 of insulation from both ends of the wire Be careful not to nick the conductors 3 From the component side place one stripped end of the wire into the...
Page 23: ...the component side double check 1 polarity of diodes matching the banded end on the silk screen 2 polarity flat end or molded bar end of LED D7 3 polarity of C1 minus sign away from the indicated plus...
Page 24: ...ten the screws yet 2 Use two 6 32x1 4 screws to fasten the PCB to the mounting brackets and heat sink Don t tighten the screws yet Figure 19 mounting the PCB to the heat sink 3 Place a dab of thermal...
Page 25: ...endicular to the plane of the board Figure 21 a completed amplifier module 5 Remember to tilt the board up and solder the LM3886 pins on the solder side as usual 6 Inspect your soldering from both sid...
Page 26: ...th ends of the wire 2 Insert one end of the wire into the GND eyelet this is different from the PGND eyelets of the power supply PCB Insert it from the solder side and solder it on the component side...
Page 27: ...first end of the white wire into the OUT eyelet of the PCB inserting it from the solder side and soldering it on the component side 11 Tin the remaining end of the white wire and insert it through th...
Page 28: ...elded cable attached Figure 25 shows the construction details The wire lengths called out on the figure specify the before stripping lengths of the wires Build two harnesses as shown 1 Complete one ha...
Page 29: ...d and gets soldered on the silk screen side Figure 26 Ground Lifter PC Board Designation Value Marking Done R1 24 9 Red Yellow White Gold Brown C1 10 nF 10nJ100 BR1 GBPC3506W 1 Locate the green 18 AWG...
Page 30: ...e feet here AC Power Wiring 1 Locate the 1 foot long white and black 18 AWG wires with FASTONS on both ends Twist the wires together This minimizes the radiated hum fields Figure 29 FASTON connector 2...
Page 31: ...5 Connect the green wire from the ground lifter assembly to the ground terminal of the power entrance connector It will be the top most terminal and the last open terminal on the connector 6 Dress the...
Page 32: ...eft Amplifier Module 1 Identify by wire lengths or masking tape tags if you made them the left amplifier module e g the amplifier that installs in the back of the chassis as viewed from the front 2 Th...
Page 33: ...le prettier insides of the amp Spread a thin film of thermal compound on the 1 4 wide ridge of the heatsink the side with two 6 32 mounting holes 3 Fit the right amplifier module in place and secure i...
Page 34: ...floor 3 Slip the 10 lug from the white 18 AWG white wire that connects to the left amplifier module OUT terminal onto the RED speaker binding post stud Position the lug as shown in Figure 36 then use...
Page 35: ...The kit builder must supply a country specific 240 Volt power cord Locate the 5 long black and white 18 AWG wires with FASTON connectors pre installed on one end Also locate the 3 16 diameter clear h...
Page 36: ...the splice ii Slide the heat shrink tubing evenly over the splice iii Use the tip or the barrel of the iron to shrink the heat shrink tubing 8 Make a Western Union splice between the blue violet and...
Page 37: ...the switch cut out in the front panel Connect them to the indicated switch terminals Place black over black and white over white Figure 39 connecting up the power transformer 3 Insert the switch in fr...
Page 38: ...ps open you probably have placed the fuse in the spare location as opposed to the active location Figure 40 Showing active and storage locations in the fuse drawer 2 Make sure that the power switch is...
Page 39: ...y the red black zip cord that connects to the right amplifier module VCC and PGND pins Route them along the chassis floor and toward the VCC and PGND pins of the power supply a Insert the red wire int...
Page 40: ...rounding Stud Detail Install the Wall and Fasten the Transformer Down If you ve been following along the transformer is not yet fastened in place This will allow you to slide it toward the right chass...
Page 41: ...nting bolt Make it snug but do not over tighten Figure 43 Toroidal Transformer Mounting 5 Fasten the wall to the bottom of the chassis using two 6 32x3 8 black screws installed from the bottom of the...
Page 42: ...ht channel outputs 1 Measure the DC voltage between the red and black speaker binding posts with no speaker connected You may see as much as 1 volt which represents 1 mA of leakage current in the larg...
Page 43: ...l at 20 Hz into a 4 Ohm load 1 channel driven Small Signal Bandwidth wider than 5 Hz to 50 kHz at 3 dB points Damping Factor 1 kHz wrt 8 Ohms 80 Signal to Noise Ratio nearly 136 dB below 50 Watts into...
Page 44: ...Page 44 of 52 Figure 44 Power Supply Schematic...
Page 45: ...Page 45 of 52 Figure 45 Amplifier Module Schematic...
Page 46: ...Page 46 of 52 Figure 46 Overall Wiring power transformer is wired for 120 VAC...
Page 47: ...the positive rail but then we wouldn t be able to directly connect the drain to a grounded heatsink That direct connection makes for the most effective heatsinking Regulator Control Circuits and their...
Page 48: ...ifier which changes the power supply from constant current to constant voltage operation From 54 volts to 72 volts the output would rise quickly were it not for the effect of C1 which continues to giv...
Page 49: ...ut coupling capacitor couples the amplifier s output to your speakers L1 wound around C11 and R15 isolate capacitance in the speaker also assuring stability for all load types C11 at 10 000 F makes a...
Page 50: ...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...
Page 51: ...e 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 jacket With a sharp...
Page 52: ...wire exposed It works best if you twist the insulation in the same direction as the drain strands are twisted If it s difficult to get it started then cut off a little bit of the end of the drain wire...
