Related Manuals for AkitikA GT-102
Summary of Contents for AkitikA GT-102
- Page 1 GT-102 STEREO AUDIO POWER AMPLIFIER ASSEMBLY MANUAL © 2017 AkitikA LLC All rights reserved Revision 1p14 May 13, 2017 Page 1 of 52...
-
Page 2: Table Of Contents
Table of Contents Table of Contents ........................ 2 Table of Figures ........................3 Section 1: About This Manual .................... 5 Who Should Attempt this Project? ................. 5 Tools You’ll Need......................5 Project Overview ......................5 Important Safety Notes ....................6 About Components ...................... -
Page 3: Table Of Figures
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 ...................... - Page 4 Figure 19-mounting the PCB to the heat sink ..............24 Figure 20-Spread a thin film of thermal compound on the LM3886, but keep it off the leads ..........................25 Figure 21-a completed amplifier module ................25 Figure 22-from left to right, #6 lug, #10 lug, RCA connector ground lug ....... 26 Figure 23-power supply with attached ground wire ............
-
Page 5: Section 1: About This Manual
Section 1: About This Manual This manual gives the information you need to build Akitika LLC’s GT-102 Stereo Power Amplifier. Who Should Attempt this Project? You can build this kit if you can: 1. solder (using normal rosin core solder and a soldering iron). -
Page 6: Important Safety Notes
60/40 Rosin Core solder. Akitika LLC’s liability shall in no event exceed the cost paid to Akitika LLC for the kit. Page 6 of 52... -
Page 7: Section 2: Building The Power Supply Pcb
The bare power supply PCB is shown in Figure 1. Figure 1-Component side of power supply PCB before loading Begin by carefully emptying the contents of the envelope marked “GT-102 PSU Module” into a broad soup bowl, as shown below. In general, you’ll start with the components that lay closest to the board, working your way towards the taller components. -
Page 8: Figure 2-Installing Resistors
Figure 2-Installing resistors We recommend the following procedure: 1. Insert all the resistors of the same value, e.g. R2, R3 and R4. 2. Bend the leads as described above. 3. Solder the leads on the back of the board. 4. Clip the leads. Track your progress by placing a check-mark in the done column as you install each resistor. -
Page 9: Install The Diodes
Figure 3-R11 location (PCB's are missing the silk screen for R11) Install the Diodes Now install the diodes. Be careful to observe the polarity markings on the diodes. You’ll notice that one end of the diodes has a band. That band indicates the cathode of the diode. Match the banded end of the diode with the banded end of the silk screen. - Page 10 D4-D7, opaque D12, D13, D1, D2, D8- black plastic package type D11, D14, package DO-41, opaque package type black plastic DO-35, glass package package Keep track of the diodes as you install them using the following table. Remember to watch the polarity of the diodes, matching the banded end of the diode to the banded end of the silk screen.
-
Page 11: Install The Last Resistor
Figure 4-Form the cathodes of D4-D7 as shown (banded end denotes cathode) Designation Type, Package Description Done? () 6A4, R-6 6A, 400 PIV, rectifier diode 6A4, R-6 6A, 400 PIV, rectifier diode 6A4, R-6 6A, 400 PIV, rectifier diode 6A4, R-6 6A, 400 PIV, rectifier diode Install the Last Resistor... -
Page 12: Install The Integrated Circuits
Install the Integrated Circuits Install the integrated circuits. Orient U1 so that pin 1 on the chip matches pin 1, the square pin, on the PCB. Orient U2 to match the silk screen outline. Designation Type Description Done? () LM258 or LM358 8 Pin DIP TL431, TO-92 Programmable shunt regulator... -
Page 13: Final Inspection Of The Circuit Board
Final Inspection of the Circuit Board After you’ve taken a break, look over your completed circuit board one more time. Looking on the component side, double check: 1. polarity (banded end) of diodes matching the banded end on the silk screen. 2. -
Page 14: Figure 7-Placing Thermal Compound On Q5
Figure 7-Placing thermal compound 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 screws: a. -
Page 15: Figure 10-Assembled Power Supply Mounted On Heat Sink
b. 2 that hold the brackets to the heatsink c. 1 that holds Q5 to the heatsink. 6. Solder the three leads of Q5 on the component side of 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. -
Page 16: Section 3: Assembling The Amplifier Circuit Boards
This section details the process of building the amplifier module circuit boards. We start with an overview on this page. Begin by carefully emptying the contents of one of the envelopes marked “GT-102 Amplifier Module” into a broad soup bowl, as shown in Figure 12. -
Page 17: Install The Resistors
Figure 13-Close-up of Amplifier board prior to U1, K1, and L1 installation Install the Resistors In general, you install the resistors by placing the body on the 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 resistors from falling out until your solder them in place. -
Page 18: Figure 14-Four Of The Same Value Resistors Are Installed, Leads Bent On The Back Side, Then Soldered And Clipped
Color Code column and the resistor from left to right. Note: The GT-102 is a dual channel amplifier. You will build two identical channels. We’ve provided two Done columns, Done1 for the first channel you build, and Done2 for the second channel. -
Page 19: Install The Small Capacitors And The Diodes
40K2 Yellow, Black, Red, Red, Brown 49K9 Yellow, White, White, Red, Brown 49K9 Yellow, White, White, Red, Brown The following resistors are 1 Watt resistors, having a larger body than the resistors installed in the previous section. 1000 (1 Watt) 5% Brown, Black, Red, Gold. -
Page 20: Last Capacitors And The Transistors
sure you’re putting the diodes in the right way! The cathode of the LED is indicated by a bar (negative sign) molded into the package. On some packages, there is no bar, but seen from the top, the circular outline with have a flat side. That flat side is the cathode. - Page 21 Install the non-polarized capacitors. Either orientation is fine for these capacitors: Designation Value Marking Done Done 1 µF, 63 V 105K, 63 V or 100V (box shaped mylar capacitor) May also be marked 1J63 0.1 µF, 100V µ1J100, small blue box shape 0.1 µF, 100V µ1J100, small blue box shape 0.1 µF, 100V...
-
Page 22: Winding The Output Inductor
Winding the Output Inductor This step takes just a bit of finesse, but if you’ve come this far, you have nothing to worry about. If you’re a bit frazzled, take a break before proceeding. There...feel better? OK, let’s go. Just follow these steps, measuring the wire length carefully if you want to succeed the on first shot. -
Page 23: Install Relay K1
Figure 17-finishing step for the output inductor Install Relay K1 It’s important to get K1 installed flat onto the PCB. To do this: 1. Insert K1 through the PCB. 2. Solder one corner pin. Make sure the relay sits flat on the board. If it doesn’t, push it in while you re-heat that pin. -
Page 24: Install The Lm3866 And Mount The Amplifier Board To The Heatsink
Install the LM3866 and Mount the Amplifier Board to the Heatsink Figure 18-Mounting assembled PCB to heat sink 1. Use two 6-32x3/8” screws to fasten a pair of mounting brackets to the heat sink, placing the screw through the un-threaded hole in the bracket. Use the inner set of holes in the heatsink. -
Page 25: Figure 20-Spread A Thin Film Of Thermal Compound On The Lm3886, But Keep It Off The Leads
Figure 20-Spread a thin film of thermal compound on the LM3886, but keep it off the leads 4. Fasten the LM3886 to the heatsink using a 6-32x3/8” screw. Tighten all the mounting screws as you make sure that the LM3886 is perpendicular to the plane of the board. -
Page 26: Section 4: Wiring It All Together
Section 4: Wiring it All Together Get out the trusty soup bowl, and empty the contents of the “Top Level Hardware” envelope into it. Locate and have ready the “GT-102 Wiring Kit” envelope, as it’s the source of all the wire used in this section. -
Page 27: Attaching Right Module Wires
3. Remove about 1/4” of insulation from each of the four ends and tightly twist the copper strands together. 4. From one end of the Red/Black wire, insert the Red wire into the VCC eyelet, entering from the solder side. Solder the wire on the component side. 5. -
Page 28: Build The Ground Harnesses
8. Working from that same end, insert the drain wire into the INGND eyelet closest to the IN eyelet. Once again, insert it from the solder side, and solder it on the component side. 9. Cut an 11” length of 18 AWG stranded white wire. Remove 1/4” of insulation from both ends. -
Page 29: Build The Ground Lifter
Build the Ground Lifter There’s one more small circuit board to build, the ground lifter circuit board. It supplies a robust diode-bridged connection between the AC mains ground (often called Green Wire Ground or GWG) and the Chassis Ground where all the signal and power connections come together. -
Page 30: Install The Feet
Install the Feet Install the four feet into the corners of the bottom of the chassis using 6-32x 3/8” Phillips head screws (these are zinc-plated, so will look silver). Snug the screws, but don’t over- tighten. Installing the screws will protect the bottom of the chassis from damage. Figure 28-Install the feet here AC Power Wiring 1. -
Page 31: Figure 31-Power Wiring With Iec Connector Installed Into Chassis
3. Starting outside the chassis, insert the black and white wires (already connected to the IEC power connector) into the hole in the back-right corner of the chassis as shown in Figure 31. Make sure that the writing on the power connector is right side up! Push until it clicks in place. -
Page 32: Installing Amplifier Modules Into The Chassis
9. Starting with the switch outside the chassis, push the FASTONs on the bottom switch terminals as indicated in Figure 32. The black or white wire may be on either side of the switch, so long as they both attach to the bottom row of contacts. Figure 32-Installing power wires on the switch 10. -
Page 33: Install The Speaker Binding Posts
Figure 34-Installing RCA jacks 4. Insert the RCA jack and the two insulating washers and ground lug as show in Figure 36. The ground lug already has two black wires attached. Tighten the mounting nut. Note that there are shoulders on the insulating washer that keep the RCA connector’s body from touching the chassis. -
Page 34: Connect The Speaker Binding Posts
The black plastic insulators have shoulders that fit inside the mounting holes. Make sure that the shoulders are centered in the mounting holes. They keep the binding post studs from shorting to the chassis. The binding post wire-insertion holes should be horizontal, as shown in Figure 35. -
Page 35: Transformer Preparation
Figure 36-I/O Connector wiring Transformer Preparation The directions in this section cover 120 Volt wiring. For 240 Volt wiring, you’ll need the V240 kit. This kit has the parts and directions to wire the transformer for 240-volt power. The kit builder must supply a country-specific 240 Volt power cord. Locate the 5”... -
Page 36: Figure 38-Western Union Splice Has Diameter Less Than The Insulated Wires And No Sharp
1. Cut a 2.5” length of 3/16” diameter heat shrink tubing. Slide it over the blue and violet leads of the power transformer. Slide it as far from the cut ends of the wire as possible. 2. Cut a second 2.5” length of 3/16” diameter heat shrink tubing. Slide it over the gray and brown leads of the power transformer. -
Page 37: Transformer Installation
13. Once the heat-shrink tubing has cooled, test your work by tugging on the heat shrink to assure that it will remain in place. 14. Cut the black and yellow transformer wires to a length of 3.5”. Twist together the insulated portion of the black and yellow transformer wires. -
Page 38: Testing The Power Supply
Testing the Power Supply 1. Make sure that green ground wire from the IEC power entrance connector in the back-right corner of the chassis connects to the GWGND eyelet of the ground lifter PCB. Make sure that the wire from the CHGND eyelet of the ground lifter PCB connects to the grounding stud located between it and the back wall of the chassis, and that is secured by a tightened 6-32 nut. -
Page 39: Final Amplifier Wiring
b. Pull the power cord from the wall socket c. Remove the power cord from the power entrance connector on the chassis d. Go away from the amp for five minutes to celebrate and let the output capacitors discharge. The raw power supply has only light bleeder resistors. It may take 5 minutes for the main filter capacitors to discharge. -
Page 40: Install The Wall And Fasten The Transformer Down
a. The ground stud already has a #6 lug, the black wire from the ground lifter PCB, and a #6-32 nut holding the lug in place. Make sure the nut is tight. b. Above that nut, place these three #6 ground lugs: i. -
Page 41: Visual Inspection
Refer to Figure 42 to see how the power and ground wires route through the slots in the wall: 1. Route the power supply ground wire through the back hole in the wall. 2. Route both red/black power leads from the power supply and the Green Wire Ground lead from the power entrance connector through the front hole in the wall. -
Page 42: Power-Off Tests
4. Please note that with inputs disconnected, the speakers should be quite quiet. Section 6: Using the GT-102 Don’t block the ventilation holes on the sides or the top of the amplifier. The amplifier has speaker relays that keep the speaker completely disconnected from the amplifiers until about 7-10 seconds after power up. -
Page 43: Section 7: Specifications And Schematics
Protection circuits will shut the amplifier down in case of overload or abuse. If this happens: o Turn off the power o Remove the overload condition o Turn down the input level o Turn on the amplifier, and in 7-10 seconds, you’re ready to listen again. ... -
Page 44: Figure 44-Power Supply Schematic
Figure 44-Power Supply Schematic Page 44 of 52... -
Page 45: Figure 45-Amplifier Module Schematic
Figure 45-Amplifier Module Schematic Page 45 of 52... -
Page 46: Figure 46-Overall Wiring (Power Transformer Is Wired For 120 Vac)
Figure 46-Overall Wiring (power transformer is wired for 120 VAC) Page 46 of 52... -
Page 47: Section 8: Theory Of Operation
Section 8: Theory of Operation Power Supply The following discussion refers to Figure 44. Bulk DC Supply We begin at the left side of the schematic. The toroidal power transformer steps the 120V or 240 V AC mains (selected as a wiring) option to about 70 Volts RMS . -
Page 48: Start-Up Circuits
deliver. R24 and R11 form a voltage divider that applies 0.352 volts to the positive input of U1. The negative input of U1 (pin 6) is driven by a low pass filter that senses the power supply output current. The DC current limit is set by 352 mV/0.1 Ohms (R12) at 3.5 Amps. -
Page 49: Reference Voltage Generator
Reference Voltage Generator R1, R7, R8, D8, and U2 establish a 36-volt reference at node V36. D8 assures that 26 volts appears across U2, keeping it well within its 36-volt rating. R2 isolates V36. D5 helps charge C1 more quickly during turn-on, establishing the output voltage relatively quickly. -
Page 50: Appendix 1 - Resistor Color Code
Appendix 1 - Resistor Color Code Figure 47-demonstrating the resistor color code Here’s an extreme close-up of a ¼ W metal film 20K (20,000) Ohm resistor, designated by the standard resistor color code. The colors map to numbers: Color Number Black Brown Orange... -
Page 51: Appendix 2 - Preparing A Shielded Cable End
Appendix 2 - Preparing a Shielded Cable End This section tells how to prepare the ends of the shielded cable. This process will be repeated four times, at both ends of both input cables (although the cables will have different overall lengths). 1. -
Page 52: Figure 48- Shield Wire End Prep Completed
6. Peel back and remove the foil. Remove the plastic wrap from the red and black wires. The drain (bare wire), red, and black wires are exposed now that gray insulating jacket, foil shield, and plastic over-wrap have been removed. 7.
Need help?
Do you have a question about the GT-102 and is the answer not in the manual?
Questions and answers