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Summary of Contents for AkitikA GT-101 STEREO
- Page 1 GT-101 STEREO AUDIO POWER AMPLIFIER ASSEMBLY MANUAL © 2013 AkitikA LLC All rights reserved Revision 1p37 October 29, 2013 Page 1 of 44...
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Page 2: Table Of Contents
Table of Contents Table of Contents........................ 2 Table of Figures ........................3 Section 1: About This Manual .................... 4 Who Should Attempt this Project? ................. 4 Tools You’ll Need......................4 Project Overview ......................5 Important Safety Notes ....................5 About Components ......................5 Recommended Solder ..................... -
Page 3: Table Of Figures
Fasten the Power Supply to the Chassis ..............35 Visual Inspection ...................... 36 Install the Shield ....................... 36 Section 5: Testing It Out and Installing the Top............... 37 Install the Top ......................37 Section 6: Using the GT-101 .................... 37 Section 7: Specifications and Schematics................. -
Page 4: Section 1: About This Manual
Figure 46-demonstrating the resistor color code .............. 42 Figure 47-Shield wired end prep completed ..............44 Section 1: About This Manual This manual gives the information needed to build Akitika LLC’s GT-101 Stereo Power Amplifier. Who Should Attempt this Project? You can build this kit if you can: 1. -
Page 5: Project Overview
60/40 Rosin Core solder. Akitika LLC’s liability shall in no event exceed the cost paid to Akitika LLC for the kit. Page 5 of 44... -
Page 6: Section 2: Building The Power Supply Pcb
Section 2: Building the Power Supply PCB This section details the process of building the power supply circuit board. We start with an overview on this page. The specifics you need to start building begin on the next page. 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-101 PSU Module”... -
Page 7: 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 8: 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 9 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.
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Page 10: Install The Last Resistor
Form the leads of D4-D7 as shown in Figure 4. Solder one lead of each diode while attempting to keep the body perpendicular to the plane of the board. Ideally, the anodes of D4-D7 should sit about 1/8” to 1/16” off the board. Figure 4-Form the cathodes of D4-D7 as shown (banded end denotes cathode) Designation Type, Package... -
Page 11: Install The Integrated Circuits
Install the Integrated Circuits Install the integrated circuits. Orient U1 so that pin 1 on the chip matches pin 1 on the silk screen. Orient U2 to match the silk screen outline. Designation Type Description Done? ( ) LM258 or 8 Pin DIP LM358 TL431, TO-92... -
Page 12: 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 13: 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 Page 13 of 44... -
Page 14: Section 3: Assembling The Amplifier Circuit Boards
5. Line up the PCB, brackets, and Q5 so everything is square and fits comfortably, then tighten the 5 screws: a. 2 that hold the brackets to the PCB b. 2 that hold the brackets to the heatsink c. 1 that holds Q5 to the heatsink. 6. -
Page 15: Install The Resistors
Figure 12-Closeup of Completed Amplifier board 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 16 To track your progress, place a check-mark in the done column as each resistor is installed. Check resistor values with a meter, or by reading the color code . Orient the resistor with the fat brown band on the right, then you can read both the Color Code column and the resistor from left to right.
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Page 17: Install The Small Capacitors And The Diodes
Figure 14-Zero Ohm R22 installation detail Install the Small Capacitors and the Diodes Now we’ll install the following small capacitors: Designation Value Marking Done Done 220 pF 220 pF 47 pF Here’s what these three caps look like (not to scale): Next we install diodes D1, D4 and D5. -
Page 18: Last Capacitors And The Transistors
Next we install LEDs D2 and D3 (Light Emitting Diodes – the green light from these LEDs will be of medium brightness, and thus visible in a normally lighten room. Be careful! Light Emitting Diodes have a polarity, also! Read carefully to make 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. -
Page 19: Winding The Output Inductor
Install the transistors. Spread the outside leads a bit to make it easier to insert them into the board. Orient the transistor so its body shape matches the silk-screen outline. Leave the top of the transistor about ½” off the board! The lead length prevents stress on the body and keeps the transistor safe from too much heat during the soldering operation. -
Page 20: Final Inspection Of The Circuit Board
Figure 16-Starting to wind the output inductor Figure 17-finishing step for the output inductor Final Inspection of the Circuit Board After you’ve taken a break, look over your completed circuit board(s) one more time. Looking on the component side, double check: 3. -
Page 21: Installing The Lm3866 And Mounting The Amplifier Board To The Heat Sink
If you get one of these polarities wrong, there is a good chance that the amplifier won’t work, or there will be damage when you power it up. Look at the solder side of the board. Make sure that: 3. All component leads are soldered (it’s easy to forget one or two, and that will cause either unreliable operation, or no operation at all!) 4. -
Page 22: Figure 20-A Completed Amplifier Module
as you may choose to use the rest of its contents when you fasten the amplifier module to the chassis. 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 parallel to the plane of the board. -
Page 23: 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 “Top Level Wire” envelope, as it’s the source of all the wire used in this section. The kit has three kinds of black single conductor wire: 1. -
Page 24: Attaching Right Module Wires
7. 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. 8. From that same end of the Red/Black wire, insert the Black wire into the PGND eyelet, entering from the solder side. -
Page 25: Build The Ground Harnesses
7. Insert the black wire into the OGND hole near the center of R17, inserting it from the solder side, and soldering it on the component side. 8. Prepare a 10” length of shielded cable per the directions that begin on Page 43. Prepare both ends per those directions. -
Page 26: Install The Feet
You’ll get the best results if you’ve tinned the stripped ends of the wires before you crimp them into the solder lugs. Once all the connections are crimped in place on a given lug, solder the lugs using enough heat to make the solder flow. When you do this, the wires should be straight, as the heat will encourage the insulation to back off a bent wire. -
Page 27: Install The Speaker Binding Posts
Install the Speaker Binding Posts The two speaker output connectors are heavy duty 5-way binding posts. Remove both nuts and the washer from each binding post. Install them into the chassis according to the following diagram. Make sure that the Red binding post is on the top. You’ll use only one nut and washer to retain each binding post for now. -
Page 28: Figure 30-Wiring Iec Power Connector
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. It’s easy to get it in, and tough to get it out, so double check the orientation before you install it. 5. -
Page 29: Installing Amplifier Modules Into The Chassis
7. 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 8. -
Page 30: Figure 33-I/O Connector Wiring
Figure 33-I/O Connector wiring 8. This step can be a bit messy, and is considered optional. Completing this step assures the maximum transfer of heat into the chassis. You’re also likely to smear white thermal compound on the inside of the amplifier as you set it into place. We’ll leave the choice up to you (a little more available output power versus a little prettier insides of the amp). -
Page 31: Transformer Preparation
6. Solder the (pre-tinned) red wire of the shielded cable to the center terminal of the RCA jack. Figure 35-amps installed, wiring not complete Position the washer and lug as shown in Figure 33. 7. Spread a thin film of thermal compound on the 3/8” wide ridge of the heatsink (the side with two 6/32 mounting holes). -
Page 32: Figure 37-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 33: Transformer Installation
iii. Use the tip or the barrel of the iron to shrink the heat shrink tubing. 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. Transformer Installation 1. -
Page 34: Testing The Power Supply
3. Insert the switch in from the front of the chassis. It may be a snug fit. Make sure that the | is at the top of the opening before you insert the rocker switch into the chassis. Push the rocker switch in the rectangular opening; it will click into place. 4. -
Page 35: Final Amplifier Wiring
6. Observe the power supply, transformer, and wiring for any signs of heating or distress. 7. If everything seems cool (please pardon the pun), the probe the VCC and PGND eyelets on the power supply PCB with a DC volt meter. The voltage should be 72 volts (+/- 4 Volts) DC. -
Page 36: Visual Inspection
1. Ground Stud a. The ground stud already has a #6 lug, the green wire from the IEC power connector, 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 37: Section 5: Testing It Out And Installing The Top
4. 2 6-32x3/8” Phillips pan-head black screws Install the shield two the chassis using the diagram of Figure 42. Section 5: Testing It Out and Installing the Top Be careful. The amplifier will be energized with the top off, and hazardous voltages will be present in the amplifier. -
Page 38: Section 7: Specifications And Schematics
Section 7: Specifications and Schematics Output Power: o greater than 50 Watts per channel into 8 Ohms o nearly 100 Watts per channel at 1 kHz into a 4-Ohm load (1 channel driven) o more than 80 Watts per channel 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... -
Page 39: Figure 43-Power Supply Schematic
Figure 43-Power Supply Schematic Page 39 of 44... -
Page 40: Figure 44-Amplifier Module Schematic
Figure 44-Amplifier Module Schematic Page 40 of 44... -
Page 41: Figure 45-Overall Wiring (Powering Transformer Is Wired For 120 Vac)
Figure 45-Overall Wiring (powering transformer is wired for 120 VAC) Page 41 of 44... -
Page 42: Appendix 1 - Resistor Color Code
Appendix 1 - Resistor Color Code Figure 46-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 43: 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 44: Figure 47-Shield Wired 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.
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