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Summary of Contents for Lint Audio Legend 2
- Page 1 Legend 2 stereo headphone amplifier Lint Type TE1/2 Kit assembly instructions 12AU7 / ECC82 Hybrid Valve audio preamplifier and headphone amplifier www.lintaudio.co.za Download from the website @lintaudio December 20...
- Page 2 Contents Introduction Welcome to the world of kit building Part 1 - User guide Part 2 - Introduction Part 3 – Kit assembly The schematic and BOM is a separate file...
- Page 3 Welcome to the exciting world of Hifi kit building Thank you for purchasing a Lint Legend 2 kit. The kit is designed to introduce you to the interesting world of basic electronics. You will encounter vacuum tubes or valves, mosfets, voltage regulators, resistors, capacitors, transistors as well as soldering.
- Page 4 Legend 2 Check list “Follow the revolution” Lint Legend 2 headphone / pre amplifier with sub output Earth cable and lug Power supply 24 Volts DC – 220 VAC / 2 pin European plug The Lint Legend provides a outstanding analogue sound experience with headphones and a music source, featuring a Class AB amplifier with a 12 au7 vacuum tube, MOSFET second stage with quality capacitors allowing for an outstanding sound experience.
- Page 5 Inserting Vacuum tube (Valve) The Lint Legend is supplied with either a NOS (new old stock) or new 12au7 vacuum tube (valve). All units have been fully tested at our works with a few hours of burn in.. The design is PURE ANALOGUE and will not perform to expectations without adequate run-in time.
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Page 6: Cable Connections
Cable connections Connect headphones to the 3,5 mm audio out socket on the front, this disables pre amp output. Plug in a input 3,5 mm aux cable to the PCB, visible through the acrylic rear panel or to the RCA sockets. Plug in the RCA outputs to a amplifier and the sub to the third RCA socket this is a balanced mono so connect to LFE on sub. -
Page 7: Gain Selection
Gain selection Due to the fact that it is very difficult to make a fully universal analogue product. The Legend is so designed that the output gain may be By the user when used as a pre amplifier. It’s a very simple procedure. The Legend is factory set at a optimum gain at the output RCA jacks. -
Page 8: Tube Rolling
Tube rolling The Lint Legend is designed to provide the ultimate music headphone enjoyment. However as most music lovers that have discovered the benefits of a analogue vacuum tube type of audio amplifier is that the “Legend” is designed to be “tube rolled”... - Page 9 The kit is designed to introduce an audio enthusiast to vacuum tube technology as well as to improve the audio quality of available to the listener while providing a stepping stone to more advanced build projects that Lint Audio are developing.
- Page 10 Types of valve that may be used. The system is designed around the 12 au7 or also known as ECC82, this is a 3 wire heater circuit, it may use either 13,6 volts in series or 6,3 volts in parallel . The PCB is so designed to allow either a Lm317k regulator which may be adjusted to precisely the required voltage.
- Page 11 LM317K variable voltage regulator The LM317k mounted on the rear panel is used as an adjustable voltage regulator. It is supplied in a T03 package with a suitable heatsink. By adjustment of the trim pot RV5 on the PCB it allows the vacuum tube heater voltage to be set at 12,6 volts very precisely.
- Page 12 MOSFET output transistor The IRF 510 is used as second stage amplifier from the vacuum tube. It gives the advantage of modern electronic components coupled to the pure analogue experience of vacuum tubes. The best of both worlds ! The main advantage of a MOSFET is that it requires almost no input current to control the load current, when compared with bipolar transistors.
- Page 13 Resistor component codes If in doubt, always check values with a multimeter...
- Page 14 Capacitor codes Power and output capacitors are polarised electrolytic, the device is marked and the long leg is always the positive...
- Page 15 Soldering with examples of a dry solder joint Always ensure that the joint is not moved whilst cooling, this will cause a matt finish. A shiny joint will be correct joint. Please ensure that you use a fine tipped soldering iron DO NOT OVERHEAT JOINTS WHEN SOLDERING...
- Page 16 Bending a component lead Diode mounting Always ensure a diode is correctly Take care when bending a component lead not Inserted to the PCB or the system to damage the “die” of the component. will not work. Always use pliers to prevent undue strain on the die.
- Page 17 Part 3 Kit assembly Introduction It is expected that the kit builder has some soldering experience. The kit is level 2. Always use a fine tipped soldering iron. It is not advisable to use a heavy industrial unit. Use fine solder when assembling. It is expected that the builder has a knowledge of basic electronic components, layouts and tools.
- Page 18 24V IN 24V IN DS-210-A DS-210-A 100nF 100nF 4700uF 4700uF DPDT2WRA DPDT2WRA Bottom Bottom ON/OFF ON/OFF 2N3906 2N3906 AUDIO IN L AUDIO IN L 220R 220R 400V 400V IRL510 IRL510 V1-1 V1-1 12AU7 12AU7 100V 100V 2200uF 2200uF AUDIO OUT L AUDIO OUT L 10k log 10k log...
- Page 19 Overlay of components...
- Page 20 Complete kit of parts with each bag labeled with a part number...
- Page 21 Starting assembly Firstly, we are humans at Lint Audio, so we can and often do make mistakes ! So start by reading both the drawing and overlay. With all materials laid out, separate the key materials. Resistors, capacitors and mounting hardware.
- Page 22 PCB assembly Separate the PCB materials and start by assembling the resistors, always ensure that you bend the legs as per the instructions above. Ensure the gold bands are always facing the same direction. This makes it easier to read ! If new to electronics, just double check the resistor values with a multimeter.
- Page 23 Assemble B9 adaptor Start with the orange led (if you don’t want false heat leave out) Solder red and black leads 60 mm long and heat shroud to the LED D4, this inserts in the b9a centre hole. Twist these cables lightly.
- Page 24 Colour code of Vacuum tube base connector 12v6 LM317 Black Orange Green Black Black Yellow Not connected Blue Solder 55mm long cables to each pin, view from underneath...
- Page 25 Soldering B9a to pcb After soldering the colour cables and applying heat sleeve to the connections 1 to 8, tin cables ends and insert into PCB, When all inserted, double check and then check against the schematic. Twist the cables to arrange neatly.
- Page 26 B9 a base soldered to PCB with heater cables attached After assembly, now you can populate Capacitors C1, C2 and C3 Now clean the PCB solder flux off with Benzine...
- Page 27 PCB Overlay components top side Headphones Switch Power in Audio in Potentiometer...
- Page 28 PCB assembly complete Review your work and double check against the schematic, its hard work to fix simple mistakes later Next stage to prepare for the assembly jig. This allows the heat-sinks to align properly as well as required to position the regulators and mosfets to the PCB correctly.
- Page 29 Now double check the heater Voltage to 12,6 volts before heatsink assembly...
- Page 30 Mosfets and LM317 are supplied attached to the heatsinks Note these are left and right, mosfets to the front of the PCB...
- Page 31 Screw the pcb to the Jig first with a 5 mm spacer between the PCB and the jig. Now assemble the heat-sinks Take care which device goes to which hole set ! With the heat-sinks screwed down, tighten the TO 220 devices to the heat sinks...
- Page 32 With all heatsinks and PCB firmly tightened, turn upside down and solder the devices to the PCB…and double check the regulators and mosfets ! Now test the heater voltage and insert a valve ! You can now bias the valve at 12,5 volts to 13 volts.
- Page 33 Now the back panel assembly Whilst the PCB assembly is now soaking, a good time to complete the rear panel and assemble the RCA sockets and the earth post. The rear panel is supplied with protective film attached, so remove this and thoroughly wash with soap and water before assembly thus removing the dust.
- Page 34 Now the RCA sockets and earth bolts Example shows a switch mode power supply for 6v3 heaters...
- Page 35 Now solder the input / output cables to the PCB Ensure that you twist pair ! Colour codes Left channel white and black Right channel orange and black Sub output red and black Lm317k Red power in Adjust yellow Output orange...
- Page 36 Now calculate your output levels The objective of building a kit, besides the enjoyment of actually creating something very nice…. Many builders require specific output values for their equipment, this is achieved by means of a T pad attenuator and maybe established by means of simple calculations. But a nice web site does it for you. The pcb by default is set for two levels at 1khz.
- Page 37 T Pad attenuator (using 12au7 mu 17) The output level of the Legend 2 may be adjusted to suit the type of amplifier to be driven. A classic T pad attenuator is deployed for this reason. It may be user adjustable by means of a shunt bridge.
- Page 38 This is the gain...
- Page 39 Octal base colour coding for 6sn7 6v3 heater Follow colour sequence from the B9a base when connecting to PCB...
- Page 40 Use 6v5 SMPS regulator for this Tube Pin 9 is not connected...
- Page 41 Lint Legend V7 headphone amp Changes for SMPS (6v5) or (12v) Remove C11, R12,D5, RV5, R14, C11 Bridge C11 (allows to ground) C7, C8 remain SMPS connections Pin1 Vin, Pin 2 to ground, Pin 3 Output...
- Page 42 Assemble rear panel, just remember to leave the PCB and heat sink loose...
- Page 43 Now test the Input 3,5 mm and RCA input and outputs Firstly lets confirm that the 3,5 mm input is playing music ! Plug a audio source to the RCA input and headphones. The headphones switch the output RCA sockets off. If you are rocking the daisies, now to check your attenuation calculations.
- Page 44 Check input to 150 Mv at 1000hz (each channel)
- Page 45 Check output level at max volume setting Check both gain settings to confirm what is your requirement...
- Page 46 Panels. Tighten the PCB and heatsinks. Now wash the top panel with soap and water, Screw closed. All good now apply the stickers with soap and water. Now you can rock the daisies ! Brought to you by Paul Lintott Lint Audio Ballito, 2020 Enjoy !
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