Lux Stereo Amplifier. Le Club Hifi : V1.7. DIY HiFi Supplywww.diyhifisupply.com

Transcription

1 Le Club Hifi : V1.7 Lux Stereo Amplifier DIY HiFi Supplywww.diyhifisupply.com

2 Table of Contents Chapter 1-Introduction... Chapter Specification and Parts...5 Chapter 3 - Installation Notes...7 Chapter 4 the Hardware...8 Chapter 5 Connections...10 Chapter 6 Operational notes...9 Chapter 7 - Final Words and Tweaks...31

3 Chapter 1-Introduction The chassis is preassembled with aluminum front panel, power transformer M6 laminations in the output transformers. The OPT are the soul of any tube amp and the latest generation is CNC wound for perfect lay, low capacitance and very wide power bandwidth. The large chassis and generous size dissipates heat evenly; it is normal for the chassis and power transformer cover to feel hot due to the efficiency of heat transfer from critical parts. The unit looks good as well. Dynamics are impressive, as is openness and soundstaging. Its performance belies its price many times over. The kit builder needs to have a basic knowledge of soldering. Refer to the many diagrams to avoid wiring mistakes. Parts quality are excellent. There are scads of 300B amps on the market. Why 'Lux'? Objective - drive a DHT power tube: choice #1: pentode. offers necessary single stage gain but high output Z. tendency for highs/lows to be bandwidth limited. Clipping: not nice. Sound is delicate, immediate and pleasant 'bouquet of tone'. Fast! and retrieves the finest details as it sweeps the sonic landscape. Can swing the necessary voltage but but don't ask it to lift heavy objects. the DHT needs more muscle. choice #: triode. gain-challenged, needs more than one stage. (Hi gain versions sound like solid state). Low output impedance, wide bandwidth, great slam and dynamics. can be used with a grid choke for greater perceived power. Muscular, but lacks the refinement and delicacy of the best pentodes; leaves behind some of the fine details. choice #3: re-active interstage. pentode on the input. paralleled sections of a triode with a choke loaded cathode. direct couple to the grid of the DHT. the DHT gets what it likes: lots of swinging volts and iron fist control, even when driving the grid positve. This is Lux. the pentode does what it does best: gives tons of voltage gain driving the undemanding load of the re-active tube interstage. The interstage is loaded only with the following grid and cathode choke so bandwidth approaches DC to light and is sonically neutral, no cap coupling to the DHT. The DHT thinks the choke of the interstage is it's very own grid choke. And we still have our pentode! add to this: dual 5AR4 tube rectification (tubes=tone), dual mono HT AND PS film caps for extra speed, lifting of the veil, no ecap smog more: WE connection on the 300B for more quiet, more dynamics Result: tone and refinement of a pentode married with the slam and dynamics of a triode - something like a ballet performed by Superman and Karen Kain? Lux: stereo amplifier dual mono choke loaded power supply AND film caps on the B+ rail to the power tube anode x 5AR4 tube rectifiers x EF86 pentode input tubes (front 9 pins socket position) x 5687/cathode choke re-active direct coupled interstage (back 9 pins socket position) x 300B Direct Heat Triode

4 Illustration 1: reactive interstage principle Requirements The kit builder needs to have basic soldering skills and be able to read and understand the wiring diagrams presented. Refer to the text and diagrams at each step throughout the manual and ensure you double check all wiring at each stage. It is also advantageous to refer to the circuit diagrams at the back of the manual throughout the build. Warranty The kit cannot be returned for a refund. Defective parts will be replaced provided they are returned within 30 days of purchase and are confirmed defective and not misused. No further Warranty is expressed or implied. This is to protect you the buyer to be assured of receiving a brand new kit and not one that has been returned by someone else which may have been misused. WARNING: The high voltages present in this kit can kill and the high operating temperatures can burn. Observe all precautions and never connect the kit to an electrical supply until it has been fully assembled, checked and ready for testing. You assume total responsibility and liability for the use and operation of this kit both for yourself and people around you. Confirm that large capacitors are discharged before working on the amplifier DIY HiFi Supplywww.diyhifisupply.com This manual is the property of DIY Hifi supply Ltd and may not be reproduced or distributed by any means in whole or in part. Right to use the manual for the construction of the Lux kit is granted to the purchaser of the kit.

5 Chapter Specification and Parts Specifications Power output, 300B: 1W peak x 1KHZ Class A Frequency response: 1Hz to 47KHz (-3 db@5w) (0hz to 0k -0.5db) THD: <1% (1W@1KHz) Signal to noise: 90dB or better Input sensitivity and impedance: 0.5V, 100K Output impedance: 4, 8, 16 ohm Power: 115/30V AC +- 10%, 50Wx Dimension (mm): 41(w) x 330(W) x 00(H) Weight: 6Kg per chassis Shipping Weight: 30Kg Standard Tubes (priced separately): 300Bx, EF86x, 5AR4x, 5687x, Power transformer is low output impedance EI type, custom made with imported cores. Output transformer is larger imported core and 'perfect lay' windings. Speaker outputs: 0/4/8/16ohms non-magnetic chassis premium ceramic tube sockets and RCA connectors Unpacking Remove the bottom cover from the chassis, take out the loose kit parts and check against the list. Some minor variations in value are perfectly acceptable (ie 47k instead of 43k etc)

6 Standard Level 1 Parts List 8 Speaker binding posts (6 red, black) input jacks Plastic cable ties chass is ass embly including 4 c hokes, OPT and 1 PTX test jacks hum pots PCB for power supply k/w 180k/w 1m5/1w 100k/0.5w k 0.5w 470K 0.5w 390r 0.5w 1k/30w 1K/0.5w grid stoppers for EF86 power switch IEC power socket with fuse LED & Resistor 4 Tube Sockets 8 pin Tube Sockets 4 pin Tube Sockets 9 pin uf / >10V 3.3uF / 400V 47uf/160v 10uf/600v.uf/600v 1 10 or 47uf electrolytic to float heaters uf/350v 0.uf/600v 4.7uf/400v Level : Optimized Kiwame resistors, copper/teflon hookup wire, Obbligato coupling caps, Obbligato cathode cap, cathode wire wound resistor, teflon tube sockets, copper speaker binding posts, silver plated RCA, WE connection Obbligato caps, Oil cap and Blackgate caps on the driver anodes and cathode Level 3: As per Level but adds: Pure copper gilded RCA and speaker binding posts. Optimized Tantalum/resistors, silver wire, teflon/tinfoil coupling caps, Blackgate N-type on 5687 anode. No polarized caps anywhere on the B+ rail. Option: Tentlabs filament supply

7 Chapter 3 - Installation Notes Recommended Solder It is recommended that solder with flux, designed for electronics is used. This usually has up to % of Silver that prevents the joint from becoming brittle over time. It provides a much stronger solder joint but can be difficult to work with due to its lower wetting properties, it does not flow as easily. Some electronics solder has a small amount of copper instead which has very good wetting properties. Whichever solder you use, make sure that you avoid poor solder technique. Solder Technique Solder means to apply the iron tip to the point that needs to be soldered to heat it and at the same time apply the solder. The iron and solder come together at the same time when soldering any joint or tinning a wire and the solder should start to flow evenly around the joint. Allow the solder to cool naturally and do not blow on it. The finished joint should appear shiny and not dull. Many problems are due to poor solder technique. Clean the iron tip regularly on a wet sponge between each soldering step. Connections Always wrap the wire around the connection point to make a good mechanical connection. Connect means to dress a wire by stripping off enough insulation and soldering it to the connection point or first tinning the wire. When connecting a wire to a valve base pin it is recommended that enough insulation be removed so the wire can be wrapped around the pin to form a good mechanical joint before soldering. When attaching wires to any of the PCB s or switches you should strip off a small amount of insulation and then apply solder to the exposed wire to tin it before fixing it to the PCB. Hi purity teflon Magnet Wire - option This wire comes with an enamel/teflon coating so the part of the wire, which will form part of a joint, must have its enamel removed before fixing and soldering. This can be done by boiling off the enamel in a solder pot or by holding the tip of a hot soldering iron with a little solder on the end against the wire until you see the enamel start to boil away. Clean the iron tip on a wet sponge afterwards and then tin the newly exposed wire. You can also use a fine sand paper to remove the enamel. This wire is ideal for signal ground connections.

8 Wire layout: Most of the power supply wires run lengthwise along the chassis. Most signal wires and grounds run crossways. Try to keep power supply wires close to the chassis and running perpendicular (90 degrees) to signal and ground wires. Signal and ground wires can be a little above the chassis plane. Twisting together signal pairs and power supply pairs can also help to reduce hum and noise pickup. Do not twist signal and power supply pairs with each other. Pictures indicate which of the coloured wires to use. Tips for Successful Kit Building Read each chapter through before starting it: You should familiarize yourself with the sequence of instructions before starting a chapter. Also, many chapters have helpful pictures and drawings scattered through them that will help you understand the written instructions. Follow the sequence of instructions: These instructions were designed to make assembly as simple as possible and minimize interference between assembly steps. Identify and measure parts: Be sure of the identity/value of each part before you install it. Many kit builders actually measure the value of resistors with a multimeter before installing them. Note: the parts in your kit may not look exactly like the ones pictured here as suppliers of parts are sometimes different. Some supplied values may differ slightly in value from circuit diagram and are within tolerance for the circuit. Follow the schematic: It is a good idea to have the schematic diagram of the unit nearby and to compare the instructions with the schematic. After installation, check the instructions again: Once a part is installed, double-check the installation against the printed instructions. Check off each assembly page when completed Chapter 4 the Hardware

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10 Chapter 5 Connections

11 Choose 30v or 115v according to your country voltage standard

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30 Chapter 6 Operational notes Do not yet insert the tubes! 1. Turn the chassis bottom facing up. Plug in the power and switch on the unit with the power switch. Watch for sparking, smoke or any condition that would indicate miswiring. If you have burned out a fuse, you can find a spare inside the little drawer in the IEC that slides out from the backside. If OK proceed to the next step. If not, check for mistakes.. Insert the tubes 3. Check power tubes, pin 1-4 (the two large diameter pins for teh 300B) should be about 5VDC. Voltage across the large green 1K resistor should be about 70-80v (depending on local line conditions and tubes). Measure pin to ground. DCv should be about v. Measure pin to pin 4. Should be about 350v. All DC measurements 4. Check the voltage of the 5687 and EF86 filaments. This is ACv and should read about 6v For 5687 measure across pins 4/5 and 8. For EF86 measure across pins 4 and Measure anode voltages of EF86 and For EF86 one probe to pin 6 and the other to ground. Should be about 00V. 5687: one probe at ground and the other at pins 1/9. Should be about 50v. 6. Measure Dcv from pin 3 of 300B and ground. Should be 7-8v dc. 7. Turn off the power. 8. Connect speakers and sound source through linestage control. You should never operate the unit with no speaker load attached or with shorted speaker outputs whenever signal source is applied. 9. Turn on the power and input signal. Adjust volume to desired listening level. 10. The Lux uses film caps for faster dynamics and greater speed and clarity. Film caps will sound bright when new. They take much longer to break in than electrolytic caps. Expect about 100hrs for the sound to begin to mellow. 11. Note: Voltages can vary by as much as 0% depending on line voltage and tubes. This is a fact of life and not a problem. If you have concerns about the final operating voltages that have settled in please diyhifisupply with your quiry. Blown fuse: Use 3A for 30v or 4A for 115v 1. Metal debris has fallen inside chassis and is causing a short.. Output tube damaged. 3. Filter cap damaged. 4. PS transformer has shorted internally or has been miswired for local voltage.

31 Chapter 7 - Final Words and Tweaks The Lux requires about 100 hours running in especially if you are using new tubes. Using more exotic NOS tubes can also improve and change the sound character of the amplifier. USE IN A WELL VENTILATED PLACE TO PROVIDE AIR CIRCULATION.Copyright This manual is copyright of DIY HiFi Supply It must not be reproduced or distributed in paper or electronic form. Manual produced by: DIY HiFi Supply Ltd Version 1.7 Copyright DIY Hifi Supply Ltd

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