Velleman K8084 Volume and Tone Control Preamplifier User Manual
- June 12, 2024
- Velleman
Table of Contents
Velleman K8084 Volume and Tone Control Preamplifier User Manual
Features & specifications
When using one of our amplifiers (big or small), you always need a volume control and preferably also a tone control. This kit comes complete with all input / output connections and potentiometers. Furthermore it is possible to amplify or attenuate the input signal.
FEATURES :
stereo volume control stereo Baxandall bass and treble control bass and treble potentiometers with centre click customizable attenuation or amplification complete with knobs
SPECIFICATIONS :
Assembly hints
1. Assembly (Skipping this can lead to troubles ! )
Ok, so we have your attention. These hints will help you to make this project successful. Read them carefully.
1.1 Make sure you have the right tools:
- A good quality soldering iron (25-40W) with a small tip.
- Wipe it often on a wet sponge or cloth, to keep it clean; then apply solder to the tip, to give it a wet look. This is called `thinning’ and will protect the tip, and enables you to make good connections. When solder rolls off the tip, it needs cleaning.
- Thin raisin-core solder. Do not use any flux or grease.
- A diagonal cutter to trim excess wires. To avoid injury when cutting excess leads, hold the lead so they cannot fly towards the eyes.
- Needle nose pliers, for bending leads, or to hold components in place.
- Small blade and Phillips screwdrivers. A basic range is fine.
For some projects, a basic multi-meter is required, or might be handy
1.2 Assembly Hints :
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Make sure the skill level matches your experience, to avoid disappointments.
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Follow the instructions carefully. Read and understand the entire step before you perform each operation.
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Perform the assembly in the correct order as stated in this manual
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Position all parts on the PCB (Printed Circuit Board) as shown on the drawings.
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Values on the circuit diagram are subject to changes.
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Values in this assembly guide are correct*
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Use the check-boxes to mark your progress.
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Please read the included information on safety and customer service
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Typographical inaccuracies excluded. Always look for possible last minute manual updates, indicated as `NOTE’ on a separate leaflet.
1.3 Soldering Hints :
1- Mount the component against the PCB surface and carefully solder the leads
2- Make sure the solder joints are cone-shaped and shiny
3- Trim excess leads as close as possible to the solder joint
REMOVE THEM FROM THE TAPE ONE AT A TIME !
DO NOT BLINDLY FOLLOW THE ORDER OF THE COMPONENTS ONTO THE TAPE. ALWAYS CHECK THEIR VALUE ON THE PARTS LIST!
Construction
Test
Connect the mains voltage to the transformer; mount a 100mAT security fuse in series with the transformer. Use a high-quality power cord and plug for the connection to the mains.
When the transformer is live, the LED will light.
- Disconnect from mains.
- Mount the ICs into the socket (mind the position of the notch)
- Reconnect the mains.
- Check if the LED lights.
- Connect a device with the input e.g. MP3 player, CD player.
- Connect the output with a power amplifier.
- Turn down the volume to its minimum.
- Switch on the power amplifier.
Hint : you can also connect headphones instead of a power amplifier. You can use connections GND-TPR-TPL; GND is the ground.
Enclosure
13. Building into a enclosure
To avoid hum, it is recommended to mount the K8084 and the transformer into a Metal housing.
Drill the holes for the connections and the potentiometers.
****Hint: You can drill the holes for the knobs or the potentiometers and mount the knob afterwards.
1 hole in the print (next to RV3) is provided to connect the earthing to the housing through the metal spacers or bolts.
Hint :
****Mount the transformer as far away as possible from the circuit to avoid humming.
****It is recommended to leave this circuit under voltage; disconnect the voltage only when not in use for a long time. Always switch off the power amplifier first before switching off the preamplifier.
PCB
14. PCB
Diagram
15. Schematic diagram
