velleman WSAH8084 Volume and Tone Control Preamplifier Instruction Manual

: June 16, 2024
: Velleman

Table of Contents

velleman WSAH8084 Volume and Tone Control Preamplifier
Product Information
Specifications
Technical Data
Product Usage Instructions
- Before Starting
- Assembly Instructions
Testing
Additional Information
Contact Information
FAQ
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

velleman WSAH8084 Volume and Tone Control Preamplifier

Product Information

Introduction
This VELLEMAN K8084 kit is designed to be coupled with a Velleman amplifier for volume and tone control. It includes all necessary input and output connections as well as potentiometers. It also allows for the amplification or attenuation of the input signal.

Specifications

Stereo volume control
Stereo Baxandall bass and treble control
Potentiometers for bass and treble with center notch
Adjustable attenuation or amplification
Complete with knobs

Feature	Specification
Stereo volume control	Yes
Stereo Baxandall bass and treble control	Yes
Center detent potentiometers for bass and treble	Yes
Adjustable amplification or attenuation	Yes
Complete with knobs	Yes

Technical Data

Power supply: 2 x 12VAC / 100mA
Frequency response: 3Hz – 500kHz (-3dB)
Standard gain: x1
S/N ratio: 98dB
Harmonic distortion: < 0.005% (@1KHz)
Maximum output voltage: 5V RMS
Tone control: + and -15dB @ 20Hz, + and -15dB @ 15kHz
Input impedance: 50k ohm
PCB dimensions: 105 x 70mm

Product Usage Instructions

Before Starting

Refer to the general manual for soldering tips and other general information. The following items are required to build the kit:

Zener diodes (pay attention to polarity)
Diodes (pay attention to polarity)
Resistors
IC sockets (pay attention to the position of the notch)
Capacitors
LED LD1 (pay attention to polarity)
Transistors
Screw connector
Electrolytic capacitors (pay attention to polarity)
Dual RCA connectors
Potentiometers

Assembly Instructions

Before starting assembly, please refer to the general soldering guide and other general information. The kit requires a soldering iron with a maximum power of 40W, thin 1mm solder wire without lead, small cutting pliers, and a small screwdriver.

Construction Steps

Mount the zener diodes, paying attention to polarity.
Mount the diodes, paying attention to polarity.
Mount the resistors.
Mount the IC sockets, ensuring the notch is correctly positioned.
Mount the capacitors.
Mount LED LD1, taking care of the polarity.
Mount the transistors.
Mount the screw connector.
Mount the electrolytic capacitors, watching the polarity.
Mount the dual RCA jacks.
Mount the potentiometers.

Building Instructions:

Mount the zener diodes (pay attention to polarity).
Mount the diodes (pay attention to polarity).
Mount the resistors.

TIP: If you want to attenuate the input signal (e.g., connecting it to an output of an amplifier), choose a lower value for resistors R2 and R4. The attenuation factor is calculated as (R1/R2)+1. For example, using a value of 100ohm for R2 and R4 will divide the input by 11.

TIP: If you want to increase the input sensitivity (amplify more), adjust resistors RF and RA. The amplification factor is calculated as (RF/RA)+1. For example, if you want to double the amplification because the output of the connected device is weak, you can use a 100K resistor for RF (R22 and R23).

Mount the IC sockets (pay attention to the position of the notch).
Mount the capacitors.
Mount LED LD1 (pay attention to polarity).
Mount the transistors.
Mount the screw connector.
Mount the electrolytic capacitors (pay attention to polarity).
Mount the dual RCA connectors.
Mount the potentiometers.

Testing

Connect the power supply to the transformer and place a 100mA fuse in series with the transformer for protection. Use a proper cord with a plug for your power supply. When the transformer is powered on, the LED should light up.
Remove the power supply. Mount the ICs in their sockets (pay attention to the position of the notch). Reconnect the power supply. Check if the LED lights up. Connect a device to the input, e.g., an MP3 player or CD player. Connect the output to a power amplifier. Set the volume to minimum. Turn on the power amplifier.

Testing the Circuit
Connect a 12V x 2 / 1V min. 100mA transformer to the power connector, using a 100mAT safety fuse in series with the transformer. Use a good quality power cord with a plug for your mains supply. When the transformer is powered, the LED should light up.