Tone Adjustment Feature of Stereo Preamplifier

Tone Adjustment Feature of Stereo Preamplifier


The use of Motorola TCA5500 in this circuit is for the functionality of a tone adjustment which will be implemented in a stereo preamplifier.

Terminology Preamplifier (pre-amp) – a device normally used together with the sound equipment to be of assistance in improving the overall quality of sound by detecting and strengthening weak signals for subsequent and more powerful amplification stages and processingTCA5500 – a single chip stereo balance, volume, bass & treble control circuit designed for use in radios, TV, and audio systems with features of low output impedance, wide dynamic voltage range, more than 75dB of volume control, +14dB, wide power supply tolerance, better channel separation, low distortion, tone control defined by a single external capacitor, and four high impedance DC controls Circuit Explanation

The circuit was formed by using a few components and resources, since there are instances or applications that would require the use of simple preamplifier circuit. This circuit uses the services of an operational amplifier which is a DC coupled high gain electronic voltage amplifier with differential inputs, large voltage gain, very high input impedance, low output impedance and usually a single output. The brand of op-amp pertains to IC1 Motorola TCA5500. It contains a dual amplifier which will serve as the outputs for adjusting the VOLUME by potentiometer RV1, BALANCE by RV2, TREBLE by RV3, and BASS by RV4.

The line of monophonic linear potentiometers is responsible for the adjustment of all the parameters, which increases the facility and spacing of the assembly. The location of the potentiometers should be near the IC1 as much as possible. This is to reduce or decrease the occurrence of unwanted noise and other types of distortion. In order for the circuit to function well, it will not require a large amount of current.

Part List

R1-2-3-4=100 Kohms
RV1-2-3-4=100 Kohms Linear  pot.
C1-2-8-9=4.7uF 63V
C3-4=100nF 100V MKT
C5-14=100uF 40V
C6-7=47nF 100V MKT
C10-11-12-13=220nF 100V MKT
C15-16=10uF 63V
IC1=TCA5500 Motorola


The tone control preamplifier with volume, balance, treble, and bass have been available in the market for so many years. Some designs can emit a very low noise and features a wide range of amplification and attenuation. It can be used as software which can be loaded into mobile phones to provide the control of the parameters as compared to the desktop’s continuous and real time control of the audio functions. The controls can be used while playing computer games, listening to MP3s, and plating audio CDs. Modern electric guitars are now using these parameters for proper adjustments of tones.

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