Class A Mono Amplifier 10W – 12-30V with VU Meter Output

Class A mono audio amplifier with a bare-essentials circuit and high-end performance, with a dedicated output for connecting a VU meter.

Class A Mono Amplifier 10W – 12-30V with VU Meter Output - Image 1
Class A Mono Amplifier 10W – 12-30V with VU Meter Output - Image 3

SKU 7100-FT1794KItem type: Assembled, Kit,

Description

Audio amplifier, class A mono, designed to deliver high sound quality from an extremely simple circuit. The design uses only four transistors and a handful of passive components, which guarantees stability, reliability and excellent signal linearity.

The amplifier runs on a single 12 to 30 Vdc supply and delivers up to 10 W RMS into an 8 ohm load. The Single Ended Push-Pull output stage with two NPN transistors drives the load effectively while keeping the sound typical of class A, prized for its musicality and naturalness.

The very low distortion (about 0.1%) and the extremely wide frequency response from 20 Hz to 200 kHz give clean, detailed and dynamic audio reproduction.

The circuit also has a dedicated VU meter output, handy for connecting an analogue meter to display the audio signal level.


Soldering required for assembly. The kit is supplied complete with instructions.

Solder-it-yourself kit

Technical specifications

  • Output configuration: Single Ended Push-Pull with two NPN transistors
  • Input sensitivity:
    – 0 ÷ 2000 mVpp (@ 30 Vdc)
    – 0 ÷ 1500 mVpp (@ 24 Vdc)
  • VU meter output: provided for connecting an external meter

Circuit diagram

Choosing the heat sink

Amplificatore Classe A Mono 10W – Uscita VU Meter
The picture shows the Class A mono amplifier fitted with the heat sink, product code ADIS69X200 listed among the related products, with a thermal resistance of 1.3 °C/W. The heat sink is not included in the kit and has to be chosen and fitted by the user according to the mounting and ventilation conditions. The physical size of the heat sink may vary, as long as it dissipates the heat produced properly. The heat sink needs some mechanical preparation before use: the two metal brackets shown in the picture have to be fixed to the PCB to make the “board + heat sink” assembly rigid. In our example we used the ANG90ALLU brackets (already included with the purchase of the product). They are held by an M4 screw, a nut and a 4×12 mm washer, also included.

What this kit includes

The kit includes all the electronic components needed to build the amplifier, terminal blocks and printed circuit board included.

Important note: the heat sink and the power supply are not included and have to be purchased separately. They are however available in our shop (see related products).

Technical details

Amplifier type Class A mono
Power supply 12 ÷ 30 Vdc
Current draw 1 ÷ 1.3 A
Maximum audio power 10 W RMS @ 30 Vdc into 8 Ω
Minimum output load 8 Ω
Number of transistors 4
Voltage gain 12.7× (22 dB)
Distortion about 0.1 %
Frequency response (-3 dB) 20 Hz ÷ 200 kHz
Input resistance (theoretical) about 47 kΩ
Output resistance (measured) 0.12 Ω
Phase shift 60 ÷ 65° across the whole band

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