AVT5142 A

Lamps have been experiencing a renaissance in recent years. The characteristic, very warm and pleasant sound of tube amplifiers began to appreciate only when the shelves of stores filled up semiconductor devices. Today, the company's tube amplifier costs a lot. We recommend, therefore, the independent construction of such a device.
We present a system, the implementation of which is possible even for a less experienced electronics. The audio track consists of two parts: voltage (control) levels and power amplifiers. A line signal is supplied to the volume potentiometer, therefore the CD / DVD player will be a perfect source.
The amplifier's power supply is designed in a typical arrangement for tube devices. A suitable network transformer is a problem. Because getting ready can be impossible, we describe how to prepare it yourself.
The last block of the amplifier is the only 'semiconductor' circuit, i.e. a contact switch. Thanks to it, the amplifier is switched on / off by pressing a small microstic.

The device is especially recommended for music lovers who like 'tube' sound

Selected parameters:

• amplifier configuration - Williamson voltage system
• construction of the lamp part - 'on the spider' (without a printed circuit board)
• power output triode push-pull, class AB1
• constant polarization of power tubes
• logarithmic drive indicator
• alarm signaling - LED diode
• maximum output power (without overloading) 2x7 W (Uwej = 1.24Vrms, f = 1kHz, sinus, THD = 1.2%)
• 32Hz-18.5kHz band (for a drop of 3dB)
• load impedance dependent on the transformer (in the 3omy prototype)
• input sensitivity for 2x7 W power - 1.24 Vrms
• power supply - 230 Vac
• plate dimensions 62x37mm
• a contact switch PCB and documentation are included in the set
  
  Detailed description in
  EP 8/08