The amplifier was developed back in 1990, based on the principle: simple scheme, the details available and the minimum time required for its production. It was designed for easy volume control when recording tracks in one of the recording studios of the city on the Neva.
However, the scheme has been very successful and has shown good performance so that more than once then "cloned" as a separate compact amplifier for any headphones. And this is not surprising. After all, it is a classic amplifier circuit "A", and such amplifiers have long attracted the true music lovers to its "warm tube sound" ...
The scheme is very simple and contains at least elements (available every radio amateur), and not critical to the choice of these elements and does not require any adjustment after assembly.
The transistor T1 can be replaced by any similar (structure p-n-p), preferably with a large current gain. The transistor T2 (output) of any average power in the selection of the parameters does not need. It may be, for example - KT815, KT805, KT817 or any similar import. It needs to be put on a small heat sink.
Electrolytic capacitors in the scheme must have a working voltage not lower than the power supply voltage, and it is better to take them with some "reserve".
Power supply circuit preferably not less than 15 volts (unipolar). Chain C1R1C2 - filter. He is required if the power supply has a significant ripple in headphones listens low hum. Otherwise, it can be eliminated from the circuit.
The current consumption of the amplifier depends on the type of the applied output transistor, and resistor R8 nominal resistance headphone.
Its mean value - of the order of 200 mA (for one channel).
This amplifier can be used with headphones any resistance and acoustic power heads. Sometimes you may only require the selection of the resistor R8 - for the best sound quality in the whole volume range.
In the amplifier input signal may be fed directly to any "standard" source. For example, from your computer's sound card. The optional pre-amplifier is not required.
The sound quality will satisfy any lover of good sound.
Even headphones very budget category will be heard in a new way