The Lanzar amplifier is built according to the classical symmetrical scheme, the preliminary stages of which operate in class A, and the output stage in class AB.
The circuit of this amplifier has been known since the 80s, however, it was widely used in car amplifiers of the LANZAR company, after which the total study and repetition of this circuit by radio amateurs began in the territory of the former CIS. The amplifier circuit is completely symmetrical from input to output, which eliminates transients in the final stage, i.e. at the moment of switching on, the output of the amplifier does not have any of the spikes that are characteristic of most discrete amplifiers.
The amplifier is assembled on 1 pair of output transistors 2SA1943 and 2SC5200 TOSHIBA and is a “lite” version of the standard Lanzar with 2 pairs of output transistors.
When using 8 ohm acoustics, the supply voltage can be raised to 45-50V to obtain the equivalent power at 4 ohms.
The module is easy to set up and requires only setting the quiescent current on a warm amplifier, depending on the supply voltage. The optimal quiescent current of the output stage is 30-120mA. It makes no sense to put it higher - neither the instruments nor the tangible changes occur by ear. To set the quiescent current, the voltage on a pair of emitter resistors of the final stage is measured and set in accordance with the calculation formula (see product photo). It should also be taken into account that the quiescent current, due to the thermal stabilization circuit, is not constant and changes depending on the temperature of the radiator, so you need to remember about pauses for cooling / heating the radiator to operating temperature.
For passive cooling at a supply voltage close to the maximum and a quiescent current of up to 100 mA, a radiator of at least 750 sq. cm is required
Subjectively, the amplifier has a powerful, assertive sound, and is able to "handle" most speaker systems.
The module can be recommended for building a high-quality power amplifier and for working with acoustics with low sensitivity.
On request, it is possible to assemble this amplifier with the following pairs of output transistors:
TTA1943 and TTC5200 - TOSHIBA
2SA1302 and 2SC3281 – TOSHIBA (Dismantling)
MJL21193 and MJL21194 - MOTOROLA
FJL4215 and FJL4315 - MOTOROLA
NJW0281 and NJW0302 - MOTOROLA