V.2012 PRO. Composite Audio amplifier

[potstip]

Partlist is available, but it is in the Russian Language, it needs minor corrections.

Could you please send the corrected one in english

 

[east electronics]

The meaning of this build of the driver in the implementation of its work in the class A throughout the operating range. Application of the three pairs was simulated in the simulator, it was found that by increasing the number of pairs with one to two distortions fell on 2dB, the same picture was when increasing the number of pairs from two to three, that is, the gain was 4 dB. But with further increase in the number of transistors improvements have not been, due to the increase of the load on the previous stage, mainly in the form of input capacitance. The quiescent current of each pair of transistors is maintained constant. Additionally, if we recall an equivalent circuit of the transistors, as the capacitance between the the collector and the base and between the base and emitter, it is easy to conclude that at high frequencies is provided by the penetration of the output driver cascade directly to the amplifier output through the capacity of the transitions of the output stage. This is easily modeled in the simulator, the introduction of small resistors in the base circuit of the output stage and the view drop voltage when the test signal of rectangular shape.

I am familiar with the concept of operation though i could second question the thermal stability.
This trick is not new it was done by Harman in the past but without ballast resistors (quite tricky to stabilize without them) and made parts choice on matching critical.

Agreed worth looking at farther

Kind regards
Sakis

 

[waso]

Ok. Partlist in Microsoft Excel format.
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In addition to the above, the quiescent current of the amplifier and the emitter resistors of the output stage also has been optimized for minimum distortion, the quiescent current of the amplifier is 250mA. He's pretty cool, but with the use of an adjustable blow-off is not a problem.