Amplifier

As you know I have one pair of reprobedny.
And to tell you the truth in the future I am planning another pair. So that I can have a 4-channel - as I like to say 4.4 = 4 speakers and a bass in each.
But I've been looking into what I'm going to feed it with for a while now, my amp is fine (although next to the boxes it's probably shy) but it doesn't have 4 channels. Alternatively, having two stereo amps would be an option, but that's not a very nice solution.
So I decided to make some quality 4-channel amplifier. And if anything, with some more power, so I can get the dust off the boxes too ;-).

There were a lot of ideas. But at that time exactly what I was looking for appeared in amar (amateur radio magazine) -> so there was nothing to solve.
This amplifier was developed with the following goals in mind: high quality while keeping the price reasonable, power reserve, input going from a computer audio card.

basic technical parameters of the amplifier:

4-channels
4 ohm output impedance (can also be used with 8 ohm boxes)
maximum power per channel 140W - reality no PMPO
distortion 0.004%
signal-to-noise ratio >105dB
input excitation 1V (max 2V)
parameters more than perfect.... ;-)

Photos of most of the basic components of the amplifier: