Thank you Gourou! I always try to do my best.

Hi, First of all excuse me for the English, but my French is a rudimentary. As a matter of fact a few months ago I've built Beta22 for a friend of mine. In the process of setting-up the boards I can give you some advices if needed. I'm attaching some photos which show my approach in building the amp...

Hi Adhafera, You are in the right direction :). According to diamond buffer - yes, Q1, Q2, Q22 and Q19, Q20, Q24 form a current mirrors. Their currents are given by the current source formed by J7, R67. J2SK117 is just a 2SK117 - the model in LTSpice is named J2SK117 and I simply use it as is. The o...

Gorou, these 2.7 Ohm resistors are in the feedback loop, you must not forget that. That's why their resistance are divided by the NFB loop gain. If we suppose that NFB loop gain is ~ -40 dB, then 3/100 = 30 mOhm. Since the output transistors work in class A, these resistances are in parallel, but OT...

Gorou, a little clarification, if I can: 2SK240 and 2SJ75 are real 2SK170 and 2SJ74 pairs - 2SK240 pair of two 2SK170, 2SJ75 - pair of two 2SJ74. They are manufacture matched and tied together with an aluminium cap. For curiosity, they are matched by Up (pinch-off voltage) but not by Idss, as is wid...

Hi again! As a matter of fact, the points R - R are connected together and connected to the one of the servo OPAmp output (R output). The same for the points L. I draw them in such a way in order to mess with less wires and beside that, simulator accepts this concept. May be this drawing will be cle...

Hi, guys! Sorry for writing in English but my French is very rudimentary (left from high school) :(. First of all, thank you for your interest about my design. about DC servos - it's impossible to have only one servo in case when schematic has two independent outputs. Yes, the servos are attached to...