After closer look it looks like a inverted VFA, build with symmetrical singletons ??
That's why it has DC offset. If you couple it with signal source via big capacitor, offset gets better in the sim.
In real life, when transistors are not perfectly matched, this DC offset will be even bigger.
But square waves have kinks in the middle of the rise, it needs some fix...
Slew rate seems to be low, maybe 5V/us
Where does the feedback return to the input?
That's also CFA... It will need servo to correct DC offset..
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I see T1, but where is the other end on the input side?
Oh, I see T1 now on the input end (left lower corner). It looked like ground...
So it's inverted CFA. I'm sure it will need the servo...
Should be fast.
And only 4 transistors in the input stage. Not too bad. But the servo spoils it...
Oh, I see T1 now on the input end (left lower corner). It looked like ground...
So it's inverted CFA. I'm sure it will need the servo...
Should be fast.
And only 4 transistors in the input stage. Not too bad. But the servo spoils it...
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Maxim - do you think this amp here can be converted to use LMK/Wiederhold style VAS?
Input stage connected to the Emitter of VAS transistor?
It looks promising (SR 44V/us) , perhaps would get even better if connectivity between input stages and VAS was converted to LMK/W style...
Very stable, fast, square waves look good, low Thd, FFT also look fine.
Input stage connected to the Emitter of VAS transistor?
It looks promising (SR 44V/us) , perhaps would get even better if connectivity between input stages and VAS was converted to LMK/W style...
Very stable, fast, square waves look good, low Thd, FFT also look fine.
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Interesting topology. Industrial "Kumir" and "Pulsar" with a complementary troika were produced on it. Good sound but low power.
If you can't - I can attach images as well (FFT, Thd, etc..) so you can see the numbers/graphs right away.
Latest asc file was configured with square waves sim.
If you don't know how to switch between sinus/squares, I could attach 2 versions of the file - if this is going to make things easier for you.
Let me know.
All the models are included in my files, so they all should run fine in your ltspice - just click 'simulate' button (running man icon in top bar).
Latest asc file was configured with square waves sim.
If you don't know how to switch between sinus/squares, I could attach 2 versions of the file - if this is going to make things easier for you.
Let me know.
All the models are included in my files, so they all should run fine in your ltspice - just click 'simulate' button (running man icon in top bar).
Anyone can be wrong...
It's all about probabilities.
He is much much less likely to be wrong than me...
