name of the game was to create SIT amp for Greedy Boyz Hordes ......
naah, I don't care for Hordes, I have all the fun
logical thing would be to put emulated SIT in same position as in DEFiSIT/SissySIT, which is positive rail; from some reasons I tried in simulations to put it down (lower rail), then realized that that approach is resulting in difficulties - choice of small P channel mosfets for Source follower/level shifter, having low threshold Ugs is much smaller than counterparts in N polarity
however, me being stubborn as I am, stayed with P channel .......
SF Ugs is important, beacuse it is additive to feed point of Schaded mosfet, which in this case we have as -3V8 (ref to output) , then Ugs of TP2640, so resulting biasing voltage at TP2640 gate is around -5V4, ref to output
in same time , Ugs of upper mosfet is +4V42, which means that resistances from rails to adjacent gates are still pretty symmetrical
one of interesting things - of all lately seen amps, only this one is having same current distribution of output parts as real DEFiSIT is having - up to clipping point of more active part, parts are working in antiphase , fighting each other..... and only at and after clipping, lesser acting part ( one with lesser xconductance) is hel;ping other onee
see attached - graph from sim, but confirmed in vivo....... though, easier to post this than capturing scope screen ..... counting on fact that I have a scope from Lee De Forest time, but before triode invention
sim shown from output sine of around 20Vpp @ 8R load
biggest sine - upper mosfet current
smaller sine - current through load
smallest sine - Schaded mosfet current
naah, I don't care for Hordes, I have all the fun
logical thing would be to put emulated SIT in same position as in DEFiSIT/SissySIT, which is positive rail; from some reasons I tried in simulations to put it down (lower rail), then realized that that approach is resulting in difficulties - choice of small P channel mosfets for Source follower/level shifter, having low threshold Ugs is much smaller than counterparts in N polarity
however, me being stubborn as I am, stayed with P channel .......
SF Ugs is important, beacuse it is additive to feed point of Schaded mosfet, which in this case we have as -3V8 (ref to output) , then Ugs of TP2640, so resulting biasing voltage at TP2640 gate is around -5V4, ref to output
in same time , Ugs of upper mosfet is +4V42, which means that resistances from rails to adjacent gates are still pretty symmetrical
one of interesting things - of all lately seen amps, only this one is having same current distribution of output parts as real DEFiSIT is having - up to clipping point of more active part, parts are working in antiphase , fighting each other..... and only at and after clipping, lesser acting part ( one with lesser xconductance) is hel;ping other onee
see attached - graph from sim, but confirmed in vivo....... though, easier to post this than capturing scope screen ..... counting on fact that I have a scope from Lee De Forest time, but before triode invention
sim shown from output sine of around 20Vpp @ 8R load
biggest sine - upper mosfet current
smaller sine - current through load
smallest sine - Schaded mosfet current
Attachments
some funny porn, as proof that I changed something
when I made those few changes from Babelfish M25 R.2 ( few resistors, TP2640), after flipping power switch - Iq came to same value as it was set for B. M25
all what was needed is to correct DC Offset, for 400mV or so
easypeasybreazy
when I made those few changes from Babelfish M25 R.2 ( few resistors, TP2640), after flipping power switch - Iq came to same value as it was set for B. M25
all what was needed is to correct DC Offset, for 400mV or so
easypeasybreazy
Attachments
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How it sounds ...... will it drive F4?
I'm gonna toss all my precious ( 'till today) SITs and VFets to OPLDF bin, cruncher is gonna work these days anyway .....
THD Spectra comparison with SissySIT - go to #7 in SissySIT R.3
I'm gonna toss all my precious ( 'till today) SITs and VFets to OPLDF bin, cruncher is gonna work these days anyway .....
THD Spectra comparison with SissySIT - go to #7 in SissySIT R.3
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much more Greenies, little more details
in the end, it is - snatch those you can easier
regarding "simple" ........ behind every decent signal xformer is serious expertise ....... price is sole funny detail when Edcor PC is in case - it is much better product than price is telling
in the end, it is - snatch those you can easier
regarding "simple" ........ behind every decent signal xformer is serious expertise ....... price is sole funny detail when Edcor PC is in case - it is much better product than price is telling
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LTSpice sez neg
I'm not measuring that:
- QA400 I have can't do that (or I don't know how)
- EMU1212 which I use routinely is having problem with other channel, and you need duplex for Phase
- have no time/will/energy to make/obtain another gadget with notch filtering, even if Pa simply adores comparative wigglywiggly pictures
I simply leave by ear preferred speaker polarity; when I'm in special mood, I even succeed in getting same polarity of both speakers
interesting, LTS is not erring much, comparing to real life
I'm not measuring that:
- QA400 I have can't do that (or I don't know how)
- EMU1212 which I use routinely is having problem with other channel, and you need duplex for Phase
- have no time/will/energy to make/obtain another gadget with notch filtering, even if Pa simply adores comparative wigglywiggly pictures
I simply leave by ear preferred speaker polarity; when I'm in special mood, I even succeed in getting same polarity of both speakers
interesting, LTS is not erring much, comparing to real life
Code:
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 3.907e+00 1.000e+00 -0.08° 0.00°
2 2.000e+03 4.109e-03 1.052e-03 -89.55° -89.47°
3 3.000e+03 5.531e-04 1.416e-04 7.76° 7.84°
4 4.000e+03 7.574e-05 1.939e-05 95.23° 95.31°
5 5.000e+03 1.130e-05 2.894e-06 -169.54° -169.47°
6 6.000e+03 1.460e-06 3.736e-07 -99.64° -99.56°
7 7.000e+03 2.508e-07 6.420e-08 167.26° 167.33°
8 8.000e+03 3.877e-07 9.925e-08 176.54° 176.62°
9 9.000e+03 3.370e-07 8.627e-08 -179.77° -179.69°
10 1.000e+04 3.027e-07 7.748e-08 -179.90° -179.82°
Total Harmonic Distortion: 0.106158%(0.106159%)
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