I have a few Sony small SIT 2SK63 and 2SK79, Mu ~30 and 120V Max Vds. Combined with a 2SJ103 GR to form Rush pair we have a non inverting gain stage. 5dB feedback allows for gain of ~20dB. Predicted THD of ~0.23%, negative phase H2 dominant with H2/H3 ~33.9dB.
I call it SERFE K79 to serve a need for spooky presentation. 🙂
Pic 2 - FFT spectra at 8Vpp output.
Pic 3 - Frequency Response.
The topology also works for other Jfets, Mosfets, Triodes and Pentodes.
Pic 4 - SERFE ECC88
Pic 5 - FFT of SERFE ECC88 with THD ~0.23%, good H2/H3 ~45.3dB
Pic 6 - Mated to M2 output stage to make 25W class A
Pic 7 - Mated to a 50W class AB composite power buffer.
Pic 8 - 14dB (5x) gain headphone amp version with ECC88
I call it SERFE K79 to serve a need for spooky presentation. 🙂
Code:
N-Period=1
Fourier components of V(out)
DC component:-0.0112158
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 4.000e+00 1.000e+00 -0.06° 0.00°
2 2.000e+03 9.232e-03 2.308e-03 90.59° 90.66°
3 3.000e+03 1.850e-04 4.624e-05 0.81° 0.88°
4 4.000e+03 6.786e-06 1.697e-06 -134.34° -134.28°
5 5.000e+03 3.998e-06 9.996e-07 -179.84° -179.78°
6 6.000e+03 3.215e-06 8.037e-07 -180.00° -179.94°
7 7.000e+03 2.755e-06 6.887e-07 -179.91° -179.85°
8 8.000e+03 2.411e-06 6.027e-07 -179.94° -179.88°
9 9.000e+03 2.144e-06 5.359e-07 -179.91° -179.85°
Total Harmonic Distortion: 0.230840%(0.230840%)Pic 3 - Frequency Response.
The topology also works for other Jfets, Mosfets, Triodes and Pentodes.
Pic 4 - SERFE ECC88
Pic 5 - FFT of SERFE ECC88 with THD ~0.23%, good H2/H3 ~45.3dB
Pic 6 - Mated to M2 output stage to make 25W class A
Pic 7 - Mated to a 50W class AB composite power buffer.
Pic 8 - 14dB (5x) gain headphone amp version with ECC88
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me likee,Mighty Indra!
you need intervention there , to comply with name - toss "pair" from thread title
(years ago, I was so bloody smart, so I invented Rush cascode/diff pair ...... was so proud for a day; not first, not last time ..........
)
have plans to put proto ?
you need intervention there , to comply with name - toss "pair" from thread title
(years ago, I was so bloody smart, so I invented Rush cascode/diff pair ...... was so proud for a day; not first, not last time ..........
)have plans to put proto ?
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Currently working on it. 
Nothing new, just another way to get something close to a SIT3 signature.
Nothing new, just another way to get something close to a SIT3 signature.
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