Some other Source Follower Configurations

again

inverted source follower:
I would like only remain that it
has good linearity,
high input impedance,
~270mA bias,
negative thermal coefficient for fets
and is so simply...
do you know other followers running @swing 30V with distortion ~-150dB?
 

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Last edited:
this time I have checked

this is clear inverted follower with voltage sources instead of big caps at the input to let ltspice make good calculations/simulation.

thd:
N-Period=1
Fourier components of V(vout)
DC component:0.0260207

Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.447e+01 1.000e+00 -0.01° 0.00°
2 2.000e+03 1.492e-02 1.031e-03 -92.14° -92.12°
3 3.000e+03 5.350e-03 3.697e-04 9.32° 9.33°
4 4.000e+03 8.804e-04 6.084e-05 80.75° 80.76°
5 5.000e+03 4.018e-04 2.777e-05 -149.71° -149.69°
6 6.000e+03 8.482e-05 5.862e-06 -113.99° -113.98°
7 7.000e+03 5.179e-05 3.579e-06 52.64° 52.66°
8 8.000e+03 1.114e-05 7.698e-07 46.49° 46.50°
9 9.000e+03 7.858e-06 5.431e-07 -115.42° -115.40°
Total Harmonic Distortion: 0.109745%
 

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guitar/line buffer

Hi
this time I have the idea of small signal pp source follower buffer with floating power supply.
the results are for 1Vpp at the input, the load is 10k.
for guitar the loads are much higher, 220k-10Meg which means lower distortion.
the circuit is easy for mounting inside the guitar together with the battery.
remember about hf blocking circuits.
 

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What do you think about using a cascaded Jfet like 370/170/309 on the output of a tube preamp? I have been thinking of good cascode devices. The 2sk2013 states 180V as its upper limit, but being a 25w part and being that it would not dissipate re than maybe 1w, I wonder if it is still usable. Any other devices you may suggest?