All Jfet Line Amp with NO FEEDBACK

This is a Borbely Erno design SE all jfet line amp in one of his article.  I have been using this as a pre-amp since 2006 with Pass power amplifiers like Aleph 60,  F4 & F5.  The gain of this pre-amp is quite high and thus it can be used to drive F4 to sufficient loudness.

The distortion level is also very low at around 0.003% at 1V and 0.026% at 4V output at balance mode.  I am only using +28V dc due to transformer only at 25V x 2 AC.

This pre-amp sound very smooth due to no global negative feedback!  But you see the distortion will increase quite fast as the output level increase!

Last update: 20th Sept, 2010: This is the pre-amp that I am still using at this moment as I like the sound of NO Feedback!!

Borbely Erno All JFET SE line amp Details Updated Sept 21, 2010

Wiring diagram

Was completed 2006/9/16, update FFT measurement on Oct 19, 2009.

FFT jfet SE Bal 1V

FFT jfet SE Bal 4V

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