I'm sure there's a reason why not?
The Jfet Mu Amp is Kool !! I just did a Minibooster...
Nothing new, 'Elektor Electronics' magazine published a design a few issues ago. They also published a FET version in about 1987 (according to a follow up article in their current mag).
QuoteI'm sure there's a reason why not?
No, there's no reason why not. Mu amps can be made with triodes, pentodes, JFETs, MOSFETs, etc. All it takes is a device with a very high input impedance for the top device, and in fact I think it works with a non-FET/non-tube lower device.
The only requirement is to get the bias voltage right for the upper device. For JFETs, the gate bias is somewhat below the upper source voltage. For MOSFETs, the gate bias is a bit above the upper source voltage. See "MOSFET Boosters" at GEO for some info on how to bias MOSFETs.
By the way, putting something like a 1K resistor between the lower drain and the upper source and taking the output from the upper source dramatically lowers the output impedance of the circuit and gives much better drive capability for the next stage. See the article "Mod your Mu-amp" at GEO for the particulars.
There is also one in my Mini-Booster newsletter...
http://www.muzique.com/amproj.htm
regards, Jack