Jfet (J201) vs. Mosfet (BS170) distortion characteristics.

[WGTP]

In the popular consumer electronics propaganda both have been touted as sounding "tube like", but I don't recall seeing anything here discussing the merits of each.  I have messed with them enough to know they sound different when spanked thoroughly, but which is more tube like???  Obviously the jfets are used in more circuits here, but the mosfet stuff seems to have an "aura" to it.  Any comments???   

[JimRayden]

I think I remember someone mentioning that while JFETs sound like triodes, MOSFETs sound more like pentodes...

I haven't played around with MOSFETs though, so I can't confirm.

---------
Jimbo

[KerryF]

^-I think your idea of triodes and pentodes sounds like how I describe them.  I think JFETs are very tubelike and can produce nice tube-like low gain to mid gain tones.  I think that MOSfets are very warm and can produce higher gain tones of a broken up tube.

[MartyMart]

I have not had lots of luck with Mosfets, though my Mr Mostorto is a cracker 

I'm quite liking Jfet and Muamp sections, getting the "slight breakup fading to clean" in the Tornado
was very satisfying.
I think the whole "compare" them to tubes is futile, now I just see them as "great" OD/Dist circuits
in their own right

MM.

[Steben]

I have not had lots of luck with Mosfets, though my Mr Mostorto is a cracker 

I'm quite liking Jfet and Muamp sections, getting the "slight breakup fading to clean" in the Tornado
was very satisfying.
I think the whole "compare" them to tubes is futile, now I just see them as "great" OD/Dist circuits
in their own right

MM.

Good for you, marty. 
Yet...  don't give up. In the transtube thread I already spoke of a mu-amp compressor... so watch out!

by the way: a good MOSfet should have a response somewhat like a mu-amp, but maybe with less gain (depends on the Jfets used).
JFets are more like triodes, because they clip more assymetrical than MOS. Mu-amps are symmetric, they are push-pull. So a mu-amp is not just a Jfet circuit.

[amz-fx]

Interesting reading:

http://www.spectrum.ieee.org/archive/1640/distortion

regards, Jack

[MartyMart]

Interesting reading:

http://www.spectrum.ieee.org/archive/1640/distortion

regards, Jack

Nice read, thanks Jack .