Matched Jfets necessary for BSIAB 2, Insanity Box, or Shaka?

[syzygy]

Is Jfet matching only for Phaser circuits, or does it apply to distortion circuits like the BSIAB 2, the Insanity Box, or Shaka Express too?

Thanks

[petemoore]

"MAtching 'is' for phasers.
 swapping Jfets in those positions like say BSIAB, you may get a little different performance out of the different performances out of individual Jfets because they're 'inconsistant'...I dont' know exactly how much...they may have different bias needs or sound just a little different.

[benfox]

No matter it will work. But it's better with matched ones cause your sound gonna be more stable. The fuzz is better sometimes in some boxes with unmatched transistors just try to change them even if they are unmatched.
benfox
Go on thrash

[syzygy]

Ok, thanks guys that makes sense, because I've only seen talk of Jfet matching when phasers were mentioned, and it does make sense that varying Jfets would cause varying distortion characteristic.

[radio]

Biasing Fets is the correct term like with the obsidian where

any mosfet should have 4.5V on Drain.

However not always 4.5 is required ,the 18Watt of ROG needs

different tension for the different fets.

Greetings JME

[will]

Hi

Is Jfet matching only for Phaser circuits, or does it apply to distortion circuits like the BSIAB 2, the Insanity Box, or Shaka Express too?

Thanks

JFet matching will give you no benefit for the BSIAB 2, the Insanity Box and other similar mini-booster circuits. The top transistor acts as voltage follower so just about any transistor, Fet, Mosfet, bipolar or tube should work for the top section almost equally well. The bottom transistor is where the tone is generated by its gain and clipping characteristics. The top transistor helps the bottom transistor give us its max gain. Thus the higher the internal gain of the bottom transistor the more clipping you are going to encounter.

JFets vary all over the place in internal gain unit to unit. So it might be a good idea to socket the bottom Fets and try a few so you can find the ones that sounds the best to you.

Regards,
Will