Cujo/Rufus Fuzz Transistor choice

[mzy12]

Hey people

I'm perfboarding a Rufus fuzz and I'm just wondering what the transistor specs I should be looking at for the pedal. I'm guessing the BJTs should just have Fuzz Face HFEs, but what about the JFETs? Is there any particular VGS off and IDSS I should look for there?

Thanks in advance

 

[Cybercow]

Considering the build calls for J202 JFETs, I'd use those.

 

[mzy12]

Only thing is that there is a wide range of VGS off measurements that a J202 could have. Just curious if there's a more concrete number to aim for or if it should in the middle of the road or something

 

[Cybercow]

That's right. All JFETs have a wide range of Vgs(Off) values. But each has their own range. With that in mind, I'd still go with the J202s and socket them. If it doesn't sound right, check the Vgs(Off) value (by measurement) and look for another pair that have a more middle-of-the-road Vgs(Off) value. When you find a set with working Vgs(Off) values, try different JFETs that have near the same Vgs(off) value and see how those work.

 

[mzy12]

Gotcha. Will update this thread with any info I find.

 

[Robert]

I think I still have one of these somewhere. If I can find it I'll pull the JFETs and measure the specs.

 

[mzy12]

Thanks, that would be a great help.