MPF102 Substitution

[chris.knudson]

In the middle of a build that calls for an MPF201, which I cannot find. I know I can sub a J113 or a 2N5485, which I also don't have. Just wondering if I can safely swap it out for a J201, which I have plenty of.

 

[bean]

The j201 and 2n5457 can generally be be subbed for an MPF102 without issue.

 

[hamerfan]

I recently socketed a BSIAB which calls for 3 stages with those jfets. My experience was that the 2n5457 and thd j201 had a slight difference in gain, but the mpf102 was remarkably lower that the other two. I settled with the 2n5457 being in the middle.

 

[temol]

What is the build?

 

[chris.knudson]

What is the build?

Madbean Wavwelord.

 

[chris.knudson]

I recently socketed a BSIAB which calls for 3 stages with those jfets. My experience was that the 2n5457 and thd j201 had a slight difference in gain, but the mpf102 was remarkably lower that the other two. I settled with the 2n5457 being in the middl

The j201 and 2n5457 can generally be be subbed for an MPF102 without issue.

Ok, so I have both the J201 and the2N5457, which should I use for the Wavelord?

 

[temol]

Use 5457

 

[hamerfan]

Use 5457

Yep.

 

[Feral Feline]

Why not give a reason "why" to use the 2N5457?

Is it the better choice because its gain, though higher than an MPF102, is lower than a J201?

 

[benny_profane]

I would think a J201 would be a better choice for a source follower biased to Vref given that the Vgs(off) for the J201 is 0.3–1.5V and the 2n5457 is 0.5–6.0V. A 2n5457 on the upper extreme of the spec could clip, right?

 

[Feral Feline]

So much for me to learn still. I thought the J201 would distort sooner than the 2N5457

I need to sit down and figure out this Vgs business.

 

[chris.knudson]

So much for me to learn still. I thought the J201 would distort sooner than the 2N5457

I need to sit down and figure out this Vgs business.

That's exactly why I asked the question to begin with. I know that I can swap out one JFET for another. But, I don't know what the trade off is when I do.