What is most important when comparing the 2n5484 jfet to other jfets, especially in the Geo-Baracuda

[Polymer]

I don't have a 2n5484 jfet and have been looking at datasheets for possible replacements.

George, I think you must have chosen the 2n5484 instead of an extra 2n5485 in this circuit for a specific reason.
What could this reason be?

I am wondering what part of the jfet specs are more relevant/important here.
All other things being equal, is it the lower Vpinch (or Vgs?) range or the lower Idss range?

Strangely enough the datasheets for many different jfets are not really uniform and sort of confusing to me.

I hope I have formulated my question in an understandable way.

Here's a quick lookup pic of the 2n5484/5/6 specs.

Thank you.

[kt315]

i told many times use BF245 inverted 180 grad.
they are very unexpensive on ebay and them are much.

[kt315]

https://www.ebay.com/itm/10PCS-RF-VH...oAAOSwk-1aHQ6T

[Altra]

These would work also as replacements

J113

2n4393

[Qiaozhi]

The only reason the Geotech Baracuda uses a 2n5484 for Q4 is because that's what was being used in the original Baracuda. The main purpose of the Geotech REV-A version was to fix the unreliability issues and design errors that existed in the various incarnations of the original Baracuda, and therefore the majority of the design remains as is.

You should be able to replace the 2n5484 with a 2n5485, or a J113. I doubt there will be any difference in performance.

[Polymer]

Thanks for all your replies. I have a comparison list for j-fets, but was wondering about the why of the 2n5484.
Couldn't find any on the old Baracuda versions I have - just 2n5485's there. Will be completing my Geotech Baracuda soon.
I especially like the "all lying down resistors" on this one plus the lead holes are nice and big compared to the old version.

[nonkapo]

I've used BF256B on the KT315 board and mpf102 on Silverdog one and both are working. I've read in the forum someone with the genuine Baracuda have on the board all 5485's and single mpf102.