hello all. i've been building some effects lately that call for j201s. the closest easy-to-find jfet my local parts shop has is the nte457 (1/3 the cost of the nte458!)...so, i've been using the cheaper ones. anyone out there have any experience with the nte457? and would a mpf102 from rat shack work as well? i'm using them in amz boosts and such. my builds all work, but i wanted to know what i'm missing if anything. thanks in advance. jon
mpf102's can be made to work but they are lower gain that J201's. If you are using a FET for a buffer then just about any NChannel JFET should work, however, for distortion purposes, a J201 is preferred because it is higher gain.
I have a question to add to this, are there any drop in replacements for J201's that are higher gain and easy to get?
I'm not sure about the easy to get part, but there is a J202 that is higher gain. Might require bias adjustment, but thats true of J201's as well. 8)