How to match SMD JFET’s for XC Phase?

Jbanks

Jbanks

Active member
Hi,

I’m about to build the XC Phase and have a question about the JFET’s. How do I match 4 SMD JFET’s? Do they already have a close enough tolerance as SMD, or do I need to match them somehow? Google results were telling me to use some kind of jig to measure various stats, but have no idea how to build the jig to test. Is there a simple, cheap way to measure these, if they even need to be measured. I believe I bought the SMD JFET’s from PedalPCB.

Thanks
James
 
Yea, it is best to match the jFets. However, you can use something a device like a Peak DCA75, but you will need their jig or make one.

Another option is to make a jFets matcher. Here is one option: https://tagboardeffects.blogspot.com/2012/07/greatly-improved-jfet-matcher.html?m=1

I had made this circuit once without matching the jFets and I still thought it was great. However, it is best practice to match the jFets for this circuit.
 
I made the jfets matcher.


@Robert would it be worth getting a PCB designed, that has this jfet matcher, some read points as a project so we can build a neat one?

There was that project for the R.G. Keen transistor tester too? in that particular case maybe including a 2.49K resistor prepopulated?
 
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