Matching FETS

[MikeH]

I'm working on a Phaser build that requires 4 Matched FETs (2N5952 to be exact).  About how many do I have to buy to be able to get 4 good matches?  I know you'll be guestimating, but and info would be helpful.  20?  30?  40?

[boogietube]

I've never done it, but I've read 30 a few times.

[mdh]

I recently bought 50 Fairchild 2N5485's (R.G. often recommends these for Phase 90 builds), which IIRC have a slightly tighter Vgsoff spec than 2N5952. In any case, in this lot of 50, I got at least two quartets that were perfectly matched within the precision of my meter, and a few more that matched with spreads of 1-2mV.

If you're going to buy 2N5952's, the price breaks at Mouser are such that buying 100 costs just about the same as buying 50, so you might go for that. I bought my 50 2N5485's on eBay for about $7 shipped.