matching FETs.......with a multi meter?

[peps1]

I'd like to match some 2N5952 FETs (for tonepad Phase90), can it be done with a multi meter and simple circuit?

[frequencycentral]

http://www.geofex.com/Article_Folders/fetmatch/fetmatch.gif

[peps1]

thank you!

[jkokura]

Yes. that image from geo is the basic schem. there's a layout for a fet matcher here: http://www.aronnelson.com/gallery/main.php/v/Richard-Boop-RLBJR65/album81/album75/Jfet_Matcher_6.gif.html

Also, along with that image from RG's site there's an article that talks about it in greater detail, helpful to read. Search on GEO and ye shall find.

Jacob

[mattthegamer463]

Relevant Threadjack:

I'm also building a tonepad Phase90 and I've never done FET matching, so I ordered 16 2N5952's, is that enough to find 4 that match close enough or am I going to need to order more?

[jkokura]

In 12 jFets I got 2 sets that matched really well, within 1/100th at least. However, if you're looking to match 4 within that tolerance - that might be more challenging. You will likely get 2 sets of 2 like I did, but I hope you're able to get 3 or 4 closer. Let me/us know what numbers you end up with and perhaps we can do a trade if I have a number you need and I get another one that matches better for a future build.

Jacob

[mattthegamer463]

I guess I'll have to get 4 of then as-close-as-possible, then see what happens with the circuit.