freestompboxes.org

I can't find an alternative to the N-channel JFET 2SK772

Are these for a matched set of Fets? Which phaser model is it for?

Yazoo55 wrote: ↑02 Jul 2022, 23:22 Are these for a matched set of Fets? Which phaser model is it for?

Arion SPH-1

Saw this over on r/DIYPedals as well, but maybe somebody can add more clarity here about which Idss bin it uses:

Do you have any info on which Idss bin this pedal uses: 2SK772D, 2SK772E, or 2SK772F? If it's anything like the Arion SCH-1, then it's probably the F-variant (2SK772F).

Here are the specs for comparison:

• 2SK772 - Vp: -0.3-2.5V, Idss: 1.2-12mA - F-variant is the high-Idss bin, so Idss = 5-12mA
• 2SK184BL - Vp: -0.2-1.5V, Idss: 1.2-14mA - BL-variant is the high-Idss bin, so Idss = 5-12mA
• 2N5952 - Vp: -1.3-3.5V, Idss: 4-8mA
• Maybe: MPF4393 - Vp: -0.5-3V, Idss: 5-30mA (mine usually run Vp ~1.7V / Idss ~14mA)

This thread (use Google Translate) talks a bit about different versions of the phaser & other JFETs people have tried. If you can find them (they're obsolete & out of production), I'd go with either 2N5952 or 2SK184BL.

They will likely need to be matched pretty closely, so you'll have to buy more than 4 to get a decently matched quad. I included MPF4393 on that list as it's still in production & easy to find for cheap. If you're having trouble finding those older JFETs, you may want to buy 10-20 and give them a shot instead.

Small Bear has 2N5952 in quantity for $0.59 USD, https://smallbear-electronics.mybigcomm ... et-2n5952/ . They also have 2SK184 green and yellow, but not blue.

There is also this Arion SPH-1 thread with some mods and either schematic corrections/variations.

viewtopic.php?p=243186#p243186

Surely any reasonably close N FET will do the job, 2SK30 for instance, nothing special about the ciruitry.