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amc184 10th January 2013 11:57 PM

FS: Toshiba 2SJ109-V Dual JFETs
5 Attachment(s)
Updated 18th November 2015:

I've now got less than 100 JFETs left, and I'll be keeping about half of them for my own use. I've measured the remaining 2SJ109s for IDSS, and sorted them into 0.5mA bins, and they're a mix of the two batches. Here is what I've got:

11.5 to 11.9: 6
12.0 to 12.4: 1
12.5 to 12.9: 2
13.0 to 13.4: 2
13.5 to 13.9: 4
14.0 to 14.4: 8
14.5 to 14.9: 10
15.0 to 15.4: 8
15.5 to 15.9: 12
16.0 to 16.4: 4
16.5 to 16.9: 3
17.0 to 17.4: 13
17.5 to 17.9: 8
18.0 to 18.4: 2

It's been almost three years, they're almost gone, get them while you can. The price is USD16 each, PM me for a postage quote, the postage prices below are well out of date.

Thanks to everyone who bought some JFETs,

PS: For inspiration, below are some pictures of a project I've used these in:

I've got a substantial quantity of Toshiba 2SJ109 JFETs to sell. They're all V grade, about half are batch 8A, the other half are batch 8C. They're new, old stock, I think the number part of the batch means year, so they're probably from 1998 (I think these weren't produce as late as 2008).

These are the genuine article. I've posted some pictures below, the first is of a 2SK389 / 2SJ109 JFET IDSS tester that I made out of a surplus PCB. The second is of that tester being used to test a 2SJ109. The third is a close up of a 2SJ109 in the tester. I tested a sample of 16 (8 from each batch) in the tester, and I got a range of results, from 11.6 to 17.4mA. The V grade IDSS bin is from 10 to 20mA, so that's what you'd expect.

The best test of all though is that I built a couple into a preamp, see picture four. They sound good, that's the most important thing! Picture five shows them with boxes from another, different, batch of 2SJ109s. I don't actually have the original packaging from the batch I'm selling.

I'm selling these for USD16.00 each, plus postage, in lots of 2 to 20. Payment can be made by PayPal. Postage prices depend on your zone, you can find which zone you're in here. For any orders of more than eight 2SJ109s I'll only ship them by tracked courier, anything sent by airmail is at the buyer's risk. The prices are:
- Zone A airmail USD5.80, international economy courier USD21.20
- Zone B airmail USD8.50, international express courier USD54.50
- Zone C airmail USD9.80, international economy courier USD37.00
- Zone D airmail USD11.10, international economy courier USD38.70
- Zone E airmail USD11.10, international express courier USD58.80

Any questions, please don't hesitate to ask. I may be willing to do trades for other parts. Items I'd be interested in are Japanese audio transistors, lateral MOSFETs, R2R DACs, audio film and electrolytic capacitors, all new or new, old stock and genuine only.

EDIT - I'm now selling matched sets as well for no extra cost. At the moment I have measured the whole of batch 8C for IDSS and grouped them in 0.5mA IDSS bins. I have at least 10 2SJ109s in most bins from 11 to 18mA.

Algar_emi 11th January 2013 01:32 PM

Hi. Do you have the schematic of this preamp using the J109? I may be interested to buy FET if I can use into a nice preamp. Thanks... SB

qusp 11th January 2013 02:38 PM

hmm, need to think on that at that price. already have enough J74 and a few J109BL, but no V. looks like you may have enough of them to have them around for a few days, i'll drop you a line after the weekend. may want 4-6 just airmail to Au, will you offer matched at all?

EUVL 11th January 2013 03:29 PM

The photo indicates 2SJ109BL.
You sell those as well ?
How about 2SK389 as marked on your test PCB ?
(even though one can get LSK389 as well, so N-FET is not the problem.)


sidiy 11th January 2013 03:52 PM

I'm in for 4... only :( ...
Although I would like > 15 and match them myself, I would pay a small premium for having them matched to a certain value (~14-15mA).

john curl 11th January 2013 07:48 PM

Almost possible to build a Blowtorch!

amc184 11th January 2013 11:36 PM

@Algar_emi: It's only new, and I'm still working out a couple of issues, so I'm not ready to release any schematics. The Pumpkin Pre uses 2SJ109s I think, maybe give that a look.

@qusp: I can match them, but it's not something I'm that keen to do. Any matching I do will only be to the nearest 0.5mA IDSS. Everyone, please only request matching if you actually need it. I've matched a few, but I'm not going to match them all, there's just too many.

@EUVL: Yes, I've got 2SK389-Vs and 2SJ109-BLs, but they're not for sale unfortunately.

@sidiy: Do they absolutely need to be matched?

DaveG 12th January 2013 12:46 AM

some sort of matching would be preferred over completely random selection.

sidiy 13th January 2013 08:33 PM


Originally Posted by amc184 (
@sidiy: Do they absolutely need to be matched?

Not in-between them, to the last uA, but more like a in a current range...that will improve my chances to pair them with the n-channels I have.
I just re-checked my stash of 2SK389V (6 in total :sad:) and all I have are 'leftovers' from my projects, in the low end of the V-grade between 11.6mA and 14mA.
So if I can reformulate my request it will be for all 4 in this range. I perfectly understand that answering to such personalized requests is not what you have hoped for and I will take them anyway, fingers crossed :dice::dice:!


amc184 14th January 2013 08:11 AM

Okay, I've sent you a PM.

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