[sdiy] Dual Matched N JFET from Linear

[S Ridley]

I think they're used in ribbon mic preamps like the Cloudlifter.

See US Pat. 9.167,327B1


On Sat, 21 Jun 2025 at 08:51, Mike Bryant <mbryant at futurehorizons.com>
wrote:

> The difference to most other dual JFETs is they are on the same silicon
> die, so are inherently better matched.
> Zetex are one of the biggest suppliers of duals - bipolar, JFET and MOSFET
> - but they always use two die in the same package and these could come from
> different locations on the wafer so won't be quite as well matched, nor are
> they so well thermally bonded.
>
> That said, in most applications this isn't really an issue.  I think the
> very low noise space probe detectors is the only application that really
> needs them.
>
> ------------------------------
> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Roman
> Sowa via Synth-diy <synth-diy at synth-diy.org>
> *Sent:* 21 June 2025 05:12
> *To:* synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] Dual Matched N JFET from Linear
>
> Reading just a few lines from the site reveals this is some audiophile
> mumbo jumbo, so possibly very high price, and not so much better than
> other dual jFETs.
> Let me check... yes, the price is about 10x higher than others. One
> popular store lists 98 various dual jFETs.
> I mean, this is rather destined for discrete audio amps, so why bother f
> there are so many over the top opamps cheaper than those FETs. Surely
> for experimenter and audiophile market.
>
> Roman
>
> W dniu 2025-06-20 o 22:34, Tim Parkhurst via Synth-diy pisze:
> > Hey, Analog Hounds,
> >
> > Linear Systems is promoting a new Matched Dual JFET, and you might
> > even be able to get a sample or two. Useful? Not?
> >
> >
> https://www.linearsystems.com/post/why-engineers-choose-the-lsk389-for-high-precision-analog-design?utm_campaign=d2b0395f-db24-487d-8e02-adcff714e7a8&utm_source=so&utm_medium=mail&cid=a05ef50a-a9c5-473d-950b-37f3f1a2d83d
> > <
> https://www.linearsystems.com/post/why-engineers-choose-the-lsk389-for-high-precision-analog-design?utm_campaign=d2b0395f-db24-487d-8e02-adcff714e7a8&utm_source=so&utm_medium=mail&cid=a05ef50a-a9c5-473d-950b-37f3f1a2d83d
> >
> >
> > Tim (define "useful") Servo
> > ---
> > "Imagination is more important than knowledge." - Albert Einstein
> >
> >
> >
> >
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