Actually, Jim - for 160 and 80m, where you could tolerate some capacitance,
you could even try back-to-back 1 amp rectifiers, like IN4004-1N4007. You
surely wouldn't blow those out! :-) I'd probably start with the 1N4148,
though.
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of James
Rodenkirch
Sent: Sunday, August 25, 2013 4:43 PM
To: Charlie Cunningham; 'Paul Christensen'; topband@contesting.com
Subject: Re: Topband: Anyone have a boat load of J-310s?
I've found what I'll need, Charlie, courtesy of Andy Ikin! Thanks to all
for the assistance on this "project"! 72, Jim Rodenkirch K9JWV
> From: charlie-cunningham@nc.rr.com
> To: w9ac@arrl.net; rodenkirch_llc@msn.com; topband@contesting.com
> Date: Sun, 25 Aug 2013 15:55:21 -0400
> Subject: Re: Topband: Anyone have a boat load of J-310s?
>
> Jim,
>
> If you really have trouble getting some J-310s, let me know. I'd really
> have to hunt -probably out in my garage. The J-310s that I have, if I
could
> find them, are, I expect, at least 20 years old and pre-date the
shenanigans
> that Paul is warning you about. The ones that I had, are, as I recall,
> either ON Semi or NSC. I probably should find mine, I guess. I bought
the
> JFET version of the old AMECO preamp, from my friend, Bill, K4CIA, so I
> might need some spares someday. The vacuum tube version of the AMECO
preamp
> didn't have those vulnerabilities, and worked great on all the low bands
up
> through 30m, for the same purpose that you are using yours for.
>
> Paul's giving you some good advice. That's why I asked if you had tried
> Digi-Key. GL!
>
> 73.
> Charlie, K4OTV
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Paul
> Christensen
> Sent: Sunday, August 25, 2013 2:44 PM
> To: James Rodenkirch; topband@contesting.com
> Subject: Re: Topband: Anyone have a boat load of J-310s?
>
> Jim,
>
> The major semiconductor manufacturers (e.g., Fairchild) who once
> mass-produced JFETS in TO-92 style cases have now "obsoleted" most of
them.
> This occurred approximately 2-3 years ago. When shockwaves of the news
hit,
>
> many folks (and the on-line bottom feeders), started hoarding the
remaining
> supply. Even the SMD versions are now in danger of going obsolete.
> Presently, only InterFET Corporation and Linear Systems appear to be
> manufacturing both through-hole and SMD versions of high-performance JFETs
> although their per-piece prices are very high. Before the wave hit, I
> purchased hundreds of various JFETs in TO-92 style cases -- J310s being
one
> type. You're welcome a to a few. True, in many applications it may not
> make a big difference between say a J310 and MPF-102, but it unnerves me
> when I don't know exactly what I'm using in a circuit.
>
> Be careful when sourcing any semiconductor. As you noticed, JFETs are
widely
>
> available on the Asian market but when making a purchase through small
> on-line retailers - and the big auction site, it's not possible to trace
the
>
> supply chain of the component to its origin. For example, some Toshiba
> low-noise bipolar transistors are in fact re-labeled 2N3904 devices.
Unless
>
> the purchaser has access to a curve tracer and a means to perform critical
> noise and frequency response testing, one is left to trust the seller for
a
> clean "chain of custody" between the time of manufacture and point of
sale.
> When China is the only source of many TO-92 JFETs, the red flags are up
(no
> pun intended). Because of this, I have only purchased semiconductors
direct
>
> from the OEM or through well-established distributors including Newark,
> Mouser, Digi-Key, Arrow, AvNet, and Allied. For an interesting
perspective
> concerning the severity of the counterfeit semiconductor market, see the
> following report issued by the Semiconductor Industry Association (SIA):
>
> http://tinyurl.com/l9hqpw6
>
> Let me know if you're address is currently good on QRZ.
>
> Paul, W9AC
>
>
> ----- Original Message -----
> From: "James Rodenkirch" <rodenkirch_llc@msn.com>
> To: <topband@contesting.com>
> Sent: Sunday, August 25, 2013 9:16 AM
> Subject: Topband: Anyone have a boat load of J-310s?
>
>
> >
> > The J-310s in my little preamp are kaput - I looked at Mouser but the
> > shipping costs are way too high for a couple of little Jfets - any body
> > have lots of extra J-310 (or equivalent) they could spare? What ever
your
> > costs would be, including mailing them off, would be far cheaper than
what
>
> > it would cost me to buy them outright!
> >
> > Thank you, in advance, for any help -- reply off line works good for
> > me....72, Jim Rodenkirch
> >
> > _________________
> > Topband Reflector
>
> _________________
> Topband Reflector
>
> _________________
> Topband Reflector
_________________
Topband Reflector
_________________
Topband Reflector
|