Topband: Anyone have a boat load of J-310s?

[James Rodenkirch]

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 at nc.rr.com
> To: w9ac at arrl.net; rodenkirch_llc at msn.com; topband at 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 at contesting.com] On Behalf Of Paul
> Christensen
> Sent: Sunday, August 25, 2013 2:44 PM
> To: James Rodenkirch; topband at 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 at msn.com>
> To: <topband at 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 
> 
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> Topband Reflector
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> Topband Reflector