Hi John,
My hat goes off to Linear Systems, but to the best of my knowledge they are not making P-channel duals. Is that correct?
I seem to recall that a few months ago some of your own design decisions were being affected by Parasound's concern about having enough of the P-channel JFETs. That tells me there is a problem.
Cheers,
Bob
Heck, I'd be delighted if I could find *non-cheap* low noise pFETs. I'm leery of Ebay purchases of supposed NOS- too many fakes.
Comparable to (sane) tube prices. 😀
Serious answer: cheap enough that buying two of them won't discourage builders of a diy phono preamp design, but that can be considerably higher than the price of, say, J271s.
Serious answer: cheap enough that buying two of them won't discourage builders of a diy phono preamp design, but that can be considerably higher than the price of, say, J271s.
Somehow my question appeared twice.
I ask because I know for a fact that there are stocks of the Toshiba parts
simply waiting for the price to get high enough.
😎
I ask because I know for a fact that there are stocks of the Toshiba parts
simply waiting for the price to get high enough.
😎
John, I appreciate the kind offer! Unfortunately, it's not just for me. I want to use them for a published design, so they'd have to be available in quantities sufficient for anyone who wants to build it to get them.
The 20 centers are the ones I worry about because of counterfeits. 😀
What does LS have that would be suitable for phono inputs?
What does LS have that would be suitable for phono inputs?
The j271 is an OK device, and I am pretty sure that they would be OK for your purpose. They might be more expensive (somewhat) than what you can buy from major distributors advertising on the internet.
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Presumably you are talking about the 2SJ74, which was discontinued about three years ago. For an EOL buy, we ordered 500,000. This earned us a visit from the head of discrete semiconductor sales for North America. He couldn't tell us much (due to his "client-attorney" privilege) but he told us that nobody else in audio was buying any significant stocks in North America.
We later learned that another "gun for hire" who shall remain unnamed bought 50,000 of them, but he probably obtained them from overseas. Besides neither he nor I are likely to be selling any of our stocks. They have far more value being turned into multi-thousand dollar products than as $2 discrete transistors.
There were two companies that used to stock them as "grey market" parts that were obtained from Japanese distributors. It is possible that they are sitting on some. I have dealt with both of those firms and would trust their product to be genuine. Any other source I know of would have to be in Hong Kong, Taiwan, or China. I would be very hesitant to purchase anything from that part of the world. (Some of you may remember the J109/K389 group buy fiasco from a few years back.)
Ignoring inflation, they will never be worth more than a few dollars. Linear Systems has already made some pilot runs and it is only a matter of time before they reach full production. I would say that if somebody is sitting on them, trying to manipulate the market by artificially creating a scarcity, that they are going to get burned in the end. It's not like they bought them for $1 and will be able to sell them for $10.
I personally don't need many (4 or 5), but I need something that anyone reading my article could buy. A 2SJ74 would work perfectly, but I can design around anything that has a low enough en.
Hi Charles,
Apart from availability, it seems the big problem with the 2SJ74 is the fact that it is not a dual-matched pair. How much trouble do you have to go though matching all the JFETs for one of these complementary input stages?
Cheers,
Bob
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