John Curl's Blowtorch preamplifier part II

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Bob Cordell

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Joined 2006
cordellaudio.com
john curl said:
We haven't run out of complementary jfets as of yet! That is why we are not reaching for alternatives. We will never really run out of P channel jfets, just CHEAP, low noise, P channel jfets. Linear Systems is taking up the slack AND they make lots of jfets monthly, quality bipolars too.
It will just be more expensive, kind of like it is with tubes today.
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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
 
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Charles Hansen

R.I.P.
Joined 2003
Nelson Pass said:
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.
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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.
 
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Bob Cordell

Member
Joined 2006
cordellaudio.com
Charles Hansen said:
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.
Click to expand...

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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