I got 17 pieces of this old dual Jfet ...can somebody help me where to use this thing....I plan to use this as LTP input for power amp since they are pretty matched...
Does anybody has some schema to share or guide me to good working schematics...best if there's available PCB layout.
Thanks
Does anybody has some schema to share or guide me to good working schematics...best if there's available PCB layout.
Thanks
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Jun, know someone looking for those, will you be willing to sell a pair?
a phono stage can use those....
a phono stage can use those....
Hi,
here´s a Datasheet from NEC. 😉
On first glance it looks to be a superb MC-Inputstage device with its very low enoise and high gm.
Unfortunately those features also come with high input capacitance.
They are quite close to Toshibas SK369 and -apart from capacitance and speed- the single BF862.
If used in a MM-Input stage it needs to be cascoded, to keep input capacitance of the stage just acceptably low.
A I/V converter stage like EUVL´s Zen might also be a nice circuit for them.
I wouldn´t ´waste´ them for Input stage devices for a line level or power amp.
jauu
Calvin
here´s a Datasheet from NEC. 😉
On first glance it looks to be a superb MC-Inputstage device with its very low enoise and high gm.
Unfortunately those features also come with high input capacitance.
They are quite close to Toshibas SK369 and -apart from capacitance and speed- the single BF862.
If used in a MM-Input stage it needs to be cascoded, to keep input capacitance of the stage just acceptably low.
A I/V converter stage like EUVL´s Zen might also be a nice circuit for them.
I wouldn´t ´waste´ them for Input stage devices for a line level or power amp.
jauu
Calvin
I agree with Calvin.
Use them in something special and cascode them.
Have a look at Salas RIAA pre.
There will be others.
Oh and prove to yourself they are genuine start with the really easy Idss @ 5Vds (unusually low cf. the normal 10Vds used elsewhere). Follow up with Vp. Borbely shows a little jig for these two measurements.
Find those that make really good pairs. Batch them into mA Idss.
Use them in something special and cascode them.
Have a look at Salas RIAA pre.
There will be others.
Oh and prove to yourself they are genuine start with the really easy Idss @ 5Vds (unusually low cf. the normal 10Vds used elsewhere). Follow up with Vp. Borbely shows a little jig for these two measurements.
Find those that make really good pairs. Batch them into mA Idss.
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They would make great swap devices to someone willing to part with well matched k170/j74
A pair of these k194 could be worth a fair bit of money !
A pair of these k194 could be worth a fair bit of money !
I will set up a test Jig and see...these are sure genuine since they are from and old electronics store whom i accidentally found on disposal items wrapped in a nice anti static plastic.
Thanks andrew....I might swap the other for k170/j74 but my worries most of them are fakes...
Thanks andrew....I might swap the other for k170/j74 but my worries most of them are fakes...
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