Jfet sub and specs for life/parentheses/ache?

J

jwin615

Well-known member
Building a EL Ache(modded life).
I don't have any PF5102s but have a dozen other jfets on hand. J201, J11x, 5457s...
Can anyone advise on a good sub for the 2 5102s in the parentheses and what idss and vgsoff to shoot for? I always struggle with swapping jfets via data sheet due to the spread of specs. it looks as they're being used as buffers more so that gain stages so I'm guessing indont need a high ratio.
I have a DCA75.

Also, is the PF5102 just a tighter spec J111? The on semi datasheet for the 5102 states this in the description:
See J111 for characteristics
 
Musikding supplied me with 2N5457 for the Parentheses kit. On his site, the page for the unavailable PF5102 says: "Since the PF5102 are no longer manufactured, and unfortunately there are also many fakes in circulation, the FET will probably no longer be available in the future. However, the 2N5457 can be used as a replacement type in most cases:" on his site."

Mine works. No idea if there's an actual difference to be heard between the two? Never measured them by the way... (no tool for that yet; found this https://synthcube.com/cart/ian-fritz-fonik-transistor-match-pcb) so can't help you out in that respect.
 
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They’re just buffers so it’s really whatever. The PF5102 was already a sub for what would’ve been a 2N5458 in the RAT chunk of the circuit, and a 2N5458 is like 99% the same as a 2N5457 (IIRC same manufacturing process just binned for different Vgs(off) ranges, but even those ranges have *tons* of overlap).
 
manfesto said:
They’re just buffers so it’s really whatever. The PF5102 was already a sub for what would’ve been a 2N5458 in the RAT chunk of the circuit, and a 2N5458 is like 99% the same as a 2N5457 (IIRC same manufacturing process just binned for different Vgs(off) ranges, but even those ranges have *tons* of overlap).
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Thanks manifesto and @tegendemuur for the replies. Is there a range to shoot for/stay away from at all?
 
For history/completeness sake, found a good thread over at diysb.
Will report back with findings/results. If anyone has anything to add in the meantime, by all means.
Also, read through the CDB jfet threads again.
 
Nostradoomus said:
Every time I throw random jfets in that circuit it works.
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You obviously don't have my luck. :ROFLMAO:
I spent the money on the DCA75, may as well pretend to use it.
But seriously, the diysb thread has some pretty good guidance on selection. I know it's not as imperative in a buffer scenario but..
It's also a bit for recording keeping sake.
This worked before so should work again. I recall the jfet portion of classes occuring 10 years ago but Im trying to brush up and avoid the socket it til it works approach.
 
jwin615 said:
You obviously don't have my luck. :ROFLMAO:
I spent the money on the DCA75, may as well pretend to use it.
But seriously, the diysb thread has some pretty good guidance on selection. I know it's not as imperative in a buffer scenario but..
It's also a bit for recording keeping sake.
This worked before so should work again. I recall the jfet portion of classes occuring 10 years ago but Im trying to brush up and avoid the socket it til it works approach.
Click to expand...
Reading up on that device. Seems like a good investment; good value for the money, and the only Peak I need alongside my decent DMM.
 
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Feral Feline said:
I've been waiting for that to be restocked for a VERY long time...
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Yeah, I was afraid of that. And with the company having become a bit, unstable... I am a bit wary of ordering there as well. Also, combining this with a cheap tester ala LCR-TC2 would bring me already halfway there in price with the DCA75. So, a no go! I'll just save up a bit...
 
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