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how about using J111 J175 Jfets in F5
how about using J111 J175 Jfets in F5
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Old 4th October 2017, 04:30 AM   #1
rhythmsandy is online now rhythmsandy
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Default how about using J111 J175 Jfets in F5

was going through the Fairchild website and found these Jfets as I see they have low pf and good Yfs and yet low noise. Can we use these instead of 2sk170 and 2sj74?
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File Type: pdf J175-1120772.pdf (405.5 KB, 30 views)
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Old 4th October 2017, 05:04 AM   #2
Zen Mod is offline Zen Mod  Serbia
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how about using J111 J175 Jfets in F5
maybe pair of them , in each position

however , 50 greenies for LSK from Store is hardly greatest investment in entire amp , while critical position
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Old 4th October 2017, 05:59 AM   #3
WalterW is offline WalterW  Netherlands
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how about using J111 J175 Jfets in F5
I see it in more datasheets from JFET's: "Sourced from process 51" .....
What does that mean? What is the manufacturer trying to tell us with that information?
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Old 4th October 2017, 07:54 AM   #4
dimkasta is offline dimkasta  Greece
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I bought a bunch of them a few months ago to play with and/or use as CCSs to save on SK170s.
The Idss was too much in all of them. Around 17-20mA.
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Old 4th October 2017, 07:56 AM   #5
rhythmsandy is online now rhythmsandy
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Quote:
Originally Posted by dimkasta View Post
I bought a bunch of them a few months ago to play with and/or use as CCSs to save on SK170s.
The Idss was too much in all of them. Around 17-20mA
That's Idss I believe is not a drawback.
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Old 4th October 2017, 08:06 AM   #6
dimkasta is offline dimkasta  Greece
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Quote:
Originally Posted by rhythmsandy View Post
That's Idss I believe is not a drawback.
Papa explains it nicely on the F5T article (page 5)
Although I can't remember if vanilla runs on lower V.

At 8mA they operate close to 200mW
You can get away with a bit above that, but you have to ensure proper ventilation

20mA (will work a bit lower because of the degeneration) will push them close or above max power dissipation levels

So you will probably have to increase the degeneration resistors to tame them
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Old 4th October 2017, 09:33 AM   #7
rhythmsandy is online now rhythmsandy
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Quote:
Originally Posted by dimkasta View Post
Papa explains it nicely on the F5T article (page 5)
Although I can't remember if vanilla runs on lower V.

At 8mA they operate close to 200mW
You can get away with a bit above that, but you have to ensure proper ventilation

20mA (will work a bit lower because of the degeneration) will push them close or above max power dissipation levels

So you will probably have to increase the degeneration resistors to tame them
will be hardly using in 2.5ma so I believe there is no need of heatsinking on them.
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Old 4th October 2017, 10:54 AM   #8
Zen Mod is offline Zen Mod  Serbia
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how about using J111 J175 Jfets in F5
xconductance , degeneration , Idss , thus value of drain resistors to open mosfets ..... at least OLG (and control of output gates) is going doooooown

no way Jose ...... plenty of factors to solve successfully , and to have much worse than original

as I sad 50 bucks for LSK is peanuts in overall sum , especially when you count what's price of original FW F5 ........ and we got all what's important ( both brain and ball$ ) for nuttin'

so , too much of cheapskatin' is on verge of disrespect ...... and deeply in foolishness

(said ZM, biggest cheapskate of all Greedy Boyz)
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Old 4th October 2017, 10:57 AM   #9
rhythmsandy is online now rhythmsandy
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but in general will those Jfets work? out of curiosity.
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Old 4th October 2017, 11:07 AM   #10
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how about using J111 J175 Jfets in F5
yeah , it will

same as 6DJ8 with 15V at anode
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