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Old 18th March 2002, 01:14 PM   #11
sonnya is offline sonnya  Denmark
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Try something like 2n3904/6 as inputpair and MJL1302a/3281a as output pair.
R1 = R2 = 3.3ohm => idle current in MJL @ 82mA

R3 = R5 = 100ohm

R4 = R6 = 10k.

And a output cap to block ~100mV offset.

Should work. with something like -3dB@~3MHz

Sonny
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Old 18th March 2002, 01:15 PM   #12
sonnya is offline sonnya  Denmark
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Would like to hear the results.

Sonny
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Old 18th March 2002, 01:38 PM   #13
JoeBob is offline JoeBob  Canada
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Sure, I'll tell you how it goes.

But one more query. Would keeping the 2N3904/6 as the input pair degrade the sound that much? For I know they aren't the most linear devices...
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Old 18th March 2002, 01:44 PM   #14
sonnya is offline sonnya  Denmark
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Hi JoeBob, maybe try 2n5401/5551 instead, but they have higher parasitic caps and less currentgain than 2n3904/6.

They are more linear but will maybe generate more offset at a given input resistance compared to 2n3904/6.

Sonny
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Old 18th March 2002, 01:45 PM   #15
JoeBob is offline JoeBob  Canada
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Oh well. I'll just stick with a pair of 2N3904/06 and see how it goes instead...
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Old 18th March 2002, 07:22 PM   #16
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Douglas Self has a set of very good articles based around the BJT, including unity gain emitter followers. Not exactly what you need, but very educational.

http://www.dself.demon.co.uk/
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Old 18th March 2002, 08:27 PM   #17
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Joe Bob:

You need some better parts! I'll give you some....if you pay postage.

Just don't ask for a thousand or so.

Jocko
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Old 19th March 2002, 07:52 AM   #18
sonnya is offline sonnya  Denmark
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Jocko is right!!
There is a reason why whe all mention parts like zetex or toshiba.
But if you can't get other parts like 2nXXXX or BCXXX etc.. Then you have a little problem.. There must be some audio/video parts store in your country.. They will have parts like 2sc2240 2sa970.

Sonny
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Old 20th March 2002, 11:59 PM   #19
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Cool B.J.T.

Buffer with Jfet Transistors. Jfet buffer with Toshiba K170s biased at 4 mA. Borbely topology based on White cascode follower. Point to point wiring with four nines silver with loose teflon sleeving. Corning RN60D resistors, Sidereal, Wondercap, Panasonic HFQ, and Rifa caps. Silver soldered.

H.H.
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Old 9th July 2002, 01:33 AM   #20
dorkus is offline dorkus  United States
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Default cool!

hi harry,

well it looks like it's been months since anyone posted in this thread but i was just doing a search for "JFET BUFFER" and i came up with your little baby here. could be very useful in Son of Dork! how does it sound? it is capacitor coupled obviously but do you find the strengths of the circuit overcome the coloration of the caps?

cheers,
dorkus
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