2SJ201... Is it the same as J201??

freezx · January 30, 2009, 05:22:51 PM

Quote from: slideman82 on January 29, 2009, 12:23:16 PM
No, the pcb for N-channel small signal Jfets... which small signal JFET's can you get?

You'll need a power amp pcb for those 2sj201 (would be a completly waste if you put them in a stompbox...). There's a 18W amp in redcircuits.com, http://www.redcircuits.com/Page123.htm, but you'll need the other complementary pair mosfet, the 2sk1530. Can you obtain that 2sk1530?

Yeah, i probably can. but isnt the 2sj201 a little too powerful? P-FET 200V 12A 150W
oh and i cannot get the BC550C but instead i can get the BC550B. I'm not too good at this so i have to ask, will the BC550B work the same?

slideman82 · January 31, 2009, 10:17:32 AM

The 2sj201 are rated for a maximum current of 12A and 200V, so, if you use it with less current and voltage, there's no problem! They are not powerful in the sense that will give you more distortion, used as ouput devices in power amps, there's no difference with different kinds of power mosfets like an IRF530 (audio mosfet will probably sound better and will have better behaviour with increasing temperature).

Just don't use those 2sj201 for a stompbox! keep learning and when you are ready, build a mosfet power amp!

BC550b and BC550c are the same, just differs in gain (hFE): "a" stands for lower gain, "b" for medium and "c" for higher gain. In larger bipolar transistors (suited for auido output, for example), like to-220 or to-03p package, stands for maximum operating voltage (from a to d, lower to higher voltage).

freezx · February 02, 2009, 09:13:09 AM

I think i can solve my problem. About the 2sj201s, i'm planning to use them to make this amp http://www.elecfree.com/electronic/basic-mosfet-amplifier-100w-with-2sk15302sj201/ and i managed to find the 2SK1104, which i think can substitute J201.

slideman82 · February 02, 2009, 08:16:18 PM

I'll tell you later... but seems ok, but that 2sk1104 is not the complementary pair for the 2sj201, you should find that 2sk1530.. seems they are for audio prupose, excellent!

The whole article, with pcb's! http://users.swing.be/edwinpaij/ampli_mosfet_simple.htm

I'm finishing that distortions mentioned before pcb! Remember, it was an improvisation! I don't know how it's gonna sound!

mac · February 02, 2009, 09:06:57 PM

Best replacement I found for j201 are 2sk117/170. Low Vgsoff:(0.5 - 1.5v), gain: 15mS, very low noise.

BTW, I'm looking for high voltage fets, 100-300V, for a preamp.

mac

freezx · February 03, 2009, 04:42:38 AM

I found the 2sk1530

i just tought i can substitute the J201 with 2sk1104 for the pedal.

freezx · February 03, 2009, 11:34:43 AM

... or not?

slideman82 · February 03, 2009, 07:06:23 PM

Well, I've seen 2sk1104 won't work, just use the 2sk1530! Seems 2sk1104 won't have the same gain as J201... but MAC is right, 2sk117 will! they're great!

I don't know any JFETs for 100V... would be great, better than tubes! I just use them with 24V and work really good, quite linear, but warmy!

freezx · February 04, 2009, 06:14:39 AM

hmm.. maybe this can help
2SK373
N-FET 100V 0.6mA Up<3.5V -7a

oh and thanks for the help!

slideman82 · February 04, 2009, 08:20:47 AM

Ok! Great data! Thanks! If mac could find this, would be glad!

mac · February 04, 2009, 08:59:56 PM

QuoteWell, I've seen 2sk1104 won't work, just use the 2sk1530! Seems 2sk1104 won't have the same gain as J201... but MAC is right, 2sk117 will! they're great!
I don't know any JFETs for 100V... would be great, better than tubes! I just use them with 24V and work really good, quite linear, but warmy!

Quotehmm.. maybe this can help
2SK373
N-FET 100V 0.6mA Up<3.5V -7a
oh and thanks for the help!

I want to build a demo, at least 100v to be on tube territory, all fet preamp (maybe a Fet Junior), a power mosfet, SE or push pull, and OT of course

I was thinking of a 2sk117 minibooster since they are 50v, but I'm not sure if voltage swings can be as high as 100v.
I'm going to look for those 2sk373, Toshiba I bet.

mac

slideman82 · February 05, 2009, 06:43:51 PM

Go get it, mac! You'll have a lot of gain with 2sk117 with a regulated 24Vdc... try 45V dc with a zener and 4700uF filter cap... that will blow your head! But they become pretty linear..

mac · February 05, 2009, 09:59:07 PM

QuoteGo get it, mac! You'll have a lot of gain with 2sk117 with a regulated 24Vdc... try 45V dc with a zener and 4700uF filter cap... that will blow your head! But they become pretty linear..

All my new projects are 18v or higher. Have you tried a 18V Fuzz Face?

If linearity destroys 2nd order harmonics then it is a problem.

mac

slideman82 · February 06, 2009, 08:09:02 AM

So, how does it sounds? I don't think it will destroy 2nd order harmonics, just lower it's presence (= amplitude... volume... etc).

LEON.01 · February 06, 2009, 10:04:22 AM

Hi Freezx,
I've been having the same trouble! cant find J201's anywhere! Have found a couple that are the same and a bit easier to come by-
BF245c and K117.

....and, i think 2N5457 is the same!

cpm · February 06, 2009, 06:54:40 PM

BF245C tipically is a Vgs of 2v and up
BF245A is colser to J201 as it ahs Vgs from 0.6 to 1,5 average

mac · February 07, 2009, 12:37:14 PM

BF245C are more like MPF102, good for buffers, most of them put the source near 4.5v.

BF245A work on almost every project, I mean compressors, tremolos, etc. It seems that they have the best Vgsoff when used as variable resistors.

mac

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2SJ201... Is it the same as J201??