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

[freezx]

Ive been searching for a J201 transistor for a while now, and the only transistor i found is the toshiba 2SJ201, so i was wondering if its the same as the J201. Thanks in advance.
Sorry if my English isn't perfect.

Best regards,
FREEZX

[CynicalMan]

They are completely different devices.
The J201 is a N-channel JFET.
The 2SJ201 is a P-channel MOSFET.

[orangetones]

Order them from Fairchild Semicondutor at www.fairchildsemi.com.  They still make them.  Or Smallbear at www.smallbearelec.com

[freezx]

Thanks a lot. By the way does anyone know a good schematic on which i can use the 2SJ201 FETs that i already bought?

[cpm]

maybe use it for a discrete red-llama-type circuit
positive ground millenium bypass, or booster.

[freezx]

I cannot find the goddamn J201 in my country. Any substitutes i can use? BTW I cannot find any schematic with the 2sj201.

[newfish]

Hi.

PM'd you.

May be able to help.

Cheers.

[slideman82]

Try the 2SK161, they have the same pinout as the J201... I'm sick of those J201, they're all around! there are a lot of 2SKxxx that sound quite good, and aren't that gainy! I like the 2SK30 better.

[cpm]

arent 2sk30 mosfet? at least is what datasheets say

[slideman82]

No, they are J-FETs. N-channel... D G S pinout.

[WGTP]

http://www.diystompboxes.com/analogalchemy/sch/obsidian.html

http://www.diystompboxes.com/smfforum/index.php?topic=65845.0

http://www.aronnelson.com/gallery/main.php/v/WGTP/Mosfet_Incenerator.jpg.html?g2_imageViewsIndex=1

These might help with an P-channel mosfet, although the bias will probably need to be adjusted.

Check out the last stage of the Mosfet Incenerator designed by Gus Smalley.  He states that by adjusting the 2.2M resistor most Mosfets will work.  With P-channel Mosfets the electrolytic caps (if any) and the battery polarity have to be reversed.  

[freezx]

Interesting stuff... too bad i only have 2 2SJ201s and they were pretty expensive. 11$ a piece. anyt distortion with less mosfets? Thanks for your help.
Best regards
freezx

[slideman82]

You can try something like the Fatboost and some PNP's bipolars with negative supply... something like a fatboost followed by a PNP stage, buffer, baxandall tonestack... and a last bipolar stage... could be some kind of fuzz! (That's all an improvisation! I don't know if it will sound cool! Just gave an idea for a new stompbox!). Also a pnp booster before the cascoded stage could work! All this would sound better with higher supply, like -15V or -18V, better fot the cascoded stage (the fatboost stage).

Any suggestions?

I think one of these day I'm gonna draw the PCB...

[slideman82]

Just buy a couple of N channel Jfets, some npn bipolars and use positive supply! seems that this 2sj201 is a power Mosfet, so, if you can buy its complemetary pair 2sk1530 you could build a mosfet power amp! That would be a nice project... tubey sound, as some people say (including me). You could handler high power with these, easily 100 or 120W! That's why they costed you so much (200V 12A mosfets!)

[freezx]

You can try something like the Fatboost and some PNP's bipolars with negative supply... something like a fatboost followed by a PNP stage, buffer, baxandall tonestack... and a last bipolar stage... could be some kind of fuzz! (That's all an improvisation! I don't know if it will sound cool! Just gave an idea for a new stompbox!). Also a pnp booster before the cascoded stage could work! All this would sound better with higher supply, like -15V or -18V, better fot the cascoded stage (the fatboost stage).

Any suggestions?

I think one of these day I'm gonna draw the PCB...

Good idea! when you draw the PCB let me know.

Just buy a couple of N channel Jfets, some npn bipolars and use positive supply! seems that this 2sj201 is a power Mosfet, so, if you can buy its complemetary pair 2sk1530 you could build a mosfet power amp! That would be a nice project... tubey sound, as some people say (including me). You could handler high power with these, easily 100 or 120W! That's why they costed you so much (200V 12A mosfets!)

Allright! schematics please

[DougH]

If you are ever curious about part numbers you can always google for the datasheet:

http://www.google.com/search?q=2sj201+datasheet&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[JDoyle]

2SJxxxx = P-Channel FET
2SKxxxx = N-Channel FET

Now, whether it is a MOSFET or a JFET, you will have to that look up.

In general though, if it is a 2SJ and the number is under 110, there is a very high chance it is a JFET, over that, it is almost definitely a MOSFET; if it is a 2SK and the number is under 380, there is a good chance it is a JFET (under 110, the odds get much higher), over that, there are very few JFETs, and most are surface mount.

Short version: Follow Doug's advice and just look it up.

Regards,

Jay Doyle

[slideman82]

It's definitly a mosfet! Check the datasheet!

good point, JD! there are some cases, I remember 2SJ49 or 2SK134, complementary power mosfet pair for audio purposes.

I don't know if this pair (2sj201 - 2sk1530) it's suited for audio (there are some differences between audio mosfets and switching mosfets). I recommendo you a couple of mosfet power amps placed in redcircuits.com, Flavio Dellepiane has done vey good and simple desings (I tried the 60W PA, absolutely the best SS I've ever listened to! and I used switching mosfets!).

Give me some days, probably weeks, and I give you (freezx) that PCB!

[freezx]

It's definitly a mosfet! Check the datasheet!

good point, JD! there are some cases, I remember 2SJ49 or 2SK134, complementary power mosfet pair for audio purposes.

I don't know if this pair (2sj201 - 2sk1530) it's suited for audio (there are some differences between audio mosfets and switching mosfets). I recommendo you a couple of mosfet power amps placed in redcircuits.com, Flavio Dellepiane has done vey good and simple desings (I tried the 60W PA, absolutely the best SS I've ever listened to! and I used switching mosfets!).

Give me some days, probably weeks, and I give you (freezx) that PCB!

The PCB that uses 2sj201?

[slideman82]

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?