2SK389 from Bluestar

beetle · 10th December 2009, 08:00 PM

Hey all,

i recently brought some 2SK389 from bluestar. For some reason they look different from them I have running in my XOno for years.

The letters are more solid then the one in my XOno. "K389 BL°4F" is written on them. Is there a way to make shure that I have brought genue 2SK389s?

Regards,
Rene

Zen Mod · 10th December 2009, 08:16 PM

just measure their Idss ; if they behave as Jfets - they're real one

beetle · 10th December 2009, 08:25 PM

Hey Choky,

yea... ehm... and how to? I was allready bothering google.

Ehh... Got one! http://www.diamondstar.de/transistor_matching_jfet.html

beetle · 10th December 2009, 08:45 PM

3.9mA is good?

Zen Mod · 10th December 2009, 08:50 PM

it is .

just look this : http://140.120.11.1/prophys/ael/File...eet/2SK389.pdf

beetle · 10th December 2009, 09:08 PM

Awesome!

StevenOH · 12th December 2009, 02:47 PM

<<3.9mA is good? >>

Not for BL.
Make shure, that you measure Idss properly.

beetle · 03:19 PM

Hey Steven,

I meassured some other 2SK389 and found two with about 4.8mA. I did the meassurement with 9V from Drain over Source and Gate. Exactly like explained in the link I posted.

StevenOH · 12th December 2009, 04:29 PM

I hope you see, that something is not right here...
9 V is fine, it will not affect your readings that much as the difference of several mA against the specs you do have already. Test circuit is OK in theory.
I would recommend to always include resistor of several KOhm, connected in series with (and very close to) the gate lead. At this point you don't want to solder your leads, so try to find any type of socket you can plug the 3 leads into (transistor or IC type, than you can solder the resistor to the socket).
If this will not change your readings, than you have a problem. At that point I would actually measure the Gm of the FETs to know what kind of problem you have: counterfeit? relabeling BL for GR?
In the end you will have to decide if you want to report/send them back for refund. The measurments will substantiate your claim.
That situation is the FIRST - I have never heard of THIS kind of problem.

beetle · 13th December 2009, 01:54 PM

Hm... I can not come to the conclusion that they are counterfaits. I was meassuring some 2SK170 BL and GR. The BL type are having about the same Idss like my 2SK389BL from bluestar. The Idss of the GRs are slightly below of BL, both 2SK389BL and 2SK170BL.

10th December 2009, 08:00 PM	#1
beetle diyAudio Member Join Date: Mar 2008	2SK389 from Bluestar Hey all, i recently brought some 2SK389 from bluestar. For some reason they look different from them I have running in my XOno for years. The letters are more solid then the one in my XOno. "K389 BL°4F" is written on them. Is there a way to make shure that I have brought genue 2SK389s? Regards, Rene

10th December 2009, 08:16 PM	#2
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	just measure their Idss ; if they behave as Jfets - they're real one __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb

10th December 2009, 08:50 PM	#5
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	it is . just look this : http://140.120.11.1/prophys/ael/File...eet/2SK389.pdf __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb

12th December 2009, 02:47 PM	#7
StevenOH diyAudio Member Join Date: Jun 2004 Location: USA	<<3.9mA is good? >> Not for BL. Make shure, that you measure Idss properly. __________________ The truth is out there. Who can handle the truth?

12th December 2009, 03:11 PM	#8
beetle diyAudio Member Join Date: Mar 2008	Hey Steven, I meassured some other 2SK389 and found two with about 4.8mA. I did the meassurement with 9V from Drain over Source and Gate. Exactly like explained in the link I posted. Last edited by beetle; 12th December 2009 at 03:19 PM.


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10th December 2009, 08:25 PM	#3
beetle diyAudio Member Join Date: Mar 2008	Hey Choky, yea... ehm... and how to? I was allready bothering google. Ehh... Got one! http://www.diamondstar.de/transistor_matching_jfet.html

10th December 2009, 08:45 PM	#4
beetle diyAudio Member Join Date: Mar 2008	3.9mA is good?

10th December 2009, 09:08 PM	#6
beetle diyAudio Member Join Date: Mar 2008	Awesome!

12th December 2009, 04:29 PM	#9
StevenOH diyAudio Member Join Date: Jun 2004 Location: USA	I hope you see, that something is not right here... 9 V is fine, it will not affect your readings that much as the difference of several mA against the specs you do have already. Test circuit is OK in theory. I would recommend to always include resistor of several KOhm, connected in series with (and very close to) the gate lead. At this point you don't want to solder your leads, so try to find any type of socket you can plug the 3 leads into (transistor or IC type, than you can solder the resistor to the socket). If this will not change your readings, than you have a problem. At that point I would actually measure the Gm of the FETs to know what kind of problem you have: counterfeit? relabeling BL for GR? In the end you will have to decide if you want to report/send them back for refund. The measurments will substantiate your claim. That situation is the FIRST - I have never heard of THIS kind of problem. __________________ The truth is out there. Who can handle the truth?

13th December 2009, 01:54 PM	#10
beetle diyAudio Member Join Date: Mar 2008	Hm... I can not come to the conclusion that they are counterfaits. I was meassuring some 2SK170 BL and GR. The BL type are having about the same Idss like my 2SK389BL from bluestar. The Idss of the GRs are slightly below of BL, both 2SK389BL and 2SK170BL.

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