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Old 8th September 2007, 05:45 AM   #121
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very good information.
thanks
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Old 8th September 2007, 06:57 PM   #122
anatech is offline anatech  Canada
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Hi Santhosh,
Quote:
I am not sure if I can post a shop name on this forum.
Sure you can. Just as long as you aren't advertising for them with a commercial interest.

-Chris
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Old 18th September 2007, 05:08 PM   #123
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Hello!

What do you think about this MOSFET I think this is counterfeit? I have never seen this MOSFET in this case. Its looks like professional but I think it doesn't mean anything. If I search in google 2SK1058 I found only in other case. .

I try to measure the Vgs/Id characteristic but it wasn't successful and at moment its behavior is like should be shortstop between Drain-Source legs. Presumably its dead.
Earlier I measured IRFP240 and it worked very well. Of course I used same measure circuit but the components have different values because IRFP has higher Vgs value.

Does somebody have measure circuit for 2SK1058?

It would be very important because I have started to build hybrid amplifier and I would like use 4 pieces of 2SK1058.
I'm going to order matched them for safety sake from Borbely Audio. I would like to draw characteristic curve for every MOSFETs.

Gyuri (George)
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Old 18th September 2007, 05:51 PM   #124
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sorry bud, but that picture is hilarious
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Old 19th September 2007, 09:35 AM   #125
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I don't understand you jacco vermeulen. What is your problem?

Here is an original 2SK1058 and I can see lot of difference between the two device.
In the datasheet case of semiconductor also like this.
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Old 19th September 2007, 11:00 AM   #126
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Maybe if you place your "Hitachi" next to the IR power device you'll understand.
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Old 19th September 2007, 07:46 PM   #127
K-amps is offline K-amps  United States
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Quote:
Originally posted by topicreader
I don't understand you jacco vermeulen. What is your problem?

Here is an original 2SK1058 and I can see lot of difference between the two device.
In the datasheet case of semiconductor also like this.

Sorry could'nt resist, looks like a transistor on Viagra.
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Old 27th September 2007, 06:12 PM   #128
Mooly is offline Mooly  United Kingdom
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Remember buying 30 or so MPSA06/56 npn/pnp pairs a few years back.A few of the MPSA56 pnp's were actually npn's -unbelievable.Also some MJE340/350 's did'nt look too clever, a quick rub with iso revealed some obscure 40xxx no.All from reputable source as well.
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Old 4th October 2007, 03:57 PM   #129
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There are counterfeit 2SA1943s (and presumably 2SC5200s) floating around in Bangalore - if the plastic encapsulation is green in colour, it is definitely a fake. Even those in black encapsulation are suspect - memorize the pictures of the good ones at the beginning of the thread to distinguish the originals from the fakes. Apart from the heatsink outline (if the straight edges are not exactly straight, but rough or jagged, it's a fake), look at the plastic moulding - if there are pieces of plastic chad hanging off the seams, it's a fake. The genuine Toshiba has smooth moulding edges and the plastic at the seams of the two halves is smooth. OTOH, the surface with legend on it is matt, and the legend is harder to read on the genuine than the counterfeit.

The good news - I have located genuine ones priced at around Rs.100 (~$2.50) a pair, while the fakes are priced at Rs.120-Rs.150 a pair - go figure the economics, it beats me. Anyway, I'm tempted to stock up and offer them to forum members in Bangalore if there's sufficient interest.
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Old 5th October 2007, 02:22 PM   #130
sant_ka is offline sant_ka  India
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Hello Linuxguru,

I had posted earlier in this thread about having purchased these transistor in Bangalore ( from Darshan Electronics on SP road ) for Rs90 a pair.

While the parts seem genuine (I even cracked one open just to check ) , I found quite a difference in the hFE values between the PNP and NPN devices at Ic = 1A. Makes it a pain to get a decently matched pair.

None of the parts failed, but then I am yet to run my amp at its rated supply. I have a lousy PSU right now.

Cheers,
Santhosh
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