2SK135 / 2SJ50 replacements

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I have a Perreaux PMF-3150 amplifier with 6 pairs 2SK135 / 2SJ50 MOSFet powertransistors. I mailed Perreaux New Zealand if the Exicon 10N20 / 10P20 are drop in replacements but got no answer. According to Exicon / Profusion their MOSFets are substitutes for the 2SK135 / 2SJ50 but I wonder if anybody tried this in his Perreaux or other MOSFet amp.

Thanks in advance,

Robert
 
Why do you need to replace them? They very rarely fail.
If you try to read drain to source voltage drop with your DVM after checking gate to source voltage, they will read short circuit! If you momentarily short the gate to drain, they will read OK again, due to the high gate - source capacitance and low leakage current.
I inspected a repair at a colleagues work shop a few years ago and his 'engineer' condemned a Harrison 1000 amplifier due to not understanding the way these particular Mos Fets work.
If they are faulty, any of the early H&H or Harrison amplifiers are stuffed full of them.


Exicon Lateral MOSFETS - Our Product Range
 
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Why do you need to replace them? They very rarely fail.
If you try to read drain to source voltage drop with your DVM after checking gate to source voltage, they will read short circuit! If you momentarily short the gate to drain, they will read OK again, due to the high gate - source capacitance and low leakage current.
I inspected a repair at a colleagues work shop a few years ago and his 'engineer' condemned a Harrison 1000 amplifier due to not understanding the way these particular Mos Fets work.
If they are faulty, any of the early H&H or Harrison amplifiers are stuffed full of them.


Exicon Lateral MOSFETS - Our Product Range

Hi Jon,

Thanks for you fast respons.

As stated I have a Perreaux PMF-3150 amplifier from 1986 with 6 pairs 2SK135 / 2SJ50 MOSFet powertransistors. As far as I know those MOSFets aren't in production anymore for over 15 - 20 years.
The amp is old and I wondered if (and I did not know that they rarely fail) those MOSFets ever fail or the amp shortens due to my fault (it has only railfuse and main fuse protection) can I use the mentioned Exicons as replacements or not and if somebody already used those Exicons in a Perraux from that era or any other amp that has 2SK135 / 2SJ50 MOSFet powertransistors implemented.
 
I replaced my 2SK135/2SJ50 in the Elektor Crescendo amplifier from the 80ies and they worked fine. I also have seen several GOLDMUND clone working with the Exicon parts (original equipped with Hitachi 2SK134/2SJ49, due to lower rail voltages). If you really have to replace them, profusion plc offers those in a S-version


Here is a text passage from their site.


'The ECF10N20 is a suitable equivalent or replacement for the 2SK135 or 2SK176.
The S version has been tested and graded into colour bands based on the technical spec shown below to ensure close matching. We cannot guarantee a specific colour band upon request but orders will be supplied from the same colour band. If you have a particular requirement, please contact us before ordering.'

That says, you not need to match them for Ugs/Id (current distribution through the MOSFETs).


BR
Günni
 
I replaced my 2SK135/2SJ50 in the Elektor Crescendo amplifier from the 80ies and they worked fine. I also have seen several GOLDMUND clone working with the Exicon parts (original equipped with Hitachi 2SK134/2SJ49, due to lower rail voltages). If you really have to replace them, profusion plc offers those in a S-version


Here is a text passage from their site.


'The ECF10N20 is a suitable equivalent or replacement for the 2SK135 or 2SK176.
The S version has been tested and graded into colour bands based on the technical spec shown below to ensure close matching. We cannot guarantee a specific colour band upon request but orders will be supplied from the same colour band. If you have a particular requirement, please contact us before ordering.'

That says, you not need to match them for Ugs/Id (current distribution through the MOSFETs).


BR
Günni

That's great to hear you have hand on experience with replacement of the 2SK135/2SJ50 with those Exicons.
Thanks for your swift and informative respons in this matter!
 
hi nigel,


does it really make sense, buying test equipment for nearly the same price as the 6 pairs would cost at profusion? usually you can use a tester from china, which costs about €10, or replace the Fets with newer one from exicon, and keeping the removed ones for spare?
 
hi nigel,


does it really make sense, buying test equipment for nearly the same price as the 6 pairs would cost at profusion? usually you can use a tester from china, which costs about €10, or replace the Fets with newer one from exicon, and keeping the removed ones for spare?

It wouldn't if you use the tester once, but I am often finding myself using the tester for matching and fault finding etc.
 
Nigel,


fully agreed with you. I also use my tester (AVR china clone) most time for checking devices (resistor, capacitor values, transistors (sometimes for matching).
If you want to measure power MOSFETS, you need a source delivering about 1A. This is only possible, if you use a mosfet checker, like publisched by Nelson Pass or David Hafler). For matching POWER MOSFETs, the suggested PEAK ATLAS DCA is not the ideal equipment, it only can give you the basic iformation 'go or no go' I think the Perreaux needs matched MOSFETs, since there are no source resistors implemented in the design.



BR
Günther
 
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