2SK135/2SJ50 history

[latala]

i can remember going to an audio fair in London during the Late 70,s 77 I think and being introduced to the Hitachi mosfet hma 7500 power amplifier the origional model was silver fronted
At the time I ordered for the company a unit with the matching preamp !
When delivered it turned up in black
What a sound it was the finest amplifier we had ever heard at the time .
well thirty years have gone by and I still have 1 and its stilll one of the best amps around
to list it features the lateral mosfets
Dual power supplies
seperate power supplies for the voltage /current sections
All in all a great amplifier
Yes and fitted with 2sk/2sj devices
I have many amplifiers in my collection but rate the power amp as 1 of the best
Moving on to the preamp What a load of garbage !!!!!
They must have had seperate design teams and only met at the end of the production cycle
regards Trev

 

[miklos]

Right on. Me remember to ,reading in a Swedish audio magazin at the time a test report about that Hithachi amp. The reviewers said the same thing as you, they never heard an amp as good as this Hitachi. If one of these amps comes up for sale on the bay ,it allways fetch good money.

 

[revintage]

It seems like the plastic 2SK1058 and its complementary has exactly the same specifications as 2SK135/2SJ50.

 

[miklos]

yes, as far as I know

 

[AndrewT]

Max Tj/Tc maybe different between the plastic package and the hermetically sealed To3 package.

 

[PigletsDad]

Adding to Zero Cool's list of amps, the NZ-made Mclaren 801, 702, 902, 703 and 903 power amps.

There was also an integrated amp, but I can't remember the model number of that.

At the time, they were a competitor to Perreaux.

 

[IanAS]

Where to get K135 and J50

I just bought some from RS Components.

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0299660

 

[IanAS]

I wonder how many of them ended up like this one from a Perreaux 3150.

 

[mlloyd1]

WOW!

was that a real 2SK135?
i was using those for years since 1981 and abused them in all kinds of ways as i was learning about them. i only destroyed 4 by accidentally applying 65V gate to source voltage. 😱 😱
none of mine ever opened up like that!

mlloyd1

I wonder how many of them ended up like this one from a Perreaux 3150.

 

[IanAS]

Yes. When I measured them unpowered in situ, it was shorting gate to source and pulling down the other 5 gates.

But still playing OK for a couple of weeks. The owner hadn't noticed anything was wrong.

Until he noticed one cold heat sink which gave him the clue that something was not as it should be.