Aleph From Hafler

[george a]

Hi all

Pardon my ignorance, but what would be the viability of using mosfets out of old Hafler dh200's (hitachi 2sk134 & 2sj49) for output stage of an Alpeh amp??

I have a few of these transistors lying around and the specified units are not readily available/costly??

Thanks in advance

[joensd]

Hi,
take a look here : my little Aleph3

SK134 140V 7A 100W <1,7Ohm
SK135 160V 7A 100W <1,7Ohm


Jens

[george a]

Thanks Jens


What modifications did you make to the circuit?

[uli]

Originally posted by joensd
Hi,
take a look here : my little Aleph3

SK134 140V 7A 100W &lt;1,7Ohm
SK135 160V 7A 100W &lt;1,7Ohm

Hi Jens,
Just be careful with the 390R in the drain of diff amp
as the Hitachis have a completely different turnon V!
With 390R you get about +4V Gate-Source thats way
too much for 2S...

Uli

[joensd]

He mates, don´t worry!
I´m not building it myself.
Was just remembering the link reading through some threads.
I was actually wondering myself if it will work so well.
Aren´t those Hitachi´s lateral mosfets!?
Will the current source work as it should be with the negative temperature coefficient of the laterals?
Obviously it works.

Jens - always wondering that it works

[sianturi]

Originally posted by uli


Hi Jens,
Just be careful with the 390R in the drain of diff amp
as the Hitachis have a completely different turnon V!
With 390R you get about +4V Gate-Source thats way
too much for 2S...

Uli

Uli,
do you have the datasheet for 2SK134/135? I once had it, but lost it. I search from Hitachi website, but all I've got is 2SK1340/1/2.... which is in different package (not TO-3).

Another thing, is "turnon V" you mentioned above the same as Vgs(off) (Gate-Source Cut-Off Voltage)? I'm looking at Exicon L-Mosfet specs, and they use "Vgs(off)" term. I compare it with IR Mosfet specs, and IR use "Vgs(th)" (Gate Treshold voltage).

Is Vgs(off) used in Exicon specs the same as Vgs(th) used in IR specs?

Thx!

[franktren]

I'm brand new to the forum. I'm seeing questions about Hafler DH200/DH220 amp MOSFETS. Seems that Hitachis are no longer available. I talked with John Hillig of Musical Concepts about the Exicons. He uses them when necessary to repair and will sell them at what I consider a fair price. Saves me shipping from overseas, duty, VAT, etc. He states they are rugged and he has never had a bad one in over two years.
I am installing his latest driver boards in my 20+ year old Hafler, which has already received much updating. The outputs are not bad, but at this age I was nervous about spending $$ if there was a chance the outputs might fail. I'm very happy with John and his product.
franktren