Equivalent transistors

[juoto]

Hello!

Does enybody known equivalent transistors to 2SA634/2SC1096?
I am building an amplifier from next link:

Jean Hiraga's Super Class-A Amplifier

Thanks!

 

[Tekko]

BD139/140 or MJE340/350.

 

[AndrewT]

These two alternatives are so different in their characteristics/parameters that they cannot possibly be equivalent.

 

[juoto]

Can anybody help?

Can I use 2SA634/2SC1096 as drivers and 2SA1943/2SC5200 as power transistors?

Juoto

 

[AndrewT]

I don't have data for 2sa634. I suspect not many Members have downloaded that data.

 

[jez]

MJE15030 and MJE15031 would be excellent substitutes.

 

[embrown057]

Sub's

You can go to the B&D enterprises site to download the data sheets for the 636/1098. I belive they have stock on them.

2SA636

 

[mjf]

my comparison table says:
2sa634 pnp af-s-power uc=40/30v ic=3a ptot=10w at 25celsius
ft=55MHz current gain = 40...250
and i found this:

http://www.datasheetcatalog.org/datasheets2/49/49053_1.pdf

 

[triode_al]

What I remember is important, is the constant Hfe, and the BD139/140 have that.
And the Cob of the 2SA634/2SC1096 is selected to fit the output pairs. On that I cannot comment as it is trial and error for Hiraga.

Hiraga writes in 1980:

These transistors, NEC 2SA634 and 2SC1096 allow, coupled with the output transistors 2SA649 and 2SD218, an optimum combination. The only regret is that this complementary pair of power transistors is not manufactured any more. Giving the 50W class-A Kanéda amplifiers (connection in parallel) the best results that one can have, these pairs are now replaced by the 2SC188 and 2SA627 which are fortunately of very similar quality.

So I doubt if current vendors have them - I would call that fakes by definition, not even replacements.
Same specs is not same sound by default. . . just to spoil the game, I'm sorry.
albert,