Cascaded Amps

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Hi!

I found somewhere the attached schematic and I would like to know about it a bit more....
Is there anybody who know this amp?

Greets:

Tyimo
 

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The 2SK77 was made by Yamaha and used in the B1 amplifier, a 150W/8R class AB push-pull unit.

They are un-obtainable, and were a non-standard case style.

It would be possible to cascode the Lovoltec power J-FETs and duplicate this device.
 
Hi DJK!

Thanks for the infos, but I know them already, because I am coming from the Pass forum too. :)

I was asking about the attached schematic from me and not about the B1.
I meant with my question: is that schem realy an existing amp or only a theoretical plan?

Greets:

Tyimo
 
Hi Tyimo!

That was from Michael Kosarev:

http://www.k-amps.8m.com/circuits.htm

I don't know if it is a real amp, I think not.

The FETs were only available as a replacement part for the Yamaha B1 amplifier, only made for a few years in the mid 70s. I was an authorized service center at that time.

The 100W/8R rated B2 used the smaller TO-3 case FETs. Yamaha told us they lost money on the sale of every B2 at $850. The replacement cost for a set of FETs was around $250, and they came mounted on the heatsinks.
 
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