X0 preamp question

[Tyimo]

Hi!

I have a question about the X0 circuit.
I attached the X0's inside picture. There is a section (marked with red line) what is not included in the sevicemanual's schematic but it is on the parts layout!
It has one 2sk389, one IRF9610, one 3.32K-5W resistor, one 100uF25V cap and a dozen of small resistors.
Could somebody tell me what is the function of that part of the circuit?

Thanks and greets:

Tyimo

 

[Tyimo]

Nobody??
Mr. Pass??

 

[macka]

From the description it maybe SE (a single ended output stage.)

Normally you would use the balanced outputs but the SE stage allows SE connection to your power amps.

If you go to passlabs.com diy pages there is a great article on discrete opamps.

 

[rsbay]

It is a balanced to single ended stage build with a discrete operational amplifier with a single ended class a output stage.

Regards

Ralph

 

[Tyimo]

Thanks Macka and Ralph!

I thought it is easyer way to make Balanced to SE like in the BOSOZ....
Is this Opamp something like in the Opamp article?

Greets:

Tyimo

 

[rsbay]

I think the discrete opamp consist of an input stage with a 2SK389 and a current source. The output driver is single ended build with a IRF9610.

Ralph