[Doktor bob]

This is a power amplifier i bild 5 years a go.
it measers as follows :
Uout 14V 20hz    0,30%      25W bij 8ohm
Uout 14V 1kc    0,90%      25W bij 8ohm
Uout 14V 10kc    1%      25W bij 8ohm
Uout 2,8V 20hz    0,08%      1W bij 8ohm
Uout 2,8V 1kc    0,02%      1W bij 8ohm
Uout 2,8V 10kc   0,03%      1W bij 8ohm
         
R.out 20Hz tot 20kc    0,45ohm      df =18 bij 8ohm
10V 8ohm    10hz -0,4db  tot 200kc -3db      
         
28db (0,6V =14volt out)   

it is stil in use by a freind of mine in combination with Ariel (lynn olson)   
         

[JakeJ]

Welcome to AC, Doktor bob.  Output transformerless?

[Doktor bob]

Well yes, it is output transformerlles in the sense that there is no transformation off impedance.
The best way to describe it is i think as two coil loaded source followers.
The nice thing is that if you take one core fore both off the coils and connect them in opposite phase you dont magnetize the core white dc.

[Doktor bob]

This is the schematic off the supply and dc protection .
There is also a temperature switch off protection (Tc)

[Doktor bob]

 A few images of the seb amplifier