1969 Oliver P502 Powerflex (top)A P502 restoration photo Series can be found on the Vintage-Blue website.
O'Neill B15-100 Bass (top)This blue check clad beauty is Aussie Mark's O'Neill B15-100, a custom designed and built 100W bass amp based on the B-15N. It has a number of useful features including a DI Output, a user friendly adjustable bias, and speaker cabinet impedance selector switch.
CtG electronics FCBN 51B (top)The most recent take on the B15N concept from Keith Carle at CtG electronics. This is Keith's enhanced version of his original FCN-51-B, which featured many of the same design concepts as the Heritage B15, while predating Ampeg's version. Keith provides wonderful documentation of his designs.
More information can be found here.
CtG FCBN 51B
Building an SB-12(top)An SB-12 clone is designed and built here. They use KT77 Tubes in the power amp.
London Power(top)Kevin O'Connor devotes a chapter in his book The Ultimate Tone 3 to the design of a Portaflex clone.
The Flipster Pedal (top)The Flipster is a pedal based on the SB-12. They adopted the circuit topology and substituted transistors for the Tubes. It is available as a kit for those wanting to build one. Love the logo.