FSSA Description

 The FSSA amplifier can deliver up to  120Wrms into 8 ohms in class AB depending on power supply Reducing the Reducing  much as possible the sound signature of the USSA with some differences since it is a class AB (although with medium DC bias). It is similar to the "VSSA-Fab" and "Fab-Four" amps done several years ago but the  FSSA is more simple. 

My main observation regarding the sound difference between USSA (class A)  and FSSA (class AB) Is that USSA is more suitable for jazz, classical, soft rock music and FSSA is better for harder

 rock music since bass is tighter. However, it is not too tight that bass becomes thin as for some other amplifiers. FSSA has also medium and high frequencies with a natural feel and soft too.  

The topology has similarities with other amplifiers such as the Grand Mos of Solectron but the differences should make it a different sounding amplifier based on my experience.

s The FSSA amplifier can deliver up to  120Wrms into 8 ohms in class AB depending on power supply Reducing the Reducing  much as possible the sound signature of the USSA with some differences since it is a class AB (although with medium DC bias). It is similar to the "VSSA-Fab" and "Fab-Four" amps done several years ago but the  FSSA is more simple. 

FSSA-1:

this is a class AB power amp based on USSA-3  class A front end circuit but with follower configuration as output. The bias  is relatively high for a clas AB allowing about 3Wrms class A into 8 ohms. The VAS transistor is a Mosfet for Audio type.

FSSA-2:

this is a class AB power amp based on USSA-3  class A front end circuit but with follower configuration as output. The bias  is relatively high for a clas AB allowing about 3Wrms class A into 8 ohms. The VAS transistor is a darlington BJT for Audio type.

The FSSA amp is still a prototype. Stay tuned for pcb availability for diy. The  same pcb can be used for both FSSA versions.ed