TECH F5, F6, ALEPH J

Some words about the output stage of the ALEPH J2 amplifier.

 The sense of similar schemes is the elimination of class-A shortcomings: inefficiencies, huge power consumption, parallel transistors … In other words – small idle current (1,3 - 2A) is sufficient for a SE amplifier up to 50-100W.

 The existing SRPP topology has considerable advantages over the previous version of an active CS. The simplified charts show the changes.

  Work in LF is improved. The output cascade turned into DC-stage - there are no capacitor connections. Absence of the capacitor gives other sound’s benefits. Efficiency also has been increased - two consecutive resistors disappeared. The SRPP stage a big step forward.

 I want to believe in existence of further steps. So I just do it! In the ALEPH J KIT I give you the chance to get one more improvement of similar topology. Let's consider the work of the traditional SRPP cascade. Load - 4 Ohms, output voltage - 20V, F - 500 Hz.

Work of the scheme is well visible - the top transistor has a sharp cut-off, with the corresponding consequences in operation of the lower transistor.

 Here is the improved version of the SRPP. Load - 4 Ohms, output voltage - 20B, F - 500 Hz

  Now both transistors work in a class-A. 

 

 Here is the actual operation of the amplifier with the traditional SRPP stage. The current cut-off occurs at very low powers.

Improved SRPP.

 The real sample is tuned very conservatively. Nevertheless, the top transistor remains in a class-A. The result is reached without exotic semiconductors. In the presented sample I use ordinary IRFP.

 The offered ALEPH J KIT allows using both SRPP topologies – classical and improved. Also you have opportunity to regulate work of the top transistors.

Mike P.