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HYBRID POWER AMPS


PRACTICAL ELECTRONICS 80W RMS HYBRID 1991
Hybrid power amps are an attempt to combine the best qualities of valve pre-amplification with the ease of a solid state output stage. Unfortunately most commercial designs of this type are usually compromised by over complex design and capacitive coupling. This inevitably leads to poorer performance. The HA1 moscode amplifier uses a relatively low operating voltage and direct coupling throughout.
 
It has the same transparent midrange and treble as the best valve amps but features a mosfet output stage which is easier for the valve to drive and delivers a solid non waffley bass response.

Large numbers of this circuit were built in 1991 when the design was first published. Now the circuit has been revisited and revised to incorporate higher quality parts. Based on an EL34 driver valve and new horizontal audio grade Mosfets the kit will be offered again from this site.
 


ETI HYBRID POWER AMP

ANOTHER  real blast from the past. This circuit and accompanying kit also sold  well  and generated a great deal of interest. Using a transistor driver stage directly coupled to a pair of EL34 operated in push pull to give a genuine 45W rms/channel with a bandwidth of 30Hz-50kHz and a thd of less than 0.25% at all levels below clipping. An extremely simple circuit recomended for the beginner.A enhanced kit for this amp will be issued shortly.

The CIRCUIT DIAGRAM (JPEG) DOWNLOAD