Double EL84 PP mini kit

just pcb 25€/excl vat

complete powersupply for stereo 125€ excl vat

all components incl tubes & transfo for 1 channel 125€ excl vat

Hello to all

This is one of my latest designs , i needed a cheap high quality safe amplifier , so i chose for the el84 with 300 volts on the plate you get approx 10 watts ,

so in parallell PP you get some 20 watts . what is so interesting in this design , is its simplicity , based on my experience with the ppEL34

the circuit is similar except that due to low plate voltages for the first tube i had to opt for a ecc88 , and because of reliability concerns

i opted for cathode bias , which in general i am not such a big fan of , allthough it gives the amp a nice
Warm sound (and it slows it down as well) but this amp was designed for home-theater , it is used for the surround speakers ,

a five channel amp ( front uses PP300B ) and this serves as the rear speaker amplifiers .

If we look at the circuit we see that it is fairly simple ,

The first triode produces all the gain and note it uses local feedback , since it is not decoupled and extra global negative feedback

( think positive ?) , a little feedback makes the amp sound warmer and better (it really does especially with penthodes and when

the transformers & other components are not top quality it helps ))
The second triode is a split load fase inverter coupled to a push pull output stage and then straight into a toroid PP output transformer ,

the tubes are triode mounted because the transformer comes from the PP300B..

The amp delivers 20 watts and has very warm timbre , so its also suitable as you're first tube amp .

 



kit stereo contains :

8 EL84 + sockets
2 ECC88 + sockets
pcb fur jeden verstarker
2 PP transfos eingepot oder nicht
2 powersupply transfo
dale resistors
rca teflon & goldplated input sockets
goldplated speaker terminals
mkp signal caps
all powersupply components
pcb psupply included



 

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