• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

SS to drive 300b


Disabled Account
2015-10-18 8:00 pm
I tried before the SS follower with IRF, the sound was in the middle from tube to Solid stage amp. One week ago I listened the Nagra 300p who drive the 300b with SS and I liked it, in this case we don´t need to think in the preamp tubes all effort go to the beam tubes and OPT transformer.

My first idea:

Voltage gain . LND150

Current gain. SS follower: IRF720 or FDPF5N50FT ( I have in stock both )

Who have tried before or listened similar configuration.


Paid Member
2004-09-17 12:16 pm
IRF720 or FDPF5N50FT

Vds Ciss Coss Crss
IRF720 400 410 120 47
FDPF5N50FT 500 650 88 7.5

I tried theses as source follower to output tube/s/:
2SK2700 900 750 70 10
2SK3564 900 700 75 15
2SK3566 900 470 50 10

the best of
AOT1N60 600 160 17.5 2.2
C2M1000170D 1700 200 12 1.3

p.s blog motor remove paginations. :-(
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