• 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.

MOSFET IRFIBE20G equivelant?


Can some one please help? I'm working on a project a Tube Pre amplifier that uses these MOSFETs in the the power section. Not exactly sure to what but this part is definitely faulty as the "Gate" is always open. Online videos explain this very clearly!

The part number is this - IRFIBE20G I already ordered some online but they were fake! My partner in crime also ordered some and guess what? Fake!

My experience in MOFESTs are extremely limited, all I know in amplifiers they sound better than "other" technologies :)

Does anyone know of a replacement? There is 2 onboard and only 1 was faulty. Any help in the right direction appreciated!


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2018-08-31 12:32 pm
What exactly do you mean "gate is open"? Is there a dead short from S to D with no voltage applied to gs?

While fakes are unsurprising, what makes you sure they are fakes?

And lastly, why do you need to find any equivalent? It seems the parts are still available through RS components (a legitimate source) for a few dollars a piece.
Sorry my mistake, the gate does not open it just keeps charging up. There is no continuity between S to D.

Still trying to understand this technology!

The other are fake as they dont behave like a MOSFET is suppose to according to online videos.

Again apologies, it seems you are right you can get them for RS! Bit expensive!