What does a FET driven amp mean?

ErictheRed

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A FET is a type of transistor, it stands for Field Effect Transistor. You hear the word MOSFET a lot too, which stands for Metal Oxide Semiconductor Field Effect Transistor. Basically they are transistors that turn off or on based on an applied electric field (hence the name).

Like any other transistor, they can be used to clip a signal or can be used as amplifiers. You can have a tube amp that uses FETs at the front end to add clipping and/or gain (which is basically like having a built-in Tubescreamer or similar), or you could have an entire amp made of FETs, which would be a solid state amp.
 
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Lhdr

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Ahh thanks, That explains why I’m hearing low volume breakup on the Supro 1x12.
 

dspelman

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Ahh thanks, That explains why I’m hearing low volume breakup on the Supro 1x12.
It may or may not.
I've got an old (if 1971 is old) guitar amp that puts out near 200W that has FETs and it's hard to make it break up.
 

ehb

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FETs are voltage operated somewhat similar to jugs from law of charges standpoint...
Standard transistors are current operated..... Very different...

You have to back FETs off to a controllable level. You have to force standard transistors to conduct....

No better no worse.....depends on application/design.... With anything......
A Dirt does not automatically sound better with Ge vs Si... It can, done right, but it is not a given.... Ge starts fwd leaking before full fwd bias a lot sooner than SI.... More sensitive... Easier to slap around...so it 'can' sound different/better/worse....

Circuit design determines where the Spanky Stank starts....
 

eslover

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Back in the day it meant Frickin’ Eliminated (the) Tubes. I’ve come to learn that may not always be a bad thing.
 

THDNUT

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I have a MosValve 962 power amp coupled with a solid state Marshall model 9004 pre amp. It sounds really good for high volume mild to medium over driven guitar. I've never been able to dial in a good clean sound though.

It is just a stereo power amp, with two large FET power transistors per channel output, directly connected to the speaker terminals. There are no output transformers.

Here it is.

 
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