Line-out vs Pre-out

[lowell]

is there a difference? Is the line-out from the output stage and the pre from before the PI?

[Enzo]

Depends on the amp. If there are both on an amp, I'd say yes. if you only have one or the other, I would check the schematics to find out what they did.

[lowell]

Enzo, if there were both on an amp what would the difference be?

[d95err]

Preamp out would be taken from between the preamp and poweramp. This is usually the same as "FX Send" if the amp has an effects loop.

A line out can be anything, depending on the amp. In DIY tube amps, line out is typically taken from the speaker output, i.e. after the poweramp. This means the sound will include

If you have an amp that gets it's distortion mainly from poweramp distortion, a preamp output is not very useful, while a line out can be useful for recording.

Modern amps that creates their sound mainly in the preamp, and transistor amps usually take the line out directly from the preamp. Sometimes, speaker simulating circuits are added to enable direct recording.