Tube Design

Can somebody answer a dummy question what’s the difference if a tube preamp design like the PSA pre is done with 2 tubes only without or with 3 incl. an add. Rectifier tube?

There can be many different circuit differences. One obvious one will be that rectification will be handled by a non-tube device, a diode perhaps, or a solid state rectifier. The different types of rectification definitely influences the sonic character of the preamp. A tube item of course can differ from type and brand, each may change the sound and produce different outputs and distortion levels.

I meant and understood the 3rd existing or non existing tube to be a rectifier tube.

Don’t know what it’s for or what’s the difference if it’s there or not.

Though geared for guitar amplification, I think the information on this page is good at explaining the rectifier, its use and impact.