How Do Amps Affect Soundstage?

Lots of noise above. An eight watt amp can produce an amazing soundstage. "Can" when the loudspeakers are carefully chosen and properly positioned in the room. It is not about power or monoblocs. It is simply a matter of good design and implementation.

Standing waves and room reflection have the most impact on soundstaging and imaging (often confused but different qualities), speaker choice and positioning second, selection of electronics third, and choice of cabling is likely last. Within that third category, "electronics" is source which is admittedly a bit sloppy when the source is vinyl but certainly the cartridge and phono stage are essential and electronic.

@Mossy, that business of the Ref 6 Pre having a badly designed volume control is pure garbage. You have ten posts (Yes, my profile only shows 80 some but I had to change from Fsonicsmith to Fsonicsmith1 due to password problems and have hundreds and hundreds of posts). What is your basis and where did that allegation come from? No need to answer. I don’t particularly care to know.

@mossyrocks I humbly apologize. Now I am going to offend you again :-) but it is Parts Connexion. I don't know Chris. If you told him the same thing that you said above, that

I was finding I could not get the system to 'juice.

Than perhaps what he meant is that the volume control design of the Ref 6 is such that it is the chief cause of a high-ish (footnote here) output impedance. Footnote-the output impedance of the Ref 6 is not, in relative terms for a tube pre, all that high.

The Ref 6 in balanced mode has output impedance of 600 ohms and the recommended load of the amp for the Ref 6 is 20k ohms or higher. In balanced mode the load of your amp is 30k ohm so you don't have a mismatch on paper but it the margin is not great. This would primarily affect frequency response though it also affects maximum power transfer.

So again, yes, the match is not great. But the OP was asking about soundstaging and you SEEM to be talking about power transfer with "I was finding I could not get the system to 'juice.