How Do Amps Affect Soundstage?

Many good responses above.

Anytime an electrical signal passes through an electrical component or circuit or device, it will affect the music.  Be it distortion adding, soundstage, etc.

The discussion regarding the amp (Audio Research REF 6) paired with the Bryston is a great example.

Each device has a manufacturer's recommendation regarding input impendence, output impedance, sensitivity, etc.

If you try to match a pre-amp to a particular amp without paying attention to the manufacturer's technical recommendations, you are asking for trouble.

this is like trying to pair a particular amp to a particular speaker without paying attention to the specifications and requirements.

The REF 6 is one of the best pre-amps made.  I bet it doesn't match well technically to the Bryston amp and the specs probably indicate a mismatch.

Assuming that amps are amps, or pre-amps are pre-amps is the problem.

Of course different amp will affect soundstage.  They have totally different circuitry. Not an apples to apples comparison.

And by-the-way, don't fall for the old solid state vs tube argument.  There are some outstanding solid state amps out there that are just excellent.  Just as there are some outstanding tube amps out there.

I have heard some crappy tube amps and some crappy solid state amps also. Totally depends on the design, construction, circuitry, power supply, etc.  each is different.

It's funny.  I'm a member of a Mopar car club.  You know, Chrysler, Dodge, Plymouth.  I restore classic cars and currently have a restored 1970 in-violet, 340 four speed pistol grip Plymouth Barracuda ("Cuda").  Anyway,  People in my group always hype Mopar and with good reason and talk down about other cars.  I will step up and say loudly, you mean to tell me that if someone gave you the keys to a 1963 Split window corvette you wouldn't take it in a heartbeat?  They all laughed and said absolutely they would.

Tube or solid state.  What ever suits your needs and likes.

enjoy

@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.

In my admittedly limited experience, amplifier soundstaging is most affected by channel separation/crosstalk (hence, all else being equal mono blocks better than true dual mono better than stereo), sufficient real power (voltage and current), and competent design. For a moderate power and price amplifier, see Stereophile and Audio Science Review test results of the Benchmark AHB2.

The more info I have the better thanks

Amplifiers matter because of noise, white noise accumulated through signal conditioning and amplification stages. Dead quiet to loud matters. Tubes, like jfets, and mosfets do not have a lot of current input and therefore have almost zero current noise. Voltage noise can be mitigated relatively easily. The listening  experience that enlightened me is from a Counterpoint Solid 2, blown up, that I fixed and changed minutely to drive, any speaker or simply weld to music. I was completely blown away after getting it going.. I wanted to listen to this thing, testing forever with my elac 6.2 debut monitors. My friend Dave, the amps owner was blown away too. Preamps because of noise, and of course speakers the biggest deal.