question of soundstage

Soundstage is a test you should use to evaluate an amp.  Cayin is not a high end tube amp and it isn't surprising for it to be outperformed.   My guess is that it is PC board based rather than point to point.  but that is speculation.

I'm not knowledgable on sugden, but they claim to be hand made in the UK for many years so that would point toward quality.

Jerry

I have Sugden Mono blocks, Before that I had the Sugden SPA-4 power amp. Same huge soundstage.I have a Sugden IA-4 in the basement,on my second system, same quality. Could be part of the Class A, or the synergy with the other components as others have stated.

I had a Krell FPB 600 hooked up to an ARC Ref 6 SE. I then upgraded my Krell to the ARC Ref 750s. Huge difference in sound stage. Soundstage definitely comes from the amp imo. 

different tubes have different characteristics even the same numbered ones. For example, the Sylvania Chrome Domes are not as side as the Linlai 6SN7 tubes in our preamp.  .Same goes for preamp vs amplifiers.

....and I've been subject to the delusion(s) of 'sound stage' (the perceived width x 'location(s) of performers/instruments') is more a function and/or 'synergy' 'twixt speaker types/room placement/room response...And the 'mixdown' of the applied musical selection...

Whereas, the electronics and the medium from which the selection is applied is (or ought to be) +/- a 'non-participant'...

I'm willing to accept and allow a %tage for LP's and 'physical media' of it's type....*s*

Devils' Advocate Hour.... ;)

Your equipment, cables, et all....ought NOT to add 'color' or 'warmth', which has already been and chided over as being terribly....subjective...*gasp!*L*