Now, I'm confused.

I've setup quite a few pair of Vandersteen 1/2/3 series of speakers.  IMHO, the most crucial setup aspect is the TILT back.  This time aligns the speaker drivers to your listening position.  Get this right and set just a smidgen of toe-in and you'll get a pretty decent soundfield.

I agree with the few above that you could upgrade most of your gear.

By simply changing the fuse in my Bryston pre-amp to a SR Blue the sound stage improved; how much?  I don't really know, but it did improve and for only $150 

+1 1Graber and others.

I totally believe changing the preamp -- and perhaps the amp -- will give dramatic sonic advantages. Not familiar with Vandersteen speakers, but am sure people who commented above are right.

Oh, yes -- a cartridge change always offers huge possibilities for improvement in sound. What do you currently have?

What kind of budget do you have?

G

"I doubt changing the preamp will give you a wider soundstage"

Wrong!

The NAD's always sound too dark and confined to me. The GFA555 is capable of a very nice wide sound stage indeed. If I were the OP I would find a GFP565 this is a great sounding pre amp and they cost around $300 used. Sold new for $800 and it has a great phono section too.

Matt M

I too wonder about the Nad, but also how it combines with the warmish sounding Vandys.

the OP is hoping for a bigger sound stage but doesn’t say anything about his cables.  Some clean open sounding speaker cables might be just the trick.  I’d suggest Morrow Audio in this case, they have good silver content.