Crisp sounding tubes for Modwright 5400ES

I also have a modwright 5400. Wonderful player. As much as I love the Mullard 5AR4, it would be moving in the wrong direction based on my experience. I would suggest you go with a new production Create Audio tube. I found this tube to be less "tubey" much quieter, and more dynamic than the vintage Mullard. I was very pleasantly surprised by this tube. Finding a new production 5AR4 that is in the same class as the rather scarce vintage Mullards is a huge deal. The dynamics might help out with the overly polite character. When I got this tube in the 5400, the Mullard went into storage. I'm not selling the Mullard, but I haven't felt the urge to put it back in either.
I use Sophia's for 6SN7's. Its the only thing I've tried other than the stock current production Tung-sol's. The sophias are a way better tube, but I'm not sure its the right tube for what you are trying to do.

Brownsfan,

Where can I get these Create tubes?

I wasn't aware that Create made a 5AR4 tube? They have the 6SN7 and the 12AT/AU/AX7's, but I've never seen a 5AR4 by them.

Here is a website that sells them:

http://aloaudio.com/accessories/vacuum-tubes/

Solentgreen, I had the same issue with the Sony. I sold it and bought the modright modded Oppo 95. I like this much better. In my opinion it is more open and extended on top and much tighter in the bass. I tried a lot of tubes with the Sony and ultimately was much happier with the Oppo.

ALO in Portland is an awesome store. Bought tubes and my headphones there.