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.

I would contact audiogon user Fork on the Create audio 5AR4. I got mine from him. It is not unusual to have to wait. Limited supply and
I hear a lot of people really like this tube. Based on my experience I think it might be a better choice for you. I found the vintage Mullard wonderful, but almost too much of a good thing in the Modwright sony.

Wig, Yes, please do let us know. I will be interested to know if you also prefer the Synergy to the vintage Mullard in the ModWright. By the way, what year production Mullard do you have? Mine was 1969.

Wig, Glad to hear the tube is showing some potential for you. At the very least, I think this tube is going to take some pressure off of the vintage Mullard market. I found the tube to be exactly the ticket for the ModWright Sony. People who use a 5AR4/GZ34 owe it to themselves to give the Create tube a try.

Poseschi. The Mullard tube is very good. In my system, the Create was better. I heard none of the bad things you heard. It is possible that the Mullard sweetness has better synergy with the rest of your system or is more to your taste, but the relatively poor performance with respect to spacial clues tells me it is a bad tube. If it were me, I'd ask for a replacement. If you don't like the replacement, I guess you have your answer. I had heard that Create had problems with a batch of these tubes a while back, so it does happen.

Podeschi,you are hearing something much different than what I heard. I got my Create tube last winter and put it into play while it was still cold from being in the mail box. It was really good from the start. It could be you got a bad tube.
My tube did not change significantly with burn in.