Crisp sounding tubes for Modwright 5400ES


I recently upgraded from a Modwright 9100ES to a Modwright 5400ES. While there were improvements, the richer mid-range and more powerful bottom end of the 5400ES tipped my previously balanced sounding system into one sounding a bit overly polite with a lack if crispness in the top end.
Can anyone advise me on what tubes (output & rectifier) and power cables to chose so as to brighten the top-end.
Grateful for your advise.
solentgreen
wig where did you put the fuse? in the power supply, the transport, or both?
I'm new to the Modwright 5400ES owners club. IME, swapping out the stock Sovtek 5AR4 with a 1965 vintage Mullard 4 notch 5AR4 (rebranded Hammond from Brent Jesse Recording & Supply) made a huge difference.

Adjectives that describe the improvements:
- dynamic
- textured
- bold
- natural
- musical

This NOS Mullard is a keeper.