5751 tubes in Herron phono

Has anyone tried a 5751 tube in the Herron VTPH-1 Phono.

I put in a Valvo E81CC '66 tube and it sounded so much better than the stock tube that it became a close call to which was better, my EAR 324, or the Herron.

Will the X7 replacement continue this trend?
I know from corresponding with keith that each tube is used a bit differently so you may get way with not changing all four. That said, I wouldn't do it unless you change all four since your going to create an unbalanced picture sonically.
Yes I have. My favourite combination is:

Brimar 12AT7 black plate
Tesla ECC803s x2
GE 5star 5751 triple mica x2

This produced the best mix of detail and warmth/body.

I’ve also been thinking about trying 5751’s in my VTPH-1. Frank Van Alstine used them in his PAS-3 mod, citing it’s superiority to the 12AX7. The 5751 is a little lower in gain and a little quieter, in general, than the 12AX7.

The EAR 324 is not the budget tube EAR phono amp, but the rather expensive ($6k) solid state one.