Modwright Oppo 105 - Upgrade Power Supply Tubes?

Thanks to the forum & a post by Mrtennis I upgraded the 6sn7 tubes to 1950's RCAs and am most pleased with the change in sound. In my 2 systems with my 2 ears the player went from digital sterile to nice and musical. I am not a fan of the supplied electro-harmonix 6SN7 that is supplied. Thanks again Mrtennis. And here is my question, has anyone found it beneficial to upgrade any of the tubes in the power supply?

Many thanks.
Bluewolf, you might want to try the new production Gold Lion 5AR4. You can pick one up for about $35-$40, and in my experience, it is better than the old production Blackburn Mullards from the 50-60's that are becoming very rare and expensive.

The new production Sophia 6SN7 is also a very nice tube if you want an alternative to your RCAs at some point
Yes, I use a MODWRIGHT 9.0SE Linestage. The biggest improvement to the Rectifier is a Mullard 5AR4 old stock or NOS.I bought mine from ANDY for around $100.00. Awesome tube :-)
I also run the RCA grey glass vt-231/6sn7GTs on my Modwright Oppo-95. They do not sound good with a Mullard 5AR4 (I have a date code F31 Mullard).... IMO, way too much of a good thing, to a point where it sounds dull and slow.

The Genalex Gold Lion GZ34/5AR4 is a decent rectifier with the RCAs. A rectifier that I personally like better with the RCAs is the Philips 5R4GYS that Upscale sells. I think its around $50. Definitely worth trying.
I have used Both the Phillips 5R4GYS and the Sovtech and the Mullard 5AR4..The Mullard is the one to go with.You see in a 5R4GYS vs 5AR4 , the plates are too close together in the phillips and while this tube will is not a good match for the Modwright 5AR4 driven power supply. Find yourself a good REAL Mullard for around $120. You don't need to run a $350 metal base. This tube will tighten the bass and give everything a little more weight.The phillips sounds bloated and blurry in the low regions.
When I had the MW Transporter, Tung Sol NOS 5u4gb was by far the best rectifier tube. It was musical, bloom, detail ... JJ GZ34 for $18 was also excellent and definitely worth a roll.

For reference, I found Mullard GZ34 too warm and rich for my taste.
An extremely musical combination that I am now using (in my Modwright Oppo-95) is a pair of shorty, chrome dome Sylvania 6SN7Gs (w/ black base, green lettering), and an RCA 5R4GY. Very natural sounding across the board, with a great soundstage, and awesome mids. Nothing seems missing in this pairing.

Sorry, I don't agree with the above statement that a 5R4GY is not a good tube match for the Modwright PS9 power supply!
Black Treasure CV181-T was the BEST signal tube in my MW Transporter. I found Sophia 6SN7 to lean for my taste.
Agree completely with mattmiller.  The Philips 5R4GYS has nothing on the low end on the Oppo.  I spent a year diagnosing what was wrong with my system.  I had never even tried the stock tube supplied by Dan.  I was ready to sell everything off in frustration when I made a last ditch effort and changed out this tube. Magic.  Try for yourself and see.