Modwright PH 9.0X Tube Rolling Question

Kristen did mention that the 5AR4 has the lowest forward voltage drop - I assume it just means more output DC voltage. Presumably this makes it possible for the unit to deliver the full spectrum of audio frequencies and hence sounds more dynamic. I still badly want to try the RCA Double Getter 5R4GY - they are supposed to rival the WE 274Bs. But I am still concerned about the wide base of the 5RrGY tilting one of the ceramic resistors. I got an email from Mod saying the tilt is fine and I should ptobably trust them. But in all my years of using tube gear - never have I seen any component touch each other with the exception of shielded wires.  Still curious if others had similar issues with this particular tube rectification mod. Please share

I had Dan update my PH9.0 to a 9.0XT. In my pro calibrated audio system (modest)

and using a Pro-ject Xtension10 turntable with a Soundsmith Paua ES cartridge, I found that without question and  in my system that for 6922/e88cc  tubes, Valvo and Philips SQ miniwatt (same tubes from Heerlen plant in Holland 1960s) sound the absolute best and even better with Herbies Rx rings toward top of tube. There sound is about identical with maybe a very small dose of additional extension with the Philips SQ tubes. These are audibly very well balanced tubes with most holography, projection, texture and tone. Only Siemens tubes came close. Other tubes didn’t quite cut it and had too many shortcomings. They were Amperex Holland (7308 with surprisingly small soundstage) , Amperex JAN USA Cryo tubes ( 7308 soundstage weirdly very tall and sound a bit off) , nos Bel India E88cc ( not bad actually) nos Mullards ( not extended enough but good tone) current production Gold Lions (meh), Valvo PCC88 7v nos tubes ( similar sound to Valvo and Philips E88cc but a bit brighter and less full sounding, but still good tubes for this phono pre)  and nos Philips JAN green label E88cc tubes ( dull). Alll tubes were measured near nos or better when purchased.

My tube of choice for the PS is Raytheon (Japanese made 1970) 5AR4 tube. It has the smallest voltage drop and sounded the most correct vs an RCA 5r4  big bottle (way too warm) and an NOS 5ar4 Mullard that everyone raves about. The Mullard sound signature was somewhere between the rca and Raytheon but wasn’t quite extended enough. I was reaching for highs that weren’t quite there. The Raytheon was closest to solid state but with just the right amount of tube goodness. The stock Sovtek tube is a good ( slight grain)  starting point but doesn’t quite deliver like the Raytheon. I could live with it and  I’d still choose it over the Rca or Mullard. I suppose the Mullard would be good in an excessively bright system. The NOS RCA is simply too warm. A Herbies Rx ring for the Raytheon took it up another notch when placed toward top of tube for better focus. This is my conclusion after much experimenting with a variety of nos tubes. 

@hifi59 ...Nice write up.

I recently pulled the 6922 Reflectors and put a set of Voskhod 1975 6N23P Rocket Logo SWGP Grey Shield`s in and they are going to stay put ! Highly recommended

@scm Agree the Reflektor in the 6922 spot is not great. The top end leaves one wanting more. However, I do highly recommend the Reflektor 6C45 if you can source them. They are much better than the stock Sovtek. I ended up selling a pair to the thread starter, @ericsch, who might be able to comment on those. 

@blisshifi the tubes that were replaced were actually Reflektor 6H23N-EB`s no less.

The Reflektor 6C45`s are in there already 👍