Modwright PS 9.0 and 9.9 Power Supply Rectifiier Tubes


After extensive listening to more than a dozen different rectifiers, I concluded that my Phillips 5R4GYS, 1949 RCA 5U4G, and 60's Mullard GZ32 5V4 were superior in the PS 9.0 and 9.9 to any 5AR4/GZ34 I have tried including NOS Mullards and the Phillips metal base 5AR4. The RCA 5U4G and Mullard 5V4 are pretty close in sound quality, and both are more articulate and natural sounding than the Phillips 5R4GYS. I also picked up an NOS 1944 Tung Sol 5U4G (not the 5U4GB) which by a small margin (lower noise floor) was the best rectifier tube I had heard in the Modwright PS 9.0 and 9.9 until the new Sophia Electric blue 274B arrived in today's mail. This special 274B is designed to be a direct replacement for the 5U4G (and substitutes). I started listening to it in the PS 9.0 and right out of the box it produced the most natural piano tone I have ever gotten from my system. With about 30 hours on it I am comfortable in saying that it is the best sounding rectifier that I have ever heard in the PS 9.0 and 9.9.

Jeff Day has reviewed this tube for Positive Feedback and on his "Jeff's Place" blog for anyone who is interested.
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@cellcbern,

thanks, I just ordered one for my PS 9.0
I have found the Sophia a tad bright on my Modwright Sony SCD 5400es.  Very open with beautiful stage depth, but a little too high frequency tilt.  I recently replaced the SE with what I believe to be a late 50’s Amperex.
I replaced the stock Sovtek 5AR4 with a new production cryogenically treated Gold Lion rectifier.  Also placed a Herbie Audio Lab rectifier damper on it.  Sound is very clean with smooth treble, tight bass and open soundspace.  Not comparing my experience to your's @cellcbern, but so far I'm enjoying the sound with the G-L's.
OK, just got my tubes in from Sophia Electric. Richard talked me into trying the EL34 tubes as well. I told him I just want a rectifier tube but he said try them and then send them back. Ha ha, I will not be sending anything back. These are the absolute best new production EL34 tubes I’ve ever heard and after a little break in might best my NOS Mullard XF2. I know this is a PS 9.0 rectifier thread but I had to mention it and I haven’t even installed the 274b but it’s next.
Thanks cellcbern....just saw this thread.  I've been using the GEC U52 in my PS 9.9 with the best results of all the above mentioned rectifiers....coincidentally this evening I just ordered the Shophia Aqua 274B.  Looking forward to getting it Saturday....so much for my plans on running in the WE 422A.  I'll post my results next week.
Thanks
Hello all,
I have had the opportunity to put just over 100 hours on the new Sophia Aqua 274A and tonight spent several hours listening to a variety of my reference cuts....the 274A is a very nice tube...huge 3D soundstage, great separation and layering.  I would call it on the warm side of neutral and perhaps just a tad rolled off in the HF....not necessarily a bad thing.  A very "tubey" presentation.  I liked it alot, but after many trials back and forth, it simply can't match the detail and refinement of the GEC U52.  It's simply more tonally accurate, more focused.  The vocals are unbelievably realistic.  I've run most of the highly regarded rectifiers thru my PS9.9, including the Western Electric 422A, Mullard Metal base GZ34, Mullard GZ-32 & 37 , Might 596, early TungSol and RCA 5U4G, Phillips 5R4GY & RCA 5R4GY.  The U52 bests them all at least in my rig to my ears.  Just a great blend of detail, accuracy and warmth...YMMV, but if you ever get the chance to snag a GEC U52 at a decent price you might want to give it a try...
Happy listening!
It took a while but I found an NOS GEC/MWT U52 5U4G.  After extended listening I find the Sophia Aqua 274B to be a little bright in my Modwright PS 9.0 power supply, and soundstage depth to be a little lacking. The U52 is more midrange centered, has superior tone and timber, and expands the soundstage particularly front to back, compared with the Aqua 274B.  It is the best rectifier I've ever heard in the PS 9.0.  2nd best among the rectifiers I tried in the PS 9.0 was a 1940's military Tung Sol 5U4G black plate.       
I like the Sophia's... Bettered the Phillips mentioned above.. Then I tried a late 1950's Mullard fat base rectifier tube.. Beats them all !!  They're not cheap.. About $250 on Brent Jessee Recording's website..