For me, the Philips 5R4GYS was highly detailed, but gutless. Almost no bass. It was my least favorite rectifier in the Decware amps.
Let me cut-and-paste my personal notes from this year... OK... got it...
Now presenting my personal "Rectifier Rolling Roundup" (using CSP2+ with HD800):
Note: All tubes ranked WORST to BEST. All opinions are my own 2c so no refunds or guarantees final sale only yada yada. I broke them up into tiers which represented notable jumps in sound quality.
And now... the RRR:
Tier one: Not ready for prime time
Philips 5R4GYS - Very detailed but not especially sweet. Weak bass. The prototypical sterile/cerebral magic-destroying tube experience. Blech.
Shuguang (stock tube) 5U4G - Decent all-round, but not remarkable in any particular way.
RCA brown base 5R4GY - Strong unfocused bass & lush midrange. Has some personality but way too sloppy and bloated.
Tier two: The steely trio
Sylvania 5Y3GT red lettering - Excellent sparkly detail up top, but suffers from that Philips-esque steely/lack of lushness/soft bass tradeoff thing.
Tung Sol 5Y3GT - Superior to the Sylvania w/slightly better bass but again a bit too flat and sterile. Voices lack the magic. Sort of "hi fi" sounding.
Bendix 6106 - Similar to the Sylvania & Tung Sol. Good range but again too steely for my tastes.
Tier three: Competent, but unremarkable
RCA 5U4G black base - The lushness is back. Good top-to-bottom control. But otherwise... meh.
Sylvania 5U4G - Very similar to the RCA 5U4G above. A bit darker.
Tung Sol 5U4G - The best of the cheap 5U4G's. Better balanced than the Sylvania above, but still unmemorable.
***you are now crossing the DMZ Line of Recommendation***
Tier four: I could live with that... if I had to
Valve Art 274B cryo - Lively soundstage, a bit bass-light, but not sterile. The first cheap & good tube I'd recommend.
Mazda 5Y3GB mini coke bottle - Another step up… I think? Neat-o heater & bottle design!
Sylvania 5Y3G mini coke bottle - Similar to the Mazda. A smidge on the delicate and distant side. Resembles a "polite USAF-596".
Brimar 5R4GY - Not the final word in sparkly detail. It's a bit too soft on top, but the pumping bass is well-controlled and the midrange is just gorgeous. A bit of a specialist but what it does, it does well.
USAF-596 - It's "all there". Very detailed, top to bottom, with no glaring weaknesses... save one... it has a subtle "lifelessness" to it that I just can't abide. Like the slightest hazy veneer on an otherwise perfect car wax.
Tier five: The ones I kept
RCA 5Y3GT - Amazingly cheap yet it ROCKS w/solid bass presence and response up and down the spectrum. It lacks that final n'th of detail, but it's hardly a dealbreaker. It's got "the tone"... lots of personality here. This was the tube featured at the Austin 2013 meet & was very well received.
EML 5U4G meshplate - Yeah, it's the most expensive of them all, but also the best I've heard. My newest (and likely final) rectifier selection. Delivers maximum detail without giving up any of that lush evocative tube magic. The only ding I could give it would be how the RCA delivers a smidge more satisfaction when it comes to slammin' gut-level bass. But the EML isn't deficient by any means. Its finesse is what ultimately carries the day. Needs to warm up at least 30 minutes for maximum effect. $$$ and fragile, but a worthy upgrade for the CSP2+ in my opinion.
Happy rolling & hope it helps!
Got the RCA yesterday,and you already know,I have the EML,but,
I have no amp,in for re-certification
Will do a a/b test ,as soon as I get the taboo back.
I'm alittle surprised on your take with the ValveArt 274B??--just my .02's though-different tubes for old cryoed ears ,like mine.