Rectifier Tubes 5AR4 : New production vs NOS


I am currently using a 2005 Cary Audio SLI 80 signature integrated amp. I had been using a new Electro Harmonix 5U4 rectifier tube, but recently was able to try out a new SovTek 5AR4. I was amazed at the meaningful sound improvement a different rectifier tube type can have on my amp. Now, I am considering investing some $ in NOS 5AR4's in the hope that will improve the sound further. However, my assumption had always been that the biggest impact NOS tubes will have over new tubes are in my preamp & driver tubes (6922 and 6SN7), since for these tubes are in the path of the music signal & they were much better made back then than the current production tubes. Would love your thoughts/experience on whether there would be much of a difference between NOS vs New 5AR4 rectifier tubes?

If there is already an extensive thread on this topic - pls point me to it, i haven't found one yet or i might just have missed seeing it online somewhere.

Thanks for your help.
I switched from a new Sovtek to a used old stock real Mullard made in the UK 5AR4 and it makes a solid difference. The Power tube can improve weight and a more solid feeling through out the whole range.
The rectifier will have a profound impact on the sound of your amp. Mullard GZ34's, manufactured in the Blackburn plant, have a well earned reputation as the best sounding and longest lasting.
I have had excellent success with new production cryo'ed Gold Lion 5AR4. For the most part, I like them as well as the more common Mullard Blackburns from the 60's. You can get the GLs for about $40-50, a substantial savings over NOS Mullards. As Rodman said, the rectifier will have a profound effect.
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I also agree the rectifier is important.

Mullard 5AR4 have set the standard for both sound quality and reliability. Look at how many are still in use, and the prices they command.

Based on Marty's recommendation, I may give the Gold Lion's a try. So far, for new production, I've tried Sovtek, JJ, and Shuguang. As usual, skip the Sovtek. JJs sound great, and a good choice if you don't want to pay for Mullard sound quality. I just wish they were more durable, as they easily arc over, then it's time for a new one. Shuguangs don't sound nearly as good, but have proven exceptionally rugged.
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I agree with the Gold Lion tube. Also Music Full Music 274B if you can swap that one?
Thank you for all your responses to my question - very informative and helpful!

I have a follow up question - i've heard that the 5AR4's provide a higher supply voltage to the rest of the amp circuitry since the voltage drop across it is less than the 5U4's. Hence, I've been cautioned against using it since it *might* operate some of the downstream components at or higher than their ratings. Anyone had issues with the 5AR4's?
Longinc, It is always best to check with the manufacturer when substituting a similar tube for the specified variety. Some say the slow start up of the 5AR4s can be easier on amps than the 5U4s.
I use a Philips 5AR4 in my Modwright LS100 and very satisfied
Marty, those JJ 5AR4 really do sound outstanding. Probably not as good as the Mullards, but at 10% the cost, pretty close. And, you know when you buy a new tube, it's actually new. But again, their threshold of arcing over sits disappointingly low. Far less than the Mullard and Shuguang tubes I've tried. Maybe it doesn't become a concern in amps outside of my Dyancos and Quicksilvers?

Like you, I'm a fan of the JJ E34L. Most high-end audio tube sellers skip them over (I've now come to realize that they've never actually tried them), but I also find their standard EL34 unexpectedly good, and a more balanced tube overall. In the right amp, biased correctly, the E34L can produce truly glorious midrange, which their EL34 will not. It's a vanilla and chocolate thing as to which I like better, and when. However, unlike most people, their KT77 doesn't sound as good as either of them to me.

274B are good rectifiers, but a different animal sonically and dynamically. I know that many prefer this and the 5U4G, and they can provide a romantic landscape, especially in an amp featuring 300B output tubes. But usually, I find them too soft and slack for me to live with compared to the far tighter and punchier 5AR4.

I trust Facten regarding the Philips, he knows his tubes.
Now I have not heard all 5ar4 tubes, but when I switched from stock rectifiers to the Philips miniwatt, it was night and day. Many have agreed also.

This was on the Cary SLP-05 preamp.