Looking for 5AR4 rectifier tube most like solid state

I very much doubt that voltage sag is the problem with a preamp. I have compare 866a tubes with 3b28 tubes, (which only drop about 15 volts and have great regulation) and they sound different, so it can't be voltage sag.

boxsoft

First off, (before you buy anything) do yourself a favor and reach out to Brent Jessee at audiotubes.com, he is the most knowledgeable and best tube supplier out there. He can help with recommendations, and probably has experience supplying tubes for your equipment.

Great tubes are expensive. I can highly recommend the NOS Philips 5R4GYS, and the NOS Mullard GZ37....if they are compatible with your gear. The Philips is magical, and the GZ37 is really close

As others have mentioned, in most gear the 6SN7s have a greater impact on SQ. For NOS tubes (and I can recommend) the 1940s Sylvania 6SN7GT/VT-231 "Black Plates",  and 1950s Sylvania VT-231 "Bad Boy" tubes......both of these will cost you $250 to $300 per pair.

For new production, my favorite is the Linlai E-6SN7s. They can be found for $155 per pair at jjyaudio, which is a very reputable Chinese supplier

First of all, I used a Cary SLP-98P for a couple of years but I got tired of the thick, sluggish sound. I now use a 6SN7 Aikido preamp of my own build, very similar to what Don Sachs was providing before he retired from that business and moved to Spatial Labs. That in turn was based on the Tubes4HiFi SP14 octal Aikido preamp. The Aikido circuit is much "faster" and more transparent than the Cary, plenty of rhythm and pace.

Secondly, I would NOT mess with solid state replacements or different types of tube rectifiers at the risk of voiding your Cary’s warrenty or worse, damaging it. IMHO the Cary sound is determined by the way they configure the 6SN7, and also the type of output caps they use. A lot of folks like that sound but like you, I found it unsatisfying, especially once I heard the Aikido-style preamp.

You COULD try a genuine Mullard GZ34. They tend to be "faster" and a bit more lively on top than most others. A current-manufacture Chinese or Russian 5AR4 will, IMO, NOT get you what you are looking for.

If you want to keep the naturalness and linearity of the 6SN7, I’d suggest a used Don Sachs SP14, or the Linear Tube Audio MicroZOTL or the new Velo, if that’s more within your budget. Also look at the Icon Audio Pure Valve. Another option might be the Black Ice F360, which also uses the 6SN7. That’s my .02. ;-)

ETA: I forgot to mention that the Tubes4HiFi SP14 is still available, and at a very good price. It’s not as tricked out as the Don Sachs version, but it’s a VERY good preamp for the money, one of the great bargains in high-end audio IMO.

Thanks, all, for your recommendations! I’ll start with that NOS Mullard, and decide whether to continue and swap the driver tubes, or to give up and move to another preamp.

FYI, the Mullard is an F32 4 Notch dual halo GZ34/5AR4, Coded F32 B3C1 (Translates to Blackburn plant, 1963, March, 1st week).

I've had a SLP05 for a few years now (at least three, if I remember correctly) with the Ultimate Upgrade, and I love the sound of mine.  I'd go so far to say as it may have been the most significant upgrade I ever made.  Unlike you, I am not finding mine to be sweet/warm/colored . . . if anything I find it to be a tad more neutral than I might like, but the detail and imaging I hear with it in my system makes up for that (for me).

I have rolled a few rectifier tubes and I, honestly, cannot say for sure I heard any difference.  I've had a Mullard 5AR4 in there for a while now.  The tubes I've heard the biggest difference with are the two balanced input tubes.  I've had a few I liked (a pair of KenRads a generous individual bestowed on me) a pair of Tunsol VT231s I liked a lot, I loved a pair of black glass RCA VT231s for the precise detail that I thought they brought out.  At the moment I have a pair of "'52 Sylvania Bad Boys" (6sn7s)  (that were described to me as the "Iron Fist") in those sockets and as of now they are my favorites.  Another generous individual turned me on to those two Sylvanias  also gave me a pair of National Union 6F8G that he described as "The Velvet Glove" and I like them, but for different reasons than I like the "Iron Fists."  If  you decide to try 6F8Gs, you will need adapters.

Good luck.  I hope you can get that pre to do what you want it to do for you.  People have different goals and expectaions from their gear, and, as I just typed, I hope you can meet yours.