What improvements would I get with a "better" preamp?

To @billpete - the PSVANE Co on the USA side was contacted by me last year about an older set that had seemed to have lost its luster.  It was determined the tubes were originally made around the time of end of pandemic, with some "known" issues. So, they agreed to replace the pair after me sending photos that I destroyed them [per their policy] with the original box/papers in photos to prove there would be no resale of those tubes. So, these were replaced by the same newer version PSVANE CV181 MKIIs, had something to do with different coating or something, dont recall exactly.  (These guys are are also members on this site, btw) and pop in once in a while. Thew new tubes have been in the front L/R position since.They sound nice for my setup.  

I was not looking for the new ultra-transparent signature we read about in the latest version [other tubes] with different names out this past two years.  I was interested in what they sent [replaced] more of the lush and midrange focused sound these yield vs. uber detail with no midrange body. With my tube systems, I’m not a fan of that type of overly-uber-detail sound. I can get that in my other Class SS amps if I crave that.  I’m using these replacements  in front two [input tube] spots, and have a leftover two sets of TJ Full Music 6SN7s in the rears driver slots. Interestingly enough, PSVANE ended up acquiring all that 6SN7 lineup from TJFM and using that in their lineup now somehow, as I understand it. I enjoy this combo, and end up mixing front/rears some and prefer it.  Here is what I’m using in front now in my Cary SLP-98 preamp. So far so good, they sound nice to my ears, in my setup >> on sale now at PSVANE Co on their site for $199/pair: PSVANE ART TII CV181-TII [Note: your results may vary and you might not like them, fwiw]. Seems to vary by the listener and how the rest of your system and room is set up - i.e. may depend on how neutral/lean -or- weighty and full sounding your room reacts now, so preferences may vary of course. Can't stress that enough, to each his own fwiw.  

@decooney Thanks for the info. I have seen Psvane respond here before, nice to have builders around. I have read a fair amount of complaints about Chinese tubes having a short life. Hope that is not the case with your new ones. It just makes me pause to think before spending $100 to $200 apiece for new Chinese tubes, especially since I know a lot of old tubes that I can buy for less..........so far anyway. I don't rule them out, that's for sure and am encouraged by what I am hearing from the Shuguangs. There are also newer Shuguangs at somewhat reasonable prices but I always worry about counterfeits. At least dealing direct with Psvane, we should be getting what we paid for. Anyway, thanks, much appreciated. 

Upon recently upgrading significantly from an integrated amp (with tube preamp) to a preamp/amplifier, the way I explained it to my audiophile buddies was this.  The upgrade in the external DAC altered the audio image in a high level, clearly performer delineated soundstage; the upgrade in the preamp resulted in more "audio data" in each of those performer positions.  Of course every piece alters the sound signature as well.

First time in the very many years I have been fascinated and participating in the hifi experience that I was able to describe my experience in such a way relative to each piece of equipment.

On the NOS tube search/comparison front, I recommend you reach out to @chickenoregg He’s a nearly limitless font of information and has great inventory. I’ve gotten great 6NS7 and 12SN7s from him.

@decooney 

To @billpete - the PSVANE Co on the USA side was contacted by me last year about an older set that had seemed to have lost its luster.  It was determined the tubes were originally made around the time of end of pandemic, with some "known" issues. So, they agreed to replace the pair after me sending photos that I destroyed them [per their policy] with the original box/papers in photos to prove there would be no resale of those tubes. So, these were replaced by the same newer version PSVANE CV181 MKIIs, had something to do with different coating or something, dont recall exactly.  (These guys are are also members on this site, btw) and pop in once in a while. Thew new tubes have been in the front L/R position since.They sound nice for my setup.  

at the risk of creating a small sidebar here

i recently ordered a set of 101d horizon tubes from psvane for my lampizator dac... they arrived, supposed to be a matched pair, but one tube had bad silkscreen imprint, and was noisy at the outset .. melody first answered quickly when i raised this as an issue... but there has been no response for a few days now since i requested replacement given that the noisy tube has stayed noisy (some get quiet after being in the circuit for a while and settled in, but not in this case...)

so we shall see