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

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  It was determined the tubes were originally made around the time of end of pandemic, with some "known" issues.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

Paging @psvaneaudio @psvane @psvaneofficial [whoever the official is]

See @jjss49 's post directly above.  Hopefully you can step in and ensure the tube replacement(s) issue gets resolved, as good as or better than you helped me out.

Please advise next steps for resolution, and then all of us here will be watching how it turns out for jjss49. Thank You   

Hello everyone, this is Melody.

Hi @jjss49 , I just took a moment to check, and it seems this order was not handled by me personally. The communication on Audiogon is currently being managed by my colleague Joe. I have just spoken with him, and he mentioned that he has already replied to you. However, it is possible that due to a system or network issue, the message was not successfully delivered, and he did not notice it either. We sincerely apologize for the delay and for keeping you waiting. He would like kindly asking whether you could break the faulty tube or cut the pins and send him a photo for confirmation. Once he receives it, he will promptly arrange a free replacement for you.

Please rest assured that this is fully in line with our after-sales policy, which is always open and transparent.

If anyone has any questions after purchasing our products, you are always welcome to contact our after-sales support email at any time.（[email protected]）

Thank you all very much for your support, understanding, and trust.

I’m surprised that Mapetree site is still up - looks like it came right out of the Geocities era! I never tried a Mapletree, but in general those very simple 6SN7 based line & headphone amp circuits (which a 2-tube circuit certainly is) can have a very nice & airy sound with good tone and numerous rolling options - but on the flip side they tend to lack in power, dynamics, punch, and overall "density".

I really prefer 6H30 based preamps - but they do have a different sound (a bit more modernized, less "sweet" tone, and towards solid state-ish sound), and many of the models here are focused on their "balanced" circuitry and XLR outs. Something with a 5687 or 7044 based output can have a LOT of "drive" and would give a very different perspective - be prepared to give up some of the 6SN&’s airiness, though. A 6922 based preamp will generally fall somewhere in the middle. Solid state preamps tend to be too far dry and sterile (read: boring) for me.