New tubes or new preamp?


I have an ARC LS15, and am considering either a set of NOS Amperex tubes, or selling it and getting a new preamp, such as an ARC LS27, or a Modwright LS 38.5.
As I'm unable to compare , what would you advise?.Will NOS tubes give me a preamp that compares with todays current ones, or is it a waste of money?
Thanks
brrgrr
Brrgrr, So far, I haven’t heard an amplifier that couldn’t be improved by upgrading the stock tubes. So, that might be enough for you; it frequently was for me - at least until I found and could afford a clearly superior amplifier. As a rule, I consider it highly advisable to seek out the right tube set for any amplifier.

Tube rolling can be chancy, expensive and frustrating; all of which become worthwhile once you find the right set. I tend to think of the manufacturer supplied tubes as a sort of blind date chosen for consensus appeal. I appreciate the effort, but only I am listening to my music with my system in my room.
Good advice all...I've recently upgrades my speakers to Magnepan 3.7's, and bought a Magtech amp. Still not getting the sweet sound I'd like. As I tried new tubes from ARC and still wasn't where I'd like to be, thought either a tube upgrade or a new tube pre might be the way to go..I can't audition, due to the fact there are no dealers anywhere near, so I"m looking for some guidance for those here who have listened to a lot of gear I can't.

I'm prepared to spend some money if the return is there, but want to make sure the difference in expense is worth it....
Thanks for your input...
When I had the LS15 I researched getting different tubes and was told by a few reputable dealers that the LS15 was not a good candidate for tube rolling, that the benefits would be minimal.
There were two versions of the LS15. If you have the older version (most easily identified as it has a captive power cord) then the cap and power supply upgrade by ARC is a very cost effective improvement.
Brrgrr,

After reading your 2nd post, I don't know if you will get the results you want by getting a new preamp. It looks like you want something to deal with your 3.7's not having a "sweet" type of sound. Getting an LS27 most likely won't help. If anything, its a more transparent preamp and will further enhance what you don't like about your speakers.

Given that, I think you have 2 choices. The first choice is to buy equipment in an effort to cover up what you don't like about your speakers. Its a very tempting option, but almost never works. You'll just end up spending a lot of money. The 2nd choice is recognize that you may have bought a pair of speakers that are not for you. If thats the case, deal with the issue directly and get a different pair of speakers. For me, personally, that would be the way to go. Deal with the problem and be done with it.