What is the best tube preamp currently available?

There is "no best".
System synergy. Personal preferences/taste. Features/cosmetics/reliability/costumer support.
It all matters.
I could have told you what I think is the "best preamp" in my opinion but it doesn't mean "Jack"...now does it ????

Check out the Audible Illusions Modulus 3A. The Modulus 3 has been the cornerstone of my system for the past 15 years. I have NEVER felt the need to upgrade. It has an extremely quiet phono preamp and uses only 4 6922 tubers or varient.

The preamp has 5 line level inputs, a tape loop, phono input and 2 sets of outputs for biamping. With the outboard power supply, it's a steal. You can find a used one on this site for as little as 1100.00 In all my years of ownership, it has been very reliable.

Bob

Berning TF12. Includes phono stage and remote. Good luck finding one though.

If I'm not being too rude in creating a parallel thread, what do you think would be the best tube-based line stage at about $1500 or less.

What are the opinions around here about Shanling? I'm wondering if their 2-in/1-out HP300 headphone preamp at $399 would make for a good minimalist line stage like the Melos SHA-1 of 12 years ago. Downside: no remote. Upside: 2 headphone jacks.

Sorry, I can't accept that your P/A can't be repaired. On this what have you to loose. My recommendation is to contact Eric Falkenhan (410) 467-3620 , one of the finest persons I know in audio restoration services. If Eric can't fix it nobody on the planet can. Give him a call & tell him Charlie Rehm referred you. All the best.