I’m retubing my 5150 head entirely. What tubes do you suggest, and what other suggestions can you make for choosing good tubes and getting good sounds
You’ve got some choices here, James. Three come to mind—namely, China, Russia, and in the U.S. These are among the few countries that still produce tubes. Your 5150 uses four 6L6s as its output tubes and five 12AX7s as its preamp tubes. China makes a reasonably priced 6L6. The ones I’ve heard have a sweeter and softer overdrive, say, the Russian 5881, which is a direct replacement for the 6L6 and has a harder, colder character to my ear. Although these tubes are not as well made as some American and British tubes (the production of tubes in both the U.S. and U.K. has dwindled to little or none), the Chinese and Russian tubes should last a reasonable amount of time, unless you’re rehearsing and gigging five nights a week.
If you’ve got lots of cash, I highly recommend buying new old stock (NOS) tubes. These are tubes that were manufactured years ago and never sold or used. A set of four NOS RCA 6L6 “backplates” will run you over $300, while the GE 6L6s go for about $150 a quartet. These tubes deliver superior quality and construction, if you can afford them. If you can’t, don’t worry. You can still get killer tone out of tubes from China or Russia.
To replace your 12AX7s, I’d recommend the Chinese-made tubes. I’ve heard a 5150 with some really expensive British military spec 12AX7s (the higher military specifications typically give you higher performance), and I actually preferred the Chinese.
When you take your amp for retubing, ask the technician to clean the tube sockets and to check that all the sockets hold the tubes firmly. It’s in the socket that the tubes connect to the amp, which is why it’s imperative that you provide the cleanest, most stable connection for highest performance. Happy motoring.