Maintenance for Tube Preamps

"If it ain't broke don't fix it." I own and have owned many pieces of vintage equipment 40+ years old that I start on a variac and they sound terrific without ever having any maintenance besides tubes.

If you’re not blowing fuses and all seems well, all probably is well. But if you’re itching to do something, I know people who swear by the improvement they realize by regularly cleaning and polishing contacts (PC, IC and tube). FYI, cj offers a “renew" service for their older models, but unless you feel that something’s wrong, I’d wait another ten years before I explored that option. I’ve always been happy with cj’s advise when I’ve called.

Other than periodically replacing the tubes (and they generally last longer than most people think), I would just occasionally treat all of the contacts with Caig Deoxit or Cramolin. You don't need much of it at all, but I think it's a good idea. For a quick treatment, just spray a tiny amount of deoxit into the end of your interconnects and then plug it in and rotate the end to spread the love.

I'd also advise testing your tubes before replacing them. Don't replace based upon some arbitrary limit. If something starts to sound wrong or you blow a fuse, test all the tubes. You can probably find an old Eico dynamic tube tester on eBay for about $200 or less.

The only other thing I could think of is just opening it up and making sure to keep it clean/dust free inside.