FWIW I only change the tubes when something goes microphonic or dies, once I've got some good working tubes in there. Many tubes have been going around here for years and years.
That's once I find some decent sounding tubes to begin with- decent meaning clear, very low noise if it's a mic preamp.
I agree. My old Siemens V78 sounds great and I think it has the original (40 years +!) tubes in it. When I purchased it, I sent it to Oliver at Tab-F for a checkup and he replied that it was so clean that it was likely a radio station "spare" that had spent it's life in storage. Other than replacing some dried out caps, he said it was good to go. And I've had the amp now for about 4 or 5 years of limited use. So tubes can last a long time.
I've just bought a used UA 6176. Are there anythings I should do as far a maintenance goes?
Isn't the 6176 a fairly recent product? Like 2 years or so? Unless it was on the road 24/7, I can't see how much could have happened yet. And if it was from a typical project studio, it's probably got less use on it than a lot of "new" gear. I can't imagine that there is much work necessary on something like this.
Lexington 125 - High Resolution Location Recording