[JCS]

It's been a long time since I used tubes.  I don't think I have had anything since the '60s with hot glass inside.  Just recently I purchased a MiniWatt tube amp to partner with a pair of Metronomes I built using Fostex F120A drivers.  Folks rave about how great Alnico sounds, and the F120A is well regarded, so I decided to jump in.  Long story short, F120A sounds seriously mediocre with any SS amp I have tried.  I was about ready to dump the F120A's when a friend brought over a tube amp one day and...WOW!  You wouldn't think it was the same driver.  Mediocre turned into marvelous! 

Being short on cash and frugal (cheap), I looked around until I found the MiniWatt.  I love the sound of the Mini driving the Mets.

Question is: How long do tubes last? I have the stock Chinese tubes that came with it (6J1 and 6P1) and a set of upgrade tubes (WE 203B and Svetlana 6P1P-EV).  Since the output tubes seem hard to find, I'm wondering how many to keep in stock so that I can expect to stay up and running for, say, the next ten years.  (I know this also depends on how many hrs per day I run them.)  I just worry about ending up with a dead amp a couple years down the road because I can't find tubes...

Thanks,  Jim

[Pez]

When people ask me this question I usually respond with this: "I don't know, how long do light bulbs last?" I have had light bulbs last for years and I have had light bulbs burn out in a matter of weeks. Tubes usually are more robust than this of course, but depending on use, implementation, and normal wear and tear there are no promises. It is not out of the ordinary to use a single set of tubes for 4-5 years and then again I had a 4 month old Svetlana tube kill itself and damage the amp it was in.

[rollo]

  Around 3000 hours. At 3 hrs per day so about 3 years. not a guarantee just expected tube life. If you really like the amp buy more tubes and your safe. If you wait the price of tubes WILL go up as they are getting rare as we speak.
   welcome to the world of tubes. ENJOY!!


charles


charles

[JCS]

Thanks!  That's what I wanted to know.  I'm just a bit paranoid moving to this old/new technology.

Cheers,  Jim

[Niteshade]

Make sure they run cool. Good air circulation can extend life considerably.

[rajacat]

I've had one tube go bad (KT66). Luckily I was present and immediately shut down the system. What would have happened if I wasn't present? Could this start a fire or would the amp just shut down on its own? Could this fry the amp making for major repairs? I often have the system on the entire day while I'm working around the house or going out for short chores. Is this taking a foolish risk? I don't particularly like having to start/stop my rig repeatedly over the entire day. 

-Roy 

[Bill O'Connell]

Roy,

 You just never know when a power tube is going to go.Like you I use to leave the house with amps on and come back an hour later just trying to keep things warmed up. After seeing a tube go that fried a resistor also I have since changed my opinion. I never leave the house with tube amps on. I leave tube preamps on and sources, just not tube power amps.

I was at a friends house and he had borrowed a tube phono stage from one of his friends that was trying to sell it, (I don't want to say the manufacturer)it wasn't Eastern Electric though. He plugged it in , turned it on and within 30 seconds the piece was burning with flames.This validated for me never to leave tube components on. Although as said previously I keep my tube source components on but not amplifiers.You take your chances, the question is Do you feel lucky,well do ya?

[Ericus Rex]

I've had three power tubes go in various amps.  Two of them took fuses with them and the other just the tube died.  Maybe it depends on how well the amp is designed?   Aside from bright flashes nothing exciting like FIRE!!!

[rajacat]

Speaking of the devil  I just had another KT66 blow. A Genelex Golden Lion no less.

Eight months on it. Now I have three of the Golden Lions and 3 of the Shuguangs.

So now I guess I have to order a new quad of??.$$ 

-Roy