[kipman725]

Over the past few months I have been building a OTL tube amp based on the headwise project using ECC83 and EL84 tubes. Today it produced its first sounds and also made some smoke due to the "5W" resistors getting rather hot and burning some insulation. It also has some severe mains hum problems but that was due to some idiotic grounding (power transformer is next to the star ground). Anyway is it ok to put it on the window sill with exposed tubes or will the tubes focus the sunlight and damage themselves?

 

[dsavitsk]

Quote:

Originally Posted by kipman725 /img/forum/go_quote.gif Anyway is it ok to put it on the window sill with exposed tubes or will the tubes focus the sunlight and damage themselves?

That is perhaps the oddest theory I've heard.

 

[Mazuki]

There are curved surfaces on the top of those tubes, but since they all have top getters, I don't think there will be any light going through.

 

[elliot42]

It's curved, but it still isn't much of a lens. When you use a magnifying glass to burn leaves there is some focusing involved to get the right tiny dot of focused energy. I doubt the surface of tubes could do this by accident.

 

[kipman725]

ah right thanks... yeah they do have silver stuff on the top which I think is called the getter and used to absorb gases.... I guess the inside of the tube is @ 2000k when running and I wasn't thinking this through fully.

 

[mrarroyo]

Quote:

Originally Posted by kipman725 /img/forum/go_quote.gif ah right thanks... yeah they do have silver stuff on the top which I think is called the getter and used to absorb gases.... I guess the inside of the tube is @ 2000k when running and I wasn't thinking this through fully.

No explanations needed. Think on your accomplishment in building the amp. Most of us here would not be able to do so. Congratulations!

 

[Uncle Erik]

I've left tubes in sunlight for awhile and they've been fine.

 

[J.D.N]

Hows about some pics of your build

 

[kipman725]

Quote:

Originally Posted by J.D.N /img/forum/go_quote.gif Hows about some pics of your build

I want to wait till all the problems are ironed out before posting pictures so wait about 1.5weeks.