n00b t00b Q: HANDLING & MAINTENANCE OF TUBES
Sep 23, 2002 at 9:37 AM Thread Starter Post #1 of 13

N@Z

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Normally, is there a proper way of handling (installation & removal) tubes? I recall that when changing bulbs from high energy light bulbs (vehicle headlamps, flood lights etc) it is important not to touch the bulbs with your bare hands during installation as the oils from our fingers can cause damage to the glass when it operates. Does it apply for the tubes used in the MG Head (or any other tubed amps for that matter)? What 'technique' does the tube 'veterans' use here
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Once the tubes are installed, is there any other general maintenance required? Like cleaning them should there be any dust particles on it.

Just in case this has already been discussed before, my apologies, please direct me to the appropriate link where applicable.

Thanks.
 
Sep 23, 2002 at 10:30 AM Post #2 of 13
For all I know, it is not recommended to handle tubes with bare hands for precisely the same reasons. I use soft cloth to install/remove tubes. Some tube amps require manual biasing of the tubes but I don't think there is a single headphone amplifier that needs that. Basically I just leave them alone.
 
Sep 23, 2002 at 1:22 PM Post #4 of 13
Basically the things to watch out for when handling tubes are:

1. Avoid subjecting tubes to shock or vibration, as the innards are delicate. Definitely don't drop them!

2. It's best to handle tubes with a soft cloth, to avoid getting fingerprints on them. Also, the printing can rub off easily, which is the biggest reason to handle tubes with a soft cloth.

3. I don't know what #3 is.
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Sep 23, 2002 at 2:57 PM Post #6 of 13
Be only as anal as you want to be. I've never given skin oils a second thought since most of my tubes are coated in thick, 50-years-collecting dust. However, I am extremely careful when it comes to preserving tube lettering. Without it, a tube is nameless and has no definite place in history.

NGF
 
Sep 24, 2002 at 9:43 AM Post #8 of 13
Thanks for all the replies!

It's not a really big issue for me right now as I've not had the MG Head for very long. Although I'm interested to do some tuberolling in the future once I am familiar with the stock sound.

zzz/Kevin P:
When I installed my tubes for the 1st time, I used a small piece of paper & rolled it over the tube's sides. No special reason for that... I didn't have a soft cloth at the time! Plus I always thought that any lint sticking to the glass might cause problems. I guess I was being too paranoid at the time... new toy, you know how it is!

braillediver:
Thanks for going to all the trouble. Yes I do remember my Dad's old Telefunken TV's tubes being covered in ALOT of dust! At that time I didn't think much of them, sure wished it was still around. It died a dastardly death... my younger brother chucked it into a bonfire! You can imagine what happened! KABLOOOWIE!!!

Tanfeton:
Wouldn't the substantial dust collected on the tube's surface cause them to perform less than their true potential? Although I do agree, a tube without it's identifying marks would be useless. BTW (not intentionally trying to crap on my own thread), did you get my last PM?

Nick:
You webpage on "tuberolling" is a good read for a novice like me. It did noticed that you didn't mention any special way of removing & inserting tubes. No new recent updates?
 
Oct 22, 2002 at 8:01 AM Post #10 of 13
As a follow up question... how would I know whether the tubes are reaching the end of it's useful life?

What specifically in terms of sound quality that starts to degrade?

Physically is there anything that changes, say in the brightness of the tubes? As I noticed different tubes have different strength of glows.
 
Oct 22, 2002 at 12:54 PM Post #11 of 13
The only reasons to keep your fingers off tubes are:

- don't rub the markings off - of course it doesn't affect performance but they are nice to keep (a cloth will do this too if you are rough)
- to keep them clean, they radiate heat better when clean. Oils from your fingers will help dust to stick to them and it acts as a blanket.

They are not like those tubular light bulbs that will die right away if they have any contaminant on the surface. They are glass, a relatively inert substance often used to store compounds far morecorrosive/basic/acidic than anything that will ever be found on your fingertips, at least as long as you're not screaming in agony.
 
Oct 22, 2002 at 2:43 PM Post #12 of 13
When tubes start to die, they get REALLY microphonic. Otherwise they will just die on the spot... probably the moment you turn on the amp. Definitely replace them if they are sounding weird.
 
Oct 22, 2002 at 3:20 PM Post #13 of 13
Quote:

Originally posted by Nick Dangerous
When tubes start to die, they get REALLY microphonic. Otherwise they will just die on the spot... probably the moment you turn on the amp. Definitely replace them if they are sounding weird.


A tube can become worthless for audio long before physical death. Dynamics become muted, music loses impact, starts to sound uninspired. A tube can last for months or years in this condition...but who would want to listen to it? End of useful life occurs long before tube death...usually
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