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Hoffman Amps Forum image Author Topic: Are Fingerprints/oils hard on tubes?  (Read 3430 times)

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Offline pompeiisneaks

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Are Fingerprints/oils hard on tubes?
« on: November 02, 2016, 01:20:14 pm »
I've had two different threads/video's I've watched recently discuss that you should be careful handling tubes, and not get fingerprints or oil on them or it will shorten the life of the tube.  I can't see how that would actually work,  I've never heard of tubes breaking due to some 'hot spot' from the oils etc,  I hear tubes dying due to the mechanical components inside of them. Is there any truth to this or just a myth/wives tale?

~Phil
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Offline sluckey

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Re: Are Fingerprints/oils hard on tubes?
« Reply #1 on: November 02, 2016, 01:51:21 pm »
Oily fingerprints will absolutely kill high intensity halogen lamp bulbs or projector bulbs. And some of the glass envelope transmitter tubes I worked with had a caution about handling with bare hands. I used a special pair of gloves when handling these tubes. These tubes were high cost items, $800 to $5000!

I'm not concerned about small receiving tubes like we use in guitar amps. I do handle power tubes with cotton gloves or paper towels and wipe the glass after installing. Some of these tubes get very hot, especially EL84s. My handling of these power tubes is a carry over from dealing with high power/heat transmitting tubes and may be overkill, but why tempt fate? I have seen guitar amp power tubes and old tv tubes that had been hot enough to melt the glass. Maybe HBP will post his pic of a melted tube.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline pompeiisneaks

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Re: Are Fingerprints/oils hard on tubes?
« Reply #2 on: November 02, 2016, 02:06:19 pm »
Cool thanks,

that is a very apropos pic from HBP, per his username :)  HotBluePlates with melted glass pics :D

~Phil
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Offline sluckey

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Re: Are Fingerprints/oils hard on tubes?
« Reply #3 on: November 02, 2016, 04:38:24 pm »
Here are some melted EL34s. I doubt greasy fingers caused this...  :icon_biggrin:

     http://el34world.com/Forum/index.php?topic=19309.msg199014#msg199014
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline pompeiisneaks

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Re: Are Fingerprints/oils hard on tubes?
« Reply #4 on: November 02, 2016, 07:39:28 pm »
Oh man those tubes look scorched!!! :P

~Phil
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Offline tubeswell

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Re: Are Fingerprints/oils hard on tubes?
« Reply #5 on: November 02, 2016, 09:11:54 pm »
I can supply bottles of heat resistant mojo hand wash for $1,000 each. You can wash your oily hands with it. Protects and enhances life with tubes.
A bus stops at a bus station. A train stops at a train station. On my desk, I have a work station.

Offline pompeiisneaks

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Re: Are Fingerprints/oils hard on tubes?
« Reply #6 on: November 02, 2016, 09:19:26 pm »
Outstanding! wait... sucker born every minute right :P ol P.T. Barnum would be proud hahahah

~Phil
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Offline Willabe

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Re: Are Fingerprints/oils hard on tubes?
« Reply #7 on: November 02, 2016, 09:37:28 pm »
I can supply bottles of heat resistant mojo hand wash for $1,000 each.

It's made from little Kiwi bird spit.      (You can only get it from New Zealand.  :wink: )

Offline pompeiisneaks

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Re: Are Fingerprints/oils hard on tubes?
« Reply #8 on: November 02, 2016, 09:39:38 pm »
Do the kiwi's live with the civet that makes the kopi luak coffee? :)

~Phil
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Offline tubeswell

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Re: Are Fingerprints/oils hard on tubes?
« Reply #9 on: November 02, 2016, 11:33:44 pm »
Do the kiwi's live with the civet that makes the kopi luak coffee? :)

~Phil


No that's from the civet in Madagascar or Indonesia (Jakarta)  I believe. Obviously for sensitive commercial reasons, I can't disclose where the mojo hand wash is sourced from, but if it was excreted by an endangered animal, would that surprise anybody?
A bus stops at a bus station. A train stops at a train station. On my desk, I have a work station.

Offline shooter

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Re: Are Fingerprints/oils hard on tubes?
« Reply #10 on: November 03, 2016, 08:25:22 am »
Quote
if it was excreted by an endangered animal,
like humans?
I did the same as Sluckey while handling high $, high power tubes.  I would spend more time wiping down the inside of PA section after a tube change than it took to change a tube.
Went Class C for efficiency

 


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