Foregoing warranty rights

[Phil Allison]

"William Sommerwanker is a lying ASS"

Phil... SHUT UP.

** **** off and die you vile TROLLING pig.


..... Phil

 

[Phil Allison]

"David Nebenzahl"

So where does that purplish glow come from? I've seen it.

** The blue/ purple glow is emanating from " impurities" in the glass - it
is generated by electrons hitting the glass at high speed.

Most audio power tubes (ie 6L6GCs, EL34s, EL84s and 6550s ) have cut outs
in the plate structures that allow this to happen.

The blue glow will be there when the tube is new ( if it's there at all )
and is not a sign of a problem.

It may be fairly steady or respond to high drive levels - ie when the
plate voltage nearly doubles in magnitude with signal peaks.


..... Phil

 

[David Nebenzahl]

Unfortunately, there's no gas in a "vacuum" tube to glow.

So where does that purplish glow come from? I've seen it.


--
The current state of literacy in our advanced civilization:

yo
wassup
nuttin
wan2 hang
k
where
here
k
l8tr
by

- from Usenet (what's *that*?)

 

[Smitty Two]

So--and this is completely out of left field, I know--what would happen
if a guy put a vacuum tube--say a biggish octal one, like a 5Y3 or a
6V6--into a microwave and nuked it?

Everything on planet Earth has been put into a microwave. Search YouTube
for "vacuum tube microwave" and you'll get several relevant hits.

 

[Meat Plow]

Impurities in the glass envelope or gas in the tube.

If gas, take an anti-acid tablet and you should be fine in a few
minutes.

<http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm> Scroll down to:
C. Blue Glow -- what causes it?
for more details.

So even after a getter flash there is still a certain amount of
impurities? I've never seen a 6L6 that didn't have some blue inside
when in operation. It looks as though the blue only occurs where the
electron beams hit the inside of the glass. At least in new tubes.

 

[Phil Allison]

"Jeff Liebermann"
"Phil Allison"

Ok. My bad grammar. I meant that if the tube is deemed "gassy", it's
probably not an air leak in the envelope or seal. It's more likely
gaseous diffusion of helium or neon through the envelope.

** Unfortunately, that idea is at odds with observations of tubes that show
internal glowing.

Egs: It happens to tubes that are used or not and are old or not PLUS most
even very old tubes show no sign of gas.

The only correlations I have seen are:

1. Certain batches all have the issue.

2. Tubes that have suffered long term overheating.

3. Tubes with visible corrosion on the pins and / or cracks in the glass
near the pins.



...... Phil

 

[William Sommerwerck]

Only helium and neon will diffuse through glass.

This is way OT, but Chicago Miniature Lamp claimed that helium diffusion
shortened the life of incandescent lamps.

 

[Cydrome Leader]

"Jeff Liebermann"
" Jeff Urban"

** ROTFL - I doubt there is even one importer or manufacturer in Australia
capable of making that determination with any accuracy. After all, how
would any of them know ?? They are NOT operating repair businesses, have
no understanding of them and generally take no interest in the topic.

Anecdote:

One time, back in the 80s, I worked for a repair business that had
"authorised" service arrangements for several brands of guitar amp -
including Marshall, Acoustic and ELFA.

The Greek lunatic who imported Acoustic into Australia decided that he could
" micro-manage " the servicing of his brand by making up " kits " of spare
parts that all service techs would have to buy to repair various classes of
fault. All one needed to do was tell HIM the fault scenario and he would
nominate the kit that you needed to purchase. Ordering individual parts as
required was simply no longer an option.

He claimed to me on the phone that all the auto importers and makers were
doing the same thing and it was more " efficient ". Soooo, I told him about
the fault in the unit I had on the bench - that it suffered from loud,
very intermittent crackling noises. After a long pause, he said to ship the
unit down to him, in Melbourne, 500 miles away.

The boss and I did no such stupid thing, of course.

Anecdote 2.

A Melbourne based maker of guitar amps ( ELFA) had issues with their latest
models:

1. The quad op-amps ( all RC4136s) in the pre-amp section were from a faulty
batch ( rejects?) with about a 50% failure rate in the first 3 months. The
maker had earmarked all their remaining stock for manufacture and REFUSED to
supply any spares to us for warranty repairs.

2. Some nut case, probably as an after thought, had fitted stereo headphone
sockets to the amps with no series limiting resistors. The left and right
earphone connections were simply linked to the internal amplifier module and
the speaker connected itself when there was no plug in place.

Soooo, soon as anyone plugged a mono jack into the headphone socket - bang
went the Sanken 60 watt amp module inside. Then, soon as the mono plug was
removed, a 40 volt DC rail was linked to the 12 inch speaker and burnt it
out.

This is great, I laughed out loud over this one!