I like to clean the dust off of old tubes so I can inspect the condition of the getter and to improve their appearance. I was pretty surprised when I used a damp paper towel to wipe some vintage Mullard GZ-34s and ended up with "no name" rectifiers as a result. Hate it when that happens. The PAS 3 I am working on has the original Dynaco labeled 12ax7 inside. I tested the writing... sure enough it will wipe right off. I don't suppose there's a trick to cleaning tubes while leaving the labeling intact?
4 posters
Now you see it...
j beede- Posts : 473
Join date : 2011-02-07
Location : California
peterh- Posts : 1833
Join date : 2012-12-25
Location : gothenburg, sweden
The trick is : "don't wipe the tubes". Blow off dust and settle with that.
GP49- Posts : 792
Join date : 2009-04-30
Location : East of the sun and west of the moon
Yes. Happens on Mullards often. Don't ask how I know.
peterh- Posts : 1833
Join date : 2012-12-25
Location : gothenburg, sweden
GP49 wrote:Yes. Happens on Mullards often. Don't ask how I know.
How do you know ?
sKiZo- Posts : 1530
Join date : 2013-04-01
Location : Michigan USA
Hey now ... he SAID don't ASK!! 
The painted logos do get fragile over time - all those hot/cold cycles destroy the structural integrity of the paint. A slightly damp pipe cleaner or Q Tip - and careful attention to detail - no dribbling and light pressure - can work wonders. Eyeglass cleaner or windex is good. then follow up with a dry one, should protect the print. Do a good enough job on the majority of the tube, and the crud remaining in the logo area kinda sorta disappears into the background.
I've also heard that you can spray a light coating of clear acrylic over the top of the logo to protect it. That's supposed to at least keep it in the same condition it was, but I'd think that would have a tendency to yellow over time. I'll leave it to someone else to experiment with that.
PS ... I've also touched up logos with a white fine tip sharpie with decent results. Don't tell anyone ... that's cheating!
The painted logos do get fragile over time - all those hot/cold cycles destroy the structural integrity of the paint. A slightly damp pipe cleaner or Q Tip - and careful attention to detail - no dribbling and light pressure - can work wonders. Eyeglass cleaner or windex is good. then follow up with a dry one, should protect the print. Do a good enough job on the majority of the tube, and the crud remaining in the logo area kinda sorta disappears into the background.
I've also heard that you can spray a light coating of clear acrylic over the top of the logo to protect it. That's supposed to at least keep it in the same condition it was, but I'd think that would have a tendency to yellow over time. I'll leave it to someone else to experiment with that.
PS ... I've also touched up logos with a white fine tip sharpie with decent results. Don't tell anyone ... that's cheating!
GP49- Posts : 792
Join date : 2009-04-30
Location : East of the sun and west of the moon
In my junkbox I have tubes that have lost their brand name logos but have their tube type number etched into the glass. Mystery tubes...one has to look at the construction to guess at who made a now-nameless 12AX7A, for example.
Then there are the Supermystery tubes where no lettering remains at all. Some Telefunkens fit that description: a glass envelope with the tell-tale diamond moulded into the base, and nothing else.
Well...he asked!!!
Then there are the Supermystery tubes where no lettering remains at all. Some Telefunkens fit that description: a glass envelope with the tell-tale diamond moulded into the base, and nothing else.
Well...he asked!!!
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