Tube disposal

[Martin]

Question: What do you do with tubes that have outlived their usefulness? Do you just throw them in the garbage, or is there a more responsible way to dispose of them?

[K O'Connor]

Hi Martin

Most cities have extensive recycling programs and you may have to visit the landfill to be able to deposit these items in the electronics recycling area. Street pickup is primarily for plastics and everything that can be shredded (cardboard, etc).

Regarding tube life: If you have read any of the TUTs (The Ultimate Tone book series), or my other comments here or on other forums, you know that the true life time for a vacuum tube is generations in length. Your great grand children will be able to enjoy the tubes you install today into an amp you built or refurbished. Even their great grand children can enjoy them.

Unless a tube is mechanically abused, its electrical life is many decades long. Disreputable tube manufacturers and resellers will tell end users that the tube life is six months or so. They just want you to keep buying tubes.

The infant sound of every tube is a bit harsh and bright. After about 100-hours of use the sound mellows and the noise reduces. The tube is now on its Tone Plateau and will sound the same for decades. Some amp manufacturers like Mesa depend on that infant tone for their overall sound, and players of such amps follow suit, replacing perfectly good tubes with new ones to be able to maintain the brittleness of "everything new". Of course, just by coincidence, Mesa sells tubes.

For the player or tube hifi enthusiast, that 100-hours may be six months of use of the equipment. The initial tone change is fairly fast and readily apparent. Once on the Tone Plateau, gain is still being lost but now at an infinitesimal rate that you won't notice over a decade or few. What you may notice are the effects of capacitor aging over time, but rarely if ever tube aging.

Manufacturers consider the tube's useful life to end when cathode emission drops to half. This takes many decades and even then the tube has a long way to go before it is truly dead.

So, there are different definitions of "outlived their usefulness". Some are costly to both the player and the environment.

[Martin]

Thanks, Kevin!
Now that you mention it, I recall taking my last cathode-ray-tube TV to a special recycling depot, I'll have to look them up again.
As for your comments on tube life, I agree completely! I have a late 70s Ampeg V4-B that I bought about 25 years ago and have never changed the output tubes. It has a set of GE 7027As that a local repair man once told me he suspected were the original set installed at the factory! I have, however, had to replace a couple of preamp tubes that went microphonic or otherwise started making undesireable noises. So, when I say "tubes that have outlived their usefulness" I mean tubes that have ceased to function properly.

[K O'Connor]

Hi Martin

With microphonic tubes, some can be saved by doing a simple test. Place a rubber band around the glass envelope and line the band with the mica supports inside the tube. The band tightens the glass a little - it is a very slow moving liquid, not a solid - and also damps the glass from vibrating. if this works, then replace the rubber band with a high-temperature O-ring.

preamp tubes are getting expensive and some older amps have odd types. best to keep the originals in place whenever possible.

An extreme fix is to install a shock-mounted tube socket. These usually have silicone grommets and require flexible wiring to them.

Also, as TUTs state, never use plastic standoffs for PCBs as these make excellent vibration conduits. Metal of any kind is preferred.