Re: For all the group

You need an adapter and that would not be a problem. A problem with such large sets is their sheer size plus the scrutiny they always get at the TSA check points.

one of the guys who still listen to AM radio when on

headphones fall apart so fast. My old Sennheisers were

it keeps falling as it is right now

Well, I live in the US and earn USD :-(

Ah, thanks! However, one has to inquire about their age because they aren't very stable and age too fast IMHO.

Ahem, the TSA guys will very likely want to keep that box there and not let you get close to any aircraft with it. They don't like home-built stuff that much ;-)

Where appropriate, I try not to make the things I prototype *look* home-built. ;-) Best regards, Spehro Pefhany

Sennheiser seems to be very good about making pads for its older 'phones available. In my experience, the foam pads are good for perhaps 5 years of occasional use, and then (yes) they tend to get crumbly.

Only a few months ago, I purchased two sets of replacement pads for my venerable HD-424 'phones, which I think I originally bought back in the early 1980s. They're around $5 per set, I believe.

Try

One would think that a company like that would have better technology in their products. Sad.

You guys really that much in the dark about body oils and polymers?

You're fairly safe if it's been stored in sealed plastic. One of my customers is a Plantronics dealer. None of the stored foam pads decompose in storage. My guess is some are perhaps 20 years old. However, the one's that have been removed from the bag, installed on headsets, and were exposed to the atmosphere, do tend to fall apart after about 8-10 years.

The material can be foam latex, styrene-butadiene rubber, or polyurethane. It's difficult to tell the difference. I'll bet on polyurethane. Anyway, all three decompose (actually de-polymerize) in the presence of aromatic solvents, as found in most urban smogs and industrial atmospheres. UV exposure causes embrittlement, which helps the process along. However, the worst offender for earphone pads are hair oil, hair grease, and deodorant. The foam absorbs these readily and eventually turns into the consistency of "The Blob" (as in the Steve McQueen movie).

If you wanna go cheap, Radio Shock sells a few "universal" replacement ear pads which might fit.

In desperation, I've also made my own out of sheet packing foam using a hot wire and hot knife. Not recommended (unless you are desperate).

And ozone, and UV light, and microbial/fungal decomposition, and etc.

I'm not critizing Sennheiser for the fact that the foam in their cushions has a limited lifetime. Quite the contrary - I *expect* it to, and I appreciate Sennheiser's willingness to continue providing suitable replacements for products that have been out of production for two decades.

Very different and much cheaper than the one I found on eBay for the HD480:

Except that normal oxygen (also present in the bag) is the primary degrading media for those polymers.

Yeah, but making a layout, having a PCB fab'd and all that quickly turns this little exercise into a major science project. I never shy away from building stuff but not if I can buy it. It's easy to sink below $5/hr when trying to re-invent wheels.

Are you sure you're not mixing up the yellowing of urethane foam from oxygen exposure, with the breakdown of the long chain polymers by solvent action? The yellowing is well known:

Note that this yellowing has no effect on the chemical or mechanical characteristics of the urethane foam. Google and I couldn't find anything on the exact mechanism of the breakdown of urethane foam into a sticky, gooey, yucky mess. Is it really oxygen induced breakdown? I doubt it because oxygen is used to cure (harden) polyurethane varnish finishes. The way I understand it, oxygen is a hardener. It might cause yellowing, embrittlement, or crumbling into a powder. However turning the urethane into a sticky, gooey, yucky mess, requires some type of (aromatic) solvent.

Apparently it's also not as simple as I suggested. There may be catalysts (lead or tin) involved:

The last time I was on an airplane with headphones, they were just cheap plastic tubes, that you plugged into two holes, and the tinny[sic] little speakers were apparently embedded in the armrest.

Cheers! Rich

Boy you haven't flown in a long time then. Or maybe it was somewhere in the boonies with Coconut Airways.

I remember those from a DC-8 ...

On a sunny day (Thu, 20 Mar 2008 01:02:02 GMT) it happened Rich Grise wrote in :

Did you know that you can suck on those tubes, and then Cola comes out?

Used to be beer but now they charge $5 a can for that even on international flights.

I haven't flown since last September... I avoid it if at all possible.

LA, San Diego, Santa Barbara... I drive if more than a one-day trip. Given all the time spent parking and arriving early for TSA check-in, renting a car on the other end, there's hardly any time lost by driving... and I can take my corkscrew ;-)

But I have a lot of clients fly in to see me.

Unfortunately Connecticut is on my agenda :-(

...Jim Thompson