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HiDef,
You're right, it is funny how things can get traded on 'eBay' and other places, and who does that trading, and what's thought of the deals. It's also funny how things can get misconstrued and blown way out of proportion. Unfortunately, that doesn't mean that those deals were in fact any good, or that being 'happy' with a deal makes sense in some cases. And while there is certainly a bunch of B.S. floating around about a huge number of things, it also certainly doesn't mean all those 'misconceptions' are as misconstrued as some people think. Dang! Some of them actually have some basis in fact, they are true! Tubes going 'soft' is one of those 'unfortunate' thingys that does have a basis in truth. It doesn't happen over night, some times quite a few nights. But it always does happen eventually. Eimac made good tubes. They made some that were less than good. But either of those types of tubes, after twenty some years, can be expected not to be of the same quality as they came off that assembly line. That name, 'Eimac', did mean quality in glass tubes at one time. It's time limit is getting very close to expiration now. You will never find one that isn't old enough to vote at this date. That doesn't mean that they are all trash, but you can bet that a bunch of them are that have never been out of the box since they were made. (Ask how those shelved tubes are stored sometime, that can tell you a bunch. If they are laid down on their sides for any length of time, they are trashed.)
Taylor tubes had a 'not good' name when they first came out, which is about normal for any newly started thingy. They did get better. They are not and will never be the same quality as one or two other brands (which aren't around anymore). That doesn't mean that they aren't any good, they are. They just will never compare to some brands.
It's good to discuss thing, but it certainly helps if you know what you are talking about when you do.
- 'Doc


I've got a string of christmas light made from 'dead' 3-500 tubes. When they flash, the lights in the neighborhood dim along with them. They don't reach completely around my house, but they cover a good part of the front of it! If I ever take them down, you can have'em. Don't hold your breath.

When Eimac first started maufacturing power glass tOObs in the 1930s their big claim to fame was the fact that nothing was inside the glass envelope other than the tube's elements. No ceramics to support stuff. The extra materials were said to be the cause of gassing out.

Those era tOObs had brittle filaments to begin with. Some people have said that during WW2 certain elements were not available for the production of filaments thus making the tOObs even more fragile.

I can say first hand that the old 250TL, 304 TH,TLs 100THs and an otherwise nice looking pair of 152TLs (try and find these anywhere) had fragile filaments. I've had all these come through here with broken filament material floating around. I did have some nice 100THs and donated them to WBCQ for their backup for the 7415 transmitter which was, is? a BC-610.

I've sold over $100,000.00 of ham radio items on Ebay in the last 7 years. Plenty of chances to play with different items.

Look at old RCA designs verses Eimac designs. The RCAs all have ceramic supports with these really cool spring like dohickies that physically keep the filaments in shape.

The 3-500Z has nothing in common with these brittle filament earlier tubes and is really an evolution of the 4-250. Very similar glass, similar 75 watt filament emission.

I've been able to light many a vacationing 3-500Z. I have a pair here right now that have an 8905 datecode that were used by the news dept at a TV station. They were placed into service just before 1990 and NEVER USED after that until the equipment was decommissioned a few years back. Probably less than 10 hours use. Guess what. They work perfectly. No gassssss. I have plenty more happy 3-500Z stories. Most of the gas is from the people in the internet who spread this kind of stuff.

You are quite correct Doc when you say that it helps to know what you are talking about when you talk. The internet is loaded with radio misinformation.
Those who have actual experience are losing the battle.