Big Tubes

[Steve - WB3HUZ]

One of, if not the biggest glass triode Eimac ever made, the 2000T - 17-3/4" tall and over 8 inches in diameter!

[KM1H]

When it comes to 304TL's two is mo betta

Beautiful pic.

Who made those plate and grid caps? My old Eimac hardware isn't half as pretty.

Thats not mine, its from an audiophool site. Mine arent as pretty and I havent been able to crank them up yet with just 250TH's to talk to.  Cant find any 450 or 750T's either, they have all but disappeared

[W2PFY]

Cant find any 450 or 750T's

There are 450th & tl's listed on eBay weekly in fact there are some on there now. Most bring about $50.00. I have purchased all my 450 TH & TL's on there and all have been good. 750TH's are seen about once a year. Another ham I know has also purchased about 1/2 dozen 450's on there and all his tested good. Your experience may be different.

[WA3VJB]

Yeah !

[W3GMS]

Ok, with all this tube stuff you made me pull out my TBK-12 and yank the final 861 tube out!  The condenser mic is a late 20 vintage home made by W3ABN (sk).
Enjoy!
Joe, W3GMS 

[Steve - WB3HUZ]

HK 1554

15" high and 4-3/4" around!

[K1JJ]

Speaking of 750TL's, here's the only (fuzzy) picture that exists of my homebrew pair of Eimac 750TL's, driven by a pair of 813's. My first big rig in 1972.  Blow it up X4 and you will see the "Picasso" outline of the 750TL's structure.

It was grid driven and neutralized.

T

[John K5PRO]

I need to photo recent additions to my big and sexy tube collection here, 2 are in the garage needing cleaning. One is an 892R (10 kW aircooled with pineapple radiator), one is a 750TL needing to be mounted on a wooden base. The photo (my "byline" on the left) is a 851, with obvious Photoshop effects to the anode. I have a 862 that I need to haul from upper midwest to NM, it was used in early 50 kw RCA xmtrs. I'll post here soon as I can get them to model for me, in the nude - of course - out of their sockets.

Meanwhile, here are a couple of big bottles, that I work with during weekdays. They aren't so sexy lookin', but each one costs over $200K. On the left is the RCA/Burle 7835 double-ended triode. On the right is the new Thales TH628 double-ended tetrode, tradenamed Diacrode. They both operate grounded grid(s) at 200 MHz, in pulsed mode, delivering 3 MW of peak power or between 250-400 kW of average power. The TH628 has run 1 MW CW too. Not sexy, but fine tubes nevertheless, showing climaxes in gridded tube development in the last 50 years.

[Bill, KD0HG]

No one with a pic of their glowing 833s yet?

Very nice rig, Tom. Reminds me of the Collins 231-D that WA8LXJ owns. He hasn't had it on the air in years. A pair of 750s modulated by a pair of 450s...With Autotune for easy QSY. I think rated at 5 KW out. Came out of the old VOA facility in Bethany, Ohio.

Someone ought to make up a calender featuring pinup pix of big glowing jugs and donate the proceeds to this site.

[Steve - WB3HUZ]

5575 rectifier - 25 inches tall and over 6 inches in diameter. Crazy!

[Bill, KD0HG]

Just took these pix yesterday. This is a Federal output tube from a 1930s 50 KW transmitter.

It's in a stand, once was used for display before being exiled to the current tower site.

Anode is a 4 foot long copper tube at the bottom of the glass portion. It was immersed in circulating cooling water. With a 4-foot long grid and anode, this thing couldn't possibly run above the BCB.

The inside is an amazing example of the craft of glassware. It must have taken a week to build each one of the things.

[W3GMS]

Very cool tube Bill!  What was the temperature of the water that cooled it?  I am assuming they re-circulated the water in some type of cooling tank.
Regards,
Joe, W3GMS   

[Bill, KD0HG]

They used an outdoor fountain for cooling, which is still there (empty of course). Sprayed the hot water in the air then pumped and filtered it.

There were several of those bad boys in the rig making a lot of heat.

[W3GMS]

Thanks Bill.  That sounds like a real "make shift" solution!  The largest broadcast transmitter I worked on was a 5KW RCA many years when I was 18 years old and worked at WCOJ so no water cooling on that one.   
Regards,
Joe, W3GMS     

[Bill, KD0HG]

OK, Joe..A lot of the early 50KW boys did use water cooling. Actually a pretty good cooling solution with a fountain. I know WLW in Cincinnati used a water fountain as well. Won't freeze up in the winter and you didn't need any air conditioning. Those plate voltages in those early rock crushers were quite extreme, 12-15 KV and up. That Federal tube in my earlier picture was a monster. I looked through the glass and I could see a chunk of the filament that had broken off. That's why it was retired. A chunk of maybe #16 tungsten.

Water cooling is really a good way to go, it takes a lot of BTUs to take water to boiling.

[KB2WIG]

Big glass needs big iron.


klc

[W3GMS]

Bill,
Thanks for the background.  All very interesting for sure!   Maybe my next final should use some water cooling    Where was the break point in which air cooling was not effective?   Maybe around 10KW but I am not sure.  There is just something about real high power that is really exciting.  No QRP around my shack for sure unless I am on CW.  My mentor was a real High Power guy building big amps that would put lots of fire in the wire.  Once you start running some soup, its tough to go backwards.  Some Ham's insist on running 100 Watts and a trap dipole up 20 feet and they are just brutal to copy unless conditions are good.  I remember a QSO I had years ago and the guy kept turning down his power until he was just above my noise floor since he wanted to run only what was required to hear him.   A SSB station came on a squashed him like a sick bug...
Regards,
Joe, W3GMS