The AM Forum

A truly manly final from Heintz and Kaufman, the Gammatron 254.

That would be nice!

Now you know where the term California kilowatt came from!!

Now THATS a final to be proud of.   I bet just lighting the filaments would make my lights dim!

No need for room lights!

That is one big honking piece of glass!
They either had a typo or renamed it as the HK 254 is a 100T clone. The biggest Ive seen from HK is the 1254 which is a 750T competitor.

That's impressive. Will it go to 30MHz?

No 'tube envy'.

Carl is right, that has to be a typo.  I have seen real HK254's, and that is not one. 

A 1254, yes indeed.

The story is Press Wireless used them, others as well but not to any real extent.

73DG

I remember the story in Electric Radio when Jack McCulloch W6CHE died. He and Bill Eitel, W6UF used to work for H-K and went into business for themselves as Eimac in 1934, since H-K did not consider the amateur radio operators as a viable market. There must have been a change of heart, as there were ads in RADIO all during the late 30's with H-K ads. I traded away all the H-K 254's I had to another list member who has an amp that uses them.Not sure why they used the number 254 on that big tube.
                                                                       

While on the topic of H-K, has anyone used one of the "gridless gammatron" tubes?  Sort of a catchy name for a high power final :)

 

That would be dissipation equivalent to a 1500T from Eimac but I dont know the H-K designation, my stuff goes only to the 1254 whch is half the Pd of the one in the photo

Found it in the 1938 Radio Handbook.

It is a HK-3054  HK calls it a general purpose triode for commercial application and states it is the largest air cooled tube made.

Plate dissipation is specified at 1.5 kw but is increased to 3.0 Kw with forced air cooling.

Other specs:

Filament 16 volts at 50 amps
Amplification factor 20
Grid to plate capacitance 15 uuf
Grid to filament 25 uuf
Maximum plate voltage 5,000
Maximum plate current 2 amps
Maximum grid current .5 amps

maximum operating frequency isn't specified in the listing

On edit, HK listing sheet advertisement shows the filament rating as 14 volts 45 amps with a maximum frequency rating of 40 Mhz.  Grid and plate are both made from tantalum.  1936 price:  $467.50

Is it big enough? Here I am with a new tube, a tetrode. It costs about what a moderate home costs, and must be lifted by crane. So far I have gotten 250 kw of average power and 3 MW of peak power from it. Later this summer, I hope to get about 350 kW of average power, when the heat exchanger for the dummy load is replaced. 

Big yes, but tubes that aren't glass don't count...new rules!

73DG

Sorry John.
No glow, no go.

Now that Sir is a man's final tube! ! ! ! ! ! ! ! !

Who sez "size doesn't matter"  :o  ;D  ;D

"  250 kw of average power "

But are they Bird watts?


klc

According to the CPI inflation calculator, that would be equivalent to $7,657.01 in 2012 dollarettes.

That tube cost the better part of the price of a car. A quad (a pair in the modulator and another pair in the final) would have cost a little over an average year's wages. One tube would have paid about 7 month's house rent.

How Much things cost in 1936

Average Cost of new house $3,925.00
Average wages per year $1,713.00
Cost of a gallon of Gas 10 cents
Average Cost for house rent $24.00 per month
A loaf of Bread 8 cents
A LB of Hamburger Meat 12 cents
Studebaker Car $665.00
Ladies Swimming Costume $6.95

http://www.thepeoplehistory.com/1936.html

An even higher inflation rate here as current Ladies swim suits are much smaller.

But that's a good thing

Ah, yes, sometimes you can really appreciate the American Way- - Pay more for less.................... ;D  ;D

I have plans for a pair mobile ;D I figure the flat bed will have to accommodate two
turbo charged CAT generators at 250kw per. Now the antenna has been a bit of an engineering problem. Due to bridge height restrictions I will pull a second low-boy trailer to maximize the height for the silver plated copper 1 foot diameter vertical; the corona ball will be 4 feet in diameter gold plated wrecking ball. The cab will of course have to be a Faraday cage. I need to work out the watts per cubic centimeter radiation emissions. Bumper sticker included "Lifes to short for QRP" ;D ::)
Please forward tank circuit designs for 27 mHz to BillyBob@trailertrash.com

Hey John. Thats exactly the Diacrode I need for the particle accelerator I'm building in my garage. They wouldn't happen to have one laying around somewhere that can be slipped into the dumpster, do they??? ;)

There are only 3 Diacrodes of that size that have been sold, and I have two of them for the project at work. 7 more will be coming from factory. Not exactly something that will find its way into the dumpster during my watch, Jared. We can wish!

And while I cannot see the plate glow (Xrays and RF levels would be severe) I can see the filament glow quite nicely through 60 small air holes around the lower ceramic. That big filament is at 1950 K, with 20 kW of heat. It makes the ceramic look bright pink. Someday I need to photograph it.

OK, so it glows, and it's a big one. When one appears on 11 meters, that'll be the day.

Lady friends have complained that womens' clothing is artificially expensive. I tend to agree, for example her jeans are smaller but cost more. For sure they do not like that but they buy the costly clothing in any case because they look so good in it.

If it ain't mostly glass, with a filament you can see, it just doesn't count.

The 851 in your avatar counts.  Bigtime.

That 'diacrode' gets eaten by the 6949 anyway.  Methinks

http://frank.pocnet.net/sheets/049/6/6949.pdf

Still no glass glow :'(

73DG

The 6949 was a mighty big tube, 40 inches overall length. but so was the UV862. The new TH628 is replacing RCA 7835 'super power' GG triodes. Compact size is important for VHF of course. 6949 runs 20kV at 50 Amps at 10 MHz. TH628 runs 28 kV at 150 amps, at 200 MHz... Only other tube that's close (and close in power only, not in max frequency) is the 4CM2500KG from Eimac. Its a brute also.

My 851 will have to do for aesthetic appeal here! See my tee shirt in the photo of the TH628 diacrode...

The 862 has to be right up there in vintage glass at 60" tall including water jacket. There were 12 in the final of the WLW 500KW rig.
Another 8 were in the modulator.

http://tubedata.tigahost.com/tubedata/sheets/049/8/862A.pdf

I guess the biggest one around here is an ML-892. Being water cooled it will likely never be used. looks pretty.

OK John, You win.
You have the best RF toys!

Dats right,
               who needs class-E when you got tubes like that to play with  ;D  ;D

Im in QRP category!

The largest glass is a pair of 6C21's which is replacing the 250TH's

The largest ceramic/metal is a YC-156 for a future amp

The most power is a 3CW20000A7  its virtually new and Im just dreaming so far. Complete with socket, filament transformer and filament blower and mounted on a ready to use plate. Came from a local tech college where it was used as a demo, never had HV applied.

So John, when you upgrade those equipments.. and throw away the old tubes... I'm guessing they don't throw out much. Do they still auction off stuff and it goes to the Black Hole or is the BH not buying much any more?

Is this for real?

(http://www.jacmusic.com/nos/images/MegaTube.jpg)

Found here http://www.jacmusic.com/nos/rectifiers.html (http://www.jacmusic.com/nos/rectifiers.html)

Sho nuf.  That is from the old Eimac site.

73DG

The old Eimac photo is their HF test set for the 8974, which was called the X2159 at the time. Ads for this tube used to be on the inside back cover of QST. Most of those tubes were used in big Continental MW transmitters in the middle east, 1 MW carrier power. We used 8 of them in 1 MW pulsed amplifiers at 50 MHz, those have since been mothballed. I grabbed one tube, just for trophy, in storage now. Its a very big tube, but not good for VHF use. The 8973 is a shorter fat tube, that had wire grids. It morphed into the X2142, then X2174 (I think) which led to the 4CM2500KG (pyrolytic graphite grids). These tubes were optimized for CW and fusion heating power.

Patrick, about 10 years ago one of the 8974s did appear in the crate at the Black Hole. I was surprised, ol' Ed wanted $500 for it. I don't know who bought the tube but its gone. Nowadays, most electronics goes to Bentley's auctions every month in Albuquerque. As for the 7835 triodes and their cavity amplifiers, likely will transfer those plus their RCA 4616 tetrode drivers to 2 other Nat Labs where they continue to use the same amplifiers in proton injector linacs.

That 3CW20,000A7 looks like a dandy final amp device. When i worked in RF heating industry in the late 1980s, we used a lot of 3CW30,000H3's at 27 MHz.
They would have been pretty bad for linear amplifiers, needing a lot of grid drive power.

Yea, but the chicken banders would have figgered out some quick and dirty way of doing it!

"Ignorance is bliss"   ::)  ;D  ;D

Here's the other photo that Eimac used in their 1970s X2159 advertisement in QST. It was more of a capabilities showing, than an endorsement for hams to buy this tube! The late George Badger was likely behind this great advertising. I showed him my 851 avatar 10 years ago at an NAB conference, and he
glowed and chuckled.

Also, here is the placard that was stapled to the side of the crate they shipped a 4CW250,000B in.