On Sun, 14 Jan 2007 05:39:33 -0800, pentalab <jim.thomson@...> wrote:
--- In ham_amplifiers@..., 1800 Toll Free
<TollFree1800@...> wrote:
Of course, since the waveform is nothing more than a squarewave
when it hits the pair of 4CX15000's, they can take being driven by
15,000 watts.
The duty cycle is a lot less than 100 percent, overall.
### I take it they run the 4 x 15's in GG.. with screen and grids
all bonded to chassis ? If they need 15 kw to drive em....
heck.. why not just grid drive em ???
No... lol.
You would think so... But they don't. Grid driven.
There are really two 'builders' of 4CX boxes that actually keep them grid driven.
One, he knows what he's doing, and his boxes are pieces of art.
The other, the only reason his Chi town built boxes aren't more wideband oscillators is because he can't get any type of spaghetti rats nest out of them. The layout is SO poor they won't support self oscillation. (that's the box in question here, BTW).
### BTW... I had a call from Arnold Howell not too long ago....
IF any of ur 11m buddy's require YC-243's... [ Eimac
SOCKETLESS version of a 3CX-6000A7 / YU-148] lemme now asap....
if he gets enough interest.... he's gonna get Eimac to do a small
production run.... BUT he won't do it unless at least 10 x tubes
are ordered.
I've already sent some email's out. Can't guarantee anything, but I'll see what I can do.
Any idea on what out the door price will be? I have a YC-156 project coming up that might be scrapped due to the enlightenment of this new tube / cooling tower. :)
One of the gentleman I sent said email to builds custom 1x and 2x 6K boxes. I'm <<thinkin>> he might jump on this, but.. You know how 11 meter people are :) lol
### The YC-243 is slick.... comes with a built in 4.25" diam grid
flange vs the 4" diam grid ring on the socketed version. The
fil assy is solid silver plated bar stock.... with two huge
threaded bolts pointed straight down, embedded in the bar stock.
I'm going to take a nice hard look at it.
If you would have said something 2 months ago, I might have ordered all 10 of them myself. Instead the wife says all monies at this point go towards house purchase. Damn family obligations :) At least I get a dedicated 10X12 ham room at the new house ;) Detached and all :)
### Just whack a hole in chassis... and bolt grid flange [ 1/8"
thick] to chassis with 12 x 1/4-20 bolts. All silver plated..
a real thing of beauty.
Sounds good... Kind of like what the YC156 should have been (what WHERE they thinking with the grid structure in that tube?)
### Economy Electronics doesn't sell em anymore either... and
it's Howell's design.
There was another "one off" tube being offered that I can't remember the name of.. It was a YC tube as well, but was the "solid state" replacement for the 3-500Z. Offered 1600 watts of plate dissipation, as I remember.
Reminded me of Kenny in San Diego and his dual 1200A7 modified L4Bs and Henry's. Nice desktop 5K units :).... I just wondered what the intelligence was behind building amps based on one off tubes.
I'm assuming these YC-243s are rebuildable, since they are basically one off designs?
### They sell for LESS than a standard socketed 3CX-6000A7... and
now that the sockets from RF parts are up to $375.00.... u save
the cost of the socket as well.
The price of tube sockets is like gas, cigarettes and sex. People will spend because they have to.
And nobody wants to tell Eimac they are doing us a disservice by NOT incorporating a socket into every tube they build.
Any other thoughts on that? My take was it's a lot more stable amp with not having a socket, as long as you get a GOOD connection ALL THE WAY around the bolt in grid flanges? Not to mention, I always liked having bolt together connections, instead of finger stock, on my 160A filaments :)
### If anybody wants the Official Eimac PDF file on this YC-243..
lemme know. I'll send it to you. Next week, I'll see if I can
post the PDF file on the "files" link .. just above .."photo's"
### I came up with a way better chimney scheme than either the
Economy Electronics grey chimeny.. or Hoewll's Teflon chimney
[which is 1/4" thick solid Teflon.. and weighs a ton].
### We built a 9.5" square box around the base of the tube... and
used the original chimney in a recessed groove on top of box.
Using a Dayton 5C508 blower.. we could get an easy 320 cfm out
the top of the tube. [at .9" h2o pressure] With a 20 deg C [68
deg F] inlet air temp.... the anode diss is 9700 W CCS !
### The whole secret was the 9.5" square box. That allows plenty
of holes in chassis. The ceramic stem on the both a 3x3 and a
3x6 is small in diam.. compared to say a YC-156, etc... and there
is plenty of intake surface fin area on the underside of a 3x6.
### The latest version uses a taller box... and a solid Teflon
top.. with a 6.125" hole in it......... eliminating the aftermarket
chimney's alltogether.
### The stock aftermarket straight up/down chimney's restricted
the airflow like crazy.... due to the smaller holes u could cut in
the chassis cuz of the smaller ID of the chimney's. They were
also too big an ID... letting even more air escape on the outside
of the tube.
I've already called someone working on a single 3x3K dring a 3x20K amp. He is going to try testing out your cooling method on his 3x3 amp, and if it works as well as it looks / claimed, he's also going to try it on the 3x20k amp.
Plate dissipation increases are always nice :)
### You can see all 50+ pix of this on the photo page . Click
on "photo's".... then "VE7RF" [it's the photo album with the
25 kw CD slug. ]
I will.
I've got a pic of a dual 15000 box being put together. The "owner" wants no "fame", so to speak, but if I can get him to let me put it up I will.
--Toll_Free
Later.... Jim VE7RF
--
*Ratings are for transistors, tubes have guidelines*
