--- In ham_amplifiers@..., 1800 Toll Free
<TollFree1800@...> wrote:
On Sun, 14 Jan 2007 05:39:33 -0800, pentalab <jim.thomson@...>
wrote:
### 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. :)
### The one I got directly from Howell was $1100.00 a few yrs
back. Packed in Foam, in the Eimac box...foam on all 6 x sides.
When u consider the current price for an Eimac 3CX3000A7 [3x3]...
then throw in the megabuck socket... you now have MORE money
invested... than if you just bought the YC-243 in the 1st place !
### Buying a new Eimac 3CX-6000A7 + mega buck socket = plane
nuts imo. The Eimac 3CX-6000A7 alone costs MORE than the YC-
243.... plus u require the same megabuck socket.
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 cost of a 2 x 6K... just for the PAIR of sockets is
insane... that's $750.00 just for a PAIR of sockets. ... and if u
bust some finger stock on the grid ring.... well I don't see
anybody selling the grid rings separately.
### 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 :)
#### I posted the PDF YC-243 file on the "file" section last
night. I got it from Reid Brandon himself. It does have some minor
error's in it that need to be corrected.
### What they did is, they took a low MU 3CX4500F3/YU-108
industrial heater tube... and stuffed the 225 W high MU grid in it.
Then they tossed the pair of flexible leads.. and used the huge
copper threaded studs instead.. and embedded em in the bar stock.
### The bigger the initial order.. the lower the price tag is. The
next drop in price is quanity's 11-49 tubes.
### 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?)
### The YC-156 is a throw away [as in can't be rebuilt] 8 min warm
up, oxide tube... with a huge diam ceramic stem.. and too small an
anode cooler [4.94"] End result is air intake on bottom sides of
fins is restricted... and hideous pressure is required to force air
through em. It requires a lot of bias too.
### 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.
### Howell also has a Hod rod version of a 1200.... called a YU-
120.... 1500 w of anode diss... plugs straight into a 3-500 Z
socket. 11m guys buy a lot of em.
I'm assuming these YC-243s are rebuildable, since they are
basically one off designs?
### Yes... rebuilt by Eimac themselves.. and also Econco.. and also
Freeland. Most guys are getting Freeland to rebuild em. Most guys
are going through Howell to have em rebuilt too... since he has a
huge pull with Freeland, and can get a way better price getting em
rebuilt for you.. as compared to you dealing directly with freeland
directly.
### Reid Brandon tells me on the phone a while back... that they
have never had any problems rebuilding em either.... and none that
have been sent in for a rebuild have come in with the grids smoked
in em either. And he's talking about YC-243's that have had the
crap driven outa them too!
### The YC-243 retains the glazed Ceramic stem from the industrial
heater 3CX-4500F7 version.. more rugged... and easily cleaned...
which is why they use that kind of ceramic stem in industrial
heater tubes.
### 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.
### Well now they Don't have to waste money on expensive sockets.
Like I said b4... the YC-243 is cheaper than buying a new 3x3 +
socket. It's too easy to damage/break the finger stock on the RF
parts grid ring.
And nobody wants to tell Eimac they are doing us a disservice by
NOT incorporating a socket into every tube they build.
### I got into that exact topic with Reid on the phone. He knows
my thoughts on this all too well. [a] we don't need a socket...
period. [b] told him to start building more socketless
triodes .... b4 Svetlana does... and Eimac could easily get a jump
on their competition. I badgered Reid for quite a while a few
years ago... and so did Howell.... then, outa the blue the YC-243
appears. Reid then informs me about another socketless triode....
called a ... 3CX-20,000C7 [socketless version of a 3CX-
20,000A7].. same deal... huge built in grid flange... just bolt it
to the chassis... 160A fil... and a 500 W grid.
### Since these tubes can be grid driven.... I'm convinced that
running em in GG.. with grid flange bolted to chassis, will increase
the overall grid diss by a little bit. [you have heatsinked the
grid to the cold chassis]
### Howell tells me on the phone 3 x weeks ago, he is getting a
socketless 35,000 A7 GG triode built by Eimac as well... so stay
tuned. It's supposed to be out shortly.
### The linearity on the YC-243 is superb. I was told several
times to getter the YC-243 for a full 48 hrs.. with just rated fil
v and blower for the entire weekend... prior to applying HV. It
worked too. It's a 7.0 v rated tube.... and power output doesn't
drop off till fil V is below 6.1 V. So it will last a long time.
[fil v measued directly at socket.. via a 1 mh choke in each
metering leg.]
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 :)
### agreed. The 4.25" built in grid flange is an intregal part of
the tube... it is NOT bolted on.. like a vac variable flange.
It's welded right to the grid ring... looks like it was cast that
way.. and all silver plated... including insides of all 12 x 1/4-20
holes. Both sides of the fil connections are all silver plated.
It's a WAY better method of making a 79 A fil connection... than
the RF parts socket.
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 :)
### Eimac specs the 3x6 at 6 kw anode diss... with 203 cfm
@ .4" h2o pressure... and with an inlet temp of 50 deg C [121 deg
F]. With 315 cfm @ .9" h20.... and a lower inlet air temp...
like 20 deg C [68 deg F] anode diss increases to 9700 W. With
an inlet air temp of 25 deg C... it's still 9200 W. And with an
inlet temp of 50 deg C [121 deg F]... it's STILL an easy 7500 W.
## This tube has such low back pressure requirements as is..
stock... it was a snatch to figure out it was gonna be real easy to
blow more air through it. The secret is in the small diam stem ...
plus the 6.125" cooler. The underside of the fins is a huge
area. The real trick is I calculated you need at LEAST as much
surface area in the form of either holes, slots, or slots cut like
a Maltese cross, in the chassis.. and preferably even more surface
area cut outa the chassis.... compared to underside of tube fin
area.
### The 9.5" square wooden box remains intact too. IF doing
this from scratch... I would suggest using the big greenlee
punches.. and whacking a ring of I think it was aprx 1 5/8" diam
holes around the base of the tube. In the photo page... u can see
the original small ring of holes, and stock grey Economy Electronics
chimney. Economy said the reason they made the chimneys bigger
diam than needed, is that for some reason.. when the tubes come back
from the rebuilders... the OD of the tube anode is always slightly
bigger than the stock 6.125". Howell said the exact same thing..
and Howell's solid Teflon chimney is now bigger ID also.
### we were NOT impressed with this "standard" set up...... hence
the 9.5" square box idea. Some will make the box outa thick
micarta... or thick teflon... but the plane wood works just fine. 2
x screws hold the box to the chassis.. so it doesn't budge.. and
makes a perfect air tight seal.
### By making the box even taller... you can toss the
economy/howell chimney's.... and just use a solid teflon flat top...
with a hole cut into it... to make an EXACT fit for the tube. And
if it comes back from the rebuilder's with a slightly bigger anode
OD.... then simply remove the teflon flat top piece.. and replace
it with another one... this time with a slightly bigger hole.
The solid 3/16" teflon top is screwed to vertical sides of box...
since vertical sides are plenty thick enough.
### End result is a TON of extra air flow.... and dirt cheap to
build... except for the teflon top.
### 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.
## That's good. Pix are worth a thousand words. Contact me
offline if u need Howell's e mail/ ph number etc.
later... Jim VE7RF
--Toll_Free
