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--- In ham_amplifiers@..., R L Measures <r@...> wrote:

On Nov 11, 2006, at 10:54 AM, Robert B. Bonner wrote:

Well I do have responses for the comments.

I do currently own a 3K-A. Have had virtually all of them in the

past.

Also have owned an L4B, Swan Mark II never SB-220 or TL-922

however

I've
worked on almost everything at one time or another.

The problem with Henry's and Heath's design is the SOCKETS. The
Johnson
socket mounted below the chassis on 4 bent metal brackets is

the

problem.

### Drake uses the same Johnson sub mounted sockets on the L4B.
[came out in 1969].. on aluminium cylinder standoffs. The 3-500Z
spec is for only .08" h2o... which is easy to achieve. That's
zip..pressure wise. Drake used real Eimac SK-410's on the older
plane jane L4 [1964]

The little holes in the Johnson socket were matched to the 4-XX
series of
tubes. 4-65, 4-125, 4-250 and were designed before they

developed

tubes the
size of 4-400, 3-400, 3-500. There is inadequate cooling around

the

bases
when using these sockets with the larger tubes.

I've seen Eimac 3-500's with the letters burned off one side in
amps like
the SB-220.

RICH SEZ...I have never seen an amplifier with a cooling system

like a SB-220's.

#### Sure their is. The Ten tec Centurion uses the same deal.
The chassis is raised UP, right where the sockets are. Resembles a
small box sitting on the chassis... with two[oposing] sides chopped
out.. so air can pass UNDERNEATH...and hit all the pins. The tiny
slots in the cab are where they screwed up... really restricts air
getting in and out.

The correct Eimac air system sockets REALLY move air through

them

in all the
right places. For instance the 410's and 510's have a collar

where you

actually hook up ducted air to the base.

### agreed. A 4-1000 Deck I bought from W6RU back in 1977 was
done exactly like that. Blower mounted below... with flexible
ducting that fit that collar like a glove.

## On HB 4-1000's... I carefully removed the pins from the SK-
510 socket... then sliced off that collar with a hacksaw... re-
asembled.. then installed em. In that case... blower was on rear
apron... pressurized the chassis.

The problem is that the 3-500Z air system socket requires a high-
pressure centrifugal blower, and Ham amps used an ordinary
centrifugal blower.

### See my note above. A 3-500Z only requires a .08" h2o pressure.

Back in 1970's it was recommended if you weren't using ducted

air,

that you
disassemble the sockets and hacksaw off the collar to allow

even

better
airflow during pressurized chassis operations.

### exactly. An if using the older aluminium Eimac sockets..
like the SK-500 and SK-400... well the pressure requirements on a
SK-500 was 50% higher than a SK-510 .9" vs .6" The 500-
+400 socket had an offset for the small diam air hose. The fix
was to take socket apart... and slice the entire bottom off
transversely with a bandsaw.... then it resembled a 510/410.. with
that collar chopped off.

### On a related note. IF anybody using a 500/400 socket...
beware... there is a screw adjustment for female pin rigidity.
The 500/400 sockets used hollow female tubes to terminate the male
pins of the tube. At the base of the female tubes.. there is an
adjustment to allow some slop or play. I have seen fellows crank
these super tight... then stress the tube seals when the tube is
inserted. IF tight... you have too much lateral force on the male
pins of the tube. Once heated.. the seals will crack.... leave em
loose.

( SO... The next problem with ham designs is the
stupid covers on the amps. Drilling holes to make the boxes look

pretty. BAD airflow. The best would be cut large holes with metal
screens barely blocking the airflow path.

### You just nailed it right there ! The top lid on my L4B's
gets hot with a severe test. I removed the top lid... repeat the
test, and all is well. Some fellow in Ore did ur mod on his
Henry 5 K. Redid the entire blower setup. The other problem with
the 5k is... the holes in the chassis were too small and severely
restricted airflow from below. He increased em by a huge
amount... and also cut nice holes above EACH 3CX-1200.. and
installed those "hamburger grilles"... [4 x hole mount grates..
like u see available for ANY fan, used to keep ur finger's away
from fan blades] In this case.. the grilles are used to keep
fingers away from the anodes... yet let air pass freely... plus
they look good.

RICH SEZ... That's how I do it. I also use a varnished cardboard

flap that hinges up to let the air out. It just doesn't look as
pretty.

### It would look like hell! Now that's what I call "K-mart
construction". Rich would call it part of his.. "ugly amplifier"
scene.

### somebody.. think it was W7RF, radio dan.. supplied curved
plexiglass covers for the henry amps.. to make the exhaust air do
a sweeping right angle... facing the back... this was supposed to
kill some noise.... it would stop dust from settling in.. when not
in use.




A Heath cover is a piece of junk. They paint more of the hole area
closed than have open...

### agreed. Both Heath and Drake woulda been better off to just
made the entire top and sides solid... and 2 x big diam holes..
with fan grilles... right above the tubes.

### here's the interesting bit. Eimac states the glass tubes
cool by infared radiation.... well my natural gas fireplace puts
out loads of radiant heat.... a 3-500Z doesn't. Even though the top
lid gets hot... the sides are stone cold. None of the flat black
sides gets warm... on the inside or out... ditto with surrounding
componnents.

### For a real eye opener... a buddy close by... built a 2 x 4-1000
in gg.... that used LEAD chimney's... made by Eimac too. They
looked identical to a Eimac Glass chimney. They each had a small
teardrop shaped inspection plate on the side... that pivoted... just
like an old oil furnace. He also had the mating 4PR-1000 tubes.
Apparently, these chimney's were used on pulse rated tubes... when
extreme HV was used in pulse service.... the lead of course,
absorbed the X-rays. Never seen a lead chimney b4 or since.
Weighed a ton. Believe they were cast aluminum chimneys... with an
inner and outer lead liner.

Later... Jim VE7RF

On Nov 12, 2006, at 3:05 AM, pentalab wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:

On Nov 11, 2006, at 10:54 AM, Robert B. Bonner wrote:

Well I do have responses for the comments.

I do currently own a 3K-A. Have had virtually all of them in the

past.

Also have owned an L4B, Swan Mark II never SB-220 or TL-922

however

I've
worked on almost everything at one time or another.

The problem with Henry's and Heath's design is the SOCKETS. The
Johnson
socket mounted below the chassis on 4 bent metal brackets is

the

problem.

### Drake uses the same Johnson sub mounted sockets on the L4B.
[came out in 1969].. on aluminium cylinder standoffs. The 3-500Z
spec is for only .08" h2o... which is easy to achieve. That's
zip..pressure wise. Drake used real Eimac SK-410's on the older
plane jane L4 [1964]

The little holes in the Johnson socket were matched to the 4-XX
series of
tubes. 4-65, 4-125, 4-250 and were designed before they

developed

tubes the
size of 4-400, 3-400, 3-500. There is inadequate cooling around

the

bases
when using these sockets with the larger tubes.

I've seen Eimac 3-500's with the letters burned off one side in
amps like
the SB-220.

RICH SEZ...I have never seen an amplifier with a cooling system

like a SB-220's.

#### Sure their is. The Ten tec Centurion uses the same deal.
The chassis is raised UP, right where the sockets are. Resembles a
small box sitting on the chassis... with two[oposing] sides chopped
out.. so air can pass UNDERNEATH...and hit all the pins. The tiny
slots in the cab are where they screwed up... really restricts air
getting in and out.

... but the Heath SB-220 does not do this.

The correct Eimac air system sockets REALLY move air through

them

in all the
right places. For instance the 410's and 510's have a collar

where you

actually hook up ducted air to the base.

### agreed. A 4-1000 Deck I bought from W6RU back in 1977 was
done exactly like that. Blower mounted below... with flexible
ducting that fit that collar like a glove.

## On HB 4-1000's... I carefully removed the pins from the SK-
510 socket... then sliced off that collar with a hacksaw... re-
asembled.. then installed em. In that case... blower was on rear
apron... pressurized the chassis.

The problem is that the 3-500Z air system socket requires a high-
pressure centrifugal blower, and Ham amps used an ordinary
centrifugal blower.

### See my note above. A 3-500Z only requires a .08" h2o pressure.

Correct, but Eimac's 0.82" water column spec is the pressure differential across the socket, and that usually means a fairly noisy blower.

... In this case.. the grilles are used to keep
fingers away from the anodes... yet let air pass freely... plus
they look good.

RICH SEZ... That's how I do it. I also use a varnished cardboard

flap that hinges up to let the air out. It just doesn't look as
pretty.

### It would look like hell! Now that's what I call "K-mart
construction". Rich would call it part of his.. "ugly amplifier"
scene.

A square of varnished cardboard with two nickels glued to the corners along one edge is light enough to rise automatically with the airflow passing through an 8170. When the amp is off the cardboard flops down, keeping spiders from constructing webs on the insides.

### somebody.. think it was W7RF, radio dan.. supplied curved
plexiglass covers for the henry amps.. to make the exhaust air do
a sweeping right angle... facing the back... this was supposed to
kill some noise.... it would stop dust from settling in.. when not
in use.

A Heath cover is a piece of junk. They paint more of the hole area
closed than have open...

### agreed. Both Heath and Drake woulda been better off to just
made the entire top and sides solid... and 2 x big diam holes..
with fan grilles... right above the tubes.

Heath's SB-220 blows cooling air horizontally and out the left side of the perforated cabinet. Holes above the tubes would do nothing.

### here's the interesting bit. Eimac states the glass tubes
cool by infared radiation.... well my natural gas fireplace puts
out loads of radiant heat.... a 3-500Z doesn't.

So objects that glow red-orange do not exhibit infra-red radiation?

...

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

--- In ham_amplifiers@..., R L Measures <r@...> wrote:

RICH SEZ... The problem is that the 3-500Z air system socket

requires a high-pressure centrifugal blower, and Ham amps used an
ordinary centrifugal blower.

### See my note above. A 3-500Z only requires a .08" h2o

pressure.

RICH SEZ... Correct, but Eimac's 0.82" water column spec is the
pressure differential across the socket, and that usually means a
fairly noisy blower.

### The actual spec for a 3-500Z is 13 cfm @ .13" h2o...... or
26 cfm @ .13"... for a pair. And that's for 500/1000 w CCS
anode diss. Now .13" pressure is zip imo. Heck... the
requirements for a SINGLE 3CX-800A7 are 19 cfm @ .5" A 4CX-
250R is 6.4 cfm @ .59" A blower capable of .13" h2o is NOT
noisy. The puny blower in the L4B is dead quiet.. a lot quieter
than the 1" diam tiny fan in my outboard 30 vdc supply for the
yaesu MK-V. [the noise in the mk-v power supply is from the slots in
the cab... not the actual 1" diam fan]

RICH SEZ... That's how I do it. I also use a varnished cardboard

flap that hinges up to let the air out. It just doesn't look as
pretty.

### It would look like hell! Now that's what I call "K-mart
construction". Rich would call it part of his.. "ugly amplifier"
scene.

A square of varnished cardboard with two nickels glued to the

corners along one edge is light enough to rise automatically with
the airflow passing through an 8170. When the amp is off the
cardboard flops down, keeping spiders from constructing webs on the
insides.

### well, at least you got 2 x nickels to rub together !

### here's the interesting bit. Eimac states the glass tubes

cool by infared radiation.... well my natural gas fireplace puts
out loads of radiant heat.... a 3-500Z doesn't.

RICH SEZ... So objects that glow red-orange do not exhibit infra-

red radiation?

### If a 3-500Z is suppose to cool partially via infrared
radiation... I think they are full of it. I can put my hands on the
left side cabinet... [which is flat black... in and out]... and it's
stone cold... and also has zero air on it. You can take the cab
right off... and put ur hand [carefully] on the insides anywhere...
and feel no heat from the infrared radiation. The outsides of the
chimney's are hot [dead cxr, tubes red]... but that's from a lack
of air. The puny blower in the L4B is good for 600W CCS anode
diss... NOT 1kw. The point is.. the infrared radiation is not
heating anything else up in the cabinet. The Fluke 62 IR confirms
this.

### Another point here. The 3CX-800A7 has got 60% MORE anode
diss than a 3-500Z.... but only requires 46% more CFM than a 3-
500Z. So much for..."cooling" by infrared radiation.

### Rich... if you operated the SB-220 at 1500W out RTTY for 1
hr... you wouldn't have enough cooling on the tubes. You would
have to use a real noisy fan. [asuming a real pwr supply, and
loads of air on tank components... like that flaky bandswitch].
The point here is the fan set up in the SB-220 is designed for 600 w
out cw operation [400 w peak anode diss, 200 w CCS].... and 1200 w
pep out on ssb [800 w peak anode diss, maybe 400-500 W CCS]
that's it.... and that asumes you are not TX'ing all the time
either.

Later... Jim VE7RF

...

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Nov 13, 2006, at 2:30 AM, pentalab wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:

RICH SEZ... The problem is that the 3-500Z air system socket

requires a high-pressure centrifugal blower, and Ham amps used an
ordinary centrifugal blower.

### See my note above. A 3-500Z only requires a .08" h2o

pressure.

RICH SEZ... Correct, but Eimac's 0.82" water column spec is the
pressure differential across the socket, and that usually means a
fairly noisy blower.

### The actual spec for a 3-500Z is 13 cfm @ .13" h2o...... or
26 cfm @ .13"... for a pair.

The Eimac spec sheet says 0.82" at sea level.

And that's for 500/1000 w CCS
anode diss. Now .13" pressure is zip imo.

Opinions count way less than manometer measurements.

Heck......

RICH SEZ... That's how I do it. I also use a varnished cardboard

flap that hinges up to let the air out. It just doesn't look as
pretty.

### It would look like hell! Now that's what I call "K-mart
construction". Rich would call it part of his.. "ugly amplifier"
scene.

A square of varnished cardboard with two nickels glued to the

corners along one edge is light enough to rise automatically with
the airflow passing through an 8170. When the amp is off the
cardboard flops down, keeping spiders from constructing webs on the
insides.

### well, at least you got 2 x nickels to rub together !

The nickels are glued down about 5" apart.

### here's the interesting bit. Eimac states the glass tubes

cool by infared radiation.... well my natural gas fireplace puts
out loads of radiant heat.... a 3-500Z doesn't.

RICH SEZ... So objects that glow red-orange do not exhibit infra-

red radiation?

### If a 3-500Z is suppose to cool partially via infrared
radiation... I think they are full of it.

They are correct -- it's called Stephan's Law and the power radiated
is a function of the object's Temp raised to the 4th power.

I can put my hands

You would have done somewhat better at this point had you put your
hands on the mouse and clicked Send. .

on the
left side cabinet... [which is flat black... in and out]... and it's
stone cold... and also has zero air on it. You can take the cab
right off... and put ur hand [carefully] on the insides anywhere...
and feel no heat from the infrared radiation. The outsides of the
chimney's are hot [dead cxr, tubes red]... but that's from a lack
of air. The puny blower in the L4B is good for 600W CCS anode
diss... NOT 1kw. The point is.. the infrared radiation is not
heating anything else up in the cabinet. The Fluke 62 IR confirms
this.

### Another point here. The 3CX-800A7 has got 60% MORE anode
diss than a 3-500Z.... but only requires 46% more CFM than a 3-
500Z. So much for..."cooling" by infrared radiation.

### Rich... if you operated the SB-220 at 1500W out RTTY for 1
hr... you wouldn't have enough cooling on the tubes.

The SB-220 has a ≈600W HV transformer. Hello!
cheers, Jim

.

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

Rich,

it says 0.082" at sea level and 500W dissipation

73
Peter