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--- In ham_amplifiers@..., "zerobeat40" <zerobeat40@...>
wrote:

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

On Oct 29, 2006, at 5:54 AM, pentalab wrote:

---

### well maybe not too stupid. 3 x YC-156's can be had for
$1100.00 vs huge bux for a 4 x 15.[plus socket]

RICH SEZ... What is Svetlana's price for an 8281?

##### They are now $1995.00 socket is $395.00... both svetlana
brand. The Eimac version of both will make u gag.

Last 8281 I bought brand new set me back about $1050, and I think I
had to add a socket. And, the tube's pushing good and hard at 20k,
while a trio of YC-156's is loafing at 30K. Remember, a YC-156 is
actually a 3CX15,000B7 with a smaller cooler.

### agreed. YC-156/YC-179's are everywhere.. and no [failure
prone} socket to mess with. Note to Tony King here. A buddy of
mine asked Eimac if they could take a YC-156... and put the
3CX15,000B7's cooler on it [7.5"]. Eimac said "no way". BTW...
a broadcast engineer school buddy of mine said they had several
problems with the SK-300A socket burning up on the local 100 kw
ERP FM tx here in town.[abt 18 yrs old now] No wonder Eimac
makes "emergency repair" kits for those sockets. The socket
had burned up twice.... b4 1994 [it was only 10 yrs old at that
point]




You CAN push more air (put the amp in another room, please) and run
them quite harder. I have a push-pull broadband pair of YC-156s
here, runs 2MHz to 40MHz braodband, for EMC measurements, driving a
TEM cell. 30kW CW not a problem. Not pushing ANY of the tube's I
or V limits, and with enough air, I keep the seals below 250C.

### These YC-156/YC-179's.. with their almost 19db of gain..

Eimac says the gain is 14.2db at 6kV.

You have to read all the conditions of that gain spec. 14.2dB is
correct with a 600 ohm load-line. That will give you 24kW PER

TUBE. If you're getting 30-35kW from three tubes, you're running
more like a 1500 ohm load line per tube. At a higher RL, the tube
exhibits more gain.

### agreed.


Also, that 14.2dB is conservative - it's into compression at

that point. Cleanly, it's another dB, then add a few more for the
higher RL.

### agreed. Most builder's appear to be getting 17 to 17.8 db
with a single tube.. running 6500 V - 7200 V ..under load. With
higher ratio's of plate load Z to input Z... gain goes UP.. as u
noted.

### 12 k out with 200 w of drive is quite common. IMO... a
lot simpler than mucking about with a 4x10, regulated screen +
bias supplies, roller's across the input globar..+ step up 9:1
trifilars, neutralizing the entire amp, megabuck sockets, etc.
A good used YC-156[$300-$400] beats a new 4x10 + socket any day.
Something to be said for simplicity. Just whack one hole in the
chassis... done. Round up a 10 kva-120 lb 4800 V hypersil pole
pig for very little.. and there's ur 6800 V no load HV supply.

Besides, nobody who's actually designing an amp depends on the
"typical application" data to predict performance.

### agreed.

You calculate gain from the characteristic curves.
### agreed.



At 20kW output and 6.5kV anode, I see YC-156s typically running
at 17dB gain.

### see my previous notes. Depending on used tube condx, ops are
reporting anywhere between 17 to almost 19db of gain.



Most of my experience in broadcasting with them was with the
3CX15,000B7 version, but they work the same...the YC-156 just needs
to be blasted with lots more air.

are
the 4-1000 for the new milenium... quick, where's that pole

pig ?

### I'm serious....

Serious people look at the mfg's spec sheet instead of

speculating.

Exactamundo. The grounded-grid curves for the YC-156 will predict

all the figures he gave. You just have to know how to use them, and

that's happily explained in "Care and Feeding."

### agreed... like zsac for a given plate V, grid current, plate
current, etc. Heck, I still have the origional Eimac... "tube
performance computer" ! [clear plastic overlay device, when
doing load lines] ... still works, still use it.

Later.... Jim VE7RF

cheers, Jim


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

________________________________

From: ham_amplifiers@... [mailto:ham_amplifiers@...]
On Behalf Of pentalab

### These YC-156/YC-179's.. with their almost 19db of gain..

RICH SEZ..... Eimac says the gain is 14.2db at 6kV.

### Who cares what Eimac sez ?

### fact is.. on a YC-156/YC-179.. folks are getting a power gain
of 50-60 = 17-17.78 db. 200 w of drive and 7200 V under load

I do not see the almost 19dbs here...
When you raise anode voltage gain will be higher with any tube.
A lot of YC-156 amps are running in Germany, none does more then 17dbs of
gain at 6KV

### Notice how Eimac sez u need 450 w to drive a 3x3 ? That put
hundreds of guys off using that tube for yrs on end. Folks didn't
like the 500 ma zsac either. Turns out with 50 w of drive = 1.5
kw out. 200 w of drive = 5200W out....

Eimac did not say you need 450W to drive a 3x3 to 1,5KW...
When you use the constant curves of the Eimac data sheet you see all this.
With 4,8KV at the anode you need 280-300W drive for 5,2KW out(we run 4
monoband amps with that tube).

### Imo... I use their number's, as a guidline. Once an amp is built
around their tube.. say a YC-156... and u talk to other builder's...
you get a feel for what kind of zsac is really
needed PER mode...

I rather do my own measurements.
Other builders talk like fishermen, when I visit them I see and measure the
truth ;-)

73
Peter

Tony King - W4ZT wrote:
<snip>

I will measure this tomorrow and report back the difference between the
measured anode to grid capacitance unmounted and sub-mounted.

Regarding YC-156/179 sub-mounted capacitance.

I measured this today on a YC-179. Sitting on the counter top grid to anode measured 40.85 pF. Sub-mounted in a chassis it measured 44.67 pF.

73, Tony W4ZT

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@...>
wrote:

a friend and I had the same problem once with a qro rig and went

with two tall insulated standoffs with a singls strand of RG8
shield. Smaller wire would fuse at lower currents. gfz

## I have used the exact same deal... used one single strand from
the multi strands in the Belden 10 kv test prod wire. One day it
blew. [op error]... and blew right away [no load] when replaced.

### Stuck my dvm between chassis and top of each insulator [all
HV wiring removed at each end, no fuse wire]... and the output
insulator read a DEAD SHORT ! How can a 1.75" tall insulator
read a dead short? Got in with a dentist mirror.... and on the
back side.... it had vapour deposited top to bottom ! Scrubbed
it off... all was well. If that had been the INPUT insulator,,, I
could have easily smoked the 3 A diodes, or something else in the
supply. Started using sandilled HV fuses after that.[ I now also
use nothing but 6A10 diodes... cheap. 1 kv-6A CCS 400 A surge,
exactly double the diam of a 1N5408... same ga wires out each
end... and same body length. You can retrofit a 1N5408 with a 6A10
very easily... they run like warm with 2 A CCS DC through em in a
test jig, a 1N5408 runs look warm with 1 A in same test jig].

### Now my buddy ate up his supply of sandfilled fuses.... so in
desperation one night.... soldered a single strand of real small
ga wire across a blown sandfilled fuse.... THEN wrapped it
with scotch 77 tape ! Now this works slick, cuz when it
blows... NO vapour deposit flying about. This way u can RE-
USE em, if needed... over and over again.

## A 2-6" long piece of round ceramic in 2 x clips, would do
exactly the same thing.... then tape the exposed fuse wire.

Later... Jim VE7RF

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

. He needs a 15k or 20k!

RICH SEZ.... Paralleling 3 tubes triples C-feedback, and that

is

not desirable unless one is trying to build an oscillator. The
tube that is best suited for 20k - 35k out is the

8281/4cx15000A.

200w will drive one in AB1.

### So what ?

RICH SEZ... Anecdotal sure-cures don't cut the parasitic mustard.

### Anecdotal?? Tell that to the 300 guys who run the above
tubes just fine...sans suppressor. IMO... having the grids bolted
right to the chassis IS 99.99% of the stabilty secret. Semi
floated grids on a 3-500Z is just asking for trbl.

Just install a globar type suppressor in each anode
lead. As is, the single YC-156 runs just fine wtih NO

suppressor at all.. and that's with it .75pf of feed through C
to boot. The single 3CX-3000A7 runs just fine sans suppressor
with it's .6 pf of feedthrough C. The 3CX-6000A7 has just .28
pf of feedthrough C. We can probably toss the suppressor on
that amp as well. At this rate, we can put globar outa business.

### well maybe not too stupid. 3 x YC-156's can be had for
$1100.00 vs huge bux for a 4 x 15.[plus socket]

RICH SEZ... What is Svetlana's price for an 8281?

### RF parts wants $1995.00 for a Svetlana 4x15.... PLUS
another $395.00 for a svetlana SK-300A socket. .. so $2400.00
in total. You can get 2 x new Eimac YC-243's for slightly less...
and crank an easy 30 k out the back door.... and cool em way
easier.

### Check the air specs on a 3x 15 or a 4 x 15.... horrendous.
Something like 840 cfm @ 6.4" h20. I saw a FM broadcast Tx
with 2 x 3x15's.... it had a 5 HP- 3 phase blower.... just to
cool em. A lousy analogy woul be like trying to stuff 100 cfm
through a key hole.

### These YC-156/YC-179's.. with their almost 19db of gain..

RICH SEZ..... Eimac says the gain is 14.2db at 6kV.

### Who cares what Eimac sez ? They either don't build amps
around these various tubes... or quote.. "estimated"
or "calculated" specs. Imo... Eimac makes a tube.... it's up
to the end user to make it work right.

### fact is.. on a YC-156/YC-179.. folks are getting a power gain
of 50-60 = 17-17.78 db. 200 w of drive and 7200 V under load =
12 k out. 10 k out, with lower plate V. So I guess
Eimac's '14.2db' is out to lunch.... who cares... just run the
tube the way u see fit.




### Notice how Eimac sez u need 450 w to drive a 3x3 ? That put
hundreds of guys off using that tube for yrs on end. Folks didn't
like the 500 ma zsac either. Turns out with 50 w of drive = 1.5
kw out. 200 w of drive = 5200W out.... and that's with just
4.8 kv under load. The tube is squeaky clean with 150 ma of zsac.
Then along comes the 11m ops... running 8 kv under load.

are
the 4-1000 for the new milenium... quick, where's that pole

pig ?

### I'm serious....

RICH SEZ... Serious people look at the mfg's spec sheet instead of

speculating.

### So where's all the missing specs for a 3CX-6000A7 in AB-2,
GG ??? Eimac just gives us FM Class C broadcast specs.... turns
out they also quote running ZERO bias. Obviously, with zero
bias... it's in AB-2... NOT class C. They are also quoting near
impossible efficiency numbers... when figuring out their 'typ op
condx' and take plate v x plate I... and their "estimated
output"... and start coming up with ridiculous eff numbers....
meanwhile with zero bias... the tube(s) are more like pushing
Class A region... and cooking on idle.

Eimac to this day can't tell you what the input Z on that tube
is. And it's not 6 kw anode diss.... it's an easy 9.7 kw. They
can't even tell u what the grid current is gonna be.... nor the
specs on the 3x6 for imd either.... turns out the 3x3 and 3x6
are the best imd triodes going. Check out their Blue 'erata
sheet'... that comes with their latest catalog.... doz's of
typo's and specs wrong.... plus a bunch more I found... that are
not listed. ..go figure.

Imo... I use their number's, as a guidline. Once an amp is built
around their tube.. say a YC-156... and u talk to other builder's...
you get a feel for what kind of zsac is really
needed PER mode... what to expect with XXX plate V... and ditto
with drive levels.... then you end up with ur own "typ op condx" +
hence... find an optimum set of condx to run the tube(s) at.

Later......... Jim VE7RF

cheers, Jim


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

a friend and?I had the same problem once with a qro rig and went with two tall insulated standoffs with a singls strand of RG8 shield. Smaller wire would fuse at lower currents. gfz

pentalab wrote:

speaking of fuse clips. do any of you guys know where?I can get some big clips for fixed vacuum caps like used in the BC610 padder cap. I need to add a padder to my antenna tuner for 160 meters. I think the end of the cap contact is about 3/4 inch od.

Frank Goenninger wrote:

Am 30.10.2006 um 19:46 schrieb pentalab:

#### SSON [surplus sales of nebraska] has tons of Buss HV
fuses. The HVU-3 is what I use. [rated at 3A @ 5 kv AC]
These are 13/16" diam on the ends, and fit standard 3/4" fuse
clips. The fuse itself is 13/16" diam x 5" long. They have the
3/4" clips too... in 2 x diff styles.... I use the slightly better
ones... with the end retainers. That way, once inserted... they
CAN'T slide out. Good, cause mine are mounted vertically in
several of my many HV supplies.

;-) Worth to remember when choosing to put them vertically.

### You can still get em new... on Cooper Bussman's
website ,buried under HV fuses. The HVU series above is
sandfilled, u can also get em without the sand..... and a lower max
interupting current rating. The new ones all have ceramic bodies,
these surplus ones all have glass bodies.

Just looked on the UK web site of Cooper Bussman and found a German distributor (a mere 100 km away from where I live. Good!) - Thanks!

### The 120mm long ones available in EU should also work. I'd
place any HV fuse BEFORE the glitch R, not after.... just in case
the glitch R comes apart... and touches the chassis/metal. I
also insert a 2nd HV fuse [in one leg only on a single phase xfmr]
between xfmr sec... and diode board.

Yes, that's what I had in mind, too. Although the SKN3F20/08 diodes I use are of the more rugged type... ;-)

later... Jim VE7RF

Thanks again!

73, Frank DG1SBG

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

On Oct 30, 2006, at 1:08 AM, Frank Goenninger wrote:

Hi all:

I am about to finish my HV power supply. One thing missing still

is

an appropriate HV fuse to be put between C bank and glitch R.

While

closely examining the pictures in the photos section of this

group I

couldn't find any European manufacturer or distributor of HV

fuses.

I found SIBA () - but they do provide fuses for
even "bigger" applications... I'd need something suitable for

the 3,5

kV / 3 A coming out of my 300 ?F C bank...

Any suggestions? Thx for feedback!

RICH SEZ.... Hello, Frank == A HV fuse in the secondary does not

protect the HV- transformer any better than a circuit breaker in
the primary. cheerz

### What about protecting everything else ???? Short the B+ to
the chassis/ anywhere... and when comparing a fast HV fuse vs the
fastest magnetic hydraulic breaker in the 240 V pri.... the
difference is blatantly obvious. Been there.. done that. The only
thing faster than the fastest breaker is... "rectifier and
semiconductor" pri fuses... available up to sevral hundred amps.
These fuses can be used to supplement a slow breaker.... OR can be
used in cases where the breaker rating is way too high to start
with. [eg: multiple sec HV taps on a plate xfmr... where u want
to run say a single 3CX-800A7 on 6m one day... and 15 kw out the
next day, with a different amp of course.]



### Primary AC protection is way too slow imo. Since my xfmr has
loads of sec taps... I use it at different voltages... so a 100 A
breaker in the primary is too big for some applications. Another
Fix is to use a pair of 50 A double pole breaker's.... and
parallel each pair. By removing the tie-bar between em.... for
50 A operation... one pole on each breaker is shut off.

### If u are gonna parallel a 2 x pole 50A breaker, so it
handles 100 A... you have to do it right.... enter on one
corner...and exit diagonally on the output. Then the current
will split 50-50 on the poles.

### This scheme also works on 3 pole breaker's. [which use 2 x
tie bars per breaker] You can parallel all 3 x poles..... and by
removing the 2 x tie bars on each breaker ...... you can have a
50-100-150 A choice. 2 x such assys are always required.... one
per hot leg on a NA single phase, 240 v circuit.

## Bottom line is.... when a HV fuse open up... nothing happens..
no big deal. They are extremely fast under fault conditions...
like <2 msecs.

Later... Jim VE7RF

73 Frank DG1SBG
...

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

Forget the link to the datasheet:



The only thing I have against the YC-156 is the noise...damn, they're
loud, if you're wanting to run power and keep 'em cool.

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

On Oct 29, 2006, at 5:54 AM, pentalab wrote:

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

On Oct 29, 2006, at 2:45 AM, pentalab wrote:

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-
060920@> wrote:

Pentalab wrote:

---

### well maybe not too stupid. 3 x YC-156's can be had for
$1100.00 vs huge bux for a 4 x 15.[plus socket]

What is Svetlana's price for an 8281?

Last 8281 I bought brand new set me back about $1050, and I think I
had to add a socket. And, the tube's pushing good and hard at 20k,
while a trio of YC-156's is loafing at 30K. Remember, a YC-156 is
actually a 3CX15,000B7 with a smaller cooler. You CAN push more air
(put the amp in another room, please) and run them quite harder. I
have a push-pull broadband pair of YC-156s here, runs 2MHz to 40MHz
braodband, for EMC measurements, driving a TEM cell. 30kW CW not a
problem. Not pushing ANY of the tube's I or V limits, and with enough
air, I keep the seals below 250C.

### These YC-156/YC-179's.. with their almost 19db of gain..

Eimac says the gain is 14.2db at 6kV.

You have to read all the conditions of that gain spec. 14.2dB is
correct with a 600 ohm load-line. That will give you 24kW PER TUBE.
If you're getting 30-35kW from three tubes, you're running more like a
1500 ohm load line per tube. At a higher RL, the tube exhibits more
gain. Also, that 14.2dB is conservative - it's into compression at
that point. Cleanly, it's another dB, then add a few more for the
higher RL.

Besides, nobody who's actually designing an amp depends on the
"typical application" data to predict performance. You calculate gain
from the characteristic curves. At 20kW output and 6.5kV anode, I see
YC-156s typically running at 17dB gain. Most of my experience in
broadcasting with them was with the 3CX15,000B7 version, but they work
the same...the YC-156 just needs to be blasted with lots more air.

are
the 4-1000 for the new milenium... quick, where's that pole pig ?

### I'm serious....

Serious people look at the mfg's spec sheet instead of speculating.

Exactamundo. The grounded-grid curves for the YC-156 will predict all
the figures he gave. You just have to know how to use them, and
that's happily explained in "Care and Feeding."

cheers, Jim


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

--- In ham_amplifiers@..., Frank Goenninger <frgo@...>
wrote:

Hi all:

I am about to finish my HV power supply. One thing missing still

is

an appropriate HV fuse to be put between C bank and glitch R.

While

closely examining the pictures in the photos section of this group

I

couldn't find any European manufacturer or distributor of HV fuses.

I found SIBA () - but they do provide fuses for
even "bigger" applications... I'd need something suitable for the

3,5

kV / 3 A coming out of my 300 ?F C bank...

Any suggestions? Thx for feedback!

#### SSON [surplus sales of nebraska] has tons of Buss HV
fuses. The HVU-3 is what I use. [rated at 3A @ 5 kv AC]
These are 13/16" diam on the ends, and fit standard 3/4" fuse
clips. The fuse itself is 13/16" diam x 5" long. They have the
3/4" clips too... in 2 x diff styles.... I use the slightly better
ones... with the end retainers. That way, once inserted... they
CAN'T slide out. Good, cause mine are mounted vertically in
several of my many HV supplies.

### You can still get em new... on Cooper Bussman's
website ,buried under HV fuses. The HVU series above is
sandfilled, u can also get em without the sand..... and a lower max
interupting current rating. The new ones all have ceramic bodies,
these surplus ones all have glass bodies.

### The 120mm long ones available in EU should also work. I'd
place any HV fuse BEFORE the glitch R, not after.... just in case
the glitch R comes apart... and touches the chassis/metal. I
also insert a 2nd HV fuse [in one leg only on a single phase xfmr]
between xfmr sec... and diode board.

later... Jim VE7RF

73 Frank DG1SBG

Am 30.10.2006 um 12:02 schrieb R L Measures:

Hello, Frank == A HV fuse in the secondary does not protect the HV-
transformer any better than a circuit breaker in the primary. cheerz

Yes, but it might protect a few other parts of the PS...

Thanks, Rich, for the heads up.

73, Frank DG1SBG

craxd wrote:

Larry,

This bound to have been in the early 70's or so. I had a GTE/Philco
19" TV I took in as a trade in and I played it myself for about a
year before I sold it. I can't remember if it was all solid state or
if it was a hybrid. Seems to me they had an old paper type light
green colored PC board in them. I think they was about the first to
own the Philco name after Ford, maybe bought it from them? North
American Phillips ended up with all three names. As far as I know,
N.A.P. no longer is selling new Philcos, only Magnavox and Sylvania.

Philco was the set for a private dealer to get a franchise on as
Sylvania and Magnavox was being pushed by the large chain stores. It
was all that was available over Lowes and a few other large stores
starting to sell them in the early 80's. Lowes was who hurt me. Now,
I don't think Lowes even handles TV sets. RCA was bad to not protect
a teritory and set someone else up a mile away so I never looked at
them. I had the Quasar sales for a while also, but they got just too
hard to work with. Now they're all chain store items.

Best,

Will

--- In ham_amplifiers@... <mailto:ham_amplifiers%40yahoogroups.com>, Larry Anderson
<larryw6lar@...> wrote:

craxd wrote:

Bill,

That is exactly the truth. When I started in repair (radio and

TV),

tube sets were still around. There, you replaced parts in a

chassis

with point to point wiring. Next came addition of PC boards with
tubes, and then the hybrid sets came having both tubes and solid
state devices. After that came the modules. That was easy fixes,
however the power supplies power components like resistors, etc

were

still mounted on tie strips, etc. Zenith modular sets were my
favorite with the upright chassis. Magnavox had one similar.
Motorola, soon to be Quasar had the "works in a drawer". Next came
the replacable chassis. No more modules, they wanted you to change
the whole chassis out. Then it was only one large flimsy PC

board. I

repaired most of these anyhow and only changed a chassis after
lightning damage. First you had a chassis and a tuner. Finally,

the

one board included both. I forgot to mention that hot chassis

started

about this time or a little earlier. I was selling and servicing
Philco TV's at the time for North American Phillips. Phillips

bought

Philco from GTE. Then, all Phillips did was run the same TV set

down

the line and put 1 of 3 name tags on them, Philco, Magnavox, or
Sylvania. About this time is when the mass marketing of TV's

began by

Lowes, K-Mart, and others large chain stores. They could sell a

set

at the same price as what a private dealer could buy one for. That
closed a lot of repair shops including mine. Eventually, sets got

so

cheap that you could throw them away as the cost of repair was at
least 50-76% of a new set. This especially true for 19 inch TV's

on

down. VCR's did the same thing too. Now you can buy a new VCR for
about $50.

All that's taught for service anymore is replacing a chassis, and
most of it is building PC's. Vacuum tube technology is not taught
anywhere I know of. After some of us older folks are gone, I

wonder

who will actually be able to do real repair work anymore?

Best,

Will

--- In ham_amplifiers@...

<mailto:ham_amplifiers%40yahoogroups.com>

<mailto:ham_amplifiers%40yahoogroups.com>, Bill Turner <dezrat@>

wrote:

We seem to be casting a lot of blame on individuals, but I

believe

the

underlying problem isn't people, it is the nature of electronic
equipment these days.

A lot of us got our start by being repairmen, and to do that

kind of

work well, one must understand the fundamentals of electronics.

These

days, you either change a PC board (if it is an expensive piece

of

gear), or you just throw it out and buy another. So-called
"technicians" anymore are mostly just parts changers, not real
repairmen. I don't see that changing any time in the near

future.

Of course there are some real technicians around, but any more

they

are working mostly at the engineering level, not the field

repair

level, and there are not a lot of them because not a lot are

needed.

Once the bugs are worked out of a design, you just make 'em by

the

millions and toss the bad ones.

Sad but true.

Bill, W6WRT

Will,
Question? When did GTE own Philco? I've been with them (GTE/

Verizon) for

43 years and I only know that they owned Sylvania.Was that before

my

time there. Just wondering.

Larry, W6LAR

Will,
I think you jogged my memory as after I ask the question I seemed to remember that just before GTE sold out the Sylvania line they did take on Philco from Ford. Boy! thats a long time ago. We used to have an "Employee Store" at selected company yards integrated with our supply department and all of the Sylvania products were offered and you could purchase on "time" payment through payroll deduction with no interest. Was a great deal for those of us just starting out to get some nice electronics. I still have a few items I purchased there. Thanks for the info Will.

Larry, W6LAR

Hi again:

Further digging into details of the SIBA web site revealed a search
function:



Specifying a voltage of 6 kV gives a result for a 8 x 120 mm fuse
having a rated current of up to 4 A. I am going to try to use one of
these...

73 de Frank DG1SBG


Am 30.10.2006 um 10:08 schrieb Frank Goenninger:

On Oct 30, 2006, at 1:08 AM, Frank Goenninger wrote:

Hi all:

I am about to finish my HV power supply. One thing missing still is
an appropriate HV fuse to be put between C bank and glitch R. While
closely examining the pictures in the photos section of this group I
couldn't find any European manufacturer or distributor of HV fuses.

I found SIBA () - but they do provide fuses for
even "bigger" applications... I'd need something suitable for the 3,5
kV / 3 A coming out of my 300 ?F C bank...

Any suggestions? Thx for feedback!

Hello, Frank == A HV fuse in the secondary does not protect the HV-
transformer any better than a circuit breaker in the primary. cheerz

73 Frank DG1SBG
...

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

Hi all:

I am about to finish my HV power supply. One thing missing still is
an appropriate HV fuse to be put between C bank and glitch R. While
closely examining the pictures in the photos section of this group I
couldn't find any European manufacturer or distributor of HV fuses.

I found SIBA () - but they do provide fuses for
even "bigger" applications... I'd need something suitable for the 3,5
kV / 3 A coming out of my 300 ?F C bank...

Any suggestions? Thx for feedback!

73 Frank DG1SBG

Larry,


This bound to have been in the early 70's or so. I had a GTE/Philco
19" TV I took in as a trade in and I played it myself for about a
year before I sold it. I can't remember if it was all solid state or
if it was a hybrid. Seems to me they had an old paper type light
green colored PC board in them. I think they was about the first to
own the Philco name after Ford, maybe bought it from them? North
American Phillips ended up with all three names. As far as I know,
N.A.P. no longer is selling new Philcos, only Magnavox and Sylvania.

Philco was the set for a private dealer to get a franchise on as
Sylvania and Magnavox was being pushed by the large chain stores. It
was all that was available over Lowes and a few other large stores
starting to sell them in the early 80's. Lowes was who hurt me. Now,
I don't think Lowes even handles TV sets. RCA was bad to not protect
a teritory and set someone else up a mile away so I never looked at
them. I had the Quasar sales for a while also, but they got just too
hard to work with. Now they're all chain store items.

Best,

Will


--- In ham_amplifiers@..., Larry Anderson
<larryw6lar@...> wrote:

craxd wrote:

Bill,

That is exactly the truth. When I started in repair (radio and

TV),

tube sets were still around. There, you replaced parts in a

chassis

with point to point wiring. Next came addition of PC boards with
tubes, and then the hybrid sets came having both tubes and solid
state devices. After that came the modules. That was easy fixes,
however the power supplies power components like resistors, etc

were

still mounted on tie strips, etc. Zenith modular sets were my
favorite with the upright chassis. Magnavox had one similar.
Motorola, soon to be Quasar had the "works in a drawer". Next came
the replacable chassis. No more modules, they wanted you to change
the whole chassis out. Then it was only one large flimsy PC

board. I

repaired most of these anyhow and only changed a chassis after
lightning damage. First you had a chassis and a tuner. Finally,

the

one board included both. I forgot to mention that hot chassis

started

about this time or a little earlier. I was selling and servicing
Philco TV's at the time for North American Phillips. Phillips

bought

Philco from GTE. Then, all Phillips did was run the same TV set

down

the line and put 1 of 3 name tags on them, Philco, Magnavox, or
Sylvania. About this time is when the mass marketing of TV's

began by

Lowes, K-Mart, and others large chain stores. They could sell a

set

at the same price as what a private dealer could buy one for. That
closed a lot of repair shops including mine. Eventually, sets got

so

cheap that you could throw them away as the cost of repair was at
least 50-76% of a new set. This especially true for 19 inch TV's

on

down. VCR's did the same thing too. Now you can buy a new VCR for
about $50.

All that's taught for service anymore is replacing a chassis, and
most of it is building PC's. Vacuum tube technology is not taught
anywhere I know of. After some of us older folks are gone, I

wonder

who will actually be able to do real repair work anymore?

Best,

Will

--- In ham_amplifiers@...
<mailto:ham_amplifiers%40yahoogroups.com>, Bill Turner <dezrat@>

wrote:

We seem to be casting a lot of blame on individuals, but I

believe

the

underlying problem isn't people, it is the nature of electronic
equipment these days.

A lot of us got our start by being repairmen, and to do that

kind of

work well, one must understand the fundamentals of electronics.

These

days, you either change a PC board (if it is an expensive piece

of

gear), or you just throw it out and buy another. So-called
"technicians" anymore are mostly just parts changers, not real
repairmen. I don't see that changing any time in the near

future.

Of course there are some real technicians around, but any more

they

are working mostly at the engineering level, not the field

repair

level, and there are not a lot of them because not a lot are

needed.

Once the bugs are worked out of a design, you just make 'em by

the

millions and toss the bad ones.

Sad but true.

Bill, W6WRT

Will,
Question? When did GTE own Philco? I've been with them (GTE/

Verizon) for

43 years and I only know that they owned Sylvania.Was that before

my

time there. Just wondering.

Larry, W6LAR

All,

I finished coding the first portion of the long formula calculations
in imperial measurements for the Maxwell Transformer Calc. When the
results are compared to the short formula for 12 kilogauss and 60 Hz
(see pic at view one), it's just about exact. I posted another pic
(View 4) showing the results for a 220 Vac primary and the 3000 watt
transformer for any interested.

View 1;



New View 4;



Best,

Will

pentalab wrote:
<snip>

### On the bench they measure 36 pf.... bolted into the chassis... they rise to 50-55pf. IMO, it's the proximity of the lower fins to the chassis that's causing this. Bring it down another 1"... and I'm betting it will increase substantially. It would take all of 5 seconds to measure
the exact pf in the submounted case. [nothing connected to anode]

I will measure this tomorrow and report back the difference between the
measured anode to grid capacitance unmounted and sub-mounted.

In the submount case, the tube will also have to be inserted

from

below ! IE: stuff the top of the anode UP through a min

4.94"

diam hole in the chassis.

TONY SEZ.... Not in the case of a YC-156 or YC-179. It works just

fine inserting it from the top.
### whoa . If the grid ring is aprx 5" diam.... the hole in the chassis has to be a tiny bit bigger... u drop it from above... then u would need offset metal standoffs to screw to the top side of the grid ring.... up and outwards beyond the hole in chassis.... to screw to chassis ??? Still, this would leave a huge hole immediately next to the tube... and loads of air will get through... way more than if u used a SK-306 chimney ?

No. The hole in the chassis needs only to be large enough to pass the
grid ring from the top, even snuggly. Once it is passed through that
hole it mounts on a plate an inch below the chassis. That plate can be
6" square or more if you want it to be. In the case of my GS-35B mounts
I use 1/8" copper plate which is supported by a 1" length of 4" square
extruded aluminum tube that has 116 1/4" holes around its perimeter.
Since it is unlikely you will find 6" square extruded tubing, a simple
standoff can be made using 1/4" thick flat 1" wide stock forming a
square that is 6" on a side. Fill the sides with 1/4" holes and the area
of the holes exceeds the difference in the area of the hole in the
chassis and the area occupied by the ceramic of the tube. You have
virtually solid ground for the grid with only a 5" hole in the chassis
which is nearly the same diameter as the anode. The straight tube PTFE
chimney works fine. In fact, you can turn a small lip on the bottom of
the chimney and let it protrude through the hole the thickness of the
chassis plate if you want to. As you stated earlier, it's heavy enough
to stay on the chassis itself and requires no mounting at all. You slip
the chimney over the tube after it is secured with its screws from the
bottom.

TONY SEZ... I have to wonder about suspending the tube out there

in the middle of the cross. There's a bit inductance gained grid to ground by doing that.

Plus there's a significant amount of loss in the conduction of

heat away from that flange.
### Point well taken! A ring of holes would result in least inductance. With the amount of airflow available.. the grid ring is still gonna get cooled allright. Notice how JA6TAY appears to use a large copper sheet.. and puts his tube, C1/C2 cap on it ?

Yep, and many folks ignore the large current path between the tank and
the tube.

<snip>

### 3 x YC-156's is totally stupid.[11m ops have successfully done it, they are obviously not stupid... maybe we should invite a few of em to this group, they seem to have a wealth of info.... like how to use LMR-1200 as a rotor loop, what blows up, what doesn't, who makes reliable pole pigs, once removed from the oil, etc.]

LOL! Some of them ARE smart... smarter than given credit... but I am
afraid that the majority seem to demonstrate the opposite.

## I can see two of em....barely. Even then,they would gobble up chassis space. My buddy asked Eimac if they could remove the 4.94" cooler from these YC-156/YC-179's... and install the larger 7.5" diam cooler from the 3CX-15KB7... Eimac said.. "no way".

We've discussed that also but way too much trouble. Considering that it
isn't just the fins that will have to be increased in size. You'd also
need more copper in the core to get the heat out to those fins.
Unfortunately there is a practical limit beyond which more air just
doesn't do enough good to keep adding it.

### Considering the typ "200 A" service most folks have, coax, flexible coax, 7-16 Dins, baluns,etc... with 10-20 kw pep out... you have usually reached an upper practical limit. The next 3db is just too impractical... requiring a 440 lb dahl, careful layout, obscene currents, bizzare component requirements etc. Still, it could be done.... and a fun engineering challenge... doable... but very expensive. The overall logistics can quickly get out of hand. Just toss some numbers into the various spread sheets for a lark....cheap entertainment.
Later... Jim VE7RF

I've done that with my spread sheet... it's pretty amazing the amount of
current from the 240 Volt line and that's just for the plate input
power! It is that fact alone that has opened the eyes of a few to
realize they couldn't really do some things that they "talked" about doing.

You can get another 3 dB above the YC's but any more than that and you
have all the problems you've mentioned and unless one is ready for
those, it occurs at lower power levels too.

Get back to you with those measurements.

Regards, Tony W4ZT