Will RF output (transmitter) be the same wattage as audio ou

[Clifford Heath]

On 02/03/17 14:38, jurb6006@gmail.com wrote:

"** The load impedance is doubled, since the max tube current cannot increase.

Double voltage into double load = double the power. "

I think you got this fucked up somehow. When the load impedance is halved then the power is doubled.

Phil meant "double the load impedance". Not half.
If you do that and double the voltage, current is the same,
so power is only doubled.

Clifford Heath.

 

On Wed, 1 Mar 2017 15:36:39 -0500, Ralph Mowery
<rmowery28146@earthlink.net> wrote:

false reading. The voltage and current is not like a fence charger. It
will dump a lot of current into you and often kill. Fence chargers are
more like a static electricity shock, lots of voltage,but little
current. They are made to shock and not to kill.

It does take some special insulated wire for the amps and other high
voltage items. Most common wires are insulated for around 600 volts or
even 300 volts. That 2700 volts will often burn through wire insulated
like that . Only 'good' thing about it,is that it will not jump much of

Long ago, I once rook some common #14 wire used for home wiring, to jump
my electric fence across to another pasture. My intent was to use
insulated wire so no one would get shocked. (There were no animals
there, so live wires were not needed.)

I quickly learned that the insulation on those wires (rated at 600V), is
useless against the 5000V of that fencer. I touched that insulation and
got jolted as bad as if I had touched bare wire.

After that, I bought the special insulated wire made for electric fences
that is made for even direct burial. That stuff is costly, but it works.

 

>" ** Like hell I did.

Try reading it AGAIN !!!

IF you double the voltage into double the load, the CURRENT stays the same.

But double the voltage at the same current is TWICE the power.

Power = V x I "

Fine, but I don't know why you expressed it that way. There is still a limit to how much voltage you can have. Generally, output tubes are not in series, they are in parallel. As such the impedance into which they work (determined by the transformer of course)must be decreased to realize any increase in power output.

>"** Any data sheet will quote max screen dissipation - usually only a few watts.

The fine steel wire will glow red or even white if the rating is exceeded.

Then guess what happens ?? "

It becomes a triode ? LOL. Not really because the suppressor grid is still in the way.

>"If the screen supply voltage is too high, it take excessive current whenever the plate voltage swings low under load. "

This is one of the things I have trouble grasping when it comes to tube technology. I am younger than you and tubes existed only at the beginning of my career. I adapted to solid state quickly and made a profit...

I wonder some things, like when the plate voltage goes lower than the screen voltage. Are you saying that the current flows from the screen grid to the plate ? Or is it pulling from the cathode ? I'd guess cathode but that is just a guess.

There are a few other things about tubes of which I lack knowledge, but I am only 56 and this is 2017. Like the suppresor grid, how the hell did they even find out they needed that ? I mean, some guys in white lab coats looking at a (probably Tektronix) scope saying "There are electrons bouncing back from the plate, we can improve this tetrode by adding another grid". How the hell did they figure that out ?

 

On Thursday, March 2, 2017 at 2:35:02 PM UTC-5, jurb...@gmail.com wrote:

" ** Like hell I did.

Try reading it AGAIN !!!

IF you double the voltage into double the load, the CURRENT stays the same.

But double the voltage at the same current is TWICE the power.

Power = V x I "

Fine, but I don't know why you expressed it that way. There is still a limit to how much voltage you can have. Generally, output tubes are not in series, they are in parallel. As such the impedance into which they work (determined by the transformer of course)must be decreased to realize any increase in power output.

"** Any data sheet will quote max screen dissipation - usually only a few watts.

The fine steel wire will glow red or even white if the rating is exceeded..

Then guess what happens ?? "

It becomes a triode ? LOL. Not really because the suppressor grid is still in the way.

"If the screen supply voltage is too high, it take excessive current whenever the plate voltage swings low under load. "

This is one of the things I have trouble grasping when it comes to tube technology. I am younger than you and tubes existed only at the beginning of my career. I adapted to solid state quickly and made a profit...

I wonder some things, like when the plate voltage goes lower than the screen voltage. Are you saying that the current flows from the screen grid to the plate ? Or is it pulling from the cathode ? I'd guess cathode but that is just a guess.

There are a few other things about tubes of which I lack knowledge, but I am only 56 and this is 2017. Like the suppresor grid, how the hell did they even find out they needed that ? I mean, some guys in white lab coats looking at a (probably Tektronix) scope saying "There are electrons bouncing back from the plate, we can improve this tetrode by adding another grid". How the hell did they figure that out ?

I think a lot of refinements are trial and error, or just plain dumb luck. Maybe some hack was assembling the plate structure and left some support wires in place instead of cutting them before stuffing the assy in the bottle and sealing the glass. Make connections to the wrong wires and..

It's the guys like Tesla who could envision things like polyphase AC before anyone else that impress the beejeezus out of me. Edison was a trial and error guy while Tesla was reading blueprints from inside his skull.

 

[Phil Allison]

jurb...@gmail.com wrote:

" ** Like hell I did.

Try reading it AGAIN !!!

IF you double the voltage into double the load, the CURRENT stays the same.

But double the voltage at the same current is TWICE the power.

Power = V x I "

Fine, but I don't know why you expressed it that way.

** You snipped the crucial line.

Looks like you NEVER read it.


There is still a limit to how much voltage you can have.


** Its about 2.5kV for a 6L6GC.

> Generally, output tubes are not in series,

** Massive red herring.

"** Any data sheet will quote max screen dissipation - usually only a few watts.

The fine steel wire will glow red or even white if the rating is exceeded.

Then guess what happens ?? "

It becomes a triode ?

** FFS the wire melts, bits come off and create shorts.




..... Phil

 

>"IF you double the voltage into double the load, the CURRENT stays the same.

But double the voltage at the same current is TWICE the power.

Power = V x I "

I had that down before I had pubic hair. The way you worded it was the subject of my comment.

>"** Its about 2.5kV for a 6L6GC. "

According to http://www.radiostation.ru/tubes/6L6GC-GE.pdf you are really pushing it. But then IIRC, that plate voltage is at quiescence and can go double. They were not rated like transistors. A transistor might say "1,000 volts" and at 1,175.3 volts it shorts out. Seems like they EXPECTED alot of voltage on tubes.

However there are limits on other components of course, and an audio circuit is not quite like an LOPT. (actually that is closer to the OP than our digression, but then this is SER so that is expected) But to bring up the LOPT, or HOT over here, that does operate in class C. Most RF outputs of course operate in class C. That is a whole different world.

Plate dissipation doesn't mean shit, it is just a matter of peak current and peak voltage, which when they don't happen at the same time are of course much easier to deal with.

>"** FFS the wire melts, bits come off and create shorts. "

I am in the "WTF was I thinking" mode now. At my young age, I guess I could say I have forgotten more about electronics than many know. That is one of the most simple concepts but yet it slipped my mind. Of course when the wires melt they go out of whack and cause problems. I got too used to transistors. You can talk about some layer in a MOSFET breaking down and causing some weird leakage or some shit, but this is mechanical. The real problem is I must be losing it because I am from a car family.

Really, I have out-trouble shot the factory guys and I can give you two examples. One was the "bulletproof" 2.5 L that ran like shit. The books all said it had timing gears and therefore would not jump time. Therefore the crank sensor was what the book said. But after I saw the shit blowing back through the throttle body I said "Tear down for timing chain", a part that the DEALERSHIP said it did not have. I was right. The dealership, after the guy paid the diagnostic said "replace engine". Instead my buddy got off with a hundred bucks ort whatever for timing irons.

Another notable thing was my ex-lawyer's pickenup truck. (he got disbarred, go figure) It was some sort of Datsun or something but he wanted to keep it. Now this guy was no dumbass, as a matter of fact he pretty much built his own house. Ad he was not dumb when it came to cars either but this had him stumped.

The problem was that at random intervals it would run like shit, and I mean not be able to get out of its own way run like shit.

The problem we traced down was about a Woodruff key i n the crankshaft. He had had the timing belt replaced not long before and apparently (and a machinist verified this) that apparently the mechanic who did the job lost the original Woodruff key which was metric.

Well he could not get a metric one so put in a USian replacement, which was loose. Over a short time it sheared because it was direct from the crank to the damper. This system also ran the camshaft. So every once in a while it went out of phase. It DID take some doing to figure that one out but the guy had no problem with money.

The reason he wanted specifically to keep this little pickup truck had to do with the suspension. (he was smart enough for that) He had a tow bar on the front and used to tow it with his camper. He said that was the only vehicle he could find that could be easily backed up, like a trailer. After I got more information on the vehicle I thinki I found out why.

It had linear torsion bar suspension. Unlike those old Dodges that had crossbar suspension, (which really wasn't all that bad) cars like the Caddilac Eldoado and the Olds Toronado had the torsion bars going front to back. They had special rims and if you look at the book they were set to (or could be) zero toe in, zero caster, zero camber.

He told me that this was the only thing he could tow that he could back up with. All other vehicles jacknifed. Start backing up and the steering wheel would go all the way one direction or the other. Not this one. Linear torsion bar suspension.

And it was a shitcan. My Toronados had that suspension but they were suspending a 455 with almost 500 horsepower. This was four cylinder ! But he liked it so we fixed it.

By the time we got to it, the Woodruff key had worn the notch in the crank so badly that a new one would not be tight either, so we brazed it in.

Sorry to be so long but then, this is Usenet. Bottom line, if anyone thinks I'm stupid, I want know what you think of the rest of the people. I mean like that broad on the video whose boyfriend asks here "If you are doing 60 miles per hour and drive for an hour, how far have you gone ?". And she could not answer it. In fact I think some asshole somewhere called that video politically incorrect.

God damn.

 

[Phil Allison]

jurb...@gmail.com wrote:

Power = V x I "

I had that down before I had pubic hair. The way you worded it was
the subject of my comment.

** You did not READ what I wrote at all

- you bullshitting, over-snipping fuckhead.

"** Its about 2.5kV for a 6L6GC. "


According to http://www.radiostation.ru/tubes/6L6GC-GE.pdf

** Fraid that ref does not mention the spec.

You bullshitting fucking idiot.

Plate dissipation doesn't mean shit,

** No, YOU don't mean shit .

Cos you are a piece of it.

I am in the "WTF was I thinking" mode now.

** Good, stay there for the rest of your miserable ife.


Wot a PITA fucking moron ......



..... Phil

 

>"** Fraid that ref does not mention the spec.

You bullshitting fucking idiot. "

Bullshit, it says 500 fucking volts. Now who cannot read ?

Let's go ahead and fuck up Usenet with a flame war ey ?

And you will lose.

 

[Phil Allison]

jurb...@gmail.com wrote:

"** Fraid that ref does not mention the spec.

You bullshitting fucking idiot. "

Bullshit, it says 500 fucking volts.

** Wrong spec - you bullshitting imbecile.

In most tube books, "plate volts" = "plate supply" voltage !!!

The **actual plate voltage** swings up to nearly double in operation, single ended or push pull. The 2.4kV figure I posted is the max, zero current plate voltage that is guaranteed. IOW, the insulation rating.

In an operating push-pull stage, plate voltage reaches max on a tube when plate the current is near zero. The opposite is true too, plate voltage reaches minimum when plate current is max on that tube.

EL34s are *speced* to operate with a 750V supply, so the pate voltage on one EL34 in a PP pair is nearly 1500V when the voltage on the other is less than 60V.

All I am saying is that 6L6s can do the same and commercial examples exist that prove the point.

You know absolutely NOTHING about tube output stages.

FYI:

Don't fret too hard, hardly anyone does.



..... Phil

 

>"The **actual plate voltage** swings up to nearly double in operation, single ended or push pull. The 2.4kV figure I posted is the max, zero current plate voltage that is guaranteed. IOW, the insulation rating. "

I am not exactly sure what you're saying here. Are you saying that tubes such as this are rated in such a way are expected to operate at twice their "max" rating ?

I never got into tubes all that much, when was getting into the field it was going solid state and I was adapting to it.

>"You know absolutely NOTHING about tube output stages."

You're pretty friendly today, did you find a good pot dealer or something ?

>"Don't fret too hard, hardly anyone does. "

How come so kind ?

But actually tubes are a bit harder to understand than like transistors etc.. Take your transconduct and and mu and sll of that and give me hfe and HFE..

But that's just one Man's opinion. If you can counter with an argument that tubes are better, bring it on.

>Don't fret too hard, hardly anyone does."

I was working in the music industry. These MFs got where they have dual purpose valve sockets and via a micrprocessor will adjust the bias for you. I mean they got sockets that will take a KT88 or a 6BQ5. I am not fretting but I am considering a career in flipping burgers. It is getting that bad, to the point where I quit my job.

Next.

 

[Phil Allison]

jurb...@gmail.com wrote:

"The **actual plate voltage** swings up to nearly double in operation, single ended or push pull. The 2.4kV figure I posted is the max, zero current plate voltage that is guaranteed. IOW, the insulation rating. "

I am not exactly sure what you're saying here. Are you saying that tubes such as this are rated in such a way are expected to operate at twice their "max" rating ?

** What I am saying is simple:

The only *plate voltage limit* on a power tube is the breakdown voltage of the insulation.

The usual weak spot is between pins 2 and 3, the heater and the plate of many audio power tubes. Having a plate connection on top of a tube instead helps a lot.

The other limits are with max cathode current and max dissipation of the plate structures or screen grids.


...... Phil

 

>"Having a plate connection on top of a tube instead helps a lot. "

It sure did with HOPs (LOPT for you all across the pond)

But IIRC in the beginning they used that top connector for the grid. Seems that later they figured out a better way.

 

On Thursday, March 9, 2017 at 4:51:22 AM UTC-5, jurb...@gmail.com wrote:

"Having a plate connection on top of a tube instead helps a lot. "

It sure did with HOPs (LOPT for you all across the pond)

But IIRC in the beginning they used that top connector for the grid. Seems that later they figured out a better way.

LOL! I remember when I was just getting started in TV repair and my dad had a 40s radio in the shop for repair. In horror, I saw him put his finger on the "plate" cap of the IF tubes as a poor man's signal tracer. Of course, my first experience with a true plate cap was my finger on a horizontal output tube..

 

>"LOL! I remember when I was just getting started in TV repair and my dad had a 40s radio in the shop for repair. In horror, I saw him put his finger on the "plate" cap of the IF tubes as a poor man's signal tracer. Of course, my first experience with a true plate cap was my finger on a horizontal output tube.. "

I bet you learned some respect for eletricity.

For me it was the cathode of a damper tube, which has even more. That SOB burned my finger all the way to the bone, and cauterised it at the same time.. The "one hand" rule did not save me from that, but really if I completed a circuit to anythihg at the time I could have been history, way back then. Actually that does not sound so bad these days, but that is not the point. Youngers who want nto this business need to know that there are more than five volts in the world.

 

On Monday, March 13, 2017 at 3:40:12 AM UTC-4, jurb...@gmail.com wrote:

"LOL! I remember when I was just getting started in TV repair and my dad had a 40s radio in the shop for repair. In horror, I saw him put his finger on the "plate" cap of the IF tubes as a poor man's signal tracer. Of course, my first experience with a true plate cap was my finger on a horizontal output tube.. "

I bet you learned some respect for eletricity.

For me it was the cathode of a damper tube, which has even more. That SOB burned my finger all the way to the bone, and cauterised it at the same time.

Anybody who does not believe the above should try it themselves. It's happened to me several times - and boy, do those pinpoint burns hurt for days.

 

On Monday, March 13, 2017 at 3:40:12 AM UTC-4, jurb...@gmail.com wrote:

"LOL! I remember when I was just getting started in TV repair
and my dad had a 40s radio in the shop for repair. In horror,
I saw him put his finger on the "plate" cap of the IF tubes as
a poor man's signal tracer. Of course, my first experience with
a true plate cap was my finger on a horizontal output tube..

I bet you learned some respect for eletricity.

For me it was the cathode of a damper tube, which has even more.
That SOB burned my finger all the way to the bone, and cauterised
it at the same time. The "one hand" rule did not save me from
that, but really if I completed a circuit to anythihg at the time
I could have been history, way back then. Actually that does not
sound so bad these days, but that is not the point. Youngers who
want nto this business need to know that there are more than five
volts in the world.

They need 4 or 5 years of union electrical school. It sure helped me.

 

>"They need 4 or 5 years of union electrical school. It sure helped me"

They don't deal with the kind of voltages we had in the old days. Working on a cellphone is not dangerous like an old tube type color TV. (or B&W for that matter) Things had hot chassis, 5 KV going to the flyback and yoke and all kinds of fun stuff. Alot of stuff runs on a walwart now that removes most of the danger.

I learned respect for electricity at a very young age. My Uncle gave me the airforce primer on it and I read every word. I also learned the hard way at times, but rarely. I also remember that when the print says "DO NOT MEASURE" they mean it, for a couple of reasons. Some things are just too much voltage, other things are sensitive to the load and might fry. I used to get the scope probe just near a horizontal output tube and be able to tell if it is running right. I had a procedure down pat, I almost always knew what was wrong within five minutes, most times in less than a minute.

The damper tube incident was because I kinda slipped or something, I knew damnwell to stay away from that thing.

I also did some electrical work and have seen some things... Shared neutrals for example. I have done older houses where the last guy misidentified the neutral and caused a shock hazard. I had to correct this shit. Nobody else seemed to be able around here.

 

[Michael A. Terrell]

bruce2bowser@gmail.com wrote:

On Monday, March 13, 2017 at 3:40:12 AM UTC-4, jurb...@gmail.com wrote:
"LOL! I remember when I was just getting started in TV repair
and my dad had a 40s radio in the shop for repair. In horror,
I saw him put his finger on the "plate" cap of the IF tubes as
a poor man's signal tracer. Of course, my first experience with
a true plate cap was my finger on a horizontal output tube..

I bet you learned some respect for eletricity.

For me it was the cathode of a damper tube, which has even more.
That SOB burned my finger all the way to the bone, and cauterised
it at the same time. The "one hand" rule did not save me from
that, but really if I completed a circuit to anythihg at the time
I could have been history, way back then. Actually that does not
sound so bad these days, but that is not the point. Youngers who
want nto this business need to know that there are more than five
volts in the world.

They need 4 or 5 years of union electrical school. It sure helped me.

Did it teach you how to wire the HV power supply in a high power TV
transmitter? Have you ever worked with 10 KV shielded cable? Years ago I
was installing a TV transmitter when the local building inspector told
me that I had to hire a local wire monkey. There was no one in tea area
that did industrial level work, so I showed him the HV cable and asked
which of the GOBs was bonded and insured for $1 million to cover any
damage to the equipment.

I showed him the table covered with the factory installation and
asked him to read the top left corner where it said "Electrician,
connect power here". All of the switchgear was bolted to a 4'x10' sheet
of 1/4" steel plate. He insisted that it had to be taken out and screwed
to a sheet of 1/2" plywood. There was over a ton of transformers and
switches that would have snapped plywood into pieces. He was not
qualified to inspect anything bigger that a small store or one of the
thousands of Condos in the area. He had no idea who the FCC was, or what
a FCC Construction Permit was. He was as clueless about the FAA permit
for the tower or the lighting requirements.

Then I handed him my copy of the NEC and asked him to show me the
relevant sections for industrial and studio wiring. He tossed it on the
table, cursed me out and said he would be right back with a 'Cease and
Desist Order to stop work on the new TV station. He never came back.


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

Michael Terrell wrote:

bruce2...@gmail.com wrote:
On Monday, March 13, 2017 at 3:40:12 AM UTC-4, jurb...@gmail.com wrote:
"LOL! I remember when I was just getting started in TV repair
and my dad had a 40s radio in the shop for repair. In horror,
I saw him put his finger on the "plate" cap of the IF tubes as
a poor man's signal tracer. Of course, my first experience with
a true plate cap was my finger on a horizontal output tube..

I bet you learned some respect for eletricity.

For me it was the cathode of a damper tube, which has even more.
That SOB burned my finger all the way to the bone, and cauterised
it at the same time. The "one hand" rule did not save me from
that, but really if I completed a circuit to anythihg at the time
I could have been history, way back then. Actually that does not
sound so bad these days, but that is not the point. Youngers who
want nto this business need to know that there are more than five
volts in the world.

They need 4 or 5 years of union electrical school. It sure helped me.


Did it teach you how to wire the HV power supply in a
high power TV
transmitter? Have you ever worked with 10 KV shielded cable?

No, no. I've mostly just driven around a van or truck with supplies here and there. I have wired up one or two places behind walls, roughed-in a few panels, outlets, etc.. and finished them, maybe. But, no. I haven't recently gone into radios, TVs or anything else and bothered anything.

 

"Did it teach you how to wire the HV power supply in a high power TV
transmitter?"

No

>"Have you ever worked with 10 KV shielded cable?"

Years ago, but not handling any real current.

>"He was not
qualified to inspect anything bigger that a small store or one of the
thousands of Condos in the area. He had no idea who the FCC was, or what
a FCC Construction Permit was. He was as clueless about the FAA permit
for the tower or the lighting requirements. "

Not surprising. Inspectors do not make what the people who do the real work make, I have found out why many times in the building trades. (but not transmitters)

"...cursed me out and said he would be right back with a 'Cease and
Desist Order to stop work on the new TV station. He never came back. "

Probably a rookie. Really. they give these guys authority without proper testing and vetting. That is the way i t works in this country and I am sure you are not all too happy about it either.

Know what else ? On a plumbing job I refuse to use teflon tape. I have personally proven it to be inferior to not only pipe dope, but even regular hand soap.

Someone lobbied for these regulations, just like any other. Government is deaf dumb and blind. they cannot do anything and that is why they are in government jobs.

There are exceptions but they are, of course exceptions. One was a very competent electrical inspector, they gave him the name "Ivan the terrible" because he really did his job. My work satisfied him even though I did not go through all the apprenticeship and all that, I learned from family. Most contractors dreaded his arrival to a job to inspect. And I have seen their work and some of it was downright dangerous. Other inspectors looked the other way but not Ivan Cucic. (the terrible) He did not want to see kids getting burnt in their beds n shit and I agree.

If you do something wrong like in electrical wiring, which is relatively simple, and it causes death or injury, you belong in jail. You should see how it is here. Licensed, bonded and insured mean nothing, all they do is pay off if you fuck up. I want it not fucked up. I never pursued that because I sold the job as "If I fuck up and your house burns down I lose my house, if the licensed, bonded and insured people fuck up an insurance people pay off. Who has the greater incentive to do the job right ? But I was never afraid of an inspection in fact I welcomed it.

I have seen things that will put hair on your chest, curl it and take it off in one fell swoop. Maybe we need a thread about that. And industrial too, why do they allow shared neutrals in commercial buildings ? And the reason that the shower goes hot when someone flushes a toilet is because it was not plumbed right, IMO. You have to not use the easiest method to avoid that.. You take the toilet supply right off the main, way before it gets to the hot water tank. But they do not do that because it costs more money. So if you get scalded it is not their problem and if it is, they are licensed, bonded and insured so they suffer no loss.

And believe me, that is prevalent here. I have pulled extension cords out of walls.