What is the most powerful vacuum tube ever made?

Water-cooled loudspeakers?

Mike.

I have seen at least 250-350 kW transmitter and AM modulator tubes, some of which are water or vapor cooled.

What is the frequency response of a pole pig transformer ?

Get a 3 phase connection, it greatly simplifies the power supply filtering requirement.

snipped-for-privacy@tubes.com wrote

Any idea yet what you wil say through that PA? And who the victims will be?

This is not the largest, but enough to blow up your pole pig transformers:

IIRC, the largest Eimac tube I've seen is a megawatt tube, but it is made on special agreement only.

Not a good idea to use tubes for that. What you want to have is available off-the-shelf both as PCB modules and 19" rack modules, it will be much lighter, much cheaper, much safer and it will work much better!

e.g.:

And when you would use tubes, you would not make the most powerful tube audio amplifier with a measly 5000 watts. Much more power was produced in modulator amplifiers of classic AM transmitters with an RF output of 100 times that. See the documentaries on WLW and info on even stronger AM transmitters outside the USA.

The real question is, do you have a single full range speakers with

If you are going to use speakers with separate (sub)woofers, why not do the crossover at low levels and use separate amplifier to feed the power hungry (sub)woofer. It would be natural to feed it with some Class-D (PWM) amplifier.

If you want to drive the rest of the spectrums with tubes, please go ahead (.e.g. to generate tube distortion by overdriving). Most likely much less power is required. In addition much smaller output transformer is required, if you can ignore the lowest 3-5 octaves.

Sounds like a bit of a Disaster Area in the making...

It is a stupid idea to build the desired distortion into an expensive and hard to replace part of the system. When you want to build a high-power amplifier with the bad performance of a tube amplifier, use a low-power tube amplifier as a preamp and drive a modern Class-D amplifier with the resulting distorted signal, to have it cleanly amplified to high power at high efficiency, low weight, etc.

Once you get tired of the "warm sound" you can always remove the tube amplifier without having to start from scratch.

A rule of thumb for the AM transmitter modulator is that the audio power needs to be at least half of the DC input power to the Class C power amplifier.

It is clear that with his 5000 watts he is about two orders of magnitude short of the most powerful tube audio amplifier ever made, let alone the most powerful tube audio amplifier possible. But maybe it would still be the most pewerful, who knows?

When I worked at the FEL (Free electron Laser) we had a SLAC Klystron that was probably 100 MW.

George H.

I was referring to electric guitar amplifiers, in which the distorting amplifier and distorting speakers are part of the electric guitar instrument.

In big (stadium size) events, a low power (100 W) tube amplifier and also suitable low power speaker is used. A microphone is placed in front of the speaker to get both the amplifier as well as speaker distortion and then amplified by a linear chain to the final kW size output :-).

With signals with high peak/average ratio, you can quite comfortably overdrive a tube power amplifier without too much problems, while you should never let a solid state amplifier chain clip. Thus the nominal power output must be several times that of a tube amplifier in order to get the same average audio SPL.

My guess is that the most powerful audio amplifiers have been modulators for big AM transmitters. The biggest I have seen is 200 kW modulator in the late Lahti AM station in southern Finland. The transmitter was made by Brown Boveri & Cie (BBC).

At least Radio Moscow has run AM on 1 MW power level, maybe also VOA in the years gone by. This would need an audio power of around 700 kW, if the power amplifier is not run as a linear amplifier, which is pretty wasteful at this power level, due to the bad carrier-level efficiency of an AM linear.

Isn't that short peak power, not average power ?

And terrible songs!

Maybe the OP is planning to be dead for a year for tax reasons.....

Cheers

Phil Hobbs

At least the 500 kW short wave AM/SSB Brown Bovery transmitters commissioned in the 1980's in Pori, Finland, used audio controlled PWM to generate the final RF tube anode voltage. So no need for a huge power audio amplifier or huge modulation transformers.

I do not know what they use in the on site 600 kW AM medium wave transmitter.

This is strange. Above I wrote pewerful because the original poster also wrote that. Now my text is quoted and it reads powerful. How can that be? Is there spelling correction in quoted text and why doesn't it happen on line 8?

It is my guess too.

Hence my claim of being about two orders of magnitude short. Of course, current AM transmitters no longer work this way.

Probably an ignitron, possibly a krytron, but the THD specs are mediocre.

Why?

The transformers are the problem.