upsidedown@downunder.com <upsidedown@downunder.com> wrote:> On 03 Aug 2018 10:10:54 GMT, Rob <nomail@example.com> wrote: > >>upsidedown@downunder.com <upsidedown@downunder.com> wrote: >>> On Fri, 03 Aug 2018 01:07:29 -0500, oldschool@tubes.com wrote: >>> >>>>What is the most powerful vacuum tube ever made? >>>> >>>>I'm looking into building the most pewerful tube audio amplifier >>>>possible. I'll be using 4 tubes in push-pull parallel. (per channel). My >>>>goal is at least 5000 watts RMS per channel (if possible). >>> >>> The real question is, do you have a single full range speakers with >>> 5000 W power handling ? >>> >>> 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. >> >>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. > > 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 :-).That is like what I wrote. Nobody would want to carry a 5000 watt tube audio amplifier to an event when they can have the same thing as a 2U rack module weighing 14kg.> 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.Such an amplifier likely contains (or requires an external) sound processor that cleverly limits the amplitude without hard clipping.
What is the most powerful vacuum tube ever made?
Started by ●August 3, 2018
Reply by ●August 3, 20182018-08-03
Reply by ●August 3, 20182018-08-03
On 08/03/2018 11:00 AM, John Larkin wrote:> On Fri, 03 Aug 2018 01:07:29 -0500, oldschool@tubes.com wrote: > >> What is the most powerful vacuum tube ever made? >> > > Probably an ignitron, possibly a krytron, but the THD specs are > mediocre. > >> I'm looking into building the most pewerful tube audio amplifier >> possible. I'll be using 4 tubes in push-pull parallel. (per channel). My >> goal is at least 5000 watts RMS per channel (if possible). I will likely >> rewind some pole pigs (power pole transformers) for output transformers, >> and possibly use one of them in reverse for the power supply >> transformer, which should supply 3250 to 7500 volts to the plates (or up >> to 15KV if I use a different pole pig rated for higher primary voltage). >> > > Why? > > The transformers are the problem. > > >For the cost of building the most powerful tube amp ever you could buy a pretty nice used sports car. Or less expense. Less dangerous. Girls will like you better.
Reply by ●August 3, 20182018-08-03
On 08/03/2018 02:07 AM, oldschool@tubes.com wrote:> What is the most powerful vacuum tube ever made? > > I'm looking into building the most pewerful tube audio amplifier > possible. I'll be using 4 tubes in push-pull parallel. (per channel). My > goal is at least 5000 watts RMS per channel (if possible). I will likely > rewind some pole pigs (power pole transformers) for output transformers, > and possibly use one of them in reverse for the power supply > transformer, which should supply 3250 to 7500 volts to the plates (or up > to 15KV if I use a different pole pig rated for higher primary voltage). > >Sounds like one of those "if you have to ask how you probably shouldn't"-kind of projects. It'll probably be cheaper in parts and labor cost to just buy one off the shelf, anyway. I mean off the floor. Reinforced concrete floor. <https://www.surplussales.com/Microphones-Audio/MicroAudio-7.html>
Reply by ●August 3, 20182018-08-03
bitrex <user@example.net> wrote:> It'll probably be cheaper in parts and labor cost to just buy one off > the shelf, anyway. I mean off the floor. Reinforced concrete floor.:-) Not only in parts and labor cost but also in human lives...
Reply by ●August 3, 20182018-08-03
On 08/03/2018 09:31 AM, Phil Hobbs wrote:> On 08/03/2018 06:09 AM, Ian wrote: >> On 2018-08-03, oldschool@tubes.com <oldschool@tubes.com> wrote: >> >>> I'm looking into building the most pewerful tube audio amplifier >>> possible. >> >> Sounds like a bit of a Disaster Area in the making... >> >> > And terrible songs! > > Maybe the OP is planning to be dead for a year for tax reasons..... > > Cheers > > Phil Hobbs >Thinking about the output device specifics is bikeshedding at this point in the design anyway. If one were serious one would be starting at the PSU and working forwards. Oh, it's gonna be a complex and glorious PSU for sure, with a pretty sophisticated fail-safing system, overvoltage/overcurrent protection, and probably uP-controlled startup sequencing and bias monitoring. Or u can just build a house-burning down murder machine I guess.
Reply by ●August 3, 20182018-08-03
On Fri, 3 Aug 2018 11:27:29 -0400, bitrex <user@example.net> wrote:>On 08/03/2018 11:00 AM, John Larkin wrote: >> On Fri, 03 Aug 2018 01:07:29 -0500, oldschool@tubes.com wrote: >> >>> What is the most powerful vacuum tube ever made? >>> >> >> Probably an ignitron, possibly a krytron, but the THD specs are >> mediocre. >> >>> I'm looking into building the most pewerful tube audio amplifier >>> possible. I'll be using 4 tubes in push-pull parallel. (per channel). My >>> goal is at least 5000 watts RMS per channel (if possible). I will likely >>> rewind some pole pigs (power pole transformers) for output transformers, >>> and possibly use one of them in reverse for the power supply >>> transformer, which should supply 3250 to 7500 volts to the plates (or up >>> to 15KV if I use a different pole pig rated for higher primary voltage). >>> >> >> Why? >> >> The transformers are the problem. >> >> >> > >For the cost of building the most powerful tube amp ever you could buy a >pretty nice used sports car. Or less expense. Less dangerous. Girls will >like you better.Some old AM or shortwave transmitters ran plate modulated above a megawatt. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●August 3, 20182018-08-03
On 08/03/2018 11:45 AM, Rob wrote:> bitrex <user@example.net> wrote: >> It'll probably be cheaper in parts and labor cost to just buy one off >> the shelf, anyway. I mean off the floor. Reinforced concrete floor. > > :-) > Not only in parts and labor cost but also in human lives... >Starting at the output devices is bikeshedding, anyone who was serious/non-crazy would be thinking (sleepless nights in horror) at what the cost in design time and parts to make a safe reliable PSU for such an amplifier would be to start.
Reply by ●August 3, 20182018-08-03
On 08/03/2018 11:47 AM, John Larkin wrote:> On Fri, 3 Aug 2018 11:27:29 -0400, bitrex <user@example.net> wrote: > >> On 08/03/2018 11:00 AM, John Larkin wrote: >>> On Fri, 03 Aug 2018 01:07:29 -0500, oldschool@tubes.com wrote: >>> >>>> What is the most powerful vacuum tube ever made? >>>> >>> >>> Probably an ignitron, possibly a krytron, but the THD specs are >>> mediocre. >>> >>>> I'm looking into building the most pewerful tube audio amplifier >>>> possible. I'll be using 4 tubes in push-pull parallel. (per channel). My >>>> goal is at least 5000 watts RMS per channel (if possible). I will likely >>>> rewind some pole pigs (power pole transformers) for output transformers, >>>> and possibly use one of them in reverse for the power supply >>>> transformer, which should supply 3250 to 7500 volts to the plates (or up >>>> to 15KV if I use a different pole pig rated for higher primary voltage). >>>> >>> >>> Why? >>> >>> The transformers are the problem. >>> >>> >>> >> >> For the cost of building the most powerful tube amp ever you could buy a >> pretty nice used sports car. Or less expense. Less dangerous. Girls will >> like you better. > > Some old AM or shortwave transmitters ran plate modulated above a > megawatt. > >Ya I think they still use them in Mexico and the Carribean to broadcast end-times ranting from that kooky old kid-toucher pastor out of SC.
Reply by ●August 3, 20182018-08-03
On Friday, August 3, 2018 at 9:28:39 AM UTC-4, upsid...@downunder.com wrote:> On Fri, 3 Aug 2018 05:53:16 -0700 (PDT), George Herold > <gherold@teachspin.com> wrote: > > >On Friday, August 3, 2018 at 2:11:15 AM UTC-4, olds...@tubes.com wrote: > >> What is the most powerful vacuum tube ever made? > >> > >> I'm looking into building the most pewerful tube audio amplifier > >> possible. I'll be using 4 tubes in push-pull parallel. (per channel). My > >> goal is at least 5000 watts RMS per channel (if possible). I will likely > >> rewind some pole pigs (power pole transformers) for output transformers, > >> and possibly use one of them in reverse for the power supply > >> transformer, which should supply 3250 to 7500 volts to the plates (or up > >> to 15KV if I use a different pole pig rated for higher primary voltage). > > > >When I worked at the FEL (Free electron Laser) we had a SLAC Klystron that > >was probably 100 MW. > >http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-10620.pdf > >(Check out the unibrow in figure 9.) > > > >George H. > > Isn't that short peak power, not average power ?Right. pulsed power. GH
Reply by ●August 3, 20182018-08-03
On 3.8.18 16:48, upsidedown@downunder.com wrote:> On Fri, 3 Aug 2018 16:20:43 +0300, Tauno Voipio > <tauno.voipio@notused.fi.invalid> wrote: > >> On 3.8.18 15:12, Rob wrote: >>> Tauno Voipio <tauno.voipio@notused.fi.invalid> wrote: >>>> On 3.8.18 11:28, Rob wrote: >>>>> oldschool@tubes.com <oldschool@tubes.com> wrote: >>>>>> What is the most powerful vacuum tube ever made? >>>>>> >>>>>> I'm looking into building the most pewerful tube audio amplifier >>>>>> possible. I'll be using 4 tubes in push-pull parallel. (per channel). My >>>>>> goal is at least 5000 watts RMS per channel (if possible). I will likely >>>>>> rewind some pole pigs (power pole transformers) for output transformers, >>>>>> and possibly use one of them in reverse for the power supply >>>>>> transformer, which should supply 3250 to 7500 volts to the plates (or up >>>>>> to 15KV if I use a different pole pig rated for higher primary voltage). >>>>> >>>>> 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.: http://www.fullfataudio.com/products/ffa-10000/ >>>>> >>>>> 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. >>>> >>>> >>>> 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 powerful, who knows? >> >> 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. > > 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.Pori has been down since over a decade ago, see: <https://yle.fi/uutiset/osasto/news/yle_ends_short_wave_broadcasts/5756519>. -- -TV
