That depends on the purpose. The modulator section of an AM radio transmitter is essentially a large audio amplifier. Power levels of 10 to 50 killowatts were built in the 1950's. The largest amp that I can remember that was intended to drive a speaker, was a 1 killowatt guitar amp using 4 X 813's in parallel push pull.
As Tubelab says, modulation amplifiers were pretty big. The Mullard data sheet for their equivalent of the 212 power triode is something like 1200W - used to allow workers in factories to hear the Light Programme as they worked.
Here is the 1000W guitar amplifier with 4 x 813 tubes in parallel push-pull.
http://www.chambonino.com/construct/const9.html
http://www.chambonino.com/construct/const9.html
I'll tell you one thing, whatever it was, it was a class B amp for modulation. And fidelity was not priority #1... efficiency was.
I saw an amplifier using some VERY big tubes driving a voice coil (loudspeaker) in a vibration tester at RIFA. Don't know the tubes nor the otput power with the thing made a SUB sound like a tweeter ...
tubelab.com said:
You needed somewhat over 50% modulator power for high quality a.m. in ham radio land.
While broadcast power in the U.S. was limited to 50kW, you could pick up stations from Mexico in the upper Midwest as they operated like a.m. blowtorches.
I used to work with an electron beam evaporator that had a massive water cooled triode in the arc suppression circuit; it wasn't exactly an AF amplifier, although it shut the HT down fast (sub milliseconds). The supply ran at 12kV and up to an amp; in normal operation we normally only pulled maybe 200mA.
The triode was made by Varian; it was massive metal and ceramic structure, I can't remember the type number.
A pair of those in push-pull would certainly be audible across the street!
The triode was made by Varian; it was massive metal and ceramic structure, I can't remember the type number.
A pair of those in push-pull would certainly be audible across the street!
I wonder why anyone would choose 813s to make a guitar amplifier?
(Apart from the fact that one might ask "why would any guitarist need a 1000W amplifier?")
Yes the 813 is a very good valve and yes it can stand high voltages, although 2500V is rather pushing the envelope.
My objection is the realities of guitar amplification - not the amplifying but the transportation. The 813's filaments are simply too fragile.
Anyone who was played in or worked with, a band will understand what I am talking about.
Now if I were wanting to make an insanely powerful amplifier for guitar purposes, I think I would opt for parallel push-pull 13E1s. Enormous power available from these.
7N7
(Apart from the fact that one might ask "why would any guitarist need a 1000W amplifier?")
Yes the 813 is a very good valve and yes it can stand high voltages, although 2500V is rather pushing the envelope.
My objection is the realities of guitar amplification - not the amplifying but the transportation. The 813's filaments are simply too fragile.
Anyone who was played in or worked with, a band will understand what I am talking about.
Now if I were wanting to make an insanely powerful amplifier for guitar purposes, I think I would opt for parallel push-pull 13E1s. Enormous power available from these.
7N7
Phil Jones did a 650W bass amp with 4x813 and my first though was for the filaments, especially considering the weight of the beast. I bet most never left their studios or homes, but even there I see no need for a 650W amp even with inefficient speakers that's not on stage without FOH support.7N7 said:
http://namm.harmony-central.com/SNAMM02/Content/Phil_Jones_Bass/PR/T-500.html
I have a report by the IEEE that details a push pull audio amp producing 3000+ watts using 2 4-1000a's
This report also has a schematic and details on winding the custom output transformer.
I have not found anything larger then this in the tube audio realm.
Nick
This report also has a schematic and details on winding the custom output transformer.
I have not found anything larger then this in the tube audio realm.
Nick
Ok I just looked at the pdf for the Bereskin and it's the same as the IEEE report that I have.
OUCH and I payed 30 dollars for it from IEEE.
Nick
OUCH and I payed 30 dollars for it from IEEE.
Nick
It would be an expensive amp.
I just got a quote for a plate transformer to run only 1 4-1000a it costs 600 dollars and weighs 100 pounds.
Just remember thats 6000 volts at 1 amp.
Hot stuff, real hot
Nick
I just got a quote for a plate transformer to run only 1 4-1000a it costs 600 dollars and weighs 100 pounds.
Just remember thats 6000 volts at 1 amp.
Hot stuff, real hot
Nick
Hi,
all these tubes used in those amps were built for anything but audio purposes.
Probabely the biggest thing designed solely(!) for audio is the T1610 of KR-Audio. A triode capable of delivering up to ~50W in SE mode.
And probabely the only one still in production and further development.
The Kronzilla DX features 2 of these paralleled per channel and is specd for 100W.
jauu
Calvin
all these tubes used in those amps were built for anything but audio purposes.
Probabely the biggest thing designed solely(!) for audio is the T1610 of KR-Audio. A triode capable of delivering up to ~50W in SE mode.
And probabely the only one still in production and further development.
The Kronzilla DX features 2 of these paralleled per channel and is specd for 100W.
jauu
Calvin
Brett said:
Yes,
The power thing is so misunderstood.
I remember years ago the band I was in at the time recorded an album. One of the tracks featured a guitar solo (me) that I recorded in a live room with close and distant mikes. The amplifier was a 1964 Watkins Westminster (ECL82s about 10W) that I still have to this day.
People used to ask: "What amp did you use? A Marshall stack?
7N7
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