Check out this monster, found it on youtube:
YouTube - 1000W Amplifier Philips EL6471 at full power
YouTube - 1kW Philips EL6471 Tube Amplifier from 1955 demonstrates its original sound - listen!
YouTube - 1000W Tube Amplifier Interference Pattern of the MV-Rectifiers
YouTube - 1000W Audio Tube Amplifier Philips EL6471 from 1955
Wouldn't like to breath the air around all those MV rectifiers if they smashed!
YouTube - 1000W Amplifier Philips EL6471 at full power
YouTube - 1kW Philips EL6471 Tube Amplifier from 1955 demonstrates its original sound - listen!
YouTube - 1000W Tube Amplifier Interference Pattern of the MV-Rectifiers
YouTube - 1000W Audio Tube Amplifier Philips EL6471 from 1955
Wouldn't like to breath the air around all those MV rectifiers if they smashed!
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I had dreams of a stereo SE amp running about 200 WPC. After firing up a single channel prototype and realizing that I would need to build a vent system to take the heat out of the house, I punted.
Even though my speakers would likely catch fire, I will still build a big amp. Reality has scaled down my definition of "big". My new definition is mandated by the obvious limitation of the American wall outlet. You get 15 amps max at roughly 120 volts per outlet and 20 amps per circuit. That is 1800 watts assuming nothing else big is running on that circuit. So to get 1 KW (500 WPC) you need an amp with a 56% total efficiency. That rules out SE, and makes a 1KW P-P amp unlikely given the power to light the tube heaters. So the definition of "big" gets changed again. OK, my OPT's are rated for 400 watts at 20 Hz so that is the goal.
With this in mind, I have been experimenting to find the best way to use up all of my OPT's power capability. I have seen 200WPC and I am nowhere near done yet!
Even though my speakers would likely catch fire, I will still build a big amp. Reality has scaled down my definition of "big". My new definition is mandated by the obvious limitation of the American wall outlet. You get 15 amps max at roughly 120 volts per outlet and 20 amps per circuit. That is 1800 watts assuming nothing else big is running on that circuit. So to get 1 KW (500 WPC) you need an amp with a 56% total efficiency. That rules out SE, and makes a 1KW P-P amp unlikely given the power to light the tube heaters. So the definition of "big" gets changed again. OK, my OPT's are rated for 400 watts at 20 Hz so that is the goal.
With this in mind, I have been experimenting to find the best way to use up all of my OPT's power capability. I have seen 200WPC and I am nowhere near done yet!
Tubelab maybe its time to switch to 3 phase wall outlet.In USA(110v) ewerything that exced 500w continous consumpsution must replaced with 3 phase suply(3x200V).Here in Europa (220v)ewerything over 1KW must be replaced with 3 phase main nec(3x380v).BTW many advantages 3 phase primary/3 phase secondary Psu have
ulsating freqency from full wave rectifier its 360 hz(USA) so smothing fillter is not so critical in comparison with 120 hz from monophase(110v).Comon primary curent is divided in 3,plus primary voltage is not 110v but 3x200v(Primary curent more down)IN extreme cases it is posible to have 3phase primary and 4phase secondary from same transformer.One of the tube which I recomend for High power SE or PP is tetrode QB5/1750(got wery good expirience from high power AM transmitter with this tube).5,6 KV UBA and ower 5KW output with 4 tubes).Or Rusiann big power pentode GU81M.Salute Tubelab
ulsating freqency from full wave rectifier its 360 hz(USA) so smothing fillter is not so critical in comparison with 120 hz from monophase(110v).Comon primary curent is divided in 3,plus primary voltage is not 110v but 3x200v(Primary curent more down)IN extreme cases it is posible to have 3phase primary and 4phase secondary from same transformer.One of the tube which I recomend for High power SE or PP is tetrode QB5/1750(got wery good expirience from high power AM transmitter with this tube).5,6 KV UBA and ower 5KW output with 4 tubes).Or Rusiann big power pentode GU81M.Salute Tubelab
At least in areas served by Florida Power and Light, 3 phase power is not available in residential areas, period. A friend of mine got a bunch of 3 phase metal working equipment, and 3 phase distribution was available near his house, and 2 of the 3 transformers were there. He even offered to pay for the installation, but FPL refused. He wound up building a mechanical MG setup.
Not true. Single phase 240 volts runs the big stuff in the house. The supply to this house is 150 amps total at 240 volts. The big hitters, Air conditioner 40 amps, hot water heater 30 amps, kitchen stove 60 amps, clothes dryer 50 amps. It would be possible to tap into the dryer circuit since it is on the other side of the wall behind my bench, but that is the easy issue.
The real problem here is heat. Here in south Florida the temperature outside can hit 100 degrees F in the summer, and 85 in the winter. My lab / listening room is small, and I have too much "stuff" in it already. So building a physically large amp is out of the question. I added an auxilliary air conditioner to this room already since the lights, computer, and other equipment was too much for the central air to handle without making the rest of the house too cold. I built an 845 SE amplifier a few years ago. It makes about 40 WPC, but it dumps about 400 watts of heat into the room. I can run it for about an hour during the day before it gets too hot in here. So, guess what, it hasn't been turned on in at least a year.
I have several good 833A tubes and some really big power transformers from transmitting equipment, so some day I will build the "big one", but for now space, time, and thermal constraints dictate working on something that would be a bit more useful.
Still those 400 watt OPT's call my name, so I have a plan. The transformers have multiple taps on the secondary, 2, 4, and 8 ohms, with a 1250 ohm primary. I have verified that they will work as a 5000 ohm OPT at the 150 watt level with an 8 ohm load on the 2 ohm tap. I have also seen 200 watts at 2500 ohms.
The plan is to build an amp with 6 tubes per channel. They can be activated in pairs for 3 different power (and heat) levels. This way I can approach the kilowatt level, but still have an amp that I can use daily at a reasonable thermal load. I have a full time engineering job that sucks up most of my weekdays, and a few other amplifier projects, so this one is a permanent work in progress. This is a reasonable but large project. For me it will be a learning experience There have been experiments going on for at least 3 years, screen drive, the universal driver board, the 6L6GC in AB2 amp, the "red board" and a few that I haven't talked about yet, that have tought me a lot about making big power that sounds good for HiFi (not MI) use with reasonable efficiency. There are a few more experiments that need to be completed before I can fully define this amp.
I was sure all ower the USA is 110/120v main(Florida at 240v-surprise for me).FPL dont wont to distribute 3phase in home thats wery wery strange to me(here in my contry is wery easy to provide 3phase main from suplyer) Think FPL know fact in single phase suply looses are higher but electrical BILS too($).Any way for BIG power Amps,Transmitter or similar 3phase main suply is rulle,mainly from two reason:Smoothing capacitor (Filtter) is with significant lower walue,Primary curent is divided in 3 phase the result is rock stable PSU and stable Amps or Transmitter operation.Heat conduction:Frend of my hawe DIY medium power (Pirat) AM transmiter(10KW output with Single Russian Ceramic Coaxial tetrode at 9KV plate voltage),moduladet this transmitter tube Plate with six QB5/1750 modulator/amplifier at 4,5KV plate voltage,they simply made two 12inch hole in wall and instal two air turbine which suck the air out of room outside(one turbine is for Transmitter ,second for Modulator/Amp.In sumertime is wery hot here too but we spend hours and hours playin with this Tramsmitter on the AM band(1600-1800 khz)and no heat in room att all( only some minor noise from two spining turbine.BTW there is comlete line of very rugged glass tube suitable for good SE or PP amps,Direct heated(thoriated tungsten cathode)with life expentancy beetwen 20000 and 50000 hours(I have seen in few Transmitter tube QB5/1750 working continuos 15 years without fail).the line is:QB/250(813), QB3/200, QB3/300, QB3,5/750, QB4/1100, QB5/1750 and QB5/2000.One more wery important thing:HIGH VOLTAGE TENSION DONT FORGIVE,ONE MISTAKE AND DEAD IS COME IN VISIT.(I hawe Expirienced 2,5 kv stroke before 20 years from DIY Transmitter PSU,I have LUCK but that painfool expirience I well NEWER forgot.Best Wishes TUBELAB
Mains power in the USA is derived from a transformer on the pole. Usually there is one per city block (sometimes 2). The transformer has a HV primary (usually 7200 volts or 14,400 volts) the secondary is 240 volts with a center tap. The center tap is grounded. All 3 secondary wires go to every house built since about 1900. The ordinary wall outlets are connected from one side of the secondary to ground resulting in about 120 volts.
The big stuff is connected across the two hot leads for 240 volts. So 240 volts is available in all modern houses, but it is not normally wired to individual rooms. In houses that heat and cook with gas (not common in Florida), 240 V may only go to the furnace (basement) for the blower motor. Here it goes to the garage (AC, dryer, and water heater), the kitchen (stove) and outside (pool pump), there are no basements (water table is 5 feet below the surface).
I am familiar with three phase HV and the associated 6 diode bridge. I installed a 5 KW HF transmitter several years ago. Note that all modern automobile alternators are 3 phase. Some are wye, and some are delta.
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Florida has a max height of around 260' (about 123M) above sea level, so George is out of luck on having a basement (I hope to never own a house without one).
I have my own transformer. Here in Johnson City Tennessee we usually have a max of two houses per transformer in residental areas. Everything is 240 split phase (as George said, two 120 phases with a common which is "Neutral" and connected to ground at the circuit breaker). This is the US standard although most people who aren't into electronics think it is 120 because that is what most wall sockets are.
I have 200A service. I could get 3-phase at my last house (I was looking at an old lathe), but not at this one.
So, power distribution is well defined as 240 split phase, but by regeon it varies a lot as to how it is implimented. In Georges case they use large transformers to supply several houses. Here they use smaller transfsormers to a small number of houses. I've seen residential areas where the power was underground and there was one transformer per house. Ugly green blocks at the curb.
I have my own transformer. Here in Johnson City Tennessee we usually have a max of two houses per transformer in residental areas. Everything is 240 split phase (as George said, two 120 phases with a common which is "Neutral" and connected to ground at the circuit breaker). This is the US standard although most people who aren't into electronics think it is 120 because that is what most wall sockets are.
I have 200A service. I could get 3-phase at my last house (I was looking at an old lathe), but not at this one.
So, power distribution is well defined as 240 split phase, but by regeon it varies a lot as to how it is implimented. In Georges case they use large transformers to supply several houses. Here they use smaller transfsormers to a small number of houses. I've seen residential areas where the power was underground and there was one transformer per house. Ugly green blocks at the curb.
Thats USA electrical delivery power sistem ist brand new information for me.Acording Your information 240vAC from wall outlet is available.Thats good up to 1KW continous consumption for Audio aplication.3 phase sistem have many advantages in high power Audio apllication(mentioned before).But there is something else:Serbian guy NIKOLA TESLA who Invented A.C. POWER POLYPHASE SYSTEM actualy propose 24 phase system(minimum 12phase).But Mediocre engineers,banks,and other without vision people adopted 3phase system which we use even today(100year after TESLA INVENTION).Can you imagine howe small smothing filtter wel be for Audio aplication.About significant less power looses is suficient to discute.Try to made calculation for 1kw main transformer in three way.first way monophase,second 3phase and third 12 phase.Man what a diference in phisycal dimension only(Electrical Transfer chararectistic is more diferent.Best wishes TUBELAB
According to the site survey my house is a whopping 11 feet above sea level. The system of canals to keep the salt water out of our water supply artificially raises the fresh water table above sea lavel. If I dig a hole in the back yard during the summer it will fill with water to about 2 feet below the surface, maybe 5 feet in winter. No basements here!
There are 9 houses on the transformer at my location. It used to be a big can, maybe 400 pounds. It got zapped by lightning 2 years ago and they replaced it with a plastic cased can about half the size of the old one. Now the distortion on my line voltage hits 12% on a hot summer afternoon, with visible flat topping on the scope.
I believe their 240V is "two" phase supply (2xL+N in 120V numenclature), not the normal L+N (230V) supply that we're accustomed to across the big pond. 240V is split using a CT transformer to obtain two phase 120V.
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