At 1320 watts just to light the filament, I will politely "just say no." We now live a couple miles outside a small town in rural West Virginia. There isn't enough power coming into my house to make good use of that monster tube, nor enough AC to remove all of the heat it would dissipate.
The biggest working tube amp I ever had made used an 833A tube that needed 100 watts of filament power (10 V @ 10 A). With 1500 volts at 280 mA flowing through the plate and OPT in A2 SE, I got around 200 watts of audio power output with about 5 watts of drive. I annoyed the neighbors with my lousy but loud guitar playing for about 2 weeks then took it apart. I still have all the parts for a single channel, but never actually built it. I had central AC in Florida, AND a 5000 BTU window mount "booster" AC in my work room and the 833A amp could only be used for about 20 minutes before it got too hot to be in there.
I did have a pair of 4-1000 tubes which are quite large and need 158 watts each on the filament and 4 to 6 KV on the plates to make 3000 to 3900 watts of audio in AB2 with about 5 watts of drive, or 2000 to 3800 watts in AB1 with zero drive power. Someone who wanted to make a BIG RF amp offered me good money for them, so I never even made a test amp. The plan was to use a large power transformer for an OPT and a big power transformer from a Harris transmitter for power.
The biggest working tube amp I ever had made used an 833A tube that needed 100 watts of filament power (10 V @ 10 A). With 1500 volts at 280 mA flowing through the plate and OPT in A2 SE, I got around 200 watts of audio power output with about 5 watts of drive. I annoyed the neighbors with my lousy but loud guitar playing for about 2 weeks then took it apart. I still have all the parts for a single channel, but never actually built it. I had central AC in Florida, AND a 5000 BTU window mount "booster" AC in my work room and the 833A amp could only be used for about 20 minutes before it got too hot to be in there.
I did have a pair of 4-1000 tubes which are quite large and need 158 watts each on the filament and 4 to 6 KV on the plates to make 3000 to 3900 watts of audio in AB2 with about 5 watts of drive, or 2000 to 3800 watts in AB1 with zero drive power. Someone who wanted to make a BIG RF amp offered me good money for them, so I never even made a test amp. The plan was to use a large power transformer for an OPT and a big power transformer from a Harris transmitter for power.
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That video brought back memories. Around 35 to 40 years ago when I was actively buying and selling industrial power tubes I have had that tube and tested it. Paul says it was good because it lighted up okay without smoking the filament. But that's only part of what needs to be done if you can't put it into actual operation. I've had big tubes that lit up fine but had virtually no emission.
First you hypot the tube between all elements with around 1500 volts (or more) AC. This checks for shorts, leakage and gas. If it passes that, then power up the filament slowly, but not necessarily as slow as he did, and then pulse test it with 2500 VDC. This is actually a mil spec test. Specifically you connect the tube elements as a diode, charge up a HV capacitor bank to 2500VDC and discharge them through the tube via a high current mercury switch. Peak current is measured as voltage across a 0.1 ohm resistor between the filament and negative source. The instrument that dose this is seen below, and now resides in my basement form it's former location.
Tester particulars:
Filament transformer 12V @ 200A
Capacitors 2 paralleled 100ufd @ 3000VDC photo flash cans
200 amp dual mercury relay (24V DC coil) (I think)
20A filament variac
10A HV variac.
Charging transformer Stancor PT-8311 (2400Vct - 225mA)
Amp meter is Hickok 150A iron vain type modified for filament voltage out at connectors.
Cathode resistor is 100 10 ohm 2W carbons for 0.1 ohm (no special reason for these)
Voltage into fast SS diode to 10uf PP 50V cap feeding high impedance VTVM sample & hold (sort of)
Calibrate - pulse 2500V into 25 ohm 200W resistor for 100 peak amps analog meter
First you hypot the tube between all elements with around 1500 volts (or more) AC. This checks for shorts, leakage and gas. If it passes that, then power up the filament slowly, but not necessarily as slow as he did, and then pulse test it with 2500 VDC. This is actually a mil spec test. Specifically you connect the tube elements as a diode, charge up a HV capacitor bank to 2500VDC and discharge them through the tube via a high current mercury switch. Peak current is measured as voltage across a 0.1 ohm resistor between the filament and negative source. The instrument that dose this is seen below, and now resides in my basement form it's former location.
Tester particulars:
Filament transformer 12V @ 200A
Capacitors 2 paralleled 100ufd @ 3000VDC photo flash cans
200 amp dual mercury relay (24V DC coil) (I think)
20A filament variac
10A HV variac.
Charging transformer Stancor PT-8311 (2400Vct - 225mA)
Amp meter is Hickok 150A iron vain type modified for filament voltage out at connectors.
Cathode resistor is 100 10 ohm 2W carbons for 0.1 ohm (no special reason for these)
Voltage into fast SS diode to 10uf PP 50V cap feeding high impedance VTVM sample & hold (sort of)
Calibrate - pulse 2500V into 25 ohm 200W resistor for 100 peak amps analog meter
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Spare OPT for which tube, the big monster seen in the video, or the 833A?
I have no need, or even a use for a monster tube amp, but I have collected all of the necessary parts for a 1 KW (500 WPC) tube amp, pending on the outcome of one more experiment. Still not sure if I'll ever build it.
The pictures show a single channel test amp that uses one of my Universal Driver Boards driving a pair of my Octal UNSET Output Boards to 512 watts at 3.79% THD. Clipping appears at 525 watts. THD at 350 watts is 0.817%. The only remaining piece of the puzzle is a suitable power supply. I have a pair of huge toroidal isolation transformers that have 4 isolated 120 volt windings. They could be used to make a conventional but heavy 600 volt supply capable of powering this amp. The overall weight of the amp could become more than I could lift as I get older, so I'm going to explore another path. I have about 20 identical 48 volt 3 amp SMPS's. If they could be interconnected in series without creating a nuclear fireball, they could lighten the amp a good bit. The OPT's are still heavy, but I have an unpotted pair that are lighter.
I have no need, or even a use for a monster tube amp, but I have collected all of the necessary parts for a 1 KW (500 WPC) tube amp, pending on the outcome of one more experiment. Still not sure if I'll ever build it.
The pictures show a single channel test amp that uses one of my Universal Driver Boards driving a pair of my Octal UNSET Output Boards to 512 watts at 3.79% THD. Clipping appears at 525 watts. THD at 350 watts is 0.817%. The only remaining piece of the puzzle is a suitable power supply. I have a pair of huge toroidal isolation transformers that have 4 isolated 120 volt windings. They could be used to make a conventional but heavy 600 volt supply capable of powering this amp. The overall weight of the amp could become more than I could lift as I get older, so I'm going to explore another path. I have about 20 identical 48 volt 3 amp SMPS's. If they could be interconnected in series without creating a nuclear fireball, they could lighten the amp a good bit. The OPT's are still heavy, but I have an unpotted pair that are lighter.
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I worked at one of several Motorola facilities in Florida over a 41 year period from 1973 to 2014. The main plant went through a major expansion in the late 1990's. One of the additions was a complete gym that was comparable to some of the larger commercial gyms in the area and it was available at no cost to employees. In 1999 I transferred back to the main plant where I started and started going to the gym nearly every weekday afternoon. I was a skinny guy that weighed around 130 pounds. There were two people working in that gym that were also going to college for degrees in the health management field, and both advised me as to what exercises to do and to eat more calories and a higher level of protein. The stats on that photo says that it was taken in 2003. The old Sony that took the picture had a nasty habit of forgetting the date, so it could be wrong, but it was before 2005. Either way I had been going to that gym nearly every weekday for 4 to 6 years. At my peak I was a muscular 205 pounds and that would have been around the 2003-2005 time period. Now 20 years later I have a few random pieces of workout gear in my basement which sees some use, but at 71 years old I do not do the same stuff I did 20 years ago. I am currently about 165 pounds and reasonably muscular.
No, walking into a Motorola plant with only a high school diploma at age 20 when 500+ people showed up for two job openings, getting hired as an assembly line tech, then leaving on my own accord 41 years later as a Principal Staff Research Engineer with a bachelors degree in computer engineering and a masters degree in electrical engineering, both of which were paid for by Motorola has to be the highlight of my professional achievement. The free gym furnished mid afternoon breaks from the computer and the decent body came along for the ride.
Keep on nuking things so others don't have to. Keep doing it for all us stay-at-homes. (variation of a Tim Curry line in Times Square)
Rock on.
Chris
Rock on.
Chris
Motorola is my favourite brand of phone and i still have one today (designed and manufactured in China🙄), the work in a production factory is not a fairy tale but your story is a kind of magic, now the vast majority of the working population is fat and i've nerver see any company with a gym but there are junk food dispensers everywhere.
Understand that the Chicago based Motorola company where I worked was forcibly dismantled by the Wall Street Wizards, most notably Carl Icahn, for fun and profit by the few, putting about 100,000 people out of work. The original nearly vertically integrated company (the company made most of the parts for its own products) was parted out like a junk car. The cell phone division was sold to Google who kept the patents, and resold the Motorola Brand to Lenovo, the Chinese company that also bought IBM's consumer computer and commercial server divisions. Fortunately, the new owners do make decent products. I have a Motorola phone and a Lenovo branded Think Center mini PC. Both work well. The "Think brand (Think Center, Think Pad, etc) used to be an IBM trademark. The semiconductor division became Freescale, the networks division was sold to Nokia, the Government Electronics division was sold to General Dynamics......
The Motorola plant was the typical non fairy tale place to work in the 70's through the early 90's. I got out of the production line environment after about a year and a half, and found my way into the Cal Lab where I was a "Mr. Fixit" for all of the test equipment used in product production. I worked on the evening shift until the mid 80's. For over 10 years I was at the beach by 10 AM usually zipping up and down the Atlantic Coast on one of two small sailboats that I owned. I had to be at work by 4:00 PM so this worked well for me. Beach Bum by day, Mr. Fixit by night.
By the early 80's it was becoming obvious that production was slowly and quietly moving overseas. The assembly lines were becoming ghost towns and engineering labs were taking their place. I started looking for work in engineering but had no formal education. After 3 years of trying, I convinced a manager to hire me to design solid state audio circuits that went into police walkie talkies. I learned as much as I could by doing, and moving from product line to product line to learn new stuff as radios became increasingly digital. As more and more engineering, product development and management jobs filled the plant it became evident to big management in Chicago that our plant and others in the US were stress factories. People were overweight and out of shape and generally stressed out. The company's health care costs and turnover rate were rising quickly. An outside company was hired to investigate and propose solutions. Several changes were implemented, and the company provided no cost gym and subsidized day care center for pre-school kids were part of the deal.
Now, 20+ years later, the old Motorola plant has been sold. About 250 Motorola employees reside in a leased building, one of the five where about 4000 people once worked. The old IBM plant where the PC was born and about 10,000 people worked has also been sold. I don't know if any IBM employees still work there as I left the area over 10 years ago. Many other tech companies that called South Florida home have also left the area or closed down.
So, your great shape is an external symptom of a "global health issue" due to the high productivity pressure period in the Motorola plant.
Thanks, now i know what there is behind the photo of a beautiful beach with a "reasonnabily 🙂" rich muscular American on it.
Thanks, now i know what there is behind the photo of a beautiful beach with a "reasonnabily 🙂" rich muscular American on it.