I have a 12 tube Phantom what is the highest deadkey some of you have put into this type of amplifier. I am putting a 3 watt radio and a 10 watt deadkey from my JB150 blackcat into amp now. Running deadkey high like this because from reports amp sounds the best and also runs more steady (not as much swing) pep this way. I would like to run even higher deadkey if possible. thanks 165 from The Great Lakes.
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12 Tube Phantom Deadkey
- Thread starter Jimbo165
- Start date
You're taking the fast track to needing a thousand dollars worth of new sweep tubes. This is the wrong approach to driving this amp altogether. It already has an internal pre driver tube that you're beating the hell out of with the JB-150. The amp runs comfortably around 1000 watts PEP and that means the carrier should be no more than 250 watts.
I did the same thing you're doing now 20 years ago. I couldn't help myself because the modulator made the meter say almost 1700 watts PEP. To gain less than a half S unit, I killed all the tubes in about a month rather than years. Keep in mind the JB-150 will peak around 100 watts. About 10 times more peak drive than the amp was intended to receive.
PS: If you start running the JB-150 over 10 watts carrier by itself, you'll kill the 8417 tube inside it too. That's because they run 400 volts on the screen and that's way too much to support any larger carrier without over dissipating the screen grid of that tube. You'll notice it glowing brighter as you stay on the key long.
I did the same thing you're doing now 20 years ago. I couldn't help myself because the modulator made the meter say almost 1700 watts PEP. To gain less than a half S unit, I killed all the tubes in about a month rather than years. Keep in mind the JB-150 will peak around 100 watts. About 10 times more peak drive than the amp was intended to receive.
PS: If you start running the JB-150 over 10 watts carrier by itself, you'll kill the 8417 tube inside it too. That's because they run 400 volts on the screen and that's way too much to support any larger carrier without over dissipating the screen grid of that tube. You'll notice it glowing brighter as you stay on the key long.
hehe yep
had a CBer in my are to use a ft101e into his,and was shocked when he flattened the tubes and also alot of other damage...40wtt dead keys...got love it...
had a CBer in my are to use a ft101e into his,and was shocked when he flattened the tubes and also alot of other damage...40wtt dead keys...got love it...
I understand the temptation to drive the amp with your favorite Yaesu or to want to place a JB-150 in front of it to gain those loud positive peaks and it can be done safely too. The trick is you have to bypass the first driver tube. Everything you need is already inside the amp. Just wire the input circuit that feeds the first tube directly to the cathode of the next stage.
It will require some tuning since this stage is usually 3 tubes and has a lower drive impedance but it's easy to do. Bypassing the driver tube also frees up some extra power from the plate supply that can be used as output power rather than drive power. Good for peaks not for extra carrier.
It will require some tuning since this stage is usually 3 tubes and has a lower drive impedance but it's easy to do. Bypassing the driver tube also frees up some extra power from the plate supply that can be used as output power rather than drive power. Good for peaks not for extra carrier.
The problem with sweep tubes is they were designed to handle enormous excursions outside the normal operating range. For example, most can handle peak cathode currents in excess of 2 amps and hold back over 6000 volts on the plate without arcing! This was required in older TV applications because at certain parts during the electron beam scan, the operating conditions can approach these levels but only for a very brief instant and extremely low duty cycle.
In linear applications this translates into a false perception that these tubes can make much more power than they can actually do comfortably. Some time ago I observed a RM amplifier with one EL-509 driving another EL-509. The amp could put out a 500 watt carrier but would trash the output tube quickly if you got long winded. Just because they were designed to take this abuse for short durations certainly does not mean they can handle it for any length of time.
It all comes down to the dissipation the internal tube elements can handle continuously. The 2 amps or 6000 volts are specs that are allowed for tiny fractions of a second and do not occur simultaneously. The EL-509 can make 500 watts but it has a plate dissipation under 40 watts so it dies very fast.
Tube life is not proportional to output power once you exceed the specifications. I've seen sweep tubes run close to specs that provided up to 2 hours of use per day for about 10 years. If you drive the amp hard to make twice the output, the tubes won't last 5 years, they may last 5 weeks if you're lucky. You'll either strip the cathode of its oxide coatings or melt the internal elements of the tube.
In linear applications this translates into a false perception that these tubes can make much more power than they can actually do comfortably. Some time ago I observed a RM amplifier with one EL-509 driving another EL-509. The amp could put out a 500 watt carrier but would trash the output tube quickly if you got long winded. Just because they were designed to take this abuse for short durations certainly does not mean they can handle it for any length of time.
It all comes down to the dissipation the internal tube elements can handle continuously. The 2 amps or 6000 volts are specs that are allowed for tiny fractions of a second and do not occur simultaneously. The EL-509 can make 500 watts but it has a plate dissipation under 40 watts so it dies very fast.
Tube life is not proportional to output power once you exceed the specifications. I've seen sweep tubes run close to specs that provided up to 2 hours of use per day for about 10 years. If you drive the amp hard to make twice the output, the tubes won't last 5 years, they may last 5 weeks if you're lucky. You'll either strip the cathode of its oxide coatings or melt the internal elements of the tube.
I also have a12 tube d&a phantom with fresh tubes,although I have a closet full of 6lq6 and many other tubes...don't drive the thing with more than about 6 watts if you wanna get any longevity preferably 2-4 watts outta this amp and it should do you good.I have had mine for 12 years puts out 800 watts on my bird 43!
Grettings Gents,
Strikesmith
Grettings Gents,
Strikesmith
12 tube driver?
Shockwave I normally run a 3 w radio 3 watt driver deadkey into amp just increased driver to 10 to stop some of swing one time and then decided to ask if I could use more deadkey and not hurt amp but I guess not. I would sure like some more info about the driver tube not sure if my amp is wired that way +.This 12 tube on low puts about 775v on top to 4 tubes and none to 8 when switched to high all 12 tubes have 700v on top. I have 100uf 450v capacitors on their way and soon as they get here will replace old caps and this will help in this area. I looked at bottom of tube wiring on first 4 which most consider to be the drivers and went from keying tube but found no specific wiring to one tube. I know running anything different from factory specs will shorten its life but as to the other person I disagree have already been driving this amp for 6 months and it is working great I know there is alot of people still running these amps and wanted to know what do they use for a driver or deadkey. Phantom amps I believe are one of the toughest amps out there as far as taking abuse my brothers have been driving their phantoms hard for years the real problem is long time keyups and heat they will take driving . I sure wish I could find more info and schematics on these amps I have 2 12 tubes and 2 10 tube triple stage amps and none are wired the same go figure right Shockwave I sure thank you and this forum for all the help.
Shockwave I normally run a 3 w radio 3 watt driver deadkey into amp just increased driver to 10 to stop some of swing one time and then decided to ask if I could use more deadkey and not hurt amp but I guess not. I would sure like some more info about the driver tube not sure if my amp is wired that way +.This 12 tube on low puts about 775v on top to 4 tubes and none to 8 when switched to high all 12 tubes have 700v on top. I have 100uf 450v capacitors on their way and soon as they get here will replace old caps and this will help in this area. I looked at bottom of tube wiring on first 4 which most consider to be the drivers and went from keying tube but found no specific wiring to one tube. I know running anything different from factory specs will shorten its life but as to the other person I disagree have already been driving this amp for 6 months and it is working great I know there is alot of people still running these amps and wanted to know what do they use for a driver or deadkey. Phantom amps I believe are one of the toughest amps out there as far as taking abuse my brothers have been driving their phantoms hard for years the real problem is long time keyups and heat they will take driving . I sure wish I could find more info and schematics on these amps I have 2 12 tubes and 2 10 tube triple stage amps and none are wired the same go figure right Shockwave I sure thank you and this forum for all the help.
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Is this the Phantom that is painted black? I was thinking of another tube configuration where they have 1 driving 3 driving 6. If you have 4 tubes driving 8 things are a little different. This can take a little more drive than amps that have a single tube as the first stage.
The thing to keep in mind is a larger carrier will kill the tubes much quicker than more swing and swing gives you louder audio than a big carrier with lower peaks. I'd back the JB-150 down so the Phantom keys around 250 watts carrier and just let it swing from there. The extra swing will still be driving the amp hard so why hit it with more carrier on top of that?
The thing to keep in mind is a larger carrier will kill the tubes much quicker than more swing and swing gives you louder audio than a big carrier with lower peaks. I'd back the JB-150 down so the Phantom keys around 250 watts carrier and just let it swing from there. The extra swing will still be driving the amp hard so why hit it with more carrier on top of that?
12 tube
Shockwave this is a Silver colored D&A 12 tuber has no model number on it anywhere and cannot find any info on it. I also have a T-600 10 tube triple stage D&A and it is all black with white lettering which is probably the one you are thinking about but it is 4 driving 6 tubes the only D&A that I know of that is 1 into 3 into 6 tubes is the PDX 400 amp. I have used JB150 into t-600 with same 3w radio 3w JB150 into t-600 and it will do almost as many watts as 12 tuber and three power levels of that amp is handy wish 12 tuber was like it. My 12 tuber has great modulation just donot like the swing it has but now it is a 150w to 200w deadkey and swings to 850+ watts on high and amp hardly gets warm after 2 hrs of skip talking always is cooler than my 10 tuber. Still would like to know what is max deadkey amp from JB150 that it will take without taking keying tube out . I know there are a hugh bunch of Phantom owners out there what deadkey are you using what kind of drivers and what is your pep. Just to make it clear I am using a 3w radio deadkey 3w JB150 deadkey but JB150 goes 3w to 100w and then into 12 tuber. 12 tuber has a 150 to 200w deadkey doing this. I set all deadkeys with mic turned to 0 I have 4 Phantoms in all right now but am going to thin the herd. Thanks
Shockwave this is a Silver colored D&A 12 tuber has no model number on it anywhere and cannot find any info on it. I also have a T-600 10 tube triple stage D&A and it is all black with white lettering which is probably the one you are thinking about but it is 4 driving 6 tubes the only D&A that I know of that is 1 into 3 into 6 tubes is the PDX 400 amp. I have used JB150 into t-600 with same 3w radio 3w JB150 into t-600 and it will do almost as many watts as 12 tuber and three power levels of that amp is handy wish 12 tuber was like it. My 12 tuber has great modulation just donot like the swing it has but now it is a 150w to 200w deadkey and swings to 850+ watts on high and amp hardly gets warm after 2 hrs of skip talking always is cooler than my 10 tuber. Still would like to know what is max deadkey amp from JB150 that it will take without taking keying tube out . I know there are a hugh bunch of Phantom owners out there what deadkey are you using what kind of drivers and what is your pep. Just to make it clear I am using a 3w radio deadkey 3w JB150 deadkey but JB150 goes 3w to 100w and then into 12 tuber. 12 tuber has a 150 to 200w deadkey doing this. I set all deadkeys with mic turned to 0 I have 4 Phantoms in all right now but am going to thin the herd. Thanks
Don't put the JB-150 into the T-600 since it has a single tube pre drive stage. That is way too much drive for that amp. I think you are safe using it with the 12 tuber as long as you keep the carrier close to where you have it. Since your maximum PEP swing output is 850 watts the most carrier output you should set the amp at with the control on the JB-150 is 212.5 watts or 25% of the PEP swing. Whatever carrier it takes from the JB-150 to make the 25% is the most you can set that at. Make sure you tune all the controls on the Phantom for maximum PEP output with steady audio.
Deadkey
I am not sure T-600 has a driver tube shockwav it looks just like 12 tube underneath and first group is 4 tubes driving 6 I believe just PDX 400 has that type of setup but I am still very much in learning process still on these amps have 3 working and 1 12tube in fixing mode right now. I donot get those magic numbers that everyone esle talks about in wattage either. Thanks to this forum again and all your great info I am looking and listening, learning.
I am not sure T-600 has a driver tube shockwav it looks just like 12 tube underneath and first group is 4 tubes driving 6 I believe just PDX 400 has that type of setup but I am still very much in learning process still on these amps have 3 working and 1 12tube in fixing mode right now. I donot get those magic numbers that everyone esle talks about in wattage either. Thanks to this forum again and all your great info I am looking and listening, learning.