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Kilovolt transmitting tubes
"Andre Jute" wrote in message ... rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Now we are back on track. This is the kind of stuff RAT needs and is famous for:-) Iain |
#2
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"Iain M Churches" wrote in message ... "Andre Jute" wrote in message ... rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Now we are back on track. This is the kind of stuff RAT needs and is famous for:-) Iain http://216.87.144.102/svetlana/techbulletins.asp I liked 38 but the link seems down now. Chad |
#3
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Iain M Churches wrote: "Andre Jute" wrote in message ... rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Now we are back on track. This is the kind of stuff RAT needs and is famous for:-) Iain One needs a special respect for working with 1,000v+ anode voltages. Its a wonder more ppl have not been killed.... The OPTs for such wonders do take quite some careful consideration, especially with SE or PP 211, because the load value is high, and the C shunt begins to have effects, so there has to be thick insulation. But the HV dictates thick insulation, and preferably potting the OPT in a can with oil and sealed terminals. An old friend has an ex WW2 transmitter with 2,500v and a pair of 813. Many older hams had RF finals with a lot of voltage. I have been reluctant to make audio amps with such high voltages for sale to the general public. The 833 has interesting possibilities, but it is a queer triode, with pentode like curves and high Ra. If I wanted to start with a HV tube, I'd use an 845. Or a pair in PP; they'd be awesome. Patrick Turner. |
#4
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"Patrick Turner" wrote in message ... One needs a special respect for working with 1,000v+ anode voltages. Its a wonder more ppl have not been killed.... This M50 monobloc has the highest B+ of any amp I have constructed (500VC) I treat it with great respectm and work only two hours at a time. Iain |
#5
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You are more likely to be killed outright by line voltage than by high
B+. 70 years of Amateur Radio statistics-most of which time hams were mostly builders-bears this out. Design commercial products with interlocks like transmitter manufacturers did for years and if you are a DIYer buy and/or build proper safety equipment and use it. Tube amps running 1 kV and above are the best sounding and most reliable-they either are built properly or fail spectacularly and in short order-way to get substantial power. The 812, 813, and a bunch of other tubes out there can sound great and give good service. You have to put some build cost in the amp, which is as it should be. |
#6
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If You want a tube for "real men", see this one:
http://info.uibk.ac.at/c/c7/c704/mus...es/rs329g.html Some are still available in Germany... Back to more palatable tubes, and considering that original 211s or 845s are hard to find or extremely expensive, my favorite tube in this league would be the Russian GM-70. It has a dissipation of 125W, a higher mu than the 845 and it doesn't need to be "swung" up to positive grid for full power like a 211, ie. the driver circuit task is easier and the final result is probably better. I played a bit with the anode curves and it seems that a B+ of about 1000 - 1100V together with an anode load of 10K gives the maximum output power in SE class A, about 45W! Or put a pair of them in PP to blast the roof... Happy to see a real RAT thread Ciao Fabio "Andre Jute" ha scritto nel messaggio ... rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Chris Hornbeck wrote: I'm a big fan of 845's; they solve a lot of speaker problems, which are much more intractible. 211's have even better curves, and three in parallel make 50 watts without grid current, and into an almost-practical 5K ohm load. Back in the 60s, when I was a student, I travelled across the States on one of those go anywhere one way Greyhound tickets that then cost 99 bucks. (Somebody said a couple of years ago that they are still only 199 bucks. Extraordinary value.) I spent months on the buses, meeting people. In the first week I won a Sony radio in a game of dice with some black men who said they were union organizers. When I observed that they gambled recklessly, one of them said, "Man, this is Charleston and the white boy thinks black union men gamble recklessly!" On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz stations that then abounded. They played real jazz, with harmony and melody and invention; the self-indulgent **** you hear today says absolutely nothing to me except that the socalled artist is committing onanism in public when I would much prefer it to be hara kiri. Later I heard those stations used 845s in their transmitters. So when the opportunity arose, I built some 845s. I have never ceased to love their sound. The 211 I like much less. To me its only advantage is an easier drive requirement, which becomes irrelevant once you decide on a triode power tube with a good bit of current on it as your driver. I typically expect Americans to like 211 sound. Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with the -30 not quite so refined. My Type 199 Millennium End amp is a Svetlana 572-xx switchable SE, PSE amp of up to 75W (theoretically more but I've never bothered, in fact I mostly use it set up for the 25W region). The KISS Amp design that I am waiting to resume describing is a version of the booster amp driving the Millennium. That's right, I use a WE300B as a pre-amp for a bigger amp. You say "an almost-practical 5K ohm load". If you merely mean availability of transformers, it is perfectly practical. The transformers designed for my T199 by Menno van der Veen are catalogued by Amplimo and Plitron. The output is rated of 90W, 190mA (design centre, 380mA in all), primary 5K014, and has secondary links 2, 4 and 8ohm to permit use of one or two SV-572-3 or -10, or two 845, or the three parallel 211 you posit, i.e. 2K5 or 5K. The power supply after rectifying gives a kilovolt at 200mA, 950V at 400mA, and also has separate windings for the drivers, input tubes, bias, filaments. I use the prototypes Menno tested for the formal description. The numbers of the prototypes, which should permit you to find them in the Plitron and Amplimo catalogues, are output VDV-JUTE-HQ5090 and power supply 6632-XO. Both firms wind both transformers. Amplimo is in The Netherlands, Plitron in Canada. Sit down before you read the prices and the shipping weights. These are monsters probably on the very edge of feasibility for amateurs (though not by the standards of the more experienced radio hams). You wouldn't happen to have a pair of 212-E for sale or trade, would you, my dear fellow? I have just the transformers for them already... One of the design specs I gave Menno was my dream of 212-E, so he returned ultra-useful experimenter's trannies. Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211 has a plate resistance of around 3800 ohm. Three in parallel would show Rp a bit under 1300R. My experience is that you want a higher multiple of Rp for RL on 211 than on 845, or, put more positively, 845 are more tolerant while 211 repay higher multiples. (That is why Kondo went to such extraordinary lengths with the output for the Ongaku, claimed to be 20K but reputedly at least 16K.) Four times a bit under 1300R is 5K1 so you will do the job handsomely with these trannies. On the other hand, with so much current capability in the OPT, you can run the 211 high and hot, somewhere over 60mA, and gain some more silence from that. HTH. Andre Jute PS. The rest of you reckless little *******s, don't start building kilovolt amps before you have built several EL34 or 300B amps and run them for a couple of years without mishap. It's not just a different ballgame, it is on a different level altogether. Think permanent state of death (a morbid joke I'm borrowing from the novelist John Gardner) and ask yourself if you really want to take a fulltime holiday there. The most common UL rating for tube amp wire, 1015, is happy with 300B voltages but not suitable for kilovolt amps; the same applies to caps which need bypasses if stacked, and resistors have to be specially rated. *Everything* you use in a kilovolt amp has to be inspected with a jaundiced eye, and you can't even measure it with the sort of meter you until now thought expensive or, very probably, the scope on your workbench; the reduction probe you bought for 80 bucks is most probably illegal and dangerous for such elevated voltages. (I don't just mean the digital or silicon electronics stuff rated 30 or 50V; a lot of common good quality high tension gear is rated 600V max. Always check the fuse rating inside the meter.) Just for the record, by kilovolt amps I mean a kilovolt and over, because the 845/211 class is rated for 1250 volts, and some other tubes we discussed or may still discuss much higher still. |
#7
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In article , Patrick Turner
writes Iain M Churches wrote: "Andre Jute" wrote in message ... rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Now we are back on track. This is the kind of stuff RAT needs and is famous for:-) Iain One needs a special respect for working with 1,000v+ anode voltages. Its a wonder more ppl have not been killed.... Well when I used to work for the old Pye Television Transmitter company they had Klystrons in the UHF Tx's, some 15 kV on the collectors, and all that was in UR67 co-ax with the screens well earthed!. All the caps and suchlike had large knife switches that were used for grounding after the power was switched off. The whole lot was controlled by a A and B key system in that a number of the B keys could open the various cabinets but in doing so they were retained in the locks until closed with an elaborate system of switched interlocks. Only when all the B keys were back in the frame that they stayed locked into, could you take the A key out to lift off the earths and turn on the power. In a remote part of Indonesia some maintenance engineer found it expedient to have a spare A key, he got a local locksmith to make up. Needless to say in that country the TX sites were a bit remote so it wasn't unusual for an engineer to go missing for a few days, which he did, and after a few more days than usual, they went looking. They found him, or what was left of him, in a high voltage cubicle and the body had much of its flesh removed by animals and insects;( proved that the companies insistence on NO spare A keys was a good thing!..... -- Tony Sayer |
#8
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#9
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In article , Andre Jute
writes rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Chris Hornbeck wrote: I'm a big fan of 845's; they solve a lot of speaker problems, which are much more intractible. 211's have even better curves, and three in parallel make 50 watts without grid current, and into an almost-practical 5K ohm load. Back in the 60s, when I was a student, I travelled across the States on one of those go anywhere one way Greyhound tickets that then cost 99 bucks. (Somebody said a couple of years ago that they are still only 199 bucks. Extraordinary value.) I spent months on the buses, meeting people. In the first week I won a Sony radio in a game of dice with some black men who said they were union organizers. When I observed that they gambled recklessly, one of them said, "Man, this is Charleston and the white boy thinks black union men gamble recklessly!" On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz stations that then abounded. They played real jazz, with harmony and melody and invention; the self-indulgent **** you hear today says absolutely nothing to me except that the socalled artist is committing onanism in public when I would much prefer it to be hara kiri. Later I heard those stations used 845s in their transmitters. So when the opportunity arose, I built some 845s. I have never ceased to love their sound. So sad to say that most MF transmitters these days are solid state in the modulators;( Apart from that theres no buddy Jazz stations on British radio to speak of anyway, So much for "broadening listener choice" OFCOM;(( -- Tony Sayer |
#10
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In article , Andre Jute
writes rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Chris Hornbeck wrote: I'm a big fan of 845's; they solve a lot of speaker problems, which are much more intractible. 211's have even better curves, and three in parallel make 50 watts without grid current, and into an almost-practical 5K ohm load. Back in the 60s, when I was a student, I travelled across the States on one of those go anywhere one way Greyhound tickets that then cost 99 bucks. (Somebody said a couple of years ago that they are still only 199 bucks. Extraordinary value.) I spent months on the buses, meeting people. In the first week I won a Sony radio in a game of dice with some black men who said they were union organizers. When I observed that they gambled recklessly, one of them said, "Man, this is Charleston and the white boy thinks black union men gamble recklessly!" On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz stations that then abounded. They played real jazz, with harmony and melody and invention; the self-indulgent **** you hear today says absolutely nothing to me except that the socalled artist is committing onanism in public when I would much prefer it to be hara kiri. Later I heard those stations used 845s in their transmitters. So when the opportunity arose, I built some 845s. I have never ceased to love their sound. So sad to say that most MF transmitters these days are solid state in the modulators;( Apart from that theres no bluddy Jazz stations on British radio to speak of anyway, So much for "broadening listener choice" OFCOM;(( -- Tony Sayer |
#11
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Waiting for Nick Sheldon to join this article thread ... :-)
Tom -- Do not meddle in the affairs of wizards, for you are crunchy and good with ketchup. |
#12
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One needs a special respect for working with 1,000v+ anode voltages. Then there are tubes like the 6BK4, intended as color TV set very high voltage voltage regulators. 25KV. It's a triode with a mu of 2000. Heard some people use them in audio amps. Electrostatic speaker drivers? |
#13
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One needs a special respect for working with 1,000v+ anode voltages. Its a wonder more ppl have not been killed.... Another thing, it would be mandatory that the tubes be fully enclosed in a cage, and that cage and the bottom lid of the amp have interlocks to disable the power supply if opened. No pretty wood boxes with bare tubes on top. You can chrome or gold plate the cage if you want to make it look pretty.... |
#14
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"Andre Jute" wrote in message ... you arrogant ****head; my job ( amongst others) in local radio station is to maintenance tube FM transmitter with 1,5KW output,and working voltage in range of 2KV. and that's Lilliput type of facility in this sort of business. betcha you never walked through transmitter? imagine that sort of energy,and imagine that sort of brain muscles needed to make that gadgets. pity,mebbe your arrogance will be smaller ......... man with brain and with balls can do that without polluting newsgroups. in any case-man with real job and proper attitude to life will never spill **** in NG ,like you do all the time. "c'mon-make my day". -- -- .................................................. ........................ Choky Prodanovic Aleksandar YU "don't use force, "don't use force, use a larger hammer" use a larger tube - Choky and IST" - ZM .................................................. ........................... |
#15
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In article ,
Iain M Churches wrote: rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Now we are back on track. This is the kind of stuff RAT needs and is famous for:-) Some might say it's in the realms of green pens for CDs and litz wire for speakers. :-) -- *Heart attacks... God's revenge for eating his animal friends Dave Plowman London SW To e-mail, change noise into sound. |
#16
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In the late 50s and early 60s I was a Rediffusion trainee learning about
high voltage (B+ of 1.6kV )audio amps. These were made by Redifon - and the older ones running 4 huge tetrodes with forced cold air intake gave nearly 2.5kW each (x eight in sync), while the newer ones with 4 later tubes in air-conned cabinets pushed out 3kW (x four in sync), both programmes into 100V line feeders which was copper-quad distributed PA-fashion over 120 square miles, to over 40,000 home subscribers, each with a channel select switch and a variable attenuator giving, after step-down to 15Ohm loudspeaker, about a 1/2 Watt either channel. Tubes started going soft about ten months of 18-hr use. I think they contained some mercury coatings, or something like that. 807s fed them, again at a high voltage, I think about 600V, on topcaps. The quality was superb... up to about 15kHz (-3dB point) on homes nearer to our station, up to10 kHz on outer radius of network. Xtalk, on a dry day, was better than 35dB below ref (43dB below peak). The cabinets were interlocked on all access doors, had isolation breakers on their o/ps, needed 2 mins for heaters to warm up, and the EHT capacitors with a bleeder across still held juice after 2 hours. Had to shunt their electrodes with a screwdriver before any corona cleaning or maint work could be done! I recall those large coupling transformer (14" cubed) laminations chattered and sang tizzily, just like a Personal stereo sounds to another individual. "tony sayer" wrote in message ... In article .com, writes You are more likely to be killed outright by line voltage than by high B+. 70 years of Amateur Radio statistics-most of which time hams were mostly builders-bears this out. Design commercial products with interlocks like transmitter manufacturers did for years and if you are a DIYer buy and/or build proper safety equipment and use it. Tube amps running 1 kV and above are the best sounding and most reliable-they either are built properly or fail spectacularly and in short order-way to get substantial power. The 812, 813, and a bunch of other tubes out there can sound great and give good service. You have to put some build cost in the amp, which is as it should be. We used to make IIRC 2-5 kW amps for the old Pamphonic company sometime in the late Sixties, can't for the life of me remember the Valves used something like PA100 or similar. Bloody great things, about a foot and a bit high!.... -- Tony Sayer |
#17
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On 15 Mar 2005 14:07:20 -0000, Andre Jute
wrote: The 211 I like much less. To me its only advantage is an easier drive requirement, which becomes irrelevant once you decide on a triode power tube with a good bit of current on it as your driver. I typically expect Americans to like 211 sound. You could also look at its drive requirement as a negative, both because of the higher Miller C and because of the great temptation to try to drive them into grid current. Their load impedance requirements are a bear too, and only eased by paralleling. The things that I *like* about 211's are their exceptional linearity, uniformity (if using GE's or RCA's) and the fact that I have a couple dozen on hand. Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with the -30 not quite so refined. Never used them, although I remember your positive comments from several years ago. You wouldn't happen to have a pair of 212-E for sale or trade, would you, my dear fellow? I have just the transformers for them already... One of the design specs I gave Menno was my dream of 212-E, so he returned ultra-useful experimenter's trannies. Sorry, I've never owned even one. Wish I had a pair now; I wouldn't have to work for a living. Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211 has a plate resistance of around 3800 ohm. Three in parallel would show Rp a bit under 1300R. My experience is that you want a higher multiple of Rp for RL on 211 than on 845, or, put more positively, 845 are more tolerant while 211 repay higher multiples. (That is why Kondo went to such extraordinary lengths with the output for the Ongaku, claimed to be 20K but reputedly at least 16K.) Four times a bit under 1300R is 5K1 so you will do the job handsomely with these trannies. On the other hand, with so much current capability in the OPT, you can run the 211 high and hot, somewhere over 60mA, and gain some more silence from that. Very well put; covers it. One avenue I've yet to explore is directly driving electrostats with a push-pull pair of "50 watters". Even a single pair of 211's would be enough for the old QUAD's, methinks. Thanks for your thoughts, Chris Hornbeck "That's where may forebears came from. Three of them anyway. Who's been sleeping in my porridge?" -F&S |
#18
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Andre Jute wrote:
rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Chris Hornbeck wrote: I'm a big fan of 845's; they solve a lot of speaker problems, which are much more intractible. 211's have even better curves, and three in parallel make 50 watts without grid current, and into an almost-practical 5K ohm load. Back in the 60s, when I was a student, I travelled across the States on one of those go anywhere one way Greyhound tickets that then cost 99 bucks. (Somebody said a couple of years ago that they are still only 199 bucks. Extraordinary value.) I spent months on the buses, meeting people. In the first week I won a Sony radio in a game of dice with some black men who said they were union organizers. When I observed that they gambled recklessly, one of them said, "Man, this is Charleston and the white boy thinks black union men gamble recklessly!" On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz stations that then abounded. They played real jazz, with harmony and melody and invention; the self-indulgent **** you hear today says absolutely nothing to me except that the socalled artist is committing onanism in public when I would much prefer it to be hara kiri. Later I heard those stations used 845s in their transmitters. So when the opportunity arose, I built some 845s. I have never ceased to love their sound. The 211 I like much less. To me its only advantage is an easier drive requirement, which becomes irrelevant once you decide on a triode power tube with a good bit of current on it as your driver. I typically expect Americans to like 211 sound. Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with the -30 not quite so refined. My Type 199 Millennium End amp is a Svetlana 572-xx switchable SE, PSE amp of up to 75W (theoretically more but I've never bothered, in fact I mostly use it set up for the 25W region). The KISS Amp design that I am waiting to resume describing is a version of the booster amp driving the Millennium. That's right, I use a WE300B as a pre-amp for a bigger amp. You say "an almost-practical 5K ohm load". If you merely mean availability of transformers, it is perfectly practical. The transformers designed for my T199 by Menno van der Veen are catalogued by Amplimo and Plitron. The output is rated of 90W, 190mA (design centre, 380mA in all), primary 5K014, and has secondary links 2, 4 and 8ohm to permit use of one or two SV-572-3 or -10, or two 845, or the three parallel 211 you posit, i.e. 2K5 or 5K. The power supply after rectifying gives a kilovolt at 200mA, 950V at 400mA, and also has separate windings for the drivers, input tubes, bias, filaments. I use the prototypes Menno tested for the formal description. The numbers of the prototypes, which should permit you to find them in the Plitron and Amplimo catalogues, are output VDV-JUTE-HQ5090 and power supply 6632-XO. Both firms wind both transformers. Amplimo is in The Netherlands, Plitron in Canada. Sit down before you read the prices and the shipping weights. These are monsters probably on the very edge of feasibility for amateurs (though not by the standards of the more experienced radio hams). You wouldn't happen to have a pair of 212-E for sale or trade, would you, my dear fellow? I have just the transformers for them already... One of the design specs I gave Menno was my dream of 212-E, so he returned ultra-useful experimenter's trannies. Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211 has a plate resistance of around 3800 ohm. Three in parallel would show Rp a bit under 1300R. My experience is that you want a higher multiple of Rp for RL on 211 than on 845, or, put more positively, 845 are more tolerant while 211 repay higher multiples. (That is why Kondo went to such extraordinary lengths with the output for the Ongaku, claimed to be 20K but reputedly at least 16K.) Four times a bit under 1300R is 5K1 so you will do the job handsomely with these trannies. On the other hand, with so much current capability in the OPT, you can run the 211 high and hot, somewhere over 60mA, and gain some more silence from that. HTH. Andre Jute PS. The rest of you reckless little *******s, don't start building kilovolt amps before you have built several EL34 or 300B amps and run them for a couple of years without mishap. It's not just a different ballgame, it is on a different level altogether. Think permanent state of death (a morbid joke I'm borrowing from the novelist John Gardner) and ask yourself if you really want to take a fulltime holiday there. The most common UL rating for tube amp wire, 1015, is happy with 300B voltages but not suitable for kilovolt amps; the same applies to caps which need bypasses if stacked, and resistors have to be specially rated. *Everything* you use in a kilovolt amp has to be inspected with a jaundiced eye, and you can't even measure it with the sort of meter you until now thought expensive or, very probably, the scope on your workbench; the reduction probe you bought for 80 bucks is most probably illegal and dangerous for such elevated voltages. (I don't just mean the digital or silicon electronics stuff rated 30 or 50V; a lot of common good quality high tension gear is rated 600V max. Always check the fuse rating inside the meter.) Just for the record, by kilovolt amps I mean a kilovolt and over, because the 845/211 class is rated for 1250 volts, and some other tubes we discussed or may still discuss much higher still. In the late 50's, I built a 4500 volt, one amp DC regulated PS. The passer tubes were 304TH's, so I guess that would qualify to be in this thread. It was pretty damned impressive with lots of interlocks. That was fortunate one time when the run contacts on the line relay failed to open. They were welded shut by the inrush on start. The fail safe system discharged 8 microfarads of cap at more than 5KV with a huge bang. Lucky ME. JLS |
#19
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Fabio Berutti wrote:
If You want a tube for "real men", see this one: http://info.uibk.ac.at/c/c7/c704/mus...es/rs329g.html Some are still available in Germany... Back to more palatable tubes, and considering that original 211s or 845s are hard to find or extremely expensive, my favorite tube in this league would be the Russian GM-70. It has a dissipation of 125W, a higher mu than the 845 and it doesn't need to be "swung" up to positive grid for full power like a 211, ie. the driver circuit task is easier and the final result is probably better. I played a bit with the anode curves and it seems that a B+ of about 1000 - 1100V together with an anode load of 10K gives the maximum output power in SE class A, about 45W! Or put a pair of them in PP to blast the roof... Happy to see a real RAT thread Ciao Fabio As it happens, I missed most of this thread, as I spent yesterday listening and "playing" about with a pair of 212's descrovering that they take quite a lot to drive properly. We did some blind comparisons some time back, and the graphite GM70 didn't come out as well as others. The copper plate GM70 on the other hand, sounded very similar to a pair of 4212, and a pair of vt1505's. Having said that I have used a GM70 for a few months and it sounded good. And nice and easy to drive. Works quite well at lowish voltage as well 800v @100ma or so. Though to my ears, I prefer the 211. Both the GM70 and 845 are more "mechanical" sounding, this is of course just IMHO. -- Nick "Life has surface noise" - John Peel 1939-2004 |
#20
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"Dave Plowman (News)" wrote in message ... In article , Iain M Churches wrote: Now we are back on track. This is the kind of stuff RAT needs and is famous for:-) Some might say it's in the realms of green pens for CDs and litz wire for speakers. :-) No, this is the real thing:-)) Iain |
#21
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"robert casey" wrote in message nk.net... One needs a special respect for working with 1,000v+ anode voltages. Its a wonder more ppl have not been killed.... Another thing, it would be mandatory that the tubes be fully enclosed in a cage, It is, for any valve amp, at least here in Scandinavia. If the owner removed the cage supplied, he does so at his own risk - just like removing the guard from an industrial saw. The risk of fire, or a child burning him/herself, although small, is statistically greater than electrocution. I have seen some American amps with a two way mains cord (probably not allowed any more) Here, a three way cord is required, with the amp chassis bonded to ground. Fixed mains cables are no longer allowed, neither is the octal plug/socket for high voltage AC or DC. The only approved mains chassis connectors are the IEC, and the Speakon AC connector. and that cage and the bottom lid of the amp have interlocks to disable the power supply if opened. The safety regs here insist that a separate psu has an interlock, and removing the umbilical cord from psu to amp from either end, shuts the psu down, and discharges it, in a time shorter than that required to remove the bottom plate to gain access. Also, high voltage DC is not allowed to be carried on an umbilical cord. I got this information from an industrial insurance safety officer. It applies to Scandinavia -. things might be different elsewhere, though I would expect regulations to be strict in the UK, which has the world's most sensible mains plug which carries its own fuse, and can only be inserted one way round:-) Iain |
#22
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"Fabio Berutti" wrote in message ... Back to more palatable tubes, and considering that original 211s or 845s are hard to find or extremely expensive, my favorite tube in this league would be the Russian GM-70. It has a dissipation of 125W, a higher mu than the 845 and it doesn't need to be "swung" up to positive grid for full power like a 211, ie. the driver circuit task is easier and the final result is probably better. I played a bit with the anode curves and it seems that a B+ of about 1000 - 1100V together with an anode load of 10K gives the maximum output power in SE class A, about 45W! Or put a pair of them in PP to blast the roof... This has really got me interested in HV tubes:-) I have just been taking a look at some graphs for the 811, 812, 813, 845, 300B, 211. Alll of these have impressive linearity - much better than the EL34, 6L6, KT88 etc that I have been accustomed to using. However, the high voltage B+ puts me off. 500V for me is something of a psychological barrier. Maybe I will try 2A3 at a humble 275V Happy to see a real RAT thread Yes! The sun is shining again on RAT:-) Iain |
#23
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In article et, robert
casey writes One needs a special respect for working with 1,000v+ anode voltages. Then there are tubes like the 6BK4, intended as color TV set very high voltage voltage regulators. 25KV. It's a triode with a mu of 2000. Heard some people use them in audio amps. Electrostatic speaker drivers? Yes they used a shunt regulator in the old Philips valve K9 ? chassis and that was in a box of its own, not so much as the high voltage but it was an X-ray generator!.... -- Tony Sayer |
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In article ,
tony sayer wrote: Yes they used a shunt regulator in the old Philips valve K9 ? chassis and that was in a box of its own, not so much as the high voltage but it was an X-ray generator!.... IIRC, G6. Excellent TV. But an interesting valves via SS comparison - it needed both output stages total valve replacement about every two years. -- *If at first you don't succeed, then skydiving definitely isn't for you * Dave Plowman London SW To e-mail, change noise into sound. |
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Fabio Berutti wrote: If You want a tube for "real men", see this one: http://info.uibk.ac.at/c/c7/c704/mus...es/rs329g.html Some are still available in Germany... Back to more palatable tubes, and considering that original 211s or 845s are hard to find or extremely expensive, my favorite tube in this league would be the Russian GM-70. It has a dissipation of 125W, a higher mu than the 845 and it doesn't need to be "swung" up to positive grid for full power like a 211, ie. the driver circuit task is easier and the final result is probably better. I played a bit with the anode curves and it seems that a B+ of about 1000 - 1100V together with an anode load of 10K gives the maximum output power in SE class A, about 45W! Or put a pair of them in PP to blast the roof... PPL using GM70 here have had great results. I have a design worked out and tried by one guy if anyone is interested. Patrick Turner. Happy to see a real RAT thread Ciao Fabio "Andre Jute" ha scritto nel messaggio ... rec.audio.tubes Kilovolt transmitting tubes Let's make a new thread here. Chris Hornbeck wrote: I'm a big fan of 845's; they solve a lot of speaker problems, which are much more intractible. 211's have even better curves, and three in parallel make 50 watts without grid current, and into an almost-practical 5K ohm load. Back in the 60s, when I was a student, I travelled across the States on one of those go anywhere one way Greyhound tickets that then cost 99 bucks. (Somebody said a couple of years ago that they are still only 199 bucks. Extraordinary value.) I spent months on the buses, meeting people. In the first week I won a Sony radio in a game of dice with some black men who said they were union organizers. When I observed that they gambled recklessly, one of them said, "Man, this is Charleston and the white boy thinks black union men gamble recklessly!" On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz stations that then abounded. They played real jazz, with harmony and melody and invention; the self-indulgent **** you hear today says absolutely nothing to me except that the socalled artist is committing onanism in public when I would much prefer it to be hara kiri. Later I heard those stations used 845s in their transmitters. So when the opportunity arose, I built some 845s. I have never ceased to love their sound. The 211 I like much less. To me its only advantage is an easier drive requirement, which becomes irrelevant once you decide on a triode power tube with a good bit of current on it as your driver. I typically expect Americans to like 211 sound. Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with the -30 not quite so refined. My Type 199 Millennium End amp is a Svetlana 572-xx switchable SE, PSE amp of up to 75W (theoretically more but I've never bothered, in fact I mostly use it set up for the 25W region). The KISS Amp design that I am waiting to resume describing is a version of the booster amp driving the Millennium. That's right, I use a WE300B as a pre-amp for a bigger amp. You say "an almost-practical 5K ohm load". If you merely mean availability of transformers, it is perfectly practical. The transformers designed for my T199 by Menno van der Veen are catalogued by Amplimo and Plitron. The output is rated of 90W, 190mA (design centre, 380mA in all), primary 5K014, and has secondary links 2, 4 and 8ohm to permit use of one or two SV-572-3 or -10, or two 845, or the three parallel 211 you posit, i.e. 2K5 or 5K. The power supply after rectifying gives a kilovolt at 200mA, 950V at 400mA, and also has separate windings for the drivers, input tubes, bias, filaments. I use the prototypes Menno tested for the formal description. The numbers of the prototypes, which should permit you to find them in the Plitron and Amplimo catalogues, are output VDV-JUTE-HQ5090 and power supply 6632-XO. Both firms wind both transformers. Amplimo is in The Netherlands, Plitron in Canada. Sit down before you read the prices and the shipping weights. These are monsters probably on the very edge of feasibility for amateurs (though not by the standards of the more experienced radio hams). You wouldn't happen to have a pair of 212-E for sale or trade, would you, my dear fellow? I have just the transformers for them already... One of the design specs I gave Menno was my dream of 212-E, so he returned ultra-useful experimenter's trannies. Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211 has a plate resistance of around 3800 ohm. Three in parallel would show Rp a bit under 1300R. My experience is that you want a higher multiple of Rp for RL on 211 than on 845, or, put more positively, 845 are more tolerant while 211 repay higher multiples. (That is why Kondo went to such extraordinary lengths with the output for the Ongaku, claimed to be 20K but reputedly at least 16K.) Four times a bit under 1300R is 5K1 so you will do the job handsomely with these trannies. On the other hand, with so much current capability in the OPT, you can run the 211 high and hot, somewhere over 60mA, and gain some more silence from that. HTH. Andre Jute PS. The rest of you reckless little *******s, don't start building kilovolt amps before you have built several EL34 or 300B amps and run them for a couple of years without mishap. It's not just a different ballgame, it is on a different level altogether. Think permanent state of death (a morbid joke I'm borrowing from the novelist John Gardner) and ask yourself if you really want to take a fulltime holiday there. The most common UL rating for tube amp wire, 1015, is happy with 300B voltages but not suitable for kilovolt amps; the same applies to caps which need bypasses if stacked, and resistors have to be specially rated. *Everything* you use in a kilovolt amp has to be inspected with a jaundiced eye, and you can't even measure it with the sort of meter you until now thought expensive or, very probably, the scope on your workbench; the reduction probe you bought for 80 bucks is most probably illegal and dangerous for such elevated voltages. (I don't just mean the digital or silicon electronics stuff rated 30 or 50V; a lot of common good quality high tension gear is rated 600V max. Always check the fuse rating inside the meter.) Just for the record, by kilovolt amps I mean a kilovolt and over, because the 845/211 class is rated for 1250 volts, and some other tubes we discussed or may still discuss much higher still. |
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In article , Dave Plowman (News)
writes In article , tony sayer wrote: Yes they used a shunt regulator in the old Philips valve K9 ? chassis and that was in a box of its own, not so much as the high voltage but it was an X-ray generator!.... IIRC, G6. Excellent TV. But an interesting valves via SS comparison - it needed both output stages total valve replacement about every two years. Yes the old G6 had it, but there was another one that was make in Sweden that also had excellent sound as well, K7 or something like that?.... -- Tony Sayer |
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Choky wrote: "Andre Jute" wrote in message ... you arrogant ****head; my job ( amongst others) in local radio station is to maintenance tube FM transmitter with 1,5KW output,and working voltage in range of 2KV. and that's Lilliput type of facility in this sort of business. betcha you never walked through transmitter? imagine that sort of energy,and imagine that sort of brain muscles needed to make that gadgets. pity,mebbe your arrogance will be smaller ......... man with brain and with balls can do that without polluting newsgroups. in any case-man with real job and proper attitude to life will never spill **** in NG ,like you do all the time. "c'mon-make my day". Choky, you have a sore head, was it the plum brandy? In Russia, they have power tubes so big people can remove a panel and walk around inside to replace a cathode. In the bad ol days they'd give the job to a dissident, and send him in with a spanner. Then the secret police would spring the door shut, evac the tube, apply 50,000v, and transmit the dissident. Their chief was heard to announce, "That'll teach that pirate radio operator a lesson after saying rotten things on air about Stalin" Shostakovitches 9th Symphony makes one live in hope when feeing down.... Patrick Turner. -- -- .................................................. ....................... Choky Prodanovic Aleksandar YU "don't use force, "don't use force, use a larger hammer" use a larger tube - Choky and IST" - ZM .................................................. .......................... |
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"Andre Jute" wrote in message
Just for the record, by kilovolt amps I mean a kilovolt and over, because the 845/211 class is rated for 1250 volts, and some other tubes we discussed or may still discuss much higher still. For me, life gets just barely interesting when you start talking about tubes like the 4CX1000. Real men play with the mid-sized stuff like push-pull pairs of 4CX5000. The last piece of tubed equipment I worked on had a 4CX3000, and about 400 other tubes. The real tubes in that box were magnetically-focussed klystrons whose part numbers were classified. |
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In article ,
tony sayer wrote: Yes the old G6 had it, but there was another one that was make in Sweden that also had excellent sound as well, K7 or something like that?.... Heh heh - the G6 certainly had appalling sound - despite being single ended valve. As soon as mine was out of warranty, I fitted a buffer amp and rep coil (live chassis) to feed it to the Hi-Fi. Very unusual in those days. We also had to do a few mods to get the vision buzz on sound sorted. -- *I must always remember that I'm unique, just like everyone else. * Dave Plowman London SW To e-mail, change noise into sound. |
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"Iain M Churches" wrote in message ... "Fabio Berutti" wrote in message ... Back to more palatable tubes, and considering that original 211s or 845s are hard to find or extremely expensive, my favorite tube in this league would be the Russian GM-70. It has a dissipation of 125W, a higher mu than the 845 and it doesn't need to be "swung" up to positive grid for full power like a 211, ie. the driver circuit task is easier and the final result is probably better. I played a bit with the anode curves and it seems that a B+ of about 1000 - 1100V together with an anode load of 10K gives the maximum output power in SE class A, about 45W! Or put a pair of them in PP to blast the roof... This has really got me interested in HV tubes:-) I have just been taking a look at some graphs for the 811, 812, 813, 845, 300B, 211. Alll of these have impressive linearity - much better than the EL34, 6L6, KT88 etc that I have been accustomed to using. However, the high voltage B+ puts me off. 500V for me is something of a psychological barrier. Maybe I will try 2A3 at a humble 275V couldnt you do a balanced supply? +500volts and -500Volts? wouldnt that solve alot of the problems associated with the HV requirements of these tubes?? Doug |
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On Wed, 16 Mar 2005 09:10:44 -0500, "Arny Krueger"
wrote: For me, life gets just barely interesting when you start talking about tubes like the 4CX1000. Real men play with the mid-sized stuff like push-pull pairs of 4CX5000. The last piece of tubed equipment I worked on had a 4CX3000, and about 400 other tubes. The real tubes in that box were magnetically-focussed klystrons whose part numbers were classified. My Army time included push-pull 250 watters from the forced-air tetrode family, but never any of the really big guys. VHF stuff, already obsolete in 1970. PCM though! You raise an interesting question: has anyone ever played with any big tetrodes with the G2 floating? I'd expect a high mu, but there might be usable exceptions. Thanks, Chris Hornbeck "That's where my forebears came from. Three of them anyway. Who's been sleeping in my porridge?" -F&S |
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"tony sayer" schreef in bericht ... In article et, robert casey writes One needs a special respect for working with 1,000v+ anode voltages. Then there are tubes like the 6BK4, intended as color TV set very high voltage voltage regulators. 25KV. It's a triode with a mu of 2000. Heard some people use them in audio amps. Electrostatic speaker drivers? Yes they used a shunt regulator in the old Philips valve K9 ? chassis and that was in a box of its own, not so much as the high voltage but it was an X-ray generator!.... PL509 tubes in the K8. Excellent Am radio finals! gr, hwh |
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On Tue, 15 Mar 2005 21:52:45 +0000, robert casey wrote:
One needs a special respect for working with 1,000v+ anode voltages. Its a wonder more ppl have not been killed.... Another thing, it would be mandatory that the tubes be fully enclosed in a cage, and that cage and the bottom lid of the amp have interlocks to disable the power supply if opened. No pretty wood boxes with bare tubes on top. You can chrome or gold plate the cage if you want to make it look pretty.... _Two_ sets of interlock switches. One to kill the power supply and one to ground the B+ lead in case a bleeder resistor opens and leaves the filter capacitors charged. I once shut down a 20KW transmitter for preventive maintenance and heard what sounded like a pistol shot as I opened the door to the power supply cabinet. |
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