Push Pull o Single Ended

MartinV56 · May 20, 2011 at 18:12

Conseguí una pareja de tetrodos 807, tubos de potencia, la primera pregunta que me hice, single ended o push pull, así las cosas busqué información en la red sobre el tema y encontré este interesante artículo que comparto con ustedes

http://homepage.mac....-v-PP-Part1.pdf

http://homepage.mac.com/tlinespeakers/vaughn/downloads/SE-v-PP-Part2.pdf

Editado October 16, 2017 at 17:49 por MartinV56

striker · May 20, 2011 at 18:33

buen dato tecnico martin

estas 807 se las traen de verdad , tienen un sonido muy bueno lo unico malo es el gorro,ademas se encuentran en stock nos de excelentes marcas...yo me iria por un single end

saludos

Biker · May 20, 2011 at 19:51

Ja ja ja.. que manera de reirme... güena Martin!

MartinV56 · May 20, 2011 at 21:14

Aquí vamos

[img]http://img190.imageshack.us/img190/3977/s4010105.jpg[/img]

[img]http://img38.imageshack.us/img38/9593/s4010107.jpg[/img]

Squonk · May 20, 2011 at 21:21

Muy bueno el articulo, gracias por el link.

Squonk

MartinV56 · May 20, 2011 at 21:30

Opciones

Push Pull

Williamson 807

página 8

[url="http://www.clarisonus.com/Archives/Trans/Acro55.pdf"]http://www.clarisonus.com/Archives/Trans/Acro55.pdf[/url]

Single Ended RH 807

[img]http://img822.imageshack.us/img822/3272/se807sch2.gif[/img]

MartinV56 · May 20, 2011 at 21:44

En ebay en este link de Bob Carver encontré unos comentarios interesantes que me permito transcribir

http://img822.imageshack.us/img822/3272/se807sch2.gif

[center][center][b][color=black][font=Arial][size=5]Tubular Joe and I finished a brand new amplifier and here it is.[/size][/font][/color][/b][/center][/center]
[center][center][b][color=black][font=Arial][size=5][/size][/font][/color][/b] [/center][/center]
[center][center][b][color=black][font=Arial][size=5]HOW IT ALL STARTED [/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[color=black][font=Arial][size=2]It was a hot mid-summer's night and I was in Chicago at the consumer electronics show.[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]I was in my booth pitching my wares, a new amp and preamp, and it was hot inside. Not the amplifier, but the convention floor, and I was getting thirsty. I wanted something cold to drink, so I decided to sneak away from my booth for a moment to get a coke. As I was sneaking, a colleague happened to walk by and said, " Hey Bob, have you seen Stu Hegeman's new preamp?"[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]I found myself getting excited, as Stewart Hegeman, the master designer of so many classic vacuum tube amplifiers and my very own hero, was here! Stu Hegeman was a true genius, having designed the Citation I, II, probably the III and countless other amplifiers for Sidney Harmon and for Lafayette.[/size][/font][/color][font=Arial][size=2][/size][/font]

[font=Arial][size=2] [/size][/font]

[color=black][font=Arial][size=2] I found him in his booth; we began talking about preamps and amplifiers, ultimately leading to a quiet corner in a close-by restaurant. Very close, as it was part of the convention itself. I finally got my coke. I could not believe I was in the presence of THE Stewart Hegeman, and he was talking to ME! We talked and talked about big solid state amps, tube preamps, solid state preamps, loudspeakers, ionic tweeters, recording lathes and finally tube power amps. And what a scientific talk it was! As the hours went by, he admitted to having been caught up in the ultra-linear fad of his day, that it was the biggest blunder of his career, and he did it only once and would NEVER design an amp with an ultra-linear output stage ever again. [/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]And he didn't. The Citation V was pure pentode, as was the subsequent Lafayette 550 and everything else he designed from then on. I asked why. He explained that when the plate pulls the top of the output transformer winding towards ground, the ultra-linear tap pushes the screen grid so low that it renders the tube unable to drive difficult loads. In addition, he pointed out that the normal idle potential on the screen grid regularly exceeded a safe voltage, often causing output tubes to blow up. The tube manufacturers hated it, but had to go along or lose market share, and so changed the specification for screen voltage in order to allow ultra-linear output stages. I can’t help but wonder if they REALLY changed the tube design, or simply changed the screen voltage specification. This conversation led to me confessing that I had always wanted to build a big tube amp that was painted the same color as my first car, a '49 metallic burgundy Mercury automobile. So I started on it. And here it is![/size][/font][/color][font=Arial][size=2][/size][/font]

[font=Arial][size=2] [/size][/font]

[center][center][b][color=black][font=Arial][size=2]A BREND NEW POWER AMPLIFIER, THE SILVER SEVEN NINE HUNDRED[/size][/font][/color][/b][color=black][font=Arial][size=2][/size][/font][/color][/center][/center]
[center][center][color=black][font=Arial][size=2] [/size][/font][/color][/center][/center]
[color=black][font=Arial][size=2]Several months ago the new Tung-Sol KT120 and new KT 100 mk II vacuum tubes became available, and I just had to try them! I found them to be utterly remarkable, with bandwidth and fidelity as good as anything I have ever experienced. In order to obtain the best from these remarkable new tubes it was necessary to design a new output stage , and what better one to start with than my own Silver Seven vacuum tube amplifier? [/size][/font][/color]

[center][center][b][color=black][font=Arial][size=5]Success ![/size][/font][/color][/b][color=black][font=Arial][size=2][/size][/font][/color][/center][/center]
[color=black][font=Arial][size=2]I was rewarded with a new and powerful amplifier that sounded as sweet and as expansive as my original Silver Seven, perhaps even better, yet easily outperformed it by delivering substantially more power and with less distortion (not that it needed it) than the original.[/size][/font][/color]

[color=black][font=Arial][size=2]
[/size][/font][/color][font=Arial][size=2] [/size][/font]

[center][center][font=Arial][size=2]
[/size][/font][b][color=black][font=Arial][size=2]The Mighty 6550 vs the KT120 and the KT100 mk II[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[color=black][font=Arial][size=2]Back to Stu. Anyway, when I asked him about his favorite output tube, he said the mighty 6550 was the one to use, and when I queried about the "kinkless" tetrodes, (the KT tubes), he held up his little pinkie finger as if to hold a tea-cup and said in a mock British accent. " Brits you know, if you want watered down tea."[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]He loved to use wide-band video pentodes in his amp designs, and did so when he could. (Read that as cost-no-object.) They were expensive then. "Why would anyone want to use a triode front-end when they could use a pentode?" he mused. Stu was single handily responsible for one of the worlds great amplifier topologies, the wide-band video pentode design. Never been done before, and it added a new category of stunning topologies to our universe. [/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]This design uses Stu's front end approach using a 12BY7. For this new Silver Seven I've used the more powerful, lower distortion version, the 12GN7 and I’ve updated and modified this amplifier to represent an expression of my latest thinking regarding power amplifier design. These modifications include a return to a pure pentode output stage, allowing substantially more output drive current than possible with, in (Stu Hegeman's) own words, the devil-begotten ultra-linear output stage. Strong words, but as we shall see, Stu was right. This amp has a DC filament supply, unheard of in power amps, but a necessary feature when using high-bandwidth pentodes in the front-end. This is the lowest noise power amp ever, with an A-weighted signal to noise ratio of minus 120 dB! Power output is hard to believe, and the sound is even more difficult to believe.[/size][/font][/color][font=Arial][size=2][/size][/font]

[color=black][font=Arial][size=2] [/size][/font][/color][font=Arial][size=2][/size][/font]

[center][center][b][color=black][font=Arial][size=2]THE DESIGN OF THE NEW SILVER SEVEN[/size][/font][/color][/b][b][font=Arial][size=2][/size][/font][/b][/center][/center]
[color=black][font=Arial][size=2]I started the design of this new amplifier by changing the color in order to protect the innocent. I changed the color from black to a beautiful strawberry burgundy red with chrome and silver highlights, just like my car. This new Silver Seven has every known de-lux circuit embodiment known to man, woman, or minor gods. As mentioned earlier, I used a 12GN7 vacuum tube for the front-end. I followed that high speed tube with several class-A drivers for the output tube grids. A cascode voltage amp is used for the gain stage that runs the dual regulator tubes, a pair of power output tubes. In the old days, huge amounts of energy storage were not practical. But today, in the vast intervening gulf of years, the technology associated with capacitor energy storage has allowed an increase of approximately ten fold in power supply capacity. This amplifier has had its energy storage increased substantially by the addition of HUGE capacitors that Stu could only dream about. This, combined with the additional DC restorer circuit eliminates every last vestige of “DC bounce” on musical transients. DC bounce and low-frequency stability have always been the result of compromises made by all amplifier designers in order to design an amplifier for the real world, that could be BUILT in the real world. Not any more, thanks to the DC restorer, HUGE capacitors, and my new output transformer which I wound my very own self. Not only that, the DC restorer works by keeping the DC component on each output tube grid the exact correct value through the entire audio signal swing, allowing perfect performance up to and even beyond clipping.[/size][/font][/color][font=Arial][size=2] [/size][/font]

[center][center][b][color=black][font=Arial][size=2] The DC Restorer and Super Long-Lasting Output Tubes[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[color=black][font=Arial][size=2]The DC restorer allows simultaneous low distortion and low idle power, allowing extreme longevity for the output tubes. The final distortion level in this amplifier is so low that I am embarrassed to write it down here, and the output tubes should last 50 years unless they have a catastrophic failure or won't bias up. This amp has a lifetime guarantee. It's my life and as long as I'm alive I will fix it free. I'll replace the output tubes free if they should become defective, even if you drop the amp on them. It's the least I can do. I know they will not become weak in our lifetimes.[/size][/font][/color][font=Arial][size=2][/size][/font]

[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[center][center][b][color=black][font=Arial][size=2]Features[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[color=black][font=Arial][size=2]Four output terminals; common ground, one, two, four, eight and sixteen ohms. A bias meter and a bias control. It has a volume control and a built-in tube tester for the output tubes. It comes in four chassis; two power supplies and two amplifiers. Built by me and Tubular Joe. Shipping weight is about 325 lbs for all four chassis plus the tubes.[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]One more thing: I accept ANY form of rational payment, and the pictures are of me, Bob Carver.[/size][/font][/color]
[font="Arial"][size=2]
[/size][/font]

[font="Arial"][size=2]Sentido homenaje de Carver a [/size][/font][font=Arial][size=2]Stu Hegeman diseñador del Harman Kardon Citation ll[/size][/font]

Q: Hi Bob Simple question. Why dont you build a 300b type tube amp with lots of power? In my opinion and many audiophiles the 300b's sound the best compared to el34, kt88/ 6550. I suspect there will and always be debate on this but the KT120's are a new tube that manufacturers are not even using. basically its just a higher output tube and the same as a KT88. Im more concerned why not a 300b tube amp?, more power does not always sound better.

A: Hi 'hadriump, That is a great question (I assume you mean an amplifier with a 300b single ended output stage). The answer is that I wanted to build the best amplifier of all time. If I thought for even one femtosecond that a powerful 300b type amplifier would sound better, I would build it. It's true when we say more power does not always make better sound, but in my long experience (I was old when Atlantis sank) more power almost always makes better sound if all else is equal, or if we only want to listen to wind-chimes at realistic levels. It just does! I have explored many, many amplifier topologies over my career, each exploration taking the form of a large series of converging experiments. The results of those experiments have taught me that a WELL DESIGNED push-pull output stage is the best sounding, and as a bonus, very practical as well as being quite energy efficient. Some history: Way back in the beginning of tube amplifiers,(in the 1930's) designers were forced to use class A single ended output stages in order to prevent a severe problem called "notch" distortion. Notch distortion resulted whenever a push-pull output stage was used. Push-pull amplifiers sounded terrible because of that nasty notch, exhibiting a harsh sound whenever the audio signal transitioned from positive to negative. As the years trolled by, many talented designers worked long hours to eliminate that notch (the reward would be huge). It took three men many long years of work to figure it out and get rid of the notch. One, a man named A.N. Williamson (of Williamson amplifier fame), and two others, Gordon Gow and Frank McIntosh. The last two guys started an amplifier company centered on the new technology. The problem was the output transformer, and these guys taught the world how to build output transformers that did not have a notch. And the high-fidelity industry took off. False beliefs often die hard, and the belief that somehow a single ended output ...Oops, I'm out of characters!

MartinV56 · May 20, 2011 at 23:18

Algo más sobre notch distortion, junto con las clases de amplificadores

[url="http://www.bcae1.com/ampclass.htm"]http://www.bcae1.com/ampclass.htm[/url]

MartinV56 · May 20, 2011 at 23:46

Otro diseño PP 807 ahora con transformadores UL Stancor

[url="http://www.technicalaudio.com/pdf/Gordon_Clark_folder/Stancor_Ultra-Linear_Williamson_Amplifier_w_A-8072_xfmr.pdf"]http://www.technicalaudio.com/pdf/Gordon_Clark_folder/Stancor_Ultra-Linear_Williamson_Amplifier_w_A-8072_xfmr.pdf[/url]

escultor · May 21, 2011 at 01:13

[quote name='MartinV56' date='20 May 2011 - 05:44 PM' timestamp='1305927857' post='62165']
En ebay en este link de Bob Carver encontré unos comentarios interesantes que me permito transcribir

http://img822.imageshack.us/img822/3272/se807sch2.gif

[center][center][b][color=black][font=Arial][size=5]Tubular Joe and I finished a brand new amplifier and here it is.[/size][/font][/color][/b][/center][/center]
[center][center][b][color=black][font=Arial][size=5][/size][/font][/color][/b] [/center][/center]
[center][center][b][color=black][font=Arial][size=5]HOW IT ALL STARTED [/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[color=black][font=Arial][size=2]It was a hot mid-summer's night and I was in Chicago at the consumer electronics show.[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]I was in my booth pitching my wares, a new amp and preamp, and it was hot inside. Not the amplifier, but the convention floor, and I was getting thirsty. I wanted something cold to drink, so I decided to sneak away from my booth for a moment to get a coke. As I was sneaking, a colleague happened to walk by and said, " Hey Bob, have you seen Stu Hegeman's new preamp?"[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]I found myself getting excited, as Stewart Hegeman, the master designer of so many classic vacuum tube amplifiers and my very own hero, was here! Stu Hegeman was a true genius, having designed the Citation I, II, probably the III and countless other amplifiers for Sidney Harmon and for Lafayette.[/size][/font][/color][font=Arial][size=2][/size][/font]

[font=Arial][size=2] [/size][/font]

[color=black][font=Arial][size=2] I found him in his booth; we began talking about preamps and amplifiers, ultimately leading to a quiet corner in a close-by restaurant. Very close, as it was part of the convention itself. I finally got my coke. I could not believe I was in the presence of THE Stewart Hegeman, and he was talking to ME! We talked and talked about big solid state amps, tube preamps, solid state preamps, loudspeakers, ionic tweeters, recording lathes and finally tube power amps. And what a scientific talk it was! As the hours went by, he admitted to having been caught up in the ultra-linear fad of his day, that it was the biggest blunder of his career, and he did it only once and would NEVER design an amp with an ultra-linear output stage ever again. [/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]And he didn't. The Citation V was pure pentode, as was the subsequent Lafayette 550 and everything else he designed from then on. I asked why. He explained that when the plate pulls the top of the output transformer winding towards ground, the ultra-linear tap pushes the screen grid so low that it renders the tube unable to drive difficult loads. In addition, he pointed out that the normal idle potential on the screen grid regularly exceeded a safe voltage, often causing output tubes to blow up. The tube manufacturers hated it, but had to go along or lose market share, and so changed the specification for screen voltage in order to allow ultra-linear output stages. I can’t help but wonder if they REALLY changed the tube design, or simply changed the screen voltage specification. This conversation led to me confessing that I had always wanted to build a big tube amp that was painted the same color as my first car, a '49 metallic burgundy Mercury automobile. So I started on it. And here it is![/size][/font][/color][font=Arial][size=2][/size][/font]

[font=Arial][size=2] [/size][/font]

[center][center][b][color=black][font=Arial][size=2]A BREND NEW POWER AMPLIFIER, THE SILVER SEVEN NINE HUNDRED[/size][/font][/color][/b][color=black][font=Arial][size=2][/size][/font][/color][/center][/center]
[center][center][color=black][font=Arial][size=2] [/size][/font][/color][/center][/center]
[color=black][font=Arial][size=2]Several months ago the new Tung-Sol KT120 and new KT 100 mk II vacuum tubes became available, and I just had to try them! I found them to be utterly remarkable, with bandwidth and fidelity as good as anything I have ever experienced. In order to obtain the best from these remarkable new tubes it was necessary to design a new output stage , and what better one to start with than my own Silver Seven vacuum tube amplifier? [/size][/font][/color]

[center][center][b][color=black][font=Arial][size=5]Success ![/size][/font][/color][/b][color=black][font=Arial][size=2][/size][/font][/color][/center][/center]
[color=black][font=Arial][size=2]I was rewarded with a new and powerful amplifier that sounded as sweet and as expansive as my original Silver Seven, perhaps even better, yet easily outperformed it by delivering substantially more power and with less distortion (not that it needed it) than the original.[/size][/font][/color]

[color=black][font=Arial][size=2]
[/size][/font][/color][font=Arial][size=2] [/size][/font]

[center][center][font=Arial][size=2]
[/size][/font][b][color=black][font=Arial][size=2]The Mighty 6550 vs the KT120 and the KT100 mk II[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[color=black][font=Arial][size=2]Back to Stu. Anyway, when I asked him about his favorite output tube, he said the mighty 6550 was the one to use, and when I queried about the "kinkless" tetrodes, (the KT tubes), he held up his little pinkie finger as if to hold a tea-cup and said in a mock British accent. " Brits you know, if you want watered down tea."[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]He loved to use wide-band video pentodes in his amp designs, and did so when he could. (Read that as cost-no-object.) They were expensive then. "Why would anyone want to use a triode front-end when they could use a pentode?" he mused. Stu was single handily responsible for one of the worlds great amplifier topologies, the wide-band video pentode design. Never been done before, and it added a new category of stunning topologies to our universe. [/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]This design uses Stu's front end approach using a 12BY7. For this new Silver Seven I've used the more powerful, lower distortion version, the 12GN7 and I’ve updated and modified this amplifier to represent an expression of my latest thinking regarding power amplifier design. These modifications include a return to a pure pentode output stage, allowing substantially more output drive current than possible with, in (Stu Hegeman's) own words, the devil-begotten ultra-linear output stage. Strong words, but as we shall see, Stu was right. This amp has a DC filament supply, unheard of in power amps, but a necessary feature when using high-bandwidth pentodes in the front-end. This is the lowest noise power amp ever, with an A-weighted signal to noise ratio of minus 120 dB! Power output is hard to believe, and the sound is even more difficult to believe.[/size][/font][/color][font=Arial][size=2][/size][/font]

[color=black][font=Arial][size=2] [/size][/font][/color][font=Arial][size=2][/size][/font]

[center][center][b][color=black][font=Arial][size=2]THE DESIGN OF THE NEW SILVER SEVEN[/size][/font][/color][/b][b][font=Arial][size=2][/size][/font][/b][/center][/center]
[color=black][font=Arial][size=2]I started the design of this new amplifier by changing the color in order to protect the innocent. I changed the color from black to a beautiful strawberry burgundy red with chrome and silver highlights, just like my car. This new Silver Seven has every known de-lux circuit embodiment known to man, woman, or minor gods. As mentioned earlier, I used a 12GN7 vacuum tube for the front-end. I followed that high speed tube with several class-A drivers for the output tube grids. A cascode voltage amp is used for the gain stage that runs the dual regulator tubes, a pair of power output tubes. In the old days, huge amounts of energy storage were not practical. But today, in the vast intervening gulf of years, the technology associated with capacitor energy storage has allowed an increase of approximately ten fold in power supply capacity. This amplifier has had its energy storage increased substantially by the addition of HUGE capacitors that Stu could only dream about. This, combined with the additional DC restorer circuit eliminates every last vestige of “DC bounce” on musical transients. DC bounce and low-frequency stability have always been the result of compromises made by all amplifier designers in order to design an amplifier for the real world, that could be BUILT in the real world. Not any more, thanks to the DC restorer, HUGE capacitors, and my new output transformer which I wound my very own self. Not only that, the DC restorer works by keeping the DC component on each output tube grid the exact correct value through the entire audio signal swing, allowing perfect performance up to and even beyond clipping.[/size][/font][/color][font=Arial][size=2] [/size][/font]

[center][center][b][color=black][font=Arial][size=2] The DC Restorer and Super Long-Lasting Output Tubes[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[color=black][font=Arial][size=2]The DC restorer allows simultaneous low distortion and low idle power, allowing extreme longevity for the output tubes. The final distortion level in this amplifier is so low that I am embarrassed to write it down here, and the output tubes should last 50 years unless they have a catastrophic failure or won't bias up. This amp has a lifetime guarantee. It's my life and as long as I'm alive I will fix it free. I'll replace the output tubes free if they should become defective, even if you drop the amp on them. It's the least I can do. I know they will not become weak in our lifetimes.[/size][/font][/color][font=Arial][size=2][/size][/font]

[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[center][center][b][color=black][font=Arial][size=2]Features[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[color=black][font=Arial][size=2]Four output terminals; common ground, one, two, four, eight and sixteen ohms. A bias meter and a bias control. It has a volume control and a built-in tube tester for the output tubes. It comes in four chassis; two power supplies and two amplifiers. Built by me and Tubular Joe. Shipping weight is about 325 lbs for all four chassis plus the tubes.[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]One more thing: I accept ANY form of rational payment, and the pictures are of me, Bob Carver.[/size][/font][/color]
[font="Arial"][size=2]
[/size][/font]

[font="Arial"][size=2]Sentido homenaje de Carver a [/size][/font][font=Arial][size=2]Stu Hegeman diseñador del Harman Kardon Citation ll[/size][/font]

Q: Hi Bob Simple question. Why dont you build a 300b type tube amp with lots of power? In my opinion and many audiophiles the 300b's sound the best compared to el34, kt88/ 6550. I suspect there will and always be debate on this but the KT120's are a new tube that manufacturers are not even using. basically its just a higher output tube and the same as a KT88. Im more concerned why not a 300b tube amp?, more power does not always sound better.

A: Hi 'hadriump, That is a great question (I assume you mean an amplifier with a 300b single ended output stage). The answer is that I wanted to build the best amplifier of all time. If I thought for even one femtosecond that a powerful 300b type amplifier would sound better, I would build it. It's true when we say more power does not always make better sound, but in my long experience (I was old when Atlantis sank) more power almost always makes better sound if all else is equal, or if we only want to listen to wind-chimes at realistic levels. It just does! I have explored many, many amplifier topologies over my career, each exploration taking the form of a large series of converging experiments. The results of those experiments have taught me that a WELL DESIGNED push-pull output stage is the best sounding, and as a bonus, very practical as well as being quite energy efficient. Some history: Way back in the beginning of tube amplifiers,(in the 1930's) designers were forced to use class A single ended output stages in order to prevent a severe problem called "notch" distortion. Notch distortion resulted whenever a push-pull output stage was used. Push-pull amplifiers sounded terrible because of that nasty notch, exhibiting a harsh sound whenever the audio signal transitioned from positive to negative. As the years trolled by, many talented designers worked long hours to eliminate that notch (the reward would be huge). It took three men many long years of work to figure it out and get rid of the notch. One, a man named A.N. Williamson (of Williamson amplifier fame), and two others, Gordon Gow and Frank McIntosh. The last two guys started an amplifier company centered on the new technology. The problem was the output transformer, and these guys taught the world how to build output transformers that did not have a notch. And the high-fidelity industry took off. False beliefs often die hard, and the belief that somehow a single ended output ...Oops, I'm out of characters!

El ampli en question http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&rt=nc&nma=true&item=180665282517&si=VfhigbO1QNwM%252FlAWJ3uhsMhiLBY%253D&viewitem=&sspagename=STRK%3AMEWAX%3AIT#ht_1715wt_1141

La verdad es que los amp a tubos de Carver suenan muy bien
[/quote]

MartinV56 · May 21, 2011 at 01:27

Se vendió por 32400 dólares[img]http://www.hifichile.cl/public/style_emoticons/default/rolleyes.gif[/img]

Juanga · May 21, 2011 at 02:16

[quote name='MartinV56' date='20 May 2011 - 08:27 PM' timestamp='1305941259' post='62214']
Se vendió por 32400 dólares[img]http://www.hifichile.cl/public/style_emoticons/default/rolleyes.gif[/img]
[/quote]

Haaaa una vicoca, yo quiero 2 de esos

Marchen 2

MartinV56 · May 23, 2011 at 16:44

[quote name='MartinV56' date='20 May 2011 - 01:12 PM' timestamp='1305915152' post='62083']
Conseguí una pareja de tetrodos 807, tubos de potencia, la primera pregunta que me hice, single ended o push pull, así las cosas busqué información en la red sobre el tema y encontré este interesante artículo que comparto con ustedes

[url="http://homepage.mac.com/tlinespeakers/vaughn/downloads/SE-v-PP-Part1.pdf"]http://homepage.mac....-v-PP-Part1.pdf[/url]

Continuación del artículo

[url="http://homepage.mac.com/tlinespeakers/vaughn/downloads/SE-v-PP-Part2.pdf"]http://homepage.mac.com/tlinespeakers/vaughn/downloads/SE-v-PP-Part2.pdf[/url]

[/quote]

escultor · May 30, 2011 at 15:45

[quote name='escultor' date='20 May 2011 - 09:13 PM' timestamp='1305940433' post='62212']
[quote name='MartinV56' date='20 May 2011 - 05:44 PM' timestamp='1305927857' post='62165']
En ebay en este link de Bob Carver encontré unos comentarios interesantes que me permito transcribir

http://img822.imageshack.us/img822/3272/se807sch2.gif

[center][center][b][color=black][font=Arial][size=5]Tubular Joe and I finished a brand new amplifier and here it is.[/size][/font][/color][/b][/center][/center]
[center][center][b][color=black][font=Arial][size=5][/size][/font][/color][/b] [/center][/center]
[center][center][b][color=black][font=Arial][size=5]HOW IT ALL STARTED [/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[color=black][font=Arial][size=2]It was a hot mid-summer's night and I was in Chicago at the consumer electronics show.[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]I was in my booth pitching my wares, a new amp and preamp, and it was hot inside. Not the amplifier, but the convention floor, and I was getting thirsty. I wanted something cold to drink, so I decided to sneak away from my booth for a moment to get a coke. As I was sneaking, a colleague happened to walk by and said, " Hey Bob, have you seen Stu Hegeman's new preamp?"[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]I found myself getting excited, as Stewart Hegeman, the master designer of so many classic vacuum tube amplifiers and my very own hero, was here! Stu Hegeman was a true genius, having designed the Citation I, II, probably the III and countless other amplifiers for Sidney Harmon and for Lafayette.[/size][/font][/color][font=Arial][size=2][/size][/font]

[font=Arial][size=2] [/size][/font]

[color=black][font=Arial][size=2] I found him in his booth; we began talking about preamps and amplifiers, ultimately leading to a quiet corner in a close-by restaurant. Very close, as it was part of the convention itself. I finally got my coke. I could not believe I was in the presence of THE Stewart Hegeman, and he was talking to ME! We talked and talked about big solid state amps, tube preamps, solid state preamps, loudspeakers, ionic tweeters, recording lathes and finally tube power amps. And what a scientific talk it was! As the hours went by, he admitted to having been caught up in the ultra-linear fad of his day, that it was the biggest blunder of his career, and he did it only once and would NEVER design an amp with an ultra-linear output stage ever again. [/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]And he didn't. The Citation V was pure pentode, as was the subsequent Lafayette 550 and everything else he designed from then on. I asked why. He explained that when the plate pulls the top of the output transformer winding towards ground, the ultra-linear tap pushes the screen grid so low that it renders the tube unable to drive difficult loads. In addition, he pointed out that the normal idle potential on the screen grid regularly exceeded a safe voltage, often causing output tubes to blow up. The tube manufacturers hated it, but had to go along or lose market share, and so changed the specification for screen voltage in order to allow ultra-linear output stages. I can’t help but wonder if they REALLY changed the tube design, or simply changed the screen voltage specification. This conversation led to me confessing that I had always wanted to build a big tube amp that was painted the same color as my first car, a '49 metallic burgundy Mercury automobile. So I started on it. And here it is![/size][/font][/color][font=Arial][size=2][/size][/font]

[font=Arial][size=2] [/size][/font]

[center][center][b][color=black][font=Arial][size=2]A BREND NEW POWER AMPLIFIER, THE SILVER SEVEN NINE HUNDRED[/size][/font][/color][/b][color=black][font=Arial][size=2][/size][/font][/color][/center][/center]
[center][center][color=black][font=Arial][size=2] [/size][/font][/color][/center][/center]
[color=black][font=Arial][size=2]Several months ago the new Tung-Sol KT120 and new KT 100 mk II vacuum tubes became available, and I just had to try them! I found them to be utterly remarkable, with bandwidth and fidelity as good as anything I have ever experienced. In order to obtain the best from these remarkable new tubes it was necessary to design a new output stage , and what better one to start with than my own Silver Seven vacuum tube amplifier? [/size][/font][/color]

[center][center][b][color=black][font=Arial][size=5]Success ![/size][/font][/color][/b][color=black][font=Arial][size=2][/size][/font][/color][/center][/center]
[color=black][font=Arial][size=2]I was rewarded with a new and powerful amplifier that sounded as sweet and as expansive as my original Silver Seven, perhaps even better, yet easily outperformed it by delivering substantially more power and with less distortion (not that it needed it) than the original.[/size][/font][/color]

[color=black][font=Arial][size=2]
[/size][/font][/color][font=Arial][size=2] [/size][/font]

[center][center][font=Arial][size=2]
[/size][/font][b][color=black][font=Arial][size=2]The Mighty 6550 vs the KT120 and the KT100 mk II[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[color=black][font=Arial][size=2]Back to Stu. Anyway, when I asked him about his favorite output tube, he said the mighty 6550 was the one to use, and when I queried about the "kinkless" tetrodes, (the KT tubes), he held up his little pinkie finger as if to hold a tea-cup and said in a mock British accent. " Brits you know, if you want watered down tea."[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]He loved to use wide-band video pentodes in his amp designs, and did so when he could. (Read that as cost-no-object.) They were expensive then. "Why would anyone want to use a triode front-end when they could use a pentode?" he mused. Stu was single handily responsible for one of the worlds great amplifier topologies, the wide-band video pentode design. Never been done before, and it added a new category of stunning topologies to our universe. [/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]This design uses Stu's front end approach using a 12BY7. For this new Silver Seven I've used the more powerful, lower distortion version, the 12GN7 and I’ve updated and modified this amplifier to represent an expression of my latest thinking regarding power amplifier design. These modifications include a return to a pure pentode output stage, allowing substantially more output drive current than possible with, in (Stu Hegeman's) own words, the devil-begotten ultra-linear output stage. Strong words, but as we shall see, Stu was right. This amp has a DC filament supply, unheard of in power amps, but a necessary feature when using high-bandwidth pentodes in the front-end. This is the lowest noise power amp ever, with an A-weighted signal to noise ratio of minus 120 dB! Power output is hard to believe, and the sound is even more difficult to believe.[/size][/font][/color][font=Arial][size=2][/size][/font]

[color=black][font=Arial][size=2] [/size][/font][/color][font=Arial][size=2][/size][/font]

[center][center][b][color=black][font=Arial][size=2]THE DESIGN OF THE NEW SILVER SEVEN[/size][/font][/color][/b][b][font=Arial][size=2][/size][/font][/b][/center][/center]
[color=black][font=Arial][size=2]I started the design of this new amplifier by changing the color in order to protect the innocent. I changed the color from black to a beautiful strawberry burgundy red with chrome and silver highlights, just like my car. This new Silver Seven has every known de-lux circuit embodiment known to man, woman, or minor gods. As mentioned earlier, I used a 12GN7 vacuum tube for the front-end. I followed that high speed tube with several class-A drivers for the output tube grids. A cascode voltage amp is used for the gain stage that runs the dual regulator tubes, a pair of power output tubes. In the old days, huge amounts of energy storage were not practical. But today, in the vast intervening gulf of years, the technology associated with capacitor energy storage has allowed an increase of approximately ten fold in power supply capacity. This amplifier has had its energy storage increased substantially by the addition of HUGE capacitors that Stu could only dream about. This, combined with the additional DC restorer circuit eliminates every last vestige of “DC bounce” on musical transients. DC bounce and low-frequency stability have always been the result of compromises made by all amplifier designers in order to design an amplifier for the real world, that could be BUILT in the real world. Not any more, thanks to the DC restorer, HUGE capacitors, and my new output transformer which I wound my very own self. Not only that, the DC restorer works by keeping the DC component on each output tube grid the exact correct value through the entire audio signal swing, allowing perfect performance up to and even beyond clipping.[/size][/font][/color][font=Arial][size=2] [/size][/font]

[center][center][b][color=black][font=Arial][size=2] The DC Restorer and Super Long-Lasting Output Tubes[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[color=black][font=Arial][size=2]The DC restorer allows simultaneous low distortion and low idle power, allowing extreme longevity for the output tubes. The final distortion level in this amplifier is so low that I am embarrassed to write it down here, and the output tubes should last 50 years unless they have a catastrophic failure or won't bias up. This amp has a lifetime guarantee. It's my life and as long as I'm alive I will fix it free. I'll replace the output tubes free if they should become defective, even if you drop the amp on them. It's the least I can do. I know they will not become weak in our lifetimes.[/size][/font][/color][font=Arial][size=2][/size][/font]

[center][center][font=Arial][size=2] [/size][/font][/center][/center]
[center][center][b][color=black][font=Arial][size=2]Features[/size][/font][/color][/b][font=Arial][size=2][/size][/font][/center][/center]
[color=black][font=Arial][size=2]Four output terminals; common ground, one, two, four, eight and sixteen ohms. A bias meter and a bias control. It has a volume control and a built-in tube tester for the output tubes. It comes in four chassis; two power supplies and two amplifiers. Built by me and Tubular Joe. Shipping weight is about 325 lbs for all four chassis plus the tubes.[/size][/font][/color][font=Arial][size=2]

[/size][/font][color=black][font=Arial][size=2]One more thing: I accept ANY form of rational payment, and the pictures are of me, Bob Carver.[/size][/font][/color]
[font="Arial"][size=2]
[/size][/font]

[font="Arial"][size=2]Sentido homenaje de Carver a [/size][/font][font=Arial][size=2]Stu Hegeman diseñador del Harman Kardon Citation ll[/size][/font]

Q: Hi Bob Simple question. Why dont you build a 300b type tube amp with lots of power? In my opinion and many audiophiles the 300b's sound the best compared to el34, kt88/ 6550. I suspect there will and always be debate on this but the KT120's are a new tube that manufacturers are not even using. basically its just a higher output tube and the same as a KT88. Im more concerned why not a 300b tube amp?, more power does not always sound better.

A: Hi 'hadriump, That is a great question (I assume you mean an amplifier with a 300b single ended output stage). The answer is that I wanted to build the best amplifier of all time. If I thought for even one femtosecond that a powerful 300b type amplifier would sound better, I would build it. It's true when we say more power does not always make better sound, but in my long experience (I was old when Atlantis sank) more power almost always makes better sound if all else is equal, or if we only want to listen to wind-chimes at realistic levels. It just does! I have explored many, many amplifier topologies over my career, each exploration taking the form of a large series of converging experiments. The results of those experiments have taught me that a WELL DESIGNED push-pull output stage is the best sounding, and as a bonus, very practical as well as being quite energy efficient. Some history: Way back in the beginning of tube amplifiers,(in the 1930's) designers were forced to use class A single ended output stages in order to prevent a severe problem called "notch" distortion. Notch distortion resulted whenever a push-pull output stage was used. Push-pull amplifiers sounded terrible because of that nasty notch, exhibiting a harsh sound whenever the audio signal transitioned from positive to negative. As the years trolled by, many talented designers worked long hours to eliminate that notch (the reward would be huge). It took three men many long years of work to figure it out and get rid of the notch. One, a man named A.N. Williamson (of Williamson amplifier fame), and two others, Gordon Gow and Frank McIntosh. The last two guys started an amplifier company centered on the new technology. The problem was the output transformer, and these guys taught the world how to build output transformers that did not have a notch. And the high-fidelity industry took off. False beliefs often die hard, and the belief that somehow a single ended output ...Oops, I'm out of characters!

El ampli en question http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&rt=nc&nma=true&item=180665282517&si=VfhigbO1QNwM%252FlAWJ3uhsMhiLBY%253D&viewitem=&sspagename=STRK%3AMEWAX%3AIT#ht_1715wt_1141

La verdad es que los amp a tubos de Carver suenan muy bien
[/quote]
[/quote]

Se figaron en estos monoblocks ??
Carver pago US 5000 por PINTARLOS ¡¡¡
SHUUU es otro mundo... aqui con cueva te pagan eso por los amps :lol:
Los pintaron con un sistema que yo domino bien.. ya saben cuando quieran
pintar un par de cajas, tendrian descuento de foro..20% serian solo us 4000
:lol: :lol: :lol:

juliovideo · June 16, 2011 at 16:48

[quote name='MartinV56' date='20 May 2011 - 08:27 PM' timestamp='1305941259' post='62214']
Se vendió por 32400 dólares[img]http://www.hifichile.cl/public/style_emoticons/default/rolleyes.gif[/img]
[/quote]

Increible !!!!

==========================

Bob Carver

This amp actually runs cool as a cucumber. The tubes idle at only nine watts plate dissipation - we can touch them without getting burned. Though I have to say it would be uncomfortable, and it would not be wise to grab them for an extended time. Here are the most important specifications: Power into one, two, four, or eight ohms is 900 watts. power bandwidth extends from 18 Hz to 24 Hz. Frequency response is from 2 Hz to 100 kHz. The signal-to-noise ratio is minus (-) 120 dB A weighted, referred to 900 watts. Idle power = 882 watts, and the total input power at full output = 3120 watts. Here's the good news: a standard 15 ampere wall-outlet will work just fine because music or voice has maximum power requirements that are about five times more than the average requirements. This means that if we play the amplifier at full-tilt-boogie maximum, right up to the point where it would start to overload, the power from the wall outlet would be be about one fifth the maximum, plus half the total idle power. The grand total is approximately 1,153 divided by five, times two, plus 506 watts plus a fudge factor = 1,100 watts. A walk in the park! Hummm, bench testing would be a different matter though. Still, and just the same, even on the bench we would probably test one amp at a time.

[img]http://i9.photobucket.com/albums/a78/Bob01605/Carverandamp.jpg[/img]

---------------------------

Editado June 16, 2011 at 16:55 por juliovideo

caello · June 16, 2011 at 19:24

El manso ni que amplificador
Le gusta ese color a este cabro al parecer...

escultor · June 16, 2011 at 19:30

[quote name='caello' date='16 June 2011 - 03:24 PM' timestamp='1308252267' post='66915']
El manso ni que amplificador
Le gusta ese color a este cabro al parecer...
[/quote]

OJO es solo uno de los monoblocks

caello · June 16, 2011 at 20:25

Uff si los vi en ebay, tremendos en todo, tienes suerte de disfrutar una de esas maravillas. Felicitaciones!

striker · June 16, 2011 at 21:52

el amp de escultor suena muy bien...sobre todo ahora que esta bien seteado
ademas pega el medio pencazo con sus cajas
hay que escucharlos con tapones en la oreja :lol:

juliovideo · June 19, 2011 at 03:55

[quote name='caello' date='16 June 2011 - 02:24 PM' timestamp='1308252267' post='66915']
El manso ni que amplificador
Le gusta ese color a este cabro al parecer...
[/quote]

Es casi el mismo color como venia el Harman Kardon Citation II.

---------------------

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