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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Tue Nov 30, 2010 8:08 pm 
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Скорострельностью не поступился! Углубил вдвое обратную связь через выходные лампы, убрал шунтирующие электролиты из катодов первых ламп, в результате удалось сниить усиление до 100. Ура! Applause

Слушаю классику... Наслаждаюсь...


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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Wed Dec 01, 2010 10:49 am 
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Simply beautiful Applause Applause Applause ... I am sure it sounds even better. Very Happy

Can't wait to hear some sample recordings from it.

btw, what are the tubes glowing green in the middle of the picture? icon_redface


 
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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Wed Dec 01, 2010 11:17 am 
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quikie22 wrote:
Simply beautiful Applause Applause Applause ... I am sure it sounds even better. Very Happy

Can't wait to hear some sample recordings from it.

btw, what are the tubes glowing green in the middle of the picture? icon_redface


They are 6Е1П magic eyes.

Yes, it sounds nice! Very transparent. Yesterday it played in the living room, I was here in the office. When I heard a female voice that mimic Armstrong's singing, I thought a first it's my daughter mumbling, but later realized that it was Ella Fitzgerald's voice recorded on that CD. Very Happy

Now I am going to add switchable pad on input, and input transformers for XLR balanced ins.

Or, leave unbalanced ins as is, -10 dB, and add transformers for 0 dB symmetrical input. Also, I need to make top and bottom covers from perforated aluminium.

Speaking of recordings, my power amps / speakers on them tend to amplify reverberation only. I am trying to make them as less audible as possible. Just clean transparent amplification of vocals and instruments, for an audience to hear the concert that I am recording.

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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Mon Dec 06, 2010 12:00 am 
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Posts: 238
what is the role of the magic eyes? how do they work? I tot they were used in radios only.


 
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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Mon Dec 06, 2010 3:17 pm 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
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Location: Pleasant Hill, California
quikie22 wrote:
what is the role of the magic eyes? how do they work? I tot they were used in radios only.


Power output indicators.

Crater is kind of anode covered by fluorescent thing that is ionized by electrons that bombard it. A gate on the path of electrons that is less positive than crater change their path, so it depends on a voltage applied to it. As the result, the closer is voltage on the gate to the voltage on the crater, the wider is the bright sector on it.
The gate is connected to one more triode inside of the same tube, so negative grid voltage is needed to "open the eye", from 0 to -15V approximately.

Image

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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Mon Dec 06, 2010 3:48 pm 
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Here is the schematic.


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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Fri Dec 10, 2010 7:28 pm 
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Копирую с форума hiend.borda.ru

=======cut here=================


majordom22 пишет:

цитата:
Гoсть Хотелось бы полностью схему.Думаю,Вы разместили схемку,чтоб народ высказался?Если честно,единственный каскад.который я бы поставил в своём усиле- это фазоинвертор с разделённой нагрузкой.А сигнал к нему приходит через делитель аж в 470К/470К?Не кошерно.Хоть бы зашунтировали полипропиленом китайским,и то дело!(К мегагерцам ближе будете)А то и КСО.Если шибко усиление большое,можно вместо 6П15 поставить 6П18/6П43,или 6П1,к примеру.Кстати,не такой холодный звук получится.Оптронно- аттенюаторную фичу воще на понял.Борьба за расширение ДД,а налицо сужение.Разве что,как защиту от дурака (отключаемую).Тогда согласен.Лучше всего-световая индикация клиппинга,но её в вакууме попробуй ещё сделать.К ГУ50 отношусь хорошо,Но бокорезами удаляю алюминивую "шляпу". Но,конечно,не в стаканах.А внешне нравится,особенно в интимном освещении.когда накалы видны.Какие выходники стоЯт,если не секрет?

ЗЫ и Цобеля-нафиг.





Еесли Цобеля нафик, то не получится, как задумано: усилок в классе АВ, с минимальными слышимыми искажениями, глубокая ОС необходима. Как по-русски будет Nested Feedback? Мы такого не изучали... Если без ОС, то класс А, а какой смысл в классе А для двухтактника, кроме меньшего выходника? Если 470К зашунтировать плёнкой, то Цобелю придётся ёмкость добавить. То на то и выходит. Я, кстати, в последнем варианте к этому вернулся, пока не понял, что фазу искажают питающие конденсаторы. Теоретически - это нелинейная ёмкость, но практически предыдущая версия усилителя работала с такой фичей, и её влияние было незаметным. Так и оставил -- теоретически это кошернее, и недоуменных вопросов меньше вызывает, типа Вашего.

Обойтись фазоинвертором с раздельной нагрузкой низзя: нужен драйвер с высоким выходным сопротивлением, ибо низкое выходное сопротивление будет шунтировать цепи локальной обратной связи с анодов выходных ламп, добавляя собственные нелинейности. А с такими пухлыми трансформаторами она не просто желательна, но и необходима, я бы сказал.

6П15П можно заменить многими другими, но погоду с усилением это не сделает. Последний вариант (фото макета в темноте, с покрытым медью зеркалом) использует 6Ж51П. Сделал раздельные хвосты, объединил их 2-мя 1К последовательно. Почему двумя - потому, что с зхвостов беру обратную связь по постоянному напряжению на экранную сетку первого пентода, чтобы стабилизировать рабочую точку -- связь-то везде гальваническая, кроме сеток выходных ламп! Благодаря раздельным хвостам получилось перевести их в триоды.

По поводу сужения динамического диапазона - это Вы погорячились. ОС глубокая, и такой "динамический" диапазон засчёт клиппинга никому не нужен. Да вообще, и без ОС клиппинг не нужен, разве что в источнике сигнала, специально организованное мягкое ограничение. Пусть лучше будет "защита от дурака". Чувствует она аккурат момент клиппинга, когда резко растут токи экранных сеток, и срабатывает за пару милисекунд. Прелесть опто-подхода ещё и в том, что скорость выше, чем выше ток через диод. Не вижу никакого смысла делать эту великолепную фичу отключаемой.

Что ещё?
Про выходные трансформаторы. Заказаны были у Edcor USA, для 100Ватт 20Гц-20КГЦ, первичка -- 10К со средней точкой. В продукцию пойдёт с теми-же трансформаторами, но уже с 8К со средней точкой. На железе М6. У меня, кстати, есть макет моноблока, с тем-же драйвером, но с четырьмями ГУ-50, на 6К. Полторы очень чистых сотни ватт, но по верхам гораздо лучше -- трансформаторы рассчитаны на диапазон от 40 герц, 200 ватт, и размер у них меньше. Этот моноблок - для акустики и голоса, там даже ниже 80 Герц не нужно (в данном случае к акустике я не отношу контрабас и ударную установку)

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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Sun Apr 10, 2011 10:29 pm 
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Posts: 21
Anatoliy, just the way you came up with a chassis impress me a lot, apart from the morgan jones book I haven't seen original approaches like yours when coming up with a chassis. Specially taking into account that in yours form follows function and looks to be like a very cost effective solution.

From what the pictures speak, you used (guess cheap to get) standard window/door aluminum angles, cutting just one side, then bending to make rectangular subchassis structures tu support the transformers, and a dual one to serve as "frame" for the perforated sheet. That was clever!

Did you have to route the aluminum in order to be able to bend it afterwards?)

Is it tricky to dirll the perforated sheet? is it aluminum or steel? What kind of rig do you use to bend it?

I see three fuses, what do you fuse? Guess one is formains, what about the other two? OPTs?

The external post talks about 80W per channel, so guess it's a push-pull design?

I also like the magic eyes a lot. I have been gathering the material for years wanting to build a killer SE all-russian amp, first thought about 6C33C, then a 6C41C, but from what I've learnt here the GU-50 is one of the best Russian power tube achievements. And definitely I'm going to build it in your chassis style, including a cage for protection.

Do you think (to try if I like the sound) I could build a GU-50 SE based one (paralleling two?) with the OPTs I already have? they're One Electron UBT-1 (5K:4,8,16Ohm, 160mA, rated for 15W). I also have a pair of Edcors GXSE 5K in a SimpleSE... that I could also use to check the sound against.


 
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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Mon Apr 11, 2011 9:18 am 
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Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7317
Location: Pleasant Hill, California
pukkita wrote:
Anatoliy, just the way you came up with a chassis impress me a lot, apart from the morgan jones book I haven't seen original approaches like yours when coming up with a chassis. Specially taking into account that in yours form follows function and looks to be like a very cost effective solution.


Yes, it is most effective if to have cheap materials: less of special equipment is needed to make such a chassis. It is "Made in Garage" design. But if to buy everything from Home Depot it is not so cheap: materials for repair are always more expensive that materials directly from plants bought in high quantities.


Quote:
From what the pictures speak, you used (guess cheap to get) standard window/door aluminum angles, cutting just one side, then bending to make rectangular subchassis structures tu support the transformers, and a dual one to serve as "frame" for the perforated sheet. That was clever!

Did you have to route the aluminum in order to be able to bend it afterwards?)


No, I just use a hand saw to make 90 degree cuts, then bend over.

Quote:
Is it tricky to dirll the perforated sheet? is it aluminum or steel? What kind of rig do you use to bend it?


Not at all, I use Greenlee hole punches. They are expensive, but worth it. I use aluminum, it is non-magnetic and transfers heat well. Copper may be better, but more expensive.

Quote:
I see three fuses, what do you fuse? Guess one is formains, what about the other two? OPTs?


Mains, and 2 secondaries (550V CT)

Quote:
The external post talks about 80W per channel, so guess it's a push-pull design?


Yes, it is push-pull, 100W per channel max, but optical limiters limit output power on 80WPC level, to avoid chances of clipping.

Quote:
I also like the magic eyes a lot. I have been gathering the material for years wanting to build a killer SE all-russian amp, first thought about 6C33C, then a 6C41C, but from what I've learnt here the GU-50 is one of the best Russian power tube achievements. And definitely I'm going to build it in your chassis style, including a cage for protection.


Actually, Russian were smart enough when they won WW-II to select best German military tubes designed by Telefunken and force Germans to redesign them for Soviet Army. Lots of them were manufactured during Cold War, I believe. Also, I heard a rumor as if 6S17K-V was made based on stolen papers about top secret American planar triodes designed by GE, and they were copied from an alien flying source captured by Americans. It is a weird rumor, but I believe what is true, is that Soviet planar triodes are based on similar American design.

Quote:
Do you think (to try if I like the sound) I could build a GU-50 SE based one (paralleling two?) with the OPTs I already have? they're One Electron UBT-1 (5K:4,8,16Ohm, 160mA, rated for 15W). I also have a pair of Edcors GXSE 5K in a SimpleSE... that I could also use to check the sound against.


It is possible, but in order to parallel GU-50 tubes you need to select them carefully. It is more complex task than to parallel 4P1L, since 4P1L are extremely linear, and very close to each other.

_________________
А женщина даже в мужской рубашке выглядит гораздо приличнее, чем мужчина в женских колготках! Be-be-be!


 
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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Mon Apr 11, 2011 11:23 pm 
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Joined: Fri Mar 19, 2010 8:59 am
Posts: 21
wavebourn wrote:
pukkita wrote:
Is it tricky to dirll the perforated sheet? is it aluminum or steel? What kind of rig do you use to bend it?


Not at all, I use Greenlee hole punches. They are expensive, but worth it. I use aluminum, it is non-magnetic and transfers heat well. Copper may be better, but more expensive.


I also have punches, when drilling I guess just it's just a matter of enlarging an already existing hole then use the punches...

How do you bend the perforated sheet?

wavebourn wrote:
pukkita wrote:
I see three fuses, what do you fuse? Guess one is formains, what about the other two? OPTs?


Mains, and 2 secondaries (550V CT)


I see... that way you can use slow blow on the mains and fast on the secondaries?

wavebourn wrote:
pukkita wrote:
I also like the magic eyes a lot. I have been gathering the material for years wanting to build a killer SE all-russian amp, first thought about 6C33C, then a 6C41C, but from what I've learnt here the GU-50 is one of the best Russian power tube achievements. And definitely I'm going to build it in your chassis style, including a cage for protection.


Actually, Russian were smart enough when they won WW-II to select best German military tubes designed by Telefunken and force Germans to redesign them for Soviet Army. Lots of them were manufactured during Cold War, I believe. Also, I heard a rumor as if 6S17K-V was made based on stolen papers about top secret American planar triodes designed by GE, and they were copied from an alien flying source captured by Americans. It is a weird rumor, but I believe what is true,
is that Soviet planar triodes are based on similar American design.


That explains a lot of things about russian military tubes being superior!

Funny (and interesting!) the 6S17K-V rumor Smile

wavebourn wrote:
pukkita wrote:
Do you think (to try if I like the sound) I could build a GU-50 SE based one (paralleling two?) with the OPTs I already have? they're One Electron UBT-1 (5K:4,8,16Ohm, 160mA, rated for 15W). I also have a pair of Edcors GXSE 5K in a SimpleSE... that I could also use to check the sound against.


It is possible, but in order to parallel GU-50 tubes you need to select them carefully. It is more complex task than to parallel 4P1L, since 4P1L are extremely linear, and very close to each other.


So I'd need the seller to burn them in, check them, then pair them... that or me buying enough to match 2 pairs... guess a dozen will be enough? I like this tube, and would be an interesting choice for guitar amps too? how does it sound when overdriven?

Also, why is the external socket "cage" needed? guess for safety? dissipation?


 
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 Post subject: Re: Pyramid-VII: home stereo vacuum tube amp
PostPosted: Thu Apr 14, 2011 9:00 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7317
Location: Pleasant Hill, California
pukkita wrote:
How do you bend the perforated sheet?


I cut 2 steel angles for sizes. One of them 15 inches, another 17 inches, the third one is bigger.
Sandwich them and clamp in a vise. Then bent by hand, helping with hammer.


Quote:
wavebourn wrote:
pukkita wrote:
I see three fuses, what do you fuse? Guess one is formains, what about the other two? OPTs?


Mains, and 2 secondaries (550V CT)


I see... that way you can use slow blow on the mains and fast on the secondaries?


No, all are slow blow

Quote:
wavebourn wrote:
pukkita wrote:
Do you think (to try if I like the sound) I could build a GU-50 SE based one (paralleling two?) with the OPTs I already have? they're One Electron UBT-1 (5K:4,8,16Ohm, 160mA, rated for 15W). I also have a pair of Edcors GXSE 5K in a SimpleSE... that I could also use to check the sound against.


It is possible, but in order to parallel GU-50 tubes you need to select them carefully. It is more complex task than to parallel 4P1L, since 4P1L are extremely linear, and very close to each other.


So I'd need the seller to burn them in, check them, then pair them... that or me buying enough to match 2 pairs... guess a dozen will be enough? I like this tube, and would be an interesting choice for guitar amps too? how does it sound when overdriven?

Also, why is the external socket "cage" needed? guess for safety? dissipation?


Both.

When overdriven it sounds like overdriven pentode.

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А женщина даже в мужской рубашке выглядит гораздо приличнее, чем мужчина в женских колготках! Be-be-be!


 
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