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Old 16th November 2011, 01:59 PM   #21
TheGimp is offline TheGimp  United States
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I haven't had a chance to breadboard it yet, but simulations show greater distortion with the screen controlled servo amp than the cathode controlled servo amp.
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Old 16th November 2011, 03:11 PM   #22
aeandm is offline aeandm  Ukraine
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I can recommend bring temporary change in diagram.
I imply real device, use oscillograph .I sure in diagram keep error.
Alternative draw another diagram, on this diagram insufficiently information .
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File Type: gif 6P41C.GIF (37.4 KB, 100 views)
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Old 16th November 2011, 06:29 PM   #23
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I haven't had a chance to breadboard it yet, but simulations show greater distortion with the screen controlled servo amp than the cathode controlled servo amp.
Too much loop gain again. Try 10-50 ohms in series with D3.

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Old 16th November 2011, 08:52 PM   #24
TheGimp is offline TheGimp  United States
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aeandm, the Zener diode actually works on the breadboard. It keeps VGs near 180V. Max screen voltage is specified as 170 for the 6P41S, and it I allow it to go much higher bias voltage must go much lower.

I do not understand your schematic. Am I supposed to bias the screen at a fixed level with the circuit shown?

janneman, I added 33 and eventually got it up to 51Ohms. that helps. tks.
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Old 16th November 2011, 09:54 PM   #25
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Quote:
Originally Posted by TheGimp View Post
aeandm, the Zener diode actually works on the breadboard. It keeps VGs near 180V. Max screen voltage is specified as 170 for the 6P41S, and it I allow it to go much higher bias voltage must go much lower.

I do not understand your schematic. Am I supposed to bias the screen at a fixed level with the circuit shown?

janneman, I added 33 and eventually got it up to 51Ohms. that helps. tks.
Ask colleague Wavebourn translate: Мне не понятна схема где питание драйвера
связано с раскачкой выходного каскада, на транзисторах реализован эл. фильтр, зачем сигнал подан на него(33К) и где минус фиксированого смещения? Поэтому и предложил временно упростить, может я
чего-то не знаю?
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Old 16th November 2011, 10:06 PM   #26
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Quote:
Originally Posted by aeandm View Post
Ask colleague Wavebourn translate: Мне не понятна схема где питание драйвера
связано с раскачкой выходного каскада, на транзисторах реализован эл. фильтр, зачем сигнал подан на него(33К) и где минус фиксированого смещения? Поэтому и предложил временно упростить, может я
чего-то не знаю?
Скорее всего Вы не знаете того, что я пытался защитить Вас от модераторов, которые Вас забанят за нарушение правил форума. Если нужна помощь - добро пожаловать в Private Messages. Попросите -- помогу, но переводить каждое Ваше сообщение, написанное по-русски в нарушение правил Форума, я не обещал.

Translation:

What you probably don't know that I tried to save you from being banned by moderators. Did you read forum rules? I offered you to help, but did not promise to translate each message. If you need help please go to Private Messages and ask me there.
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Old 16th November 2011, 10:20 PM   #27
aeandm is offline aeandm  Ukraine
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Originally Posted by Wavebourn View Post
Скорее всего Вы не знаете того, что я пытался защитить Вас от модераторов, которые Вас забанят за нарушение правил форума. Если нужна помощь - добро пожаловать в Private Messages. Попросите -- помогу, но переводить каждое Ваше сообщение, написанное по-русски в нарушение правил Форума, я не обещал.

Translation:

What you probably don't know that I tried to save you from being banned by moderators. Did you read forum rules? I offered you to help, but did not promise to translate each message. If you need help please go to Private Messages and ask me there.
Извините там слишком сложно чтобы я перевел(6П41С), а по поводу
предупреждений их можно взять и плавно переместить туда, переведите
как учетную запись aeandm можно удалить здесь мне не интересно
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Old 17th November 2011, 01:27 AM   #28
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by aeandm View Post
Извините там слишком сложно чтобы я перевел(6П41С), а по поводу
предупреждений их можно взять и плавно переместить туда, переведите
как учетную запись aeandm можно удалить здесь мне не интересно
Anatoliy is right, you need to send this to him via PM, and ask him nicely for help as he is probably very busy.. I understand English is not your native language but as he points out you are violating the English language forum policy. (However don't give up perhaps you'll get the hang of the language over time.)
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Old 17th November 2011, 05:25 PM   #29
TheGimp is offline TheGimp  United States
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This has been a rather interesting exercise. So far I've only had time to run simulations and it will probably be the weekend before I can get my tubelab back on the bench to verify the results.

Both circuits produce the same results (or so close as to be the same) given that the anode current and grid to cathode voltage are the same and the screen voltage is adjusted to produce the same cathode current. The input voltage is nearly the same to produce the same output voltage under these conditions.

Unfortunately both produce fairly high distortion (25%) at 1W, 2.8Vrms into 8 ohms.
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Old 17th November 2011, 05:34 PM   #30
kevinkr is offline kevinkr  United States
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Originally Posted by TheGimp View Post
This has been a rather interesting exercise. So far I've only had time to run simulations and it will probably be the weekend before I can get my tubelab back on the bench to verify the results.

Both circuits produce the same results (or so close as to be the same) given that the anode current and grid to cathode voltage are the same and the screen voltage is adjusted to produce the same cathode current. The input voltage is nearly the same to produce the same output voltage under these conditions.

Unfortunately both produce fairly high distortion (25%) at 1W, 2.8Vrms into 8 ohms.
Looks like an interesting exercise, and somehow I think you will eventually get it to perform the way you want, but you are most definitely the master of understatement - 25% indeed..
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