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 Post subject: Gubernator-7: 4P1L Single Ended Amplifier Design
PostPosted: Mon Jan 31, 2011 7:21 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
Here is my new project, SE stereo amp with 4P1L (4П1Л) output.
6J5P trioded will drive 6N16B cathode follower. Second halves of 6N16B will amplify signals for 6E1P indicators.


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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Mon Jan 31, 2011 9:32 pm 
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Joined: Mon Mar 22, 2010 1:10 am
Posts: 238
That looks very nice.

Why did you choose those driver tubes 6J5P and 6N16B CF? Any schematics? I have just ordered my 4P1L... waiting for the post.


 
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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 7:55 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
6J5P is a miniature version of 6J4, equivalent of 6AC7. Very nice both in triode and pentode modes, with idle current about 10 mA.

6N16B is a tiny 6SN7-like tube. I wanted to use an interstage transformer, but decided to use cathode follower instead, so 6N16B will fit well under the chassis. 6N1P or 6N6P would require additional socket.

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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 8:21 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
Some progress for today...


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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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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 9:41 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
Look here: 10 mA, 170V (LED in cathode)

http://www.tubes.mynetcologne.de/roehre ... triode.pdf

Do you like it?

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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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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 2:53 pm 
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Posts: 238
What is the criteria for a cathode follower? Correct me if I am wrong, but I thought it is supposed to provide a low output impedance with high current capability? Or in this case, the 6N16B is sufficient to provide the drive current for the 4P1L?


 
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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 3:02 pm 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
It is to provide less variable current load for coupling capacitor. Classes AB1 and AB2 exist in textbooks only. Grid current is always variable, check for example any vacuum diode curve. But when you are listening to real sounds, especially using tiny output power amp, chances that input signal hit grid positive current are high, so distortions caused by bias shift are inevitable. That's why either coupling transformers, or cathode follower, or even source follower are used to drive output tube. 6N16B is quite capable to drive 4P1L grid.

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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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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 5:59 pm 
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Joined: Mon Mar 22, 2010 1:10 am
Posts: 238
how do you implement the power supply for the direct heated cathodes? regulated DC for lower noise or use a humdinger on AC?


 
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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Tue Feb 01, 2011 6:09 pm 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
quikie22 wrote:
how do you implement the power supply for the direct heated cathodes? regulated DC for lower noise or use a humdinger on AC?


Regulated 6.3V for 6J5P, then couple of 3 Ohm resistors per side of 4P1L filament to drop excess 2.1V. Middle points of them grounded.

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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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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Thu Feb 03, 2011 9:09 am 
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Joined: Mon Mar 22, 2010 1:10 am
Posts: 238
wht would be the output transformer you will be using? I suspect it will be edcor again.... wht impedance? Really wish I was in the USA where I can get parts easily.


 
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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Thu Feb 03, 2011 9:21 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
quikie22 wrote:
wht would be the output transformer you will be using? I suspect it will be edcor again.... wht impedance? Really wish I was in the USA where I can get parts easily.


Yes, I plan to use 25W 5K there. Cool

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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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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Thu Feb 03, 2011 9:35 am 
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Joined: Mon Mar 22, 2010 1:10 am
Posts: 238
What B+ and idle current? seems 4P1L is very power limited. With 5K OT, I am guessing power output of around 1W-1.5W assuming is triode connected?


 
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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Thu Feb 03, 2011 10:03 am 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
quikie22 wrote:
What B+ and idle current? seems 4P1L is very power limited. With 5K OT, I am guessing power output of around 1W-1.5W assuming is triode connected?


235V, 40 mA, -18V, 2.5W, triode connected. According to my friend in Israel, their local audiophiles get orgasms from sound of such amps.

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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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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Thu Feb 03, 2011 3:53 pm 
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Joined: Mon Mar 22, 2010 1:10 am
Posts: 238
that would be running the output tubes very hot. looking up specs for the output tubes, max V=200V, max current 35mA. but maybe as you said, these were built to higher specs than published in fear of the Gestapo.


 
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 Post subject: Re: GU-50 Single Ended Amplifier Design
PostPosted: Thu Feb 03, 2011 5:51 pm 
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Шаман, типа...

Joined: Tue Feb 10, 2004 12:30 pm
Posts: 7302
Location: Pleasant Hill, California
quikie22 wrote:
that would be running the output tubes very hot. looking up specs for the output tubes, max V=200V, max current 35mA. but maybe as you said, these were built to higher specs than published in fear of the Gestapo.


I can't find Telefunken datasheet for the original, but Alexander from Israel found that it is the best sounding regime.

Image

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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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