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Old 17th September 2010, 08:09 AM   #1
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Default The best tube pre from Vietnam - 818 Pre

Hello!
Please introduce to you a Pre Amplifier designed by me and has been popular in Vietnam 5 years! And is considered one of the best in pre post in Vietnam. There was a lot of my friends use it, and so far they still love it!
I use a very simple design, using three types of tube are different: 6h30Pi, 6h6pi, 6dj8.
Sounds very realistic detail, balance!

This is a circuit diagram of the 818 pre! Pleas see it!
Thanks
Attached Images
File Type: jpg PRE-818-The-best-Pre-From-V.jpg (300.9 KB, 1758 views)
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Old 17th September 2010, 08:31 AM   #2
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And some all image
Attached Images
File Type: jpg Pre818-DragonVU.jpg (67.3 KB, 1602 views)
File Type: jpg Pre818-DTH.jpg (178.4 KB, 1480 views)
File Type: jpg Pre818-Lam-top2.jpg (176.9 KB, 1398 views)
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Old 17th September 2010, 08:31 AM   #3
mach1 is offline mach1  Australia
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How many minutes do the tubes last running them at 40mA per section ?
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Old 17th September 2010, 08:32 AM   #4
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and
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File Type: jpg Pre818--Lam-Top.jpg (199.6 KB, 1306 views)
File Type: jpg Pre818-NOBG-2.jpg (183.5 KB, 405 views)
File Type: jpg Pre818-NOBG 1.jpg (191.5 KB, 504 views)
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Old 17th September 2010, 08:34 AM   #5
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Quote:
Originally Posted by mach1 View Post
How many minutes do the tubes last running them at 40mA per section ?
Tube 6h30 or 6h6 I use 1/2 tube = 20mA!
So one Chanel have 2 tube, per tube 40mA, Total = 80mA!
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Old 17th September 2010, 08:44 AM   #6
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The last time I meet Salas shunt, I use it with all cap MKP!
So I say i love Salas shunt and MKP cap for supply!
I have one image!
Attached Images
File Type: jpg Pre818 Front.jpg (164.3 KB, 551 views)
File Type: jpg Pre818 Top1.jpg (213.6 KB, 529 views)
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Old 17th September 2010, 09:05 AM   #7
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One friend live in the California USA, He make 818PRE, and he measure it!
Attached Images
File Type: jpg 1.5K.jpg (205.3 KB, 507 views)
File Type: jpg 2.5VRMS.jpg (144.6 KB, 246 views)
File Type: jpg 5V distortion.jpg (113.9 KB, 214 views)
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Old 17th September 2010, 09:11 AM   #8
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And some image
And Salas shunt measure and my 818Pre
Attached Images
File Type: jpg 10VDIST.jpg (118.8 KB, 181 views)
File Type: jpg Salas-Ss1.jpg (141.4 KB, 155 views)
File Type: jpg 8118 mesure.jpg (145.7 KB, 148 views)
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Old 17th September 2010, 09:21 AM   #9
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Why is such a discrimination: you feed 6N6P with 80V more than 6N30P?
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Old 17th September 2010, 09:28 AM   #10
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Quote:
Originally Posted by Wavebourn View Post
Why is such a discrimination: you feed 6N6P with 80V more than 6N30P?
No!
At anode :
6h30pi = 90V, Ia 1/2 tube 20ma. the sound excellent
6H6pi =170 ,Ia 1/2 tube 15- 20ma, the sound it the best, i see
and 6Dj8 = 90V, Ia =5-7ma, i like

Thanks
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