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Old 14th June 2008, 06:45 AM   #61
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Default On topic please

On topic please, thanks
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Old 16th June 2008, 07:00 AM   #62
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Default waiting ...

Hello,
I am still waiting ...

Quote:
Originally #42 posted by SY
I'm sorry, I just don't have an English word for it. I'll look in a couple of texts and see if there actually is one.
I am the only who didn't know this well known factor, sorry.
It is the most important mathematical tool in triode circuit design.
Thus I am sure the experts here are able to tell me the name of it.

Thanks,

Darius
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Old 10th September 2008, 07:32 AM   #63
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Default Loftin White ... "Ultrapath" ... Broskie

Hello,
anyone noticed this blog by Broskie? read me

quoted from Radio News Feb.1930: "A condenser, C2, of about 1 microfarad is needed to form a local signal circuit in the output circuit including association of any suitable loud speaker as indicated." link

This is the so called "Ultrapath" and the green line shows this
local output circuit in my fundamental schematics.
http://rl12t15.blogspot.com/2008/03/...tin-white.html

Schematic

http://rl12t15.blogspot.com/2007/09/...tin-white.html

Schematic

I am sure Broskies text will help you understanding the "Ultrapath
aspect" of a true Loftin White design. Thanks to JRB.

Kind regards,
Darius
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Old 12th September 2008, 12:16 AM   #64
Sheldon is offline Sheldon  United States
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Go ahead and say it Darius. All that work and he almost got back to 1930, where the entire amp is floating with the output cathode - and no capacitor adjustment, no big supply caps, and no coupling cap.

Sheldon
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Old 27th December 2008, 06:00 PM   #65
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Darius,

In your schematic, where is the 1uF cap from the ground input to the cathode resistor of the input tube as shown on the original schematic? Is it necessary?

Click the image to open in full size.

Happy new 2009,
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Old 27th December 2008, 07:52 PM   #66
Sheldon is offline Sheldon  United States
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Darius exited the forum. A little to loose here for him, maybe. In any case, C2 on his schematic is the 24u cap, and Chb is the 2.2u cap. C2 on his schematic is just shown on the right side of the tube, instead of the left. But if you look closely, you will see that the connection is exactly the same (top of cathode resistor to B+). Yes, it is necessary.


Sheldon
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Old 27th December 2008, 08:01 PM   #67
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Quote:
Originally posted by Sheldon
Darius exited the forum. A little to loose here for him, maybe. In any case, C2 on his schematic is the 24u cap, and Chb is the 2.2u cap. C2 on his schematic is just shown on the right side of the tube, instead of the left. But if you look closely, you will see that the connection is exactly the same (top of cathode resistor to B+). Yes, it is necessary.


Sheldon
C2 and Chb are clear. I do not see the C1 cap at the input and the 6SN7 grid leak resistor goes straight to ground.

here is a clearer picture:

Click the image to open in full size.
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Old 27th December 2008, 10:15 PM   #68
Sheldon is offline Sheldon  United States
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Let's do this in one or the other thread, not both.

Sheldon
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Old 10th January 2009, 12:48 PM   #69
JLH is offline JLH  United States
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I want to bounce something off the group here. Which example would be the better solution in your opinion and why? Thanks in advance for your constructive criticism.

Example #1

Click the image to open in full size.




Or
Example #2



Click the image to open in full size.


Rgs, JLH
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Old 10th January 2009, 08:35 PM   #70
Sheldon is offline Sheldon  United States
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In either case, I'm not sure that I see the benefit. Darius' triode LW version references the signal circuit to the top of the cathode output resistor, to eliminate PS ripple from the output. The original does the same, but uses a pentode input tube.

In version 1, the screen grid already isolates the output tube from the effects of ripple in B1. The CCS on the input tube should isolate it from B2 ripple. The ripple compensation circuit will eliminate ripple from B2 on the screen grid, but it should be easy to get that low current supply quiet anyway.

In version 2, more or less the same things apply, but with one less cap. I'd do that one.

Sheldon
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