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Old 16th May 2008, 09:49 PM   #11
ja2dhc is offline ja2dhc  Japan
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Default Re: Chb

My E-Linear amplifier does not use the by-pass capacitor for
EL-34B cathod resister, as is shown below.

http://ja1cty.servehttp.com/E-LINEAR/E-Linear-amp.jpg

It is following to the origilal E-Linear Amplifier by Pete Millett.
His article is indicated below.

http://www.pmillett.com/elinear.htm
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Old 16th May 2008, 09:57 PM   #12
Sheldon is offline Sheldon  United States
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Default Re: C2 and Chb

Quote:
Originally posted by oldeurope
cathode cap to ground is forbidden in a Loftin White.
If you make a bypass capacitor parallel the cathode resistor,
Chb will not be able to eliminate the losses of C2.
OK, thinking about it a little more, maybe (or maybe not) I'm beginning to understand. If the amp is operated from an ordinary low impedance power supply, then decoupling the cathode resistor to ground or to B+ is essentially the same. The only difference is that power supply noise is injected out of phase to the output, with the B+ connection. With the inductor preceding the cap to cathode, however, that point is fed by essentially a constant current (high impedance). In that case, the cap keeps the voltage across the tube constant, instead of constant voltage across the cathode resistor. If I'm not way off there, my next task is to work on the meaning of that for feedback to the input tube.

Sheldon
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Old 17th May 2008, 05:20 AM   #13
Sheldon is offline Sheldon  United States
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If I have the logic right, since the output cathode resistor is not bypassed, it will create degeneration at the cathode. The AC connection to the input cathode, in essence, is a positive feedback (or regeneration?) that counters the degeneration at the output tube cathode. Looking at Darius's resistor divider, I see about 60:1, which matches the mu of about 60 for the input tube. That seems to make sense.

Those look like pretty linear tubes. Nice looking construction too. Were you happy with the sound?

Sheldon
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Old 17th May 2008, 06:47 AM   #14
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Default Re: Re: Chb

Quote:
Originally #11 posted by ja2dhc
My E-Linear amplifier does not use the by-pass capacitor for
EL-34B cathod resister, as is shown below.

http://ja1cty.servehttp.com/E-LINEAR/E-Linear-amp.jpg

It is following to the origilal E-Linear Amplifier by Pete Millett.
His article is indicated below.

http://www.pmillett.com/elinear.htm
Hello ja2dhc,
thanks,
what does the "E" mean in E-Linear?

Kind regards,
Darius
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Old 17th May 2008, 07:37 AM   #15
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Default #12 #13

link
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Old 17th May 2008, 10:09 AM   #16
ja2dhc is offline ja2dhc  Japan
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Default Re: Re: Re: Chb

Quote:
Originally posted by oldeurope

what does the "E" mean in E-Linear?
I have no idea about it. I could not find description in the original article below, either.

http://www.pmillett.com/elinear.htm

The sonic is vivid and "High Speed." I think it is given by capacitors as below.

C3g Cathode by-pass: Wet Tantalum
Coupling: ERO 1600V rated polypropylene
OPT Cold End (70uF): Sprague polypropylene Motor Run Cap

Therefore no aluminum capacitor is used in all audio signal paths.


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Old 17th May 2008, 10:17 AM   #17
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Default #16 incomplete Loftin White ...

Maybe Elliano Ultrapath ???

Kind regards,
Darius
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