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Old 25th December 2003, 12:22 AM   #1
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Unhappy Cathode bipass capacitor and transformer impedience

I have a pair of 6C33c triodes but most of the circuites I have
seen used a 600- 800 ohm transformer. (expensive) but If I don,t
use a cathode bypass cap might a 2.5k primary transformer be
ok! ?????

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Woody
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Old 25th December 2003, 01:04 AM   #2
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Hi,

From the top of my head, yes.

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Old 25th December 2003, 09:10 AM   #3
dhaen is offline dhaen  Europe
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Default Gut feeling......

Hi Woody,

I think you'll get the same power, but lower distortion with a cathode bypass cap into 2K5
Am I right or wrong
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Old 25th December 2003, 09:30 AM   #4
Colt45 is offline Colt45  Serbia
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Default Re: Gut feeling......

Quote:
Originally posted by dhaen
Hi Woody,

I think you'll get the same power, but lower distortion with a cathode bypass cap into 2K5
Am I right or wrong
Less power actually.. but yeah, lower distortion.
Just talking about the trafo itself. Cathode bypass will just increase gain and uh...

I'm going to sleep :P
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Old 25th December 2003, 11:51 AM   #5
dhaen is offline dhaen  Europe
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Default More gut feelings...

Actually on second thoughts, there should be more power transfer with the cathode bypassed. The reasoning is that the Rp will reduce and so less power will be wasted in the valve....

I'm not talking about gain....

The distortion sig will change with the cap to reduce 3rd & 5th, and increase 2nd.
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Old 25th December 2003, 10:49 PM   #6
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Hi,

Since it's X-Mass....

With Rk NOT bypassed the AC gain is reduced as degenerative feedback is introduced. Hence distortion is reduced.

Absolute power will be the same but as the Zo is higher with the cathode unbypassed a higher Zprim is preferable.

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Old 25th December 2003, 11:43 PM   #7
dhaen is offline dhaen  Europe
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Default Christmas spirit

Quote:
With Rk NOT bypassed the AC gain is reduced as degenerative feedback is introduced. Hence distortion is reduced
Yes, that's the 2H produced by the valve. But the 3H & 5H produced by the valve and transformer is increased.

Quote:
Absolute power will be the same but as the Zo is higher with the cathode unbypassed a higher Zprim is preferable.
So power transferred is independent of source impedance? I don't think so.

Of course the Zprim is best to be as high as possible, for low distortion, but not for power.
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Old 26th December 2003, 12:13 AM   #8
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Hi,

John...I think you just lost me there...

Quote:
So power transferred is independent of source impedance? I don't think so.
Especially here... Care to 'splain?

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Old 26th December 2003, 09:50 AM   #9
dhaen is offline dhaen  Europe
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Frank,

You seemed to be implying that the same output power is obtained into the load irrespective of source impedance
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Old 26th December 2003, 01:07 PM   #10
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Hi,

Quote:
You seemed to be implying that the same output power is obtained into the load irrespective of source impedance
Ah...I see what you mean.
I was referring to the bypass cap as that would only affect gain.


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