Cathode bipass capacitor and transformer impedience

[woody]

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! ?????

Regards,
Woody

 

[fdegrove]

Hi,

From the top of my head, yes.

Cheers,

 

[dhaen]

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

 

[Colt45]

Re: 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

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

 

[dhaen]

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.

 

[fdegrove]

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.

Cheers,

 

[dhaen]

Christmas spirit

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.

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.

 

[fdegrove]

Hi,

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

So power transferred is independent of source impedance? I don't think so.

Especially here... Care to 'splain?

Cheers,

 

[dhaen]

Frank,

You seemed to be implying that the same output power is obtained into the load irrespective of source impedance

 

[fdegrove]

Hi,

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.


Cheers,