Audio Project Amplifier Speaker Loudspeaker Kit
diyAudio.com diyAudio Forums Archive > Top > Amplifiers > Tubes
 
Cathode bipass capacitor and transformer impedience - Click HERE for Original Thread
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
Hi Woody,

I think you'll get the same power, but lower distortion with a cathode bypass cap into 2K5:xmastree:
Am I right or wrong :scratch:
Colt45
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:xmastree:
Am I right or wrong :scratch:

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
dhaen
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.:deerman:
fdegrove
Hi,

Since it's X-Mass....:angel:

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
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.
fdegrove
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?

Cheers,;)
dhaen
Frank,

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


Cheers,;)

Page generated in 0.032552003860474 seconds with 17 queries,
spending 0.00854707 doing MySQL queries and 0.02400494 doing PHP things.

Powered by: Search Engine Indexer and vBulletin
Copyright ©1999-2009 diyAudio.com