Cathodyne gain calculator link

[revintage]

It's a tipical Fender-style cathodyne phase inverter, 56k plate and cathode resistors (metalfilm 1%), 1.5k cathode bias resistor (mf 1%), probably a switch for a 1.5k bypass cap. Grid bias resistors are 220k, coupling caps 22n. Output tubes are EL34, 30W output.

Who said you should have a perfectly balanced cathodyne in a guitar amp? I´d say the opposite.

 

[slideman82]

Hahahaha great! I'm using a 470k grid stopper from the previous stage output (AC coupled). BTW, I believe you all... that's why I always ask here! There's some people who really knows a lot about this...

 

[slideman82]

So, how is frecuency response affected with cathode bias resistor bypassed? Does LF responce increases or decreases? It seems it increases...

 

[DF96]

You will get a small LF shelf - a cut. I do mean small: 0.23dB.

 

[slideman82]

That's almost nothing. But it seems outputs get better balance, right? I mean, with that cap.

 

[SY]

That's almost nothing. But it seems outputs get better balance, right? I mean, with that cap.

No, that only makes a tiny change in the gain and frequency response, not the balance.

 

[DF96]

slidemanm82, I suggest you get a good book which describes how the cathodyne works or see SY's article in Linear Audio. Your questions strongly suggest that you are in need of this information. I find it is much easier to design a circuit when I understand how the circuit works.

 

[slideman82]

Thanks! I've got some articles I've never read, but sure I'll do these days...