☑ Cathode Bypass Capacitor

The use of an electrolytic cathode bypass capacitor makes no discernible difference to the sound other than the value affects the frequency response. R l kw.

Switchable Cathode Bypass Capacitor For Bassman 6g6b The

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Getting To Know The Bypass Capacitor January 1962 Popular

In short the cathode bypass capacitor handles any variations in the cathode current preventing the cathode voltage to vary as well.

Cathode bypass capacitor. Cathode bypass capacitor when a capacitor is large enough it acts as a short circuit for audio frequencies and eliminates the negative feedback but acts as an open circuit for a dc thereby maintaining the dc grid bias. Lets calculate the resistance between the anode of the first tube and the ground. The cathode bypass capacitor in tube amp forms a filter that reduces the low frequency gain of the a common cathode amplifier.

Gain at 82hz low e gain at 10khz. When the capacitor is large enough it acts as a short circuit for audio frequencies eliminating the negative feedback but as an open circuit for dc thereby maintaining dc grid bias. In order to restore full gain we must suppress the feedback voltage produced at the cathode using a decoupling or bypass capacitor c3.

The cathode resistor in a typical triode preamp is bypassed with a large capacitor to eliminate a form of negative feedback known as cathode degeneration. Now lets talk about distortion. Lets title this resistance rk.

You will need to look up the data for the particular tube your are using. C k mf. The bypass capacitor c3 together with resistor r3 will form a local low pass filter.

This substantially increases gain. The interesting part is that distortion comes with the bypass capacitor. This calculation is based on langford smiths formula from radiatron designers handbook 4.

R g kw. The choice of resistor also makes no change to the sound other than carbon types might add a little noise. R k kw k kw.