Posted by Damir [ 213.202.68.46 ] on December 22, 2004 at 14:26:30:

In Reply to: Re: alright then... posted by manualblock on December 21, 2004 at 18:35:21:

CCS mean Constant Current Source, and you can imagine it like very high AC load resistance (hundreds of kOhms, even MegOhms), connected at the very high B+ supply (kiloVolts). Then our load line becomes horizontal, and in combination with linear tube like 5687 we have very little distortion and amplification about tube mu.
Output resistance of the common cathode line stage is load resistor in parallel with tube anode resistance. For 5687, rp<3kOhms, and this is our Zout in CCS case. With unbypassed cathode resistor, because of current feedback, our effective rp rise to about 9k. We can use low Zout CCS output, like Douglas said.

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