Long time ago, EC8010 suggested that : "a pair of PCF80 would make a very nice line stage/buffer. Use the triode section as a cathode follower, and sit it on the pentode section used as a constant current sink. Use a 300mA DC constant current regulated heater supply, and you'd have something with performance completely out of proportion to price."
I've a dozen of those tubes, transformers, caps, resistors and so on. Cost would we be near zero
For the cathode follower, ok, I found some articles explaining me how to design them. However, I've some problems to find a simple ccs using a pentode. Could someone link me to one ?
PS: the pcf80 : http://www.r-type.org/exhib/aaa0252.htm
I've a dozen of those tubes, transformers, caps, resistors and so on. Cost would we be near zero
For the cathode follower, ok, I found some articles explaining me how to design them. However, I've some problems to find a simple ccs using a pentode. Could someone link me to one ?
PS: the pcf80 : http://www.r-type.org/exhib/aaa0252.htm