Tube DIY Asylum

Posted by Kurt Strain (A) on March 01, 2002 at 08:08:06

In Reply to: Re: My latest phono revision unveiled posted by Lew on March 01, 2002 at 06:56:53:

The only difference between my CCS and the C4S is I chose a 5.6V zener diode in parallel with a 10uF tantalum cap where the top LED of the C4S is. The only difference is that this gives a little more current feedback because the emitter's current setting resistor needs to be a larger value because the zener is 5.6V instead of about 2V for an LED. You need the tantalum cap to filter off the zener noise.

Other options are Gary Pimm's pentode CCS if it's quiet enough, or my PMOS cascoded CCS, or whatever else there is that's the latest and greatest. But my modified "C4S" works great in these low level circuits from what I can tell, but I have not heard any other. It's all soldered together on my single proto board and not readily changeable. I will leave it this way probably for a long time.

Kurt