Posted by PakProtector [ 152.163.100.134 ] on March 21, 2006 at 18:09:05:

In Reply to: Re: 6S19P-V as line stage, driver, or phase splitter tube? posted by Norris Wilson on March 21, 2006 at 16:55:40:

Hey-Hey!!!,
Yes, I'll write up how the valves work. They're remarkably inexpensive, so I am getting a good quantity. The hybrid cascode Schmitt Inverter circuit needs near perfect match between the two triode sections.

For low mu valves, it has not been my experience to find close matches easily. For GE 5-Star 5687, they are soo close as to deserve 'perfect', but that's a whole 'nother pipe( errr...tube ).

The mu of 2-2.5 achievable with resistive plate loads is appealing. The little bit more gain than is available from a buffer circuit is just what the doctor ordered. I do hate the idea of throwing away gain like I would if I build around a crappy 12AU7. With the mu of 6 from the 12B4, and 1 from a buffer the 6C19 looks like Baby-Bear's porridge...just right!
cheers,
Douglas

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