🚀 go-pugleaf

In article <Bz7ovv.FA9@wang.com> dbushong@wang.com (Dave Bushong) writes:
>mjohnson@netcom.com (Mark Johnson) writes:
>
>>I've heard that someone designed line-level audio
>>amplifiers using Nuvistors (!) and that the results
>>were impressive (!!).  I'd appreciate any information
>>about these, ideally a schematic.  Thanks!
>
>It sounds like it was a project that had a requirement that
>all parts must be from a junkbox. VHF/UHF parts are probably the
>last active element that I'd select for in an audio amp.  Unless
>I had no choice (like I was the professor on Gilligan's Island,
>for example).

Umm... actually, I built a phono preamp (and a number of mike preamps)
using nuvistors, mostly because I needed to fit them into very small
areas.  The sound quality of the 6CW4 is magnificent, and I recommend it
as an audio device.  You have to be very careful about microphonics,
though: vibrations perpendicular to the plates are easily picked up 
although vibrations parallel to the plates aren't a problem.  This definitely
affects the design of your mounting structure.

Anyway, using the 6CW4 isn't that much different than using any other
tube in a line level stage, as far as circuit topology goes.  Remember
that your B+ is going to be much lower than you are used to, though.
--scott

  (Okay, I am currently building a power amp with the 829, but don't
   tell anyone.  This is a junk box venture, to say the least.)