On Tue, 08 Jun 2004 03:04:27 GMT, Jon Noring wrote:

I'm very interested in building such a tuner to match with
audiophile-grade tube amplifiers and pre-amplifiers now being built by
hobbyists (as well as those sold by commercial vendors.) There are
quite a few nice kits now being marketed for audiophile quality tube
amps/pre-amps, such as those made by diytube (http://www.diytube.com/
-- there are many others like diytube.) So why not similar kits (or
workable designs) for a tube-based AM tuner?

No offence Jon, but I think you're nuts. Most hifi listeners (never
mind audiophiles) wouldn't dream of using *FM* for serious listening,
because of the level of optimodding and other sound processing that
goes on. Quite a lot of commercial stations even adjust the playback
speed of their music to make the station sound more 'lively' and to
squeeze in more commercials.

AM has all that, plus very high levels of signal compression and an
effective HF cutoff of about 3.5kHz. You can't improve this by
extending the IF bandwidth, because the stations just don't transmit
anything above this.

There's nothing wrong with building your own high quality AM tuner,
either solid state or tube, but no matter how many gold lettered
Telefunken ECC83s you use it won't sound very good.

Best regards, Paul
--
Paul Sherwin Consulting http://paulsherwin.co.uk