Syl wrote:
Jon Noring wrote:

...high-performance, tube-based AM (MW/BCB)

I'm very interested in building such a tuner to match with
audiophile-grade tube amplifiers and pre-amplifiers ...

Audiophile AM is an oxymoron...

Yes, in a sense this is true if we look at it from the broadcast side
of things.

However, if an audiophile wants to add an AM tuner to their system
(such as listen to oldies, news, sports, talk radio, whatever), they
*want* to hear the broadcasts at the highest possible audio fidelity
of whatever is carried by the signal. (TRF looks especially intriguing
for the AM tuner design, which I hope John Byrns will comment on.)

Definitely, the AM tuner design must not get in the way. As Patrick
Turner noted, in Australia may of the broadcasters appear to take
advantage of having fewer stations and broadcast with higher audio
bandwidth (even though channel spacing is 9khz), so the AM tuner
should have the ability to handle that higher audio bandwidth and do a
great job at it. Variable bandwidth control is certainly indicated
(especially if the tuner will also be used for casual DXing, where the
bandwidth will need to be narrowed for resolving real weak stations.)

About volume control (as also noted by Patrick Turner), I'm not sure
if the AM tuner will need one if connected to a preamp. If it is to
connect directly to an amplifier, though, it will need a volume
control. Here, putting a "standard" passive preamp volume control at
the line out of the AM tuner is indicated, unless there is a reason
to place the volume control further upstream in the "chain."

Jon Noring


p.s., do join the YahooGroup 'am-tube-tuners' if this topic interests
you. If you already have a YahooID, you can subscribe to it via:

http://groups.yahoo.com/group/am-tube-tuners/

If you don't have a YahooID, send a blank email to: