In article , Patrick Turner
wrote:

John Byrns wrote:

In article , Patrick Turner
wrote:

Try something different, and try abandoning your prejudice,
just for an hour it takes to make something; maybe you hear
something good.

I may try the Selsted Smith detector given in the back of the RDH4. I'm
not sure what hearing something good means, sometimes what sounds good is
actually bad, or as some people call it euphonic.

RDH4 is a fine tome, but that doesn't mean you have to addopt every
syllable as
gospel.

Haven't I made it clear that I don't worship at the altar of the RDH4? My
interest in that circuit has little to do with the fact that the design is
included in the RDH4.

My CF plus following Ge diode is totally different to anything in RDH4.

Only to the extent that you have added a cathode follower to the
compensated diode circuit in the RDH4, but the cathode follower serves no
useful purpose, and of course you have removed the tracking feature from
the RDH4 circuit.

My circuit isn't anything like the RDH4 circuit, although is does use
tubes, dides, wire, R&C bits, etc..., but the topology
is quite different.
The RDH4 does not attempt to isolate the last IFT coil against the
effects of the
diode;
my circuit does, then it changes the source impedance of IF signal to a low
impedance to feed to
germanium diode + CRC. Its quite different to RDH4, and better, IMHO.

I did point out that you added the cathode follower at the input, and
deleted the bias tracking function, but the underlying idea is the same in
both cases.




The distortion reduction you
claim makes sense in that context, because your receiver as described by
the schematic you posted has an extremely poor AC/DC load ratio and I am
sure the distortion is extreme without the bias. Your bias scheme
presumably partially compensates for the poor AC/DC load ratio, rather
than somehow improving the "non linear turn on of the diode" as I had
erroneously assumed from what you have said.

The diode detector schematic I did post does have a poor AC/DC load
ratio, but
still works fine
to make a few volts without any wave clipping or added distortion
because of the
ratio.

That is the bias at work compensating for the poor AC/DC load ratio, just
as explained in the RDH4, it has nothing to do with the cathode follower.

Even better results with capacity for a much higher undistorted output
voltage is
possible
with the same first CF and Ge diode and CRC filter, but then directly
coupled to a
second CF,
which is the other half of a twin triode, and behold, there is zero AC
loading on
the detector.

Yes, I have said repeatedly that is where you should be using a cathode
follower.

Two cathode followers are better than one.

And three cathode followers would be better than two, that's not a joke, I
actually have a circuit in mind that would use three cathode follower like
circuits, although I would call it retched excess.

I leave you to your enjoyment of your ideas,
and wish you well, but with all due respect I still think you are
denying merit in a
novel approach
which I know works well, since I have tried and proven it at least to myself,
and to a few customers, who were very surprised that AM could sound so good.

I don't believe I have ever said that your circuit doesn't sound very
good, my only question is, does the cathode follower actually contribute
to the good sound, or is it just a gimmick?


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/