[R-390] 16kHz filter and SWL/BC listening

[Tim Shoppa]

To my ear when listening to SW and BC broadcasts (voice, music, whatever)
the 16kHz filter setting always sounds pretty much just like 8kHz just
with more hiss.

On a really super-strong station the hiss seems to be not so noticable.

This is a R-390A (so mechanical filters), a Hammond 600:8 ohm transformer,
and a couple different bookshelf/hi-fi speakers I've tried.

I've got both an EAC and a Motorola IF deck and they sound the same.

I have "upgraded" several of the capacitors in my audio decks to enhance
bass response (I did hear an improvement on the bass end) but between
my audio decks the sound is the same.

Is this a fundamental limitation of the AF chain, or is my hearing just
wacky, or is there some simple technical fix?

If I tapped off the diode load and fed into an outboard amp would 16kHz
suddenly sound good?

I rarely use 4kHz for SW/broadcast listening unless there's a lot of
QRM to be removed.

Maybe I'm just getting old and have lost the top end of my hearing?
I've always been bothered by tape hiss and to me the hiss on the 16kHz
setting is even more bothersome.

Tim.