It is an impedance matching buffer to allow use with medium and lower "impedance" inputs. The D-104 cartridge is easy to tame. Just disconnect the internal circuit from the audio line and solder a 470k resistor in its place. You will still have plenty of audio to drive just about any radio and it will sound good.
On Tue, 15 Apr 2025 13:51:28 -0700
"jerry-KF6VB via groups.io" <jerry@...> wrote:
On 2025-04-15 12:51, Steve Wedge, W1ES/4 via groups.io wrote:
There are D-104¡¯s that have no preamp.
*** Indeed. I don't understand why a D-104 would *need* a preamp.
Maybe if you needed a couple watts out of it to directly amplitude
modulate something?
- Jerry, KF6VB
--
73
-Jim
NU0C
Jim Shorney