[Elecraft] Good Low Cost Audio to USB Interfaces For Digital Modes

[Jim Brown]

On 3/24/2012 1:19 PM, Pierfrancesco Caci wrote:
> Jim, how do you set the little volume control?

I've never found a gain control for Record. :)  There are two inputs -- 
a Line level input that I suspect is designed to work at a few volts, 
and a Phono input which is designed to work at the level of a phono 
cartridge (the type used to play vinyl records).

The Phono input has RIAA equalization, which boosts low frequencies and 
rolls off high frequencies.  I use the Phono input with a simple RC 
filter network between the radio and the Numark.  I'm going from memory, 
but I believe what I used was 200 ohms across the output of the radio, 
200 ohms across the input to the Numark, and 0.22 uF between the radio 
and the Numark.  This simple network is designed specifically to match 
the K3. The Phono input has a LOT more gain than the Line input, so this 
gives the unit the ability to handle any signal level you're likely to 
get from a radio.

73, Jim K9YC