[Elecraft] WJST and the K3

[Paul Christensen]

> So the K3 has a fully floating ground on the line audio input, isolated 
> from
> the chassis??? Is that correct? 73 Tom

The K3's line input transformer primary is connected to the 1/8" TRS jack 
using tip and sleeve where the sleeve floats above chassis ground.

The on-line schematic of the KIO3 board was revised a few weeks ago and it 
looks like the Bourns LM-NP-1001 transformer may now be an alternative from 
Elecraft although I haven't looked at pin compatibility with the existing 
Tamura TTC-108 transformers.

According to Jack Smith's measurements, the Bourns transformers have very 
good frequency response and THD characteristics as long as input levels 
remain at typical -10 dBV from consumer-grade PC sound cards.  At just USD 
$1.75 ea. from Mouser, they look like a good value.

Paul, W9AC