20
SPKRS
ST EREO or MONO; 4 to 8
Ω
Plugging in external speaker(s) cuts off the internal
speaker. A stereo plug is recommended; tip is left
speaker, ring is right. If you only have a mono plug,
set
CONFIG:SPKRS
to
1
to disable right-channel
audio.
(Also see important note below.)
PHONES
ST EREO or MONO; 16
Ω
mi
n.
r
ec
ommended
The front and rear-panel headphone jacks are both
isolated with series resistors. This allows you to use
mono phones on one jack and stereo on the other, if
r
equi
r
ed.
You’
l
l
ne
ed stereo phones for AFX (audio
effects) and stereo dual receive (with sub receiver).
You can plug in headphones and speaker(s) at
the same time, and hear audio in both, if you set
CONFIG:SPKR+PH
to
Y ES
. However, if you set
CONFIG:SPKRS
to
1
, setting
SPKR+PH
to
YE S
will force mono headphone as well as speaker
output. You can set
SPKRS
to 2 if you use a stereo
plug at the external speaker jack, or if no external
speaker is plugged in.
MIC
MONO; hi- or low-Z
This jack accommodates an electret or dynamic
mic. Use
MAIN:MIC SEL
to select the rear panel
mic (
RP
). T ap
1
to turn on Low or High mic gain
range. T ap
2
to turn bias on/off (see pg. 28 for
recommendations based on mic type).
The
mi
c’
s
PTT signal, if used, must be routed to either the
PTT IN jack or the PTT line on the ACC connector
(pg. 18).
LINE IN
MONO, transformer-isolated; 600
Ω
(
nomi
nal
)
This
i
nput
s
houl
d
be
connec
t
ed
t
o
your
compu
t
er
’
s
soundcard output. The
MI C
gain control sets the
line input level when the
MAIN:MIC SEL
menu
entry is set to
LI NE I N
.
The LIN IN le vel should be se t carefully to
avoid transmit signal distortion due to
sat
urat
i
on
of
t
he
K3’
s
i
nput
audi
o
t
r
ansf
ormer.
In addition, sound card gain should be set 6 to 10
dB
bel
ow
t
he
l
ev
el
at
whi
c
h
t
he
sound
c
ard’
s
output stage starts clipping.
LINE OUT
ST EREO, transformer-isolated; 600
Ω
(
nomi
nal
)
Thes
e
ou
t
pu
t
s
ca
n
be
conne
ct
ed
t
o
your
c
omput
e
r
’
s
soundcard inputs. Normally, the left channel is
main receiver audio, and the right channel is sub
receiver audio (if applicable). In this case the
outputs are post-AGC but pre-AF-gain.)
Use
CONFIG:LIN OUT
to set the level, or to
switch from a fixed-level setting to
= P HO NE S
.
LIN O UT settings above 10 are usually not
ne cessary, and can in some cases cause
over
l
oadi
ng
of
ei
t
her
t
he
K3’
s
out
put
transformers or the PC soundcard inputs
(typically on noise peaks). Eithe r could degrade
the pe rformance of digital demodulation
software .
Some laptop compute rs have only ve ry high-
gain, high-impe dance mic inputs, not line-le vel
inputs. This can make it difficult to adjust the
K3’
s
LI
NE
OUT
le vel, and can also worsen noise
pickup.
If your laptop has only a mic input, you
may want to add a resistive attenuator between the
K3 and the laptop to keep the signal-to-noise level
high.
Summary of Contents for K3
Page 71: ...71 K3 Block Diagram ...
