Koch Jupiter Junior Bedienungsanleitung Seite 4

JUPITER JUNIOR BACK PANEL
[1] A.C. POWER:
INPUT: Power cord input. The JUPITER JUNIOR is
equipped with a worldwide power supply. Inside the amp a
mains selector switch can be set on one of three voltages,
100, 115 or 230. Either of these voltages will work
worldwide with minor power differences. The amp will work
on either 50 or 60 hertz. After resetting the internal mains
selector switch make sure fuses are replaced with
printed ratings on rear of amp.
FUSE: Both fuse and spare fuse are located on the sled of
the fuseholder. Fuse sled can be removed with a
screwdriver. If the fuse should fail, it must be replaced
with the same type and value in order to avoid damage
to the amp and to prevent voiding the warranty.
If the amp repeatedly blows fuses the amp should be taken
to a qualified service center for repair.
WARNING: Only a qualified technician should attempt
an input voltage change. Personel injury or equipment
damage may occur if done incorrectly.
WARNING: The fuse should be replaced or the voltage
should be reset only when the power cord has been
disconnected from its power source.
[2] EFFECTS LOOP:
SEND: This jack provides a buffered mono output from the
preamp of the JUPITER JUNIOR and can be used to
connect an external effects unit. This jack must be
connected to the input of the effects unit (see also
CONNECTION DIAGRAM).
RETURN: This jack provides an input for an external
effects unit and must be connected to the output of the
effects unit. When used, it disconnects the preamp of the
JUPITER JUNIOR from the power amp and therefore it
also allows the JUPITER JUNIOR to be used as a
"satellite" for other preamps.
NOTE: The EFFECTS LOOP's mode is serial. Its -10dBV
SIGNAL LEVEL guarantees compatibility with both
instrument-level effects like floor-pedals and guitar-
processors, as well as line-level effects like professional 19
inch rack mount devices.
NOTE: If the connection of an effects unit to the JUPITER
JUNIOR gives more hum, a ground-loop may be the cause
of it.
[3] EXTENSION CABINET JACK Provided for connection
of speaker(s) or speaker cabinet(s) with a minimum total
impedance of 8 ohms.
The Combo has an 8 ohm internal speaker, so its second
jack can be used to connect an extension cabinet of 8 or
16 ohms.
If a separate speaker cabinet is used, use KOCH
Dynacon SC608 speaker cable for the best results.
DO NOT USE GUITAR CABLE.
[4] SPEAKER ON/OFF SWITCH: This switch disconnects
the output of the amp from the internal speaker and the
and External Speaker jack This allows you to play the amp
at full power without hearing anything while using the
Recording output [5] for recording or other purposes.
NOTE: the JUPITER JUNIOR can be used safely without a
speaker connected, switching the speaker(s) OFF will NOT
cause any damage to the amp.
[5] RECORDING OUTPUT JACK:
This jack provides an unbalanced mono output suitable for
recording or PA. Its signal is derived from the speaker
output so the typical tube saturation of the power amp will
be included; it also includes Reverb and External Effects
signals. This signal is at line level (-10 to 0 dBV) and is
shaped by a special filter that emulates the typical
recording characteristic of a microphone placed in front of
a guitar speaker.
[6] FOOTSWITCH JACK: Provides an input for the (not
included) KOCH FS2 FOOTPEDAL or for a remote channel
switching unit, e.g. a MIDI switcher. When the FS2 or the
remote unit is plugged in, the CHANNELS switch [2] is
automatically disconnected.
This jack is a stereo jack.
The TIP connects with the left-hand button of the FS2
footpedal and controls switching between the COOL and
the HOT channel.
The RING connects with the right-hand button of the FS2
footpedal and controls the GAIN BOOST of the HOT
channel (and disconnects the Gain Boost switch [4] on the
front panel).
REPLACING TUBES
The JUPITER JUNIOR has two 12AX7 tubes. These tubes
wear out slowly and have to be changed from time to time
to maintain the amp's best performance.
Tubes behave like strings, they lose highs, lows and
dynamics and after a period of time they have to be
changed. Exactly when is hard to say but this is an
indication: if you play almost every day change tubes each
year, if you play once or twice a week change tubes every
2-3 years.
Preamp tubes rarely fail. If they are bad, these might be
the symptoms:
- Microphonic whistling or squealing on one or both
channels.
- No or low amp volume on one or both channels.
- Excessive noise on one or both channels.
- Excessive hum on one or both channels.
Changing a tube can be a simple and quick fix for most
problems in your amp.

SAFETY FIRST: DISCONNECT THE POWER CORD
FROM ITS POWER SOURCE AND LET HOT TUBES
COOL.

REPLACE TUBES ONLY WITH ORIGINAL KOCH
HIGH QUALITY TUBES. (IF OTHER TUBES ARE
USED THE WARRANTEE OBLIGATION EXPIRES)
If you have any doubts, please take no risks and let a
qualified technician do the job.