Koch Little Gristle User manual

OPERATING INSTRUCTIONS GB
GEBRUIKSAANWIJZING NL
2022 Koch Guitar Electronics

Fuse: 100/120V - T1.0A
220/240V - T500mA
8
VAC
25 Watts, 50/60Hz
115 230
100
Speaker Output
12 3
Back panel
15 6 7 910 23 4 8
Front panel
Input Rec/PA
Gristle Tone More Reverb
Off
On
Extra
Cab Filter
(Signal comes from speaker output)
PowerStandby
OnFull Power
OffLow Power
Little Gristle
Reverb
If the Speaker Jack is unplugged
amp’s output automatically connects
to the internal Power Soak

E N G L I S H
Thank you for choosing the LITTLE GRISTLE from KOCH. You now own a "state-of-the-art" all-tube
Single Ended full Class-A guitar amplifier of the highest quality. The LITTLE GRISTLE has been
designed and built by people who - from their own experience as musicians - take guitar sound and
quality very seriously. That is why this product was designed and built with the utmost care in order to
meet all professional standards. Our goal was not only to design an amp which sounds fantastic and is
easy to operate, but also to build it in such a way that it will serve you loyally for many years to come.
Please take your time to read this manual carefully before you switch on the LITTLE GRISTLE.
Thanks and lots of success with your new LITTLE GRISTLE !
CAUTION:
* BEFORE PUTTING INTO OPERATION READ THESE OPERATING INSTRUCTIONS
CAREFULLY.
* NO USER SERVICEABLE PARTS INSIDE.
* REFER SERVICING TO QUALIFIED SERVICE PERSONNEL ONLY.
WARNING:
* TO REDUCE THE RISKS OF ELECTRICAL SHOCK, DO NOT REMOVE THE
COVER.
* TO REDUCE THE RISK OF FIRE OR SHOCK HAZARD, DO NOT EXPOSE
AMPLIFIER TO RAIN OR MOISTURE.
* THIS APPARATUS MUST BE EARTHED.
* TUBES ARE HOT. DO NOT TOUCH DURING OPERATION.
FRONT PANEL FUNCTIONS
[1] INPUT: Input for all types of instruments, e.g.
guitars with single-coil, humbucker or active pickups.
[2] EXTRA: Increases the gain for adding extra
overdrive and distortion.
[3] GRISTLE: A Clean sound is achieved at lower
settings (1 to 4), at higher settings (4 to 10) overdrive
occurs which will produce more sustain and real
power amp distortion.
[4] TONE: Classic passive tone control for adding or
cutting high frequencies
[5] MORE: Controls the overall volume level.
[6] REVERB: Controls the amount of the Spring
Reverb signal mixed with the original dry signal.
[7] CAB FILTER ON/OFF: Activates or de-activates
the special speaker simulating filter [8] for direct
recording purposes.
[8] REC/PA:
This jack is an unbalanced mono output suitable for
recording or PA. Its signal is derived from the speaker
output. This signal is shaped by a special filter that
simulates the typical recording characteristic of a
microphone placed in front of a guitar speaker.
The output signal is at line level (-10 dBV).
[9] STANDBY SWITCH: Allows the LITTLE
GRISTLE to be placed in Standby, Low Power or Full
Power mode.
In Standby mode the tubes remain hot, but the
amplifier is not operational.
In Low Power mode the power amp delivers only 1/3
of the indicated power (4 Watt).
In Full Power mode the power amp delivers the
indicated power (12 Watt)
[10] POWER SWITCH: Turns AC power On (red
LAMP on) and Off (red LAMP off). When the switch is
Off the amplifier is completely shut down.
NOTE: When switching the amplifier On, leave the
Standby switch [9] in the “Standby” position for 5-10
seconds thus allowing the tubes to heat up before
switching to Low or Full Power mode.

REAR PANEL FUNCTIONS
[1] A.C. POWER:
INPUT: Power cord input. The LITTLE GRISTLE 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 fuse holder. 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, check for a bad
power tube. If tube-failure is not the cause, the amp
should be taken to a qualified service centre for
repair.
WARNING: Only a qualified technician should
attempt an input voltage change. Personal 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] SPEAKER OUTPUT JACK: Provided for
connection of the internal speaker of the combo.
If the plug is pulled, the power amp’s output
automatically connects to the internal POWER SOAK.
This special feature has been added for two reasons:
1. PROTECTION. The amp is always protected and
cannot be damaged as a result of operation without a
speaker or speaker cabinet connected.
2. SILENT PLAYING. Silent practicing or home
recording with use of the REC/PA output [8] can be
realised easily: just pull the speaker plug!
[3] REVERB: Two RCA connectors provided for
connecting the reverb tank.
REPLACING TUBES
SAFETY FIRST: DISCONNECT THE POWER
CORD FROM ITS POWER SOURCE AND LET
HOT TUBES COOL.
CHECK THE ‘TUBE LOCATION DIAGRAM’ ON
THE CHASSIS FOR THE CORRECT TYPE
NUMBERS AND LOCATIONS.
REPLACE TUBES ONLY WITH ORIGINAL
KOCH HIGH QUALITY TUBES. (IF OTHER
TUBES ARE USED THE WARRANTEE
OBLIGATION EXPIRES)
BEFORE REPLACING THE POWER TUBE,
REMOVE THE SAFETY GRILL FIRST.
AFTER REPLACING THE POWER TUBE, PUT
THE SAFETY GRILL BACK IN PLACE.
NOTE: The LITTLE GRISTLE has an auto-bias circuit
so it does not have to be re-biased after replacing the
power tube.
If you have any doubts, please take no risks and
let a qualified technician do the job.
Preamp and Power tubes wear out and have to be
changed from time to time to maintain the amps 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.
Tubes rarely fail. If they are bad, these might be the
symptoms:
PREAMP TUBE (ECC83, 12AX7, 7025):
- Microphonic whistling or squealing.
- No or low amp volume.
- Excessive noise.
POWER TUBE (6W: EL84, 6V6. 12W: 5881, EL34,
6L6, etc.):
- Loud crackling that is not affected by front panel
controls.
- Intermittent or regular blowing fuses.
- Weird amp ‘distorting’.
- Hum.
Changing a tube is a simple and quick fix for most
problems in your amp.
In case of failure, the POWER TUBE can be replaced
without re-biasing.
Again, if you have any doubts, please take no
risks and consult your dealer and/or a qualified
technician.

N E D E R L A N D S
Bedankt dat je je keus op de LITTLE GRISTLE van KOCH hebt laten vallen. Je bent nu de eigenaar van een "state-of-
the-art" Single-Ended volledig Klasse-A buizengitaarversterker van de allerhoogste kwaliteit. De LITTLE GRISTLE is
ontworpen en gebouwd door mensen die - vanuit hun eigen praktijkervaring als muzikant - gitaargeluid en kwaliteit heel
serieus nemen. Daarom werd dit product met extra veel zorg ontwikkeld en gebouwd om aan de allerhoogste
professionele eisen te kunnen voldoen. Het was ons doel om een versterker te ontwerpen die niet alleen fantastisch
klinkt en eenvoudig te bedienen is, maar ook om hem zo te bouwen dat hij nog vele jaren trouw zal blijven werken.
Neem rustig de tijd om, voordat je je nieuwe LITTLE GRISTLE aanzet, eerst deze gebruiksaanwijzing zorgvuldig door te
lezen. Bedankt en veel succes met je nieuwe LITTLE GRISTLE!
LET OP:
* LEES DEZE GEBRUIKSAANWIJZING AANDACHTIG DOOR, ALVORENS HET APPARAAT
IN GEBRUIK TE NEMEN.
* ER ZIJN BINNENIN GEEN ONDERDELEN DIE DOOR DE GEBRUIKER GEREPAREERD
KUNNEN WORDEN.
* LAAT REPARATIES UITSLUITEND DOOR EEN GEKWALIFICEERDE VAKMAN
UITVOEREN.
WAARSCHUWING:
* NIET DE BEHUIZING VERWIJDEREN, VANWEGE HET RISICO VAN EEN ELEKTRISCHE
SCHOK.
* STEL DE VERSTERKER NIET BLOOT AAN REGEN OF VOCHT, OM BRAND- OF
SCHOKGEVAAR TE VOORKOMEN.
* DIT APPARAAT MOET WORDEN GEAARD.
* DE BUIZEN ZIJN HEET. NIET AANRAKEN ALS HET APPARAAT AAN STAAT
FRONTPANEEL FUNCTIES
[1] INPUT: Ingang voor alle typen instrumenten, b.v.
gitaren met enkelspoel, humbucker of actieve
elementen.
[2] EXTRA: Geeft extra versterking (gain) waardoor
je meer vervorming krijgt.
[3] GRISTLE:
Een cleane sound krijg je in de laagste standen (1-4),
boven stand 4 onstaat steeds meer sustain en echte
buizen eindtrapvervorming.
[4] TONE: Klassieke passieve toonregeling om de
hoge tonen sterker of zwakker te maken.
[5] MORE: Regelt het totale volume
[6] REVERB: Regelt het volume van de
ingebouwde galmveer.
[7] CAB FILTER ON/OFF: Hiermee schakel je het
special speakersimulatiefilter [8] aan of uit.
[8] REC/PA
Dit is een uitgang die je kan gebruiken voor
opnames, of om je geluid direct naar de PA te sturen.
Het signaal komt van de speakeruitgang, zodat de
specifieke buizenkleuring van de eindversterker
meegenomen wordt. Dit signaal wordt door een
speciaal filter bewerkt, dat de typische
opnamesituatie nabootst van een microfoon voor een
gitaarspeaker.
Het signaalniveau is -10dBV (line level).
[9] STANDBY SCHAKELAAR: Zet de versterker in
de ‘rust/standby’ stand, of in de Low Power / Full
Power ‘werk’ standen.
In de ‘rust/standby’ stand (Standby) blijven de buizen
warm, maar werkt de versterker niet.
In de Low Power stand levert de eindtrap maar 1/3
van zijn vermogen waardoor je op een laag volume
toch eindtrapoversturing kan krijgen.
In de Full Power stand levert de eindtrap het
aangegeven vermogen (12 Watt)
[10] POWER SCHAKELAAR: Schakelt de
netspanning 'aan' (rode LAMP aan) of 'uit' (rode
LAMP uit). In de ‘uit’ stand is de versterker helemaal
afgeschakeld.
Laat, na het aanschakelen, de buizen altijd even
(5-10 seconden) warm worden voordat je de
versterker in de Low of Full Power stand [9] zet.