PJB BRIEFCASE User manual

PJB BRIEFCASE
OWNER’S MANUAL

CONTENTS
Read This First -------------------------------------------------------------Page 2
Overview of the BRIEFCASE-------------------------------------------Page 3
Front & Back Panel Diagrams------------------------------------------Page 4
Front & Back Panel Description----------------------------------------Page 5
Getting Started-------------------------------------------------------------Page 8
Operation & Positioning--------------------------------------------------Page 8
Operation and Positioning-----------------------------------------------Page 9
Transporting & Storing the BRIEFCASE---------------------------Page 10
Using the BRIEFCASE with a Battery-------------------------------Page 10
Battery Types and Suppliers-------------------------------------------Page 12
Specifications---------------------------------------------------------------Page 14
Simplified Schematic------------------------------------------------------Page 16
Service/Warranty Information-----------------------------------------Page 17
1

Thank you for purchasing the PJB BRIEFCASE. A great deal of
dedication and passion went into designing and building this no-
compromise, high performance compact-combo amplifier. It was
concieved to be a dedicated amplifier for the “connoisseur” bassist.
Reading this manual will enable you to get the best performance from it
so that you may enjoy many years of service.
READ THIS FIRST
• Before using the BRIEFCASE please read ALL the instructions.
• On reciept of product, check for any signs of physical damage
arising from shipping. If any damage is visible contact your dealer.
• Keep all original packing.
• Never use this product in the vicinity of water. If the BRIEFCASE
were to get wet, it could kill you by electrocution.
• Do not use this amplifier in a way that would compromise its
ventilation system. Never block the air intake or fan output.
• Do not locate this amplifier near any heat source.
• This amplifier must be connected only to a power source specified
in this manual.
• For safety do not leave the amplifier plugged into a power source
for long periods of time when not in use.
• Do not let any liquid or foreign objects fall into any openings on
the amplifier.
• Never use this amplifier if it has:
1. suffered any physical damage.
2. been subjected to any liquids, rain or moisture.
3. damaged cables connected to it.
If any of the above occurs, the amplifier should be examined by
qualified service personnel.
• Always operate this amplifier with the correctly rated fuse.
• Never use this amplifier without proper grounding.
2

OVERVIEW OF THE BRIEFCASE
The BRIEFCASE is not your usual combo-practice amp. The most striking difference
between this combo and others is that it features an extremely clean and powerful
amplifier and full range compact speaker that can run on AC or DC power. It can accept
voltages from 100 to 240 volts by using the voltage selector switch, can run on an
internal lead acid gel battery (not supplied) or even an external 12V DC source such as a
automotive starting battery.
Though it is a dedicated bass amplifier, this unit will work ideally for other instruments,
particularly acoustic variety due to its natural hi-fi sound character. This unit is also an
ideal upright bass amplifier.
The two 5 inch proprietary PJB drivers have been acoustically optimally loaded by
precise computer analysis to provide a full-range, dynamic sound that can play down to
an open E string with ease. The BRIEFCASE can handle an open B string if not too much
bass boost is used.
FEATURES
• Switchable Active / Passive input
• 5 Band Graphic EQ
• Optical Limiter
• Headphone Output
• Pre-amp Output
• Balanced Line Output.
• Drives Speakers 4-16 Ohms
• Dual AC Voltage Operation
• Works on 12V Rechargeable Battery
• 12V Charger Input
• Smart Battery Management
• Sophisticated protection circuitry
• Special “Soft-Clipping” 100watt Amplifier
• Ultra low noise pre amplifier circuit
3

FRONT & BACK PANEL DIAGRAMS
4

FRONT & BACK PANEL DESCRIPTION
1.POWER ON/OFF SWITCH.
This switches the main power on and off in the amplifier. When the power is switched off
and the unit is still plugged into a power source it will be stand by, so please do not leave
the amplifier plugged into a power source for long periods of time when not in use.
2. POWER LED INDICATOR.
With power switched on the LED light is green. When the amplifier’s protection circuits
have switched it off it will be illuminated red.
3. LIMITER ON/OFF SWITCH.
Sends signal through limiter or bypass.
4. LIMITER INDICATOR.
This blue LED will light up when the signal is being compressed. This will vary on how
hard the instrument is played and how the threshold is adjusted
5. COMPRESSION ADJUSTMENT LEVEL.
This will vary the level the limiter threshold. The compression ratio is 3dB to 1. Adjust
this to suit your playing style and output power of your instrument.
6. HEADPHONE OUTPUT JACK.
This jack accepts ¼ inch stereo headphone jacks. When a headphone is connected to the
jack, the speakers will still be connected to the sound. If you want to play on headphones
only, then simply disconnect the speaker cord at the back.
7. PASSIVE/ ACTIVE BASS INPUT SWITCH.
This switch allows you to match the BRIEFCASE to match either active or passive
basses.
PASSIVE - Higher sensitivity, high impedance input (125mV/4.7M). For bass
instruments that do not have active electronics, suited for older ‘vintage’ basses. This
setting is precisely matched to high impedance pickups enabling them to faithfully
reproduce the true frequency and dynamic range of the instrument.
ACTIVE- Lower sensitivity input setting (300mV) for basses with onboard electronics.
Input matched for low signal to noise ratio and optimum transfer of electrical signal from
modern high-end basses.
8. INSTRUMENT INPUT JACK.
This is a standard ¼ inch mono jack socket.
9. VOLUME CONTROL.
This is the master volume control and it controls how much power you send to your
speakers as well as the line out socket on the back of the amp. When setting up your tone
or plugging in your instrument, you should keep this control at a low level. All
5

instruments are different when it comes to how much output is from the pickups.
Likewise for players, depending on how hard or soft you play.
If your bass have a high output, then it could be possible to achieve the maximum volume
from the BRIEFCASE with the volume control set in a low position. If you increase the
level on this control, you will only add distortion which can damage the speakers.
10. 5-BAND GRAPHIC EQUALIZER.
This is a dedicated bass instrument equalizer designed to give you optimized tone of your
instrument. The frequency bands have been set precisely so that your desired tone can be
achieved with the minimum amount of sliders. The EQ filters are set at: 50Hz 160Hz
630Hz, 2.5KHz and 12KHz with 18dB of boost or cut. This EQ has a lot of control on
your sound so do not use too much boost, particularly on the 50Hz or 160Hz bands as this
will greatly limit just how much headroom you have.
11. XLR- DIRECT OUTPUT SOCKET.
This is an ultra-low impedance (200Ω) balanced line out for use with recording or PA
mixing consoles. This output is not controlled by the volume control. Changing the level
on your instrument will however, vary the DI output.
12. PRE AMPLIFIER OUTPUT JACK.
These are used for driving a second amplifier such as the M-500 or the PJB S-1000 slave
amplifier or even a tuner.
13. LOUDSPEAKER OUTPUT JACK.
The BRIEFCASE will work on any load from 16down to 3, which is the safe
maximum load for this amplifier. The internal speakers are 4. So if you are considering
using an extension speaker, you should not connect up the internal speakers at the same
time.
14. LOW VOLTAGE FUSE.
This is a 15amp 32 volt automotive fuse same as found on motor vehicles. It protects the
low voltage DC circuits in the BRIEFCASE. Never use a higher current rating fuse.
15. 12 V DC- BATTERY CHARGING SOCKET.
This socket is for use when the BRIEFCASE is utilizing an internal battery. The battery
can be charged up in a vehicle from a standard 12 volt socket (cigarette type). A cable is
supplied for this purpose. DO NOT ATTEMPT TO USE THIS SOCKET TO RUN THE
AMPLIFIER, ONLY USE IT FOR CHARGING PURPOSES ONLY. The current drain
of operating the amplifier is beyond the current capabilities of this socket.
16. 12 V DC- BATTERY INPUT TERMINALS.
This is the DC power feed to the BRIEFCASE amplifier. If you are using the internal
battery then these terminals must be connected to the lower battery terminals with the
link supplied. An external Heavy Duty 12volt automotive battery can be connected to
these terminals.
6

The wire between battery and terminal must be at least 12 amp rating and connections
secure and tight. The battery polarity (+ and –) must be connected correctly.
17. AC INPUT SOCKET/FUSE.
Connects the amplifier to AC power supply. Always use a grounded plug and make sure
the AC cable is more than 3A rating at 250-volt AC. If you require a longer AC power
cord, we recommend the PJB heavy duty 20 foot power cords. These are available as an
accessory. Use a slow blow ¾ inch fuse rated at 1 amp 220-240V or 2amp fuse for
110-120V.
18. AC INPUT -VOLTAGE SELECTOR.
Switches the amplifier to run on either 110-120 volt or 220-240 volt AC power. Never
try to run the amplifier on a 220-240 volt supply when switched to 110-120 volt. This
can possibly cause major damage to the amplifier.
19. INTERNAL BATTERY FUSE.
When the BRIEFCASE has the internal battery installed, this fuse protects the battery
should it be overloaded due to a short circuit.
20. INTERNAL BATTERY TERMINALS.
This is the output of the internal battery. Do not connect these terminals to anything
other than the DC input terminals of the BRIEFCASE amplifier.
21. LOUDSPEAKER INPUT JACK.
This is the input jack to feed the BRIEFCASE internal loudspeakers. The impedance is 4
ohms. These speakers must be connected via the short speaker link cable (provided) to
the BRIEFCASE speaker output jack. If you do not want sound from the speakers such as
playing through headphones only, then disconnect these speakers from the amplifier.
22. INTERNAL BATTERY TERMINAL LINKS.
These connect the output of the internal battery to the DC input of the amplifier. Make
sure these are never touching each other nor have any contact with other metal
objects.
7

GETTING STARTED
BEFORE SWITCHING ON POWER – Check that the voltage selector is set to the
correct voltage in your country. (110volt-120volt USA / Japan or 220-240V Europe/
Australia.)
ALWAYS USE A HIGH QUALITY GROUNDED AC POWER CABLE. NEVER
USE THIS AMPLIFIER WITH THE GROUND CONNECTION REMOVED. We
recommend you use original PJB cables.
OPERATION & POSITIONING
TURN THE VOLUME DOWN on the BRIEFCASE before plugging in your
instrument.
Keeping Cool
The amplifier needs a constant flow of cool air to maintain an optimal working
temperature. If it does not get the proper cooling it needs, it is possible for the amplifier’s
thermal protection circuits to operate and turn off the amplifier. The protection works on
temperature and current workings in the amplifier’s output transistors and power supply.
AC power can vary from region to region and time of day due to electricity demand. Also
because the amplifier uses forced air-cooling, the operating temperature of the amplifier
will vary somewhat due to the room temperature you are playing in. If the amplifier can
not get enough ventilation, the protection circuits could shut the amplifier off to protect
the amplifier from damage.
Positioning the BRIEFCASE for Best Sound
Often, playing in different venues will cause your bass to sound different. This is partially
due to the acoustics of the hall influencing the low frequency waves that are coming from
your speaker. Bass waves are large and room dimensions heavily influence them when
the walls reflect the sound waves, causing them to collide by adding together or canceling
each other out. This causes some fundamental notes (the ones you feel more than hear) to
ring out louder than others and some notes not to be heard at all.
8

Here is an indication of where fundamental bass frequencies are, showing open string’s
approximate frequencies and acoustic wavelength:
F# string 24Hz 46 feet
B string 31Hz 36 feet
E string 41Hz 27 feet
A string 55Hz 20 feet
D string 73Hz 15 feet
G string 98Hz 11 feet
C string 130Hz 9 feet
This may give you some indication of the offending notes (frequencies) that may be
booming or resonating louder or quieter than others. For example if your speakers are
five feet from a wall, the open A string may sound weak. That could be because the path
length of the reflected sound off the wall from your speaker is exactly corresponding to
half a wavelength on the open A string causing at that particular note to cancel out.
Where you position the BRIEFCASE will ultimately affect your low frequency limit. For
best results keep the BRIEFCASE on the floor. Placing it on objects off the floor will
cause it to sound thin and lack bass punch. Placing the BRIEFCASE with the back close
to a wall will help reinforce the lower notes. Placing it in a room corner, with the rear
vent firing into the corner, will further enhance the low notes.
Room size makes a large difference in how deep the bass will sound. The further the
distance to the listener the less the bass will be. This is due to the physics of acoustics not
the unit itself.
Unfortunately for bass players, low frequencies are always very difficult to control with
room acoustics. The reproduced wavelengths of the notes you are playing often
correspond to the room dimensions, in which case the reflected sound off the walls
interferes with the sound from the speaker as you get further away from it.
Setting Up the Limiter
Although a limiter is not essential to bass amplification, it can be a useful tool in
smoothing out the character of your instrument or playing style. The BRIEFCASE limiter
has a preset compression ratio of 3 to 1. For each additional increase of 3dB above the set
threshold, the increase in level is actually 1dB. So the dynamic range of your instrument
is reduced.
First set up the limiter by having the compression control (5) set fully clockwise. Now
switch on the limiter (4). Start playing and turn control (14) counter-clockwise. You will
see the blue light start to come on and that is the indication that the limiter is now
working. Set this control to suit your taste.
9