BASSFACE DB4.3 User manual

DB4.3 4/3/2 Channel Class D Bridgeable
Stereo 12v Micro Power Amplifier 200w
Verified RMS Power Output
Instruction manual

Thank you for choosing Bassface. From the simplest connector to our top of the range
amplifier - every element of these products has been designed to give you the best possible
performance for your money. Please take the time to read these instructions carefully as
they contain useful and important information. Modern high power audio systems can
generate voltages at the speaker similar to mains operated equipment – for some reason
everyone seems to ignore or forget this. Your wiring needs to be good to be safe. Please
remember this and take your time. Please exercise caution when setting volume levels –
powerful audio equipment can easily produce enough sound to permanently damage
hearing. Remember that audio competitors use ear protection when operating and
competing. Do remember that incorrect installation or abuse is not covered under warranty
– please make sure that your installation and any partnered product is suitable and
compatible. If you are unsure please seek qualified advice before proceeding. Always use
appropriate hand and eye protection when working with tools, and always work within your
capabilties as an installer. We offer a 12 month manufacturer warranty via your distributor
or retailer. Please retain your purchase receipt as proof of purchase. Please note that
Bassface operates a policy of continuous product development and we reserve the right to
change specification without prior notice. You can follow our process on our website by
reviewing the version history information.
Please note that we sometimes include information inside these manuals which we feel is of
potential value to the client on related subjects such as conversion charts, capacitance
values or wiring diagrams. Please feel free to copy any of this information since it is in the
public domain.

To begin, disconnect the car battery, taking note of any required precautions suggested by
the vehicle manufacturer such as alarm or radio codes, or on board computer or AGM
battery requirements.
For vehicles with front mounted batteries find a suitable point on the firewall/bulkhead to
run the power wire through. Where the cable passes through the metal it is absolutely vital
that a rubber grommet be fitted to prevent the cable from chafing through the insulation as
this would be a major fire risk. The positive wire needs to go to the + positive terminal on
the battery. A fuse of appropriate size to protect the cable needs to be fitted in line no more
than 18” from the battery.
Once you have the power cable in the car, run it back to the boot or to where you intend to
fit the amplifier. When you do this, be aware that you will need to run the remote turn on
cable and the RCA signal cable from the head unit back to the amp too.
If the wires you are running have to run over or go alongside other looms of the car, try to
cross them at right angles to avoid unwanted interference in the signal, and try not to run
them parallel with other cables either. If you can, run the power and the signal cables down
opposite sides of the car. This isn’t essential but if you do get any interference once the job
is complete the first thing to look at will be separating these wires so if you can do it first it
makes a lot of sense!
The absolutely most important aspect of the power install is the earth wire. This wants to
be very securely bolted to the chassis of the car. We recommend drilling a hole (take care
not to drill through your spare tyre, brake lines or anything else) in the boot floor and sand
off any paint to the bare metal where the wire will be connected. A bad earth is a very
common flaw in installation and can cause a number of headaches later down the line so be
sure to take care in doing this. Do not use a self tapping screw to secure the earth down, as
it will probably soon come loose and impair performance. Other common disasters include
trying to earth to rear light mounting bolts, boot lock mountings and other ways to “trap”
the cable in the hope you might get a good earth. For every volt the amplifier doesn’t see it
requires twice the power to create the same output which means poor performance and a
possible broken amplifier. Once the work is complete neatly repaint the over the finished
bolted connector and chassis of the car with some primer to prevent corrosion.
We would like to make clear that the current demands of modern high power car audio are
highly significant, and dependant upon the speaker loads, gain levels and supply voltage.
We make every reasonable attempt to publish test results showing the likely current
consumption of each of our amplifiers, and we urge installers - even ones engaged in
modest car installations - to make provision for these current demands. Poor power supply
planning and a failure to provide sufficent energy to run the amplifiers is amongst the
number one reason for premature (or instant!) failure of the unit. It can also destroy
speakers, source units and even cause fire.
On a related matter, we have been made aware of the use of Bassface products in
situations where bench power supplies (or power supplies that are not a conventional car
battery/alternator) are used to power our products. From a purely technical standpoint
there is no good reason why this cannot be accomplished successfully BUT it is absolutely
critical that current provision is made with reference to the appropriate test estimates. We
need to make clear that due to the number of possible technical hurdles we are unable to
extend warranty to any kind of installation where the power source is not a 12v

car/alternator combination that meets necessary requirements.
It is also very important that a power amplifier is not used without an appropriate speaker
load on each channel. The design of each amplifier is different, and so some amplifiers will
tolerate running with open circuit channels, wheras some absolutely will not. It is easy to
quickly damage an amplifier if channels are left open. Always make sure minimum
impedance requirements are met. The most common examples we see are four channel
units where one half of the amp is used to run a pair of speakers or a subwoofer (even
worse) and the other side is left undriven. This will almost certainly destroy components on
circuit board resulting in smoke/fire/certain failure of the amplifier. We have also seen
similar incidents where mono amps have their load removed (subwoofer taken out of the
boot on a quick release) but where the remote cable still powered up meaning the amp is
receiving a full signal! This is also likely to fill your car with expensive smoke. It goes
without saying, but we will say it anyway, that this is yet another warranty void situation.
(And like all the other ones, it is easily avoidable!)

The first step when installing an amplifier is to lubricate the terminals. The reason for this is

that sometimes, the plating applied to the screws can rub off slightly in the threads,
causing binding. This can then result in damaged threads and/or rounded screw heads. We
recommend the use of a medium thickness general purpose oil. In the UK there is a product
known as "3 in 1" oil which we like to use in the workshop, but any reasonably thick,
decently penetrating oil will work. We do not recommend the use of spray lubricants for this
job because they are too thin, wont penetrate the threads and can contaminate the
cosmetic surface of the product. Also, whilst it might sound like a simple and obvious thing
to say, please make sure that you use the correct allen key or screwdriver when operating
the amp terminals. The screws are made from relatively soft material, and can very easily
become rounded and damaged over time. We see this ALL the time in our repair centre, so
we KNOW that some of you don't read these manuals! Thanks for being one of the careful
ones.
Once your power cable, RCA and remote lead are all securely running through the car to
where you want the amp and the earth wire is fastened securely, somewhere close to the
amp, you can fit the amplifier. If applicable don’t forget to fit the amplifier remote control
wire and any speaker wires running forwards at the same time.
The amp should be mounted on a solid surface such as a boot floor. Wherever you do
choose to mount the amp, it needs sufficient ventilation; 2-3” around will be enough. (In the
case of the DB4.3 which uses a very modern chipset it is acceptable to allow less room
around the unit as long as the heat sink or any part of the body of the amp is not touching
or chafing.) The DB4.3 must not be mounted on a bass box as the vibrations can cause
damage to the internals of the amplifier over time.
You need to ensure that the load you subject your amplifier to is within specification and of
a sensible nature and that you have the appropriate cooling where applicable. It is your
responsibility to ensure the amp is kept at a sensible working temperature. Vertical
mounting or “hot boxing” can cause severe damage to the amplifier. Also take care
mounting an amp onto a board that has been covered in carpet. This can restrict airflow
under the amplifier, limiting the amount of convection cooling that can be achieved and
insulating the amplifier underneath which can build up heat inside the amp. For
installations that are space compromised the installer can add small PC style fans to
circulate air.

When choosing a speaker impedance remember that bridging a pair of output halves the
impedance – So a 4 ohm woofer bridged the amp sees 2 ohms per side. This is the
minimum safe loading for the DB4.3, accross bridged channels.
Also please remember that it is bad practice to run only "half" of a 4 channel amplifier and
leave the other "half" not connected to anything. This can cause the amplifier to fail on the
undriven channels over time. If you want to run only 2 speakers from a 4 channel amplifier
always bridge the outputs so that there is load on all four.
Time to lay on some power. We recommend a good quality, minimum 10AWG but
preferably 8AWG cable set. Note that cheap cable sets are often very large at first glance
but when you pare back the insulation you are left with very little power cable! Even worse,
sometimes, you're left with not very much quite poor quality power cable! Try the Bassface
PWK8.1 as an excellent option although any reputable manufacturer can be relied on for
cable supply. Connect the earth first, then 12V power, then remote. If you are going to use
the low level inputs then connect in the RCA cables and you can move onto setting up
sound controls on the amplifier. If you are going to use the high level inputs then connect
the black molex plug and make the connections to the vehicle speaker cables, ensuring
that the polarity is observed correctly. If you accidentally make a connection to the inputs
the wrong way around you will have an out of phase condition on the input side which will
severely reduce performance.
When connecting the high level inputs please observe the following connections:

FRONT RIGHT SPEAKER to FRONT RIGHT INPUT, for both + and -
FRONT LEFT SPEAKER to FRONT LEFT INPUT, for both + and -
REAR RIGHT SPEAKER + to REAR RIGHT INPUT +
REAR RIGHT SPEAKER - TO REAR RIGHT INPUT-
REAR LEFT SPEAKER + to REAR LEFT INPUT +
REAR LEFT SPEAKER - to REAR RIGHT INPUT - (Note this carefully - you have 7 pins and 8
connections to make!)
Setting the “Gain” or “level” on the amp is a crucial aspect and needs to be done with care,
otherwise you can easily damage your equipment. Before we move onto this we need to be
sure the crossover settings are right for the application.
Crossover settings
If you have an active crossover elsewhere in your system (such as the head unit) then you
may wish to set the crossover switch on the amp to OFF/FULL RANGE. Otherwise, in most
cases, this must be set to ON and the controls adjusted appropriately.
For subwoofer installation and setup we recommend a LPF of about 100hz initially as an
excellent starting point for most car woofers. Try 80Hz and 120Hz too – you will notice the
sound change. If you are running a 15 inch woofer then you will want to be looking at a
lower crossover frequency (like 80Hz) – if it’s an 8 inch driver then you may want to go up
to 120, 150 or even higher.

For other speakers if you are using a woofer, try to keep the HPF the same as the woofer
LPF. If you are using no woofer then a full range setting might be more appropriate. A
typical six inch driver will play from 100Hz and up. A four inch driver around 200Hz and up.
Once your crossover settings are set up, you can move on to the gain or “Level”. Before
you do anything else, please ensure that any bass boost controls on the head unit or
amplifier are set to 0 / flat / switched off. We also suggest you turn the bass remote level to
a mid setting to allow adjustment later to taste.
Gain / Level adjustment
Now it is time to disconnect all other subwoofers or speakers so that you can hear only the
speakers powered by this part of this amplifier. Next, turn the level on the amp all the way
down. Choose some music that you’re not particularly keen on that has a good range of
bass, treble and vocals (helps not to get lost in the music whilst you work on the system.)
Then go to your head unit and gradually turn up the volume until you begin to hear slight
distortion from the driver. This is normally about ¾ the way up the scale. This is the
maximum setting that you will EVER use from now on – make a mental note of it. Next, turn
the head unit down from here by around ¼. This builds in a little bit of “headroom” so
should you have a track that is recorded quieter than the others or is at a lower bit rate,
you can boost the volume without pushing anything into distortion.

Once the volume is set on the head unit, go to the amplifier and slowly start to turn the
“Level” knob up, keep going till it is at a level you are happy with (that isn’t going to deafen
you!) or until your driver(s) are just about to distort. If they do start to distort, turn back
down till they sound perfectly clear.
One thing that you need to learn is how to actually hear a speaker “distort”; you may hear
a cracking, a metallic slapping sound or a rattle as well as just that thrashing distorted
tone. It is CRITICAL that you detect this sound and back the amp off to stop it NOW before
you damage something/everything.