Zed Audio Kronos Parts list manual

Instruction and Installation Manual
KRONOS
LEVIATHAN
Designed and manufactured in the
United States of America

Index
Introduction and Technical talk Page 1-10
Installation Procedures Pages 11, 12
Specifications Page 13
Installations Pages 14 to 24
Installations Pages 25 to 36
Fault finding Page 37
Warranty and Return Policy Pages 38 and 39
Upcoming products Page 40
KRONOS
LEVIATHAN
Features of and
* Super high quality RCA sockets
* Pre amplifiers use Burr Brown chipsets standard.
* Every audio IC has its own rail decoupling components for minimal RF interference.
* All coupling capacitors are bypassed with film types for superior high frequency
response and detail.
* All power supply capacitors are low ESR types rated at 105 deg C.
* All gain dependent circuits use 1% low noise metal film resistors.
* Almost all resistors and capacitors are SMD types (Surface mount) for higher reliability.
* Clipping LEDs on every channel allows set up and help prevent amplifier clipping.
* Power supplies use TO-247 packaged MOSFETs each with 110A capability.
* Front end pre amplifiers use their own fully ground isolated power supply for ultimate
S/N ratio and noise rejection.
* The pre amplifiers run fully balanced to the class D power amplifiers.
* The class D amplifiers utilize our DELTA BRIDGE feed back design.
* has additional circuits which monitor the impedance of the speaker and if the
impedance drops to an unsafe value the power supply is instructed to limit the power.
* All level controls use parallel elements for lower wiper noise and redundancy.
* has a total of five regulated power supplies and has seventeen,
yes 17 regulated power supplies.
*The main high current supplies use the MOSFETS in the follower mode for higher
efficiency and wider bandwidth.
KRONOS LEVIATHAN
KRONOS
KRONOS LEVIATHAN

For those of you who have used our previous products, much of the information in this
manual will be familiar. We have added some new interesting titbits. Over the past four years
since the first Zed amplifiers were introduced, several events have occurred which have
moved us into a new dimension of mobile amplification.
The cost of gasoline has skyrocketed and for those of you who believe that $2.50 gasoline is
here to stay, well there is a big shock waiting just around that little corner. The world’s car
manufacturers are now forced to make smaller cars, as they have done for many years in
Europe and the far East. This means smaller electrical systems due to the smaller engines
are being used. Hybrids are cut from the same cloth in terms of the available electrical
power.
Well you may ask, what has this got to do with mobile amplifiers? Everything! The
electronics now must smaller, lighter, more efficient and of course less expensive.
Unfortunately these things do not always go hand in hand. The need for high powered
amplifiers has not diminished. Power hungry speakers and power hungry consumers prowl
the back alleys of mobile sound.
So what is required are amplifiers that use the available electrical power more efficiently
BUT with no loss of fidelity or power. Several options are available. Class B amplifiers are
notoriously inefficient due to the fact that they are linear devices and in their traditional form
waste about 70-80% of the power supplied to them as heat. Class A amplifiers do not even
think about for mobile use as their efficiency is even worse. So what options are available?
Class D is the one of them. For most audio buffs, class D has been given a bad rap owing to
the rash of really bad class D amplifiers which have been introduced to the mobile market
over the years. There are several reasons why these amplifiers sounded bad and were
unreliable. The bad sound was due to the fact that the designers/copycats had no idea on
how a class D amplifier functions. The reliability was due to bad design and almost zero
knowledge of class D amplifiers.
This technology has made leaps and bounds over the past 5 odd years. New semiconductor
devices have become available as well as a better understanding of this type of amplifier.
OK let’s get into some real “deep” issues. ALL amplifiers are basically power supplies! This
will shock almost all who read this. Audio amplifiers are really a valve between the actual
power supply and the speaker. This valve is “told” by the incoming audio signal to allow a
given amount of the voltage + current from the power supply to reach the loudspeaker
dependent solely on the amplitude and polarity of the incoming signal. This may blow away
the pre conceptions of all who read this of what amplifiers really are. Remember there are
two main components in any amplifier, a power supply which is the sole source of power and
the “amplifier” which channels the power from the power supply by virtue of “commands”
given by the driving audio signal. With this said let’s see what’s cookin’ inside our black
boxes.
Page 1

So with these facts established our class A or class B amplifiers channel power supply
energy to the speaker but waste a lot of energy performing this feat.
Class B amplifiers can be made more efficient by using some smart power supply
technology. The “enemy” of the class B amplifier is the value of the power supply voltage
required to deliver the specified output for that particular power.
The technologies available are beyond the scope of this manual but more about this issue
Is available on our website at www.zedaudiocorp on the Techtalk link.
Now back to our class D (not digital) amplifiers. These, as our analog cousins, are again
power supplies BUT with a difference. They are Pulse Width Modulated (PWM) power
supplies whose reference voltage is the incoming analog signal, ie a variable signal being
music or sine waves which changed the width of the pulses. Sounds nice of course but
due to the fact that the PWM operates at a very high frequency of typically greater than
250KHz in full range class D amplifiers, we use a reconstructive filter to remove the
carrier frequency.
I would like to find the people who listen to sine waves. I am still looking! We all listen to
music. Well music is transient in nature and the average signal level varies over quite a
wide dynamic range. Thus our cuddly class D amplifier is NOT being driven at its optimum
Please read this paragraph very carefully. When typical bench testing of amplifiers is
performed we generally use sine waves, a quite severe torture test for almost all
amplifiers. The stress on both the power supply and the actual amplifier is far greater than
with music or speech. Typically any amplifier driven to 1/8th of its absolute clipped power
(1% THD) with sine waves, expends the same energy as music driving the amplifier to
clip occasionally. Easy to verify, We use pink noise (Google it and see what it really is) to
simulate music and this proves, at least to us that pink noise driving the amplifier to clip
occasionally is the same as that 1/8th power deal. What this is all about is that the peak to
average ratio of music is between 10 to 15 percent. In other words your 1,000w brand
spanking new mega Dollar amplifier is only a very good 100 to 150w amplifier which is
capable of musical peaks of 1000 watts ASSUMING that just occasional peaks of the
musical waveform are clipped! You have all been duped over the years by the power
issue. Now I must add this: When playing certain types of music there are times where the
musical signal is remarkably similar to those brute force sine waves us engineers like to
use for testing. Pipe organ music, of which I am a fan is one of these. A sustained organ
note drives the amplifier much harder than typical music almost like a sine wave.
Now for another “bombshell”. Class D amplifiers are NOT 90+% efficient as advertised by
pretty much all companies who tout their wares. A well designed class D amplifier will be
90+% efficient based on two conditions. First that the amplifier is driven into some
optimum impedance (typically greater than 2 ohms) and secondly that the amplifier be
driven with a sine wave at just below clipping (typically 1% THD). Mmmmmm well this
now opens a new can of worms, does it not?
Now for another “bombshell”. Class D amplifiers are NOT 90+% efficient as advertised by
pretty much all companies who tout their wares. A well designed class D amplifier will be
90+% efficient based on two conditions. First that the amplifier is driven into some
optimum impedance (typically greater than 2 ohms) and secondly that the amplifier be
driven with a sine wave at just below clipping (typically 1% THD). Mmmmmm well this
now opens a new can of worms, does it not?
Page 2

Output level all the time, in fact very rarely. So referring back to the fact that the average
level is about 10-15% of the maximum or peak power of the amplifier, the efficiency is
substantially lower than the 90+%. Typically with a class D amplifier this figure is around
75-85% which is an order of magnitude better than class B amplifiers. This ability of a
class D amplifier makes it a far more viable choice than class B amplifiers for producing
efficient or green (might I say?) amplifiers.
The impedance of the speaker also determines the point at which the efficiency is
optimized. Well as was said on a famous TV show “FOREGETABOUTIT”, this is a pipe
dream. Speaker’s impedance curves are all over the map and too many car audio buffs
love to drive their megawatt class D amplifiers into low impedances, like 1 and 2 ohms.
Well now that I mention “1 ohm”, I cannot resist getting into this subject. Scenario: Kid
buys gizzilion watt amplifier with manufacturer’s specifications of x watts into 4 ohm, y
watts into 2 ohm and z watts into 1 ohm. Well let’s take a wild guess and I bet you all that
the vast majority will drive the amplifier into 1 ohm. Why? Easy, he feels that he is getting
his “moneys worth” by doing this. OK let’s see what reality is. Said amplifier is maybe
rated at say 600w into 4 ohm, 1000w into 2 ohm and 1500w into 1 ohm. We will assume
that the speaker impedance is resistive. The difference between the 4 and 2 ohm power is
2.2dB, the difference between the 2 and 1 ohm power is 1.76dB and the difference
between 4 and 1 ohm power is 3.9dB. So what do these numbers tell us. First if the
speaker is 4 ohms vs 2 ohms, no way you can hear any difference. Same issue
comparing 2 as to 1 ohm. I grant you that between 4 and 1 ohm there is almost 4dB
difference BUT at what price. Two issues. Low impedance loads affect the amplifier’s
sound quality adversely and this is quite easy to prove. Load an amplifier with a 4 ohm
woofer and listen. Add parallel resistors to the speaker to make the amplifier “think” that it
is driving a low impedance speaker and listen to the difference in sound quality. You will
be surprised. This test is not 100% valid in fact as the resistive loads added, let the
amplifier off the hook as the reactive components of the load are confined to the 4 ohm
part. The idea of this test is to keep the loudness about constant but load down the
amplifier.
The average person can just perceive a 3dB (doubling of power) difference and to
actually double the sound pressure on your eardrum, you require TEN TIMES the
amplifier power. Yes TEN TIMES no kidding!
The other consequence of driving amplifiers into these ridiculously low impedances is that
the amplifier is stressed substantially more as compared to when driven into more sane
impedances. Efficiency drops as the losses in the output stages increase dramatically
even with “super efficient” class D amplifiers.
It serves ONLY to boost the ego of the owner of the car so he can quote numbers to his
buddies.
We at Zed are absolutely against these silly loads of less than 4 ohm.
Page 3

Our design philosophies have been influenced by both the professional and home audio
markets. Traditionally the professional market has been driven by reliability with sound
quality as second. The home market was the reverse. Today however both reliability and
sound quality carry equal weight in both sectors. Cosmetics for obvious reasons are
important in any sector. My experience in designing and building professional amplifiers
has helped me in taking a similar approach in the design of mobile audio amplifiers. No
matter how pretty or good sounding an amplifier may be, if it fails then it is a bad amplifier.
The lesson learned many years ago was “silicon”, and use lots of it. All things being
equal, if an amplifier drive circuit is stable, then adding an output stage (itself stable as
well) with enough power devices will make the amplifier reliable. This assumes of course
that mechanical issues are taken care of. Zed has always been a proponent of using a
generous amount of power transistors in the output stages of our amplifiers. In addition
we design at temperatures of 80 degrees Celsius. All semiconductors must be derated at
these elevated temperatures and we use enough power devices for safe operation into
the lowest load impedance the particular amplifier has been designed to drive.
Our personal opinion about “fancy” cables and exotic passive components may shock
some of you. I have never been able to hear the difference between a cheap or an
expensive RCA patch cord. My listening has been done using double blind A-B
comparisons. Electrons are not very clever things and they have no knowledge of the type
of material through which they are flowing at the speed of light (312,000 Km/second). The
ONLY reason we recommend high quality double shielded RCA patch cords in mobile
installations is to reject noise. My opinion about speaker cables is the same. As long as
the wire is thick enough, it’s construction makes no difference. As long as the amplifier is
stable into reactive loads with phase angles of up to 60 degrees, the amplifier is none the
wiser what type of speaker cable is used.
The use of teflon, polypropylene, tantalum or other capacitors does not make a good
sounding amplifier. There are too many other variables in the audio chain that one
capacitor can make a difference. The use of metal film resistors is only of use in low noise
circuits and where tolerance is of an issue. Never forget what the music signal had to go
through to get onto your CD or vinyl. The signal began as a micro volt specimen at the
microphone, sent through a high gain pre-amplifier, passed through equalization circuits,
possible compressors, limiters or other processing gear and then mixed with all the other
tracks. In analog days and today still, this signal was sent to a 24 track tape recorder
again through a multitude of transformers, pre-amplifiers, equalizers and yikes the tape
heads themselves. Then the signals were passed back through the tape deck’s playback
circuits including the equalizer for playback, then back into the mixing console for mix-
down to two track and then this was repeated again onto a two track tape recorder, then
sent to the cutting head amplifier where the masters were then cut. A torturous journey
one could say for this fragile audio signal.
Page 4

Semiconductors have more tolerance in their specifications than any capacitor or
resistor.
A well known fact is that different types of capacitors work better at certain jobs than
others.
Example, disc ceramic capacitors are better in high frequency compensation circuits
than film types. Film types work better in audio frequency selective circuits than ceramics.
So we at Zed choose our components to suit the application.
Our quality control (QC) program and testing procedures work well for us. Over the
years we have refined these processes to what we have today.
Our philosophy is to design around potential or real problems. If we feel that a particular
item could cause a problem now or in the future, we either change the design or
improve upon it. The goal is ZERO defects.
QC begins with the initial design. The electronic design goes through as many prototype
iterations as is necessary to make sure it is working the way we want.
These prototypes are bench tested, put in to vehicles, listened to both in the vehicle
and at home then retested on the bench. We bake them in ovens and retest again.
Heat is the enemy and we want to make sure that it will not hurt our products.
Mechanicals of course do not have to be put in an oven (we do anyway).
Fit and finish must be to our standard. Samples are minutely inspected for fit and finish.
Once we approve them only then can the hard tooling be done.
Each and every product manufactured at Zed is tested using Audio Precision test
equipment. Software is written for each type of amplifier and then on final test the amplifier
must pass these rigorous tests. If not it is rejected and returned to the production line
for repair. Samples are pulled from the line for further testing.
Mechanical inspection is done throughout the manufacturing process. Before each
amplifier is packed it is fully inspected again for any cosmetic flaws. Any damaged or
any part which is out of specification is replaced.
Zed takes pride in what we design and manufacture and we trust that this shows in the
final product.
Stephen Mantz
Page 5

Zed does not recommend the use of power distribution blocks for the purpose of
distributing the +12volt voltage to several amplifiers. The reason is that the vehicle’s
battery is the lowest AC impedance point in the power grid of the vehicle. We want each
amplifier to draw it’s current from this low impedance point. Thus any modulation on any
+12v power cable (which is inevitable) is then shunted to ground by the massive
capacitance of the battery. This is the reason that “star” grounding is used in grounding
circuits/equipment so that ground current is drawn from a common point and thus no
ground loop can occur. Fortunately for us, the body of a vehicle made of steel is so large,
and is thus a very low impedance path for ground currents, that it is not necessary to
ground all equipment at one point. In fact we do not advocate it at all as this would then
necessitate the head unit’s ground running all the way to the battery location and the
amplifier’s ground(s) also running all the way to the battery.
If multiple amplifiers are being used we highly recommend the use of separate ground
points at the amplifiers’ location. This spreads out the amount of current being drawn
through one bolt connection.
tiffening capacitors - These are of NO use with our amplifiers due to the fact that the
Samplifiers have fully regulated power supplies. The power supplies will compensate
for small volt drops which exist on the +12v power cable. The amount of current drawn by
a particular amplifier would drain a fully charged 1 Farad capacitor almost instantly.
Consider the theory. Energy(Joules) = Power(Watts) x Time(Seconds). The energy in a 1
Farad capacitor = 0.5CV.V= 0.5x1x12x12= 72 Joules. Let us assume an amplifier such
as Let us assume that we are playing it such that the channels(into 4 ohms
each) are just clipping on the loudest musical peaks. This means that we are delivering
500 watts on peaks. The amplifier’s average efficiency is about 60%. The peak to
average power ratio is about 10% so average power is 10% of 500 = 50 watts. The input
power is therefore 83 watts. If the 1 Farad capacitor was charged to 12 volt and we
remove the main source of power -- the battery, the amp would remain playing for 0.86
seconds! (Put the numbers in the formula (E=PxT above and solve for time T). Now
compare this to the battery. The amplifier will play for some hours (depends on actual
battery of course) as compared to 0.86 seconds! So what good is a 1 Farad capacitor?
KRONOS.
Page 6

Setting the controls on amplifiers
evel control - This control is the most misunderstood control on any amplifier. It’s sole
Lpurpose in life is to level match the head unit’s output voltage to the gain structure of
the amplifier so that the user can use the head unit’s volume control in the “best
physiological position”. To best understand this let us look at a simple example. Assume
that the head unit is rated at 1 volt output. Now what this means is rather ambiguous.
Does the head deliver 1volt with the volume control at maximum, at 75% or where?
Unfortunately no head manufacturers supply this information. Also it depends on the
modulation level of the program material. Be it a CD/Mini Disc or FM we have no control
of this specification. Most consumers never want the volume control to be turned past 3
o’clock (We use a traditional rotary control for reference since all digital controls do not
have the same amount of digits or “little blocks” on their LCD displays to show relative
volume level). On head units which we have tested the results are all over the page so we
shall assume the 3 o’clock position as the maximum we want the control to be turned to.
So far you can see that the need for level matching is critical indeed as there are no
standards from head manufacturers. So we now have this 1 volt level. What this means is
that the output voltage from the head will approach 1 volt on musical peaks. Let assume
we have an amplifier of 100 watts. This implies that we can deliver 20 volts across a 4
ohm load. Let us assume that the amplifier needs 1 volt in for the 20 volt out - a gain
structure of 20x. So in this case with the head delivering 1 volt on peaks, the amplifier will
deliver 100 watts into 4 ohms on the same musical peaks. Well this sounds all well and
good but we have a small problem and it is that all heads are not rated at 1 volt, and all
amplifiers have variable level controls. This actually means we can change the gain
structure of the amplifiers from “x” to “y”. With no standard levels we have to set the level
control on the amplifier to “match” to that of the head. We have tested no head units
whose output level corresponds with that of the printed specifications. Typically the output
level is substantially lower than the specification. Here is our recommendation. With your
favorite music playing set the amplifier’s level control to minimum (CCW) and set the
head unit’s volume control to 3 o’clock. Assuming all crossover controls have been set,
advance the level control on the amplifier until the music is as loud as desired. This is the
only way to do this without the use of an oscilloscope.
rossover and equalizer controls - The crossover controls must be set to suit the
Cspeakers being used.
The equalizer controls can be set by ear or with instruments. This is a personal
preference. Most users only have ears and not instruments so ears must suffice!
Page 7

amping Factor - This amplifier specification has been blown out of all proportion.
DWhat it means is the ability of the amplifier to resist a change in it’s output voltage.
The formula is DF= Speaker Z / Amplifier output Z (where Z is impedance). So many
manufacturers have claimed ridiculous, and often false damping factors. A damping factor
of 1000 implies that the output impedance of the amplifier is 0.004 ohms (4 ohm load).
The only way to attain this figure is to apply masses of negative feedback (or use positive
feedback) and too much feedback makes amplifiers sound harsh and clinical. Also
damping factor changes with frequency. The lower the frequency the higher the DF
number. Typically the DF can be ten times larger at higher frequencies.
Let us take this amplifier whose output impedance is 0.004 ohms (Zout). The speaker
circuit is a series circuit and the following impedances(resistances) are in series with this
0.004 ohms. Let us assume that this DF measurement was made at the amplifier’s
speaker terminal. The first extra contact resistance is the speaker wire to the speaker
terminal (WT ohms). Then there is that of the wire itself for two conductors (W). Next is
the contact resistance of the wire to the speaker terminal (WS). Next there is the contact
resistance of the wire from the speaker terminal to the voice coil (WV) and lastly there is
the DC resistance of the voice coil itself (DCR). So what we have is a series circuit with
the following resistances in series and adding up. WT+W+WS+WV+DCR+Zout.
WT,W,WS,WV and Zout are very small indeed. Certainly less than 0.1 ohms. Whoa, look
what has happened the EFFECTIVE DAMPING FACTOR has been reduced from 1000 to
40 by just taking into account those pesky unavoidable contact resistances. Now for the
cruncher, remember that the DCR is also in series and is typically 3.2 ohms for a nominal
4 ohm speaker. So we must add 0.1+3.2 = 3.3 ohms and now EFFECTIVE DAMPING
FACTOR is now a magnificent 1.212! (4 divided by 3.3)This is the real world. We see that
the DCR of the speaker swamps all other resistances in the speaker circuit and the 0.004
ohms amplifier output impedance is almost meaningless. It has been found that a DF of
about 20 is quite sufficient to dampen the voltage spikes from the speaker. An eye opener
this one is it not? Good tube amps sound marvelous - low damping factors!!
utput Power of Amplifiers - This spec has been so badly abused it is not even funny.
OPeak power, Maximum power, Transient power, RMS power these are titles that
have been given to the power spec of amplifiers. The above all mean nothing. Peak
power needs to be associated with a time period, Maximum power is just nonsense,
Transient power is even more nonsense and RMS power is just not a specification. The
ONLY meaningful way to specify an amplifier’s output power in watts is CONTINUOUS
POWER. The formula for power is: (RMS volts x RMS amps) or (RMS volts x RMS
volts/Impedance) or (RMS amps x RMS amps x Impedance). In each of these formulae
there is an RMS number multiplied by another RMS number (or by itself) and RMS x RMS
cannot = RMS. RMS means
root mean square and it is the same as saying 4 x 4 = 4 Which we know is not true.
The answer is just 4 with no root sign attached.
So THERE IS SIMPLY NO SUCH THING AS RMS POWER.
Page 8

ridging two channels of an amplifier is not a magical thing. Most are mystified by the
Bpower figures quoted under the “bridge” column. It is actually very simple. When two
channels are driving a common load, one channel is out of phase with the other by 180
degrees. So when one channel swings positive the other swings negative. There is a
catch however. Each channel “sees” fifty percent of the common load and that means that
each channel of the bridged pair must be capable of delivering current to this lower load
impedance. Thus a 4 ohm bridged load presents a 2 ohm load to each of the bridged
channels. The power into a 4 ohm load in bridged mode is twice the rated 2 ohm power
per channel.
otal Harmonic Distortion - This specification has for years been a benchmark with
Twhich to compare one amplifier to another. This is all fine on the test bench where
pure resistive loads are used and sinewaves are amplified. Unfortunately it tells us very
little about the audible performance of an amplifier. Today it is relatively easy to build an
amplifier with THD figures in the “triple oh” region, but what do they sound like. Normally
not very good. To obtain these low THD numbers all we do is design an amplifier with
high open loop gain. That is before negative feedback is applied. Once we apply a lot of
global feedback, we improve all measured parameters such as THD, Noise, Frequency
response, Damping factor. Our amplifiers are designed a little differently. We use very
little global feedback but rather optimize each stage with local feedback. This allows us to
design an amplifier with lower open loop gain and thus we only have to apply about 8dB
of global feedback. Ultra low THD was not our goal but rather an amplifier which sounds
the way we want it to. Other factors affect THD such as PCB layout, grounding and power
distribution to the amplifier channels. Our class A/B amplifier do however achieve very
low distortion due to the fact that we follow the “rules” and their circuit design is
conduscive to low distortion.
ecibel is a unit of measurement. A 100w amplifier has 3dB more power than a 50
Dwatt amplifier. This difference is just discernable. A 100 watt amplifier has 1.54dB
more power than a 70watt amplifier. This is not audible. I has been determined that to
hear a difference in “loudness” between to like designed amplifier, one must double the
power. To hear a doubling in loudness one must have TEN TIMES the power (10dB).
eadroom - This term does not refer to how much room there is above your head!
HRather it is a specification that signifies how good or bad the power supply is. Zed
Audio has NEVER quoted a headroom specification. Why you may ask? Simple our
amplifiers have no headroom, zero dB, zip dB, nada dB however you say it. A regulated
power supply does not allow the amplifier to have any headroom. A quote from a well
respected designer who said that amplifiers with many dB of headroom simply have
poorly designed power supplies, either through ignorance or to save costs. When one
sees a specification of an amplifier quoting a headroom figure of 3dB this means that the
droop of the power supply is such that when unloaded it is capable of twice the power as
compared to it’s loaded condition.
Page 9

o a 100w/ch amplifier running into 4 ohms must develop 20 volts across the speaker
Sterminal. This requires a net (under load) rail voltage of about +/- 33 volts. Now for it to
have 3dB of headroom it must be capable of delivering 28.28 volts across the speaker
terminal. This requires a rail voltage of +/- 43 volts. So the above power supply will droop
a total of +/- 10 volts (a 23% droop!). This puts additional stress on the output devices
(Mosfets or Bipolars) because they still have to deal with this higher rail voltage . To us
this kind of power supply sounds like the amplifier is “breathing” and not the kind of
amplifier we want to listen to. Regulated power supplies are more expensive to
manufacture, are less efficient but we feel those are tradeoffs we can live with!
f one examines the specification of an amplifier, it is relatively easy to tell apart those
Iwith well regulated power supplies and those with sloppy unregulated power supplies.
The ratio of 4 ohm as to 2 ohm power will readily inform us of the quality of that power
supply. Typically if the amplifier can double or almost double it’s continuous power rating
from 4 ohm to 2 ohm at ALL battery voltages this is indicative of a well regulated power
supply. There are a few manufacturers who manipulate the rail voltages at lower speaker
impedances so that the 4,2 and 1 ohm power specs are the same. We believe that this is
a cop out to save putting in a beefy power supply which is capable of the higher currents
needed for these low impedance loads.
ubsonic filters and CLIPPING. The former are simply steep slope high pass filters with
Sa frequency range between 10 to 50Hz. Their only function is to filter out those
frequencies which lie below audibility. The woofer’s cone will not “flop” around as it does
without the use of the filter and because all the low frequency energy that we cannot hear
is filtered out, the amplifier runs more efficiently since it does not have to amplify all those
inaudible low frequencies. Remember one fact, ALL amplifiers are pretty dumb. They will
amplify anything you put into them (assuming the amplifier’s frequency response is wide
enough) and whether we can hear a particular frequency range is not the amplifier’s
concern. Put in an inaudible frequency and the amplifier dutifully does it’s thing. It does
not care about the load. This is why tweeters are easily burnt when amplifiers are
clipping. The amplifier generates high frequency harmonics and this energy is thrown to
the unsuspecting tweeter. When an amplifier is driven into clipping it basically generates
a square wave. This contains a large amount of energy but also due to the fact that the
square wave sits at a positive (or negative) state for a “long” period of time, the natural
cooling effect of a continuously moving cone/voice coil is inhibited and can lead to failure
of a speaker. Typically woofers are more tolerant of clipped power than mids and
tweeters due to the fact that they are more robust and that they do not respond to those
high frequency harmonics very well (but do not be fooled, woofers can be hurt by these
harmonics even if we cannot hear them). The inductive reactance is (2 x 3.14 x freq x
inductance) and so the higher the frequency the higher the inductive reactance of the
speaker becomes. However it’s DCR does not change with frequency.
Page 10

Installation Instructions
Location:
Choose a suitable location in the vehicle which will allow sufficient airflow over the
amplifier. The preferred mounting direction is with the heatsink fins in a vertical direction.
However we do recognize that this is not always possible.
Mounting the amplifier(s)
These amplifiers can be mounted in one of two ways. The first is by using the supplied
mounting feet. Each foot is bolted to the underside of the chassis using the supplied
metric M4 bolts. Please use a phillips screwdriver which fits the head of the bolts
correctly. Make sure that the bolts are tight but DO NOT over tighten them as you may
strip the threads in the bottom of the heat sink.
Depending on the surface to which the amplifier is mounted use either wood screws or a
machine screw with nut of either M5 or 10/32” size.
The second method is to forego the use of the four mounting feet and use metric M4 bolts
to bolt directly into the threaded holes on the underside of the heat sink. This method
requires that you determine the thickness of the mounting board and add 6mm (0.23”) to
it. Then select the correct length M4 bolt. If the bolt is too long you will feel it bottom out in
the threaded holes. Please be careful so as not to damage the threads in the bottom of
the heat sink. We supply four longer M4 bolts with each amplifier.
Fusing of amplifiers. Almost every amplifier I have worked on is OVER FUSED - period!
Over fusing is just a stupid thing to do in the first place as it affords ZERO protection and
only results in printed circuit cards being burnt together with a bunch of expensive silicon.
The formula is quite simple. For class A/B amplifiers add up the total wattage of all
channels into the impedance into which they are driven. Divide this number by 18 and use
the closest value fuse. Example a 100w x 4 at 4 ohm amplifier is 400w total. Divide by 18
= 22.22 so use a 25A fuse. A 1500w amplifier requires a 90A fuse. I prefer to make up a
final fuse value by using several lower amperage fuses in parallel. This results in better
thermal efficiency as the current flow is spread over several pieces of metal.
We advocate strongly to under fuse and if you find under hard drive that the fuses
occasionally open up then it is way less drag on your wallet to replace some fuses with a
slightly higher value.
A repeat here for those who did not read the “low impedance” point I made. The higher
the impedance of the speaker (>4 ohm) the better the sound quality. These amplifiers are
NOT SPL tools, they are for listening to good music at reasonable levels - protect your
ears!
Use 4 or 8 ohm speakers and you will be surprised at the results.
Page 11

Connecting the Amplifier
Once the amplifier has been correctly mounted the electrical connections can now be
made. The first step is to connect the loudspeakers. Using the appropriate size of wire
(we recommend a min of #14) connect the speakers as shown in later diagrams,
depending on which amplifier(s) are being installed. The next step is to connect the line
inputs using high quality RCA-RCA cables. The source to which the line inputs are
connected depends on the amplifier type and the particular installation. Again refer to
later diagrams.
The next step is to connect the power inputs. The first is the ground wire. This wire is
connected to the (-) connection on the 3 terminal power connector. Using #8 wire or
larger(#4 max) insert one end into the connector’s GROUND terminal after stripping off
about 19mm (0.75”) of insulation. Trim the wire to a maximum length of 1 metre (39”) this
ground wire (normally BLACK in colour) is then crimped (and preferably soldered) into an
appropriate size ring lug. This lug is then bolted to the chassis of the car (normally in the
trunk). The hole to which the lug shall be bolted must be rust and paint free. It is also a
good idea to use a star washer between the lug and the chassis of the vehicle. We prefer
the use of a machine bolt and nut rather than a self tapper. The torque that the machine
bolt can exert is greater than that of a self tapper and due to the large currents flowing
through this ground connection the contact resistance shall be lower with the machine
screw.
Next is the remote turn on wire. This is normally connected to the remote output of the
head unit. Using #14 wire, stripping one end to 19mm (0.75”), insert one end into the
smaller centre hole of the power connector. Run this cable to the head unit’s location and
connect to the “remote out” terminal of the head.
Last is the +12volt connection. Using #8 (#4 max)or larger, strip the wire to 19mm (0.75”)
and insert in to the hole marked BATT (+) on the power connector. Run the cable (away
from all audio cables) to the location of the vehicle’s battery. At the battery location install
the a fuse holder no further away from the battery (+) terminal than 300mm (12”). Insert
this end of the +12volt power cable into the fuse holder. Making sure that the fuse is
removed, connect the other end of the fuse holder to the battery’s (+) terminal using
appropriate high quality battery connectors. Insert the supplied fuse. DO NOT
OVERFUSE as this can be a fire hazard.
The power connector on our amplifiers can accommodate wire with a copper diameter of
up to 7mm (0.275”).
Please be sure to use a 0.25A fuse at
the head. This fuse will blow if any portion of the remote wire is accidentally shorted to
chassis ground.
Page 12

Specifications
Specification LEVIATHAN
KRONOS
Continuous Output Power into 2 ohm per channel 500wx2 250wx6
Continuous Output Power into 4 ohm per channel 250wx2 150wx6
Typical Output Power into 4 ohm per channel (1% THD) 290wx2 175wx6
Continuous Output Power 2 channels bridged into 4 ohm 1000wx1 500wx3
Continuous Output Power 2 channels bridged into 8 ohm 500wx1 300wx3
Minimum Speaker Impedance per channel 2 ohm 2 ohm
Minimum Speaker Impedance in Bridge Mode 4 ohm 4 ohm
Power Response at any power into 4 ohms/channel 10-30KHz -3dB 10-30KHz -3dB
Frequency Response at rated power into 4 ohms/channel 10Hz-25KHz -0.5dB 10-25KHz -0.5dB
Input Voltage range for rated power into 4 ohms 0.25-8.6 volt 0.25-8.6 volt
Input Impedance at 2KHz 37K ohm 37K ohm
Noise below rated output (30KHz limited) -101dB -98dB
Channel separation at 2KHz >80dB >80dB
Damping Factor at 20Hz with 4 ohms >80 >80
Total Harmonic Distortion with 4 ohm 20Hz-20KHz
From 1 watt to rated power. Typically less than 0.05% <0.2% <0.2%
Intermodulation Distortion <0.2% <0.2%
Phase response at 20KHz Lagging 12 deg Lagging 12deg
Slew rate (volts per micro second)-In”Flat” mode 12 12
Low Pass Crossover (all are 24dB/octave) 46Hz-3.4KHz 80Hz-4KHz
40Hz-240Hz
High Pass Crossover (all are 24dB/octave) 46Hz-3.4KHz 80Hz-4KHz
Subsonic Crossover24dB/octave 11Hz-48Hz 11hz-48Hz
Equalization (Zero to +12dB variable control) Bass Boost @40Hz No
Line Output Yes No
Protection - Short Circuit, DC, Thermal Yes Yes
Power Source ----------10-14.5v DC Negative Ground -----------
Current Consumption with Sinewave at 4 ohms 50A 105A
Current Consumption with Music at 4 ohms 16A 30A
Idling Current <1.5A <2A
Fuse rating with 4 ohm load/channel 20A 20-25A
Fuse rating with 2 ohm load/channel **** 40A 60A
Size W x H (247mmx55mm/9.7”x2.1”) x L 272mm/10.7” 410mm/16.1”
Shipping Weight (Kg/Lbs) 5.9/13 6.8/15
**** Under normal operating conditions the fuse rating for 4 ohm loads will suffice for 2 ohm loads. If the amplifier is driven for long periods of time into
2 ohm loads per channel the fuse rating may be increased as shown.
++
++
++
++
++
++ Driving amplifiers with continuous sine wave power is very stressful and is not indicative of an
amplifier’s real world performance. We actually prefer to use PINK NOISE as our test signal as it very
closely replicates typical music which is what our amplifiers were intended for in the first place. Our
amplifiers will double the 4 ohm power at 2 ohm when driven with pink noise
DO NOT OVER FUSE ANY AMPLIFIER.
Page 13

This, the first of our new full range high quality class D amplifiers has been in
development for the past 15 months. The switch to class D was not taken lightly and the
target of these new amplifiers was quite simple. Perform as well as our “traditional” class
A/ B amplifiers. This target was achieved and of course with the added advantage of the
higher efficiency of class D.
The idea of producing was to have a relatively high powered amplifier which
would fill the role of both a regular two channel unit as well as fulfill the duties of a mono
block. has some very unique features never seen before on any mobile
amplifier.
The idea of incorporating a BALANCE control was that we had so many requests due to
the fact that ganged level controls do not track perfectly and the BALANCE control allows
you to compensate for this. This is especially useful when running in bridge
mode as the two channels can be balanced for perfect symmetry.
The high and low pass crossovers are Linkwitz 24dB/octave types. Their frequency
ranges are sufficient to allow to be part of tri-amplified systems. The addition of
an extra switch allows to be run as a bandpass amplifier with the high and low
pass crossovers setting the upper and lower frequency cut off points of the band pass.
So with running as a two channel amplifier, the RCA sockets marked “3” and “4”
are simple loop throughs or line outs. This allows easy daisy chaining of amplifiers.
The heart of any great amplifier is the power supply. After all this is where all the energy is
derived from. A well regulated power supply with low noise is essential for good audio
performance. We at Zed have been building regulated power supplies for over 25 years
and feel that they sound superior to unregulated or “sloppy” power supplies. A small
lesson here. The audio section of an amplifier is only a variable valve from the power
supply to the speaker. How the valve is varied depends on the class of amplifier. In this
case we use a Pulse Width Modulated system (Class D). Any voltage fluctuations on the
power supply rails will manifest themselves as a form of distortion. So if the source of
energy is poor, sound quality will be poor no matter how well the audio amplifier (valve) is
designed. It is synonymous with adding a poor quality fuel to your automobile. It will
perform poorly if the source of energy is poor. The same argument applies to amplifiers.
KRONOS
KRONOS
KRONOS
KRONOS
KRONOS
KRONOS
KRONOS
KRONOS
Oh! Did I forgot to mention that comes standard with Burr
Brown chip sets in the front end.
Page 14

The PWM amplifier utilizes a high frequency carrier which is modulated by the incoming
audio signal. The resultant series of variable width pulse trains are switched by the main
high current switching amplifier. This section uses ultra high speed precision integrated
circuits to precisely control the on and off times of the output Mosfets. Two high current,
high voltage Mosfets are used. Each has a current capability of 65 amps in a circuit
limited to less than 16 amps. The output filter utilizes low loss iron cores and high quality
film capacitors.
The turn on/off function of the audio section is done with opto-isolators which allows us to
keep the control circuits fully isolated from the audio circuits.
Do NOT power up with the volume level high. The internal
initializing circuits will “see” this as a fault condition and shut the amplifier down. The
protection LED will light and the amplifier will have to be powered down for >5
seconds and then reset. This has been done to protect all components in the system,
including YOUR ears!
Important note: KRONOS
AMBER
Please we aware that ALL class D amplifiers have
high frequency emissions and therefore the
amplifier must be kept well away from the antenna.
Please we aware that ALL class D amplifiers have
high frequency emissions and therefore the
amplifier must be kept well away from the antenna.
Page 15

Converting to run as a subwoofer amplifier is simple. Push in the switch from
“2ch LP” to “Mono LP. has some added features. The RCA sockets “3” and “4”
are now another pair of inputs and so all four inputs can accept signals from the head
unit’s front and rear outputs. This allows for constant subwoofer fading. Some additional
circuitry is added to the mix (no pun intended). The four inputs are mixed to mono, routed
into a 24dB/octave Linkwitz high pass crossover (subsonic) and passed through a nifty
new low eq circuit. This allows for up to 12dB of boost with a centre frequency of 40Hz.
The signal then passes onto the low pass crossover where we only use one channel
(remember the signal is mono now) and then it flows onto the balance and level controls.
Please note that all FOUR inputs are required for the level control’s sensitivity to be
correct. The loss of each RCA input means a 6dB reduction in signal level
The final drive from the preamplifiers to the power amplifiers is done in the balanced
domain. Our amplifiers all have the preamplifiers running on their own 100% fully ground
isolated power supplies. This design guarantees no ground loops and thus no
engine/alternator noise.
The main class D amplifiers are a new design which incorporate the output filter within the
feedback loop. This method guarantees a flat response no matter the load impedance.
We use a pair of 65 amp TO-247 MOSFETs per channel. These are low gate charge
types which are utilized for their unique characteristics which are beneficial for class D full
range amplifiers.
The power supply is almost an all new design. Fully regulated, yes of course, as this is the
only way to build a good amplifier. A bad power supply is like putting bad fuel in your
auto’s gas tank. The PWM controller drives a brand new driver circuit which ensures rapid
turn and turn off of the eight high current MOSFETs. This is a four stage drive circuit
incorporating some novel features. The MOSFETs I have chosen are each rated at 110
amps....well in the real world I would never dream of running that kind of current through
the relatively skinny leads of each MOSFET. Rather I chose these devices because they
are fast, high current and are in TO-247 packages which allows them to dissipate heat
better than traditional TO-220 packages. A custom autoformer converts the switched
battery voltage to the higher supplies we require.
Each of the eight MOSFETs has its own bypass capacitor which helps to reduce the
current spikes due to PCB and busbar inductance. The MOSFETs are run in a unity gain
configuration thus their bandwidth is maximized.
When the amplifier is powered up, the power supply takes several seconds to initialize
itself for high current operation. The most dangerous time for a power supply is when it
powers on. Big old electrolytic capacitors must be charged and these present a virtual
dead short to the power supply. To reduce turn on current and stress to the power supply
an innovative circuit controls the ramp up of the supply to limit stresses to a minimum.
KRONOS
KRONOS
Page 16

WE ARE ABSOLUTELY 100% AGAINST THESE LOW IMPEDANCE
LOADS. There is no reason to run a “daily driver” or SQ system into
these loads. The aim is quality after all and not sound pressure. The
ego trip of boasting that you have “x mega watts” in the car is just that,
an ego trip and serves no other purpose besides boosting the ego of
the owner.
We believe that the person who chooses to own one of our amplifiers
has one interest only and that is sound quality. The flexibility, weight,
size and cosmetics are to a small degree secondary concerns.
Clip LEDs are there for a reason, when they light DO NOT TURN THE VOLUME HIGHER!
Clipping is the arch enemy of loudspeakers and amplifiers. Sure the occasional clipped
waveform is fine but when the music becomes square waves that is when all the trouble
begins.
Let’s get back to the balance control. Here is some technical information for those of you
who wish to get the best out of . When a pair of channels of an amplifier are
bridged, the process is: One channel is in phase with the incoming signal and the other is
180 degrees out of phase. So a positive going incoming signal will drive the non-inverting
channel’s output in a positive direction and the inverting in a negative direction. So what
we have achieved is essentially a doubling of the power supply voltage. So bridging
into an 8 ohm load outputs 500 watts, a 4 ohm load outputs 1000 watts and DO
NOT EVEN THINK ABOUT BRIDGING INTO 2 OHMS. More about this later.
The balance control allows precise setting of the gain of each of the bridged channels so
that in bridge mode you have a symmetrical waveform. The process to adjust is relatively
simple. On line their are many sources to obtain sine wave signals. Burn a CD which now
becomes your signal source. If you have a signal generator well that is of course the
easiest way. 100Hz -1KHz signals are best for this test.
Establish the setting of the LEVEL control which you will use. This is important as the
channel tracking does change slightly as you change the settings of the LEVEL control.
KRONOS
KRONOS
NO SPEAKER IS REQUIRED FOR THIS TEST AND SHOULD NOT BE USED AT ALL.
Page 17

Feed the test signal into BOTH inputs. Using an AC voltmeter connect it to one channel of
the amplifier and note the reading. Set the balance control to centre. Then connect the
voltmeter to the other channel. Hint keep one lead of the meter to either ch1 - or ch 2 +
speaker terminals as these are common ground. Then you can simply “poke” the other
meter lead into each of ch 1+ or ch2 - speaker terminals.
Then set the BALANCE control until the readings on the meter are the same when
“switching” between ch1 and ch 2.
1
MODE
PASS
2
3
4
LOWEQ BALANCE LEVEL
BP
LP
LP
2ch LP
FLAT HP LP/BP
PASS SONIC
CLIP
12
MONO
HIGH LOW SUB
INPUT
3+4
LOOP OUT
3+4 = INPUTS
0.25v
8.6v
2
1
0dB +12dB
48
44
40
27
17
11
52 3.4K
200
65 1.3K
52 3.4K
200
65 1.3K
PROT
POWER
DESIGNED AND ASSEMBLED
IN THE USA by ZED AUDIO
BATT+
REM
GND
POWER CONNECTIONS
SPEAKER CONNECTIONS
1+ 12+ 2
BRIDGE
__
SIGNAL SOURCE
SET ALL CONTROLS AS THEY WILL BE USED
AC VOLT METER
1 2 3 4
Page 18