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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

Summary of Contents for Kronos

Page 1: ...Instruction and Installation Manual KRONOS LEVIATHAN Designed and manufactured in the United States of America...

Page 2: ...es 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...

Page 3: ...out 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...

Page 4: ...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 nois...

Page 5: ...er 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 wa...

Page 6: ...ns 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 qual...

Page 7: ...nt 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 m...

Page 8: ...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 po...

Page 9: ...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 amp...

Page 10: ...e 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 r...

Page 11: ...ach 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 a...

Page 12: ...p 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...

Page 13: ...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 fu...

Page 14: ...f 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...

Page 15: ...lat 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 E...

Page 16: ...igh 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...

Page 17: ...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...

Page 18: ...te 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...

Page 19: ...ridged 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...

Page 20: ...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...

Page 21: ...4 INPUTS 0 25v 0 25v 8 6v 8 6v 2 2 1 1 DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 12dB 48 44 40 27 17 11 52 3 4K 200 65 1 3K...

Page 22: ...INPUTS 0 25v 0 25v 8 6v 8 6v 2 2 1 1 DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 12dB 48 44 40 27 17 11 52 52 3 4K 3 4K 200...

Page 23: ...PUTS 0 25v 0 25v 8 6v 8 6v 2 2 1 1 DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 12dB 48 44 40 27 17 11 52 3 4K 200 65 1 3K 52...

Page 24: ...S 0 25v 0 25v 8 6v 8 6v 2 2 1 1 DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 12dB 48 44 40 27 17 11 52 52 3 4K 3 4K 200 200 65...

Page 25: ...AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 0dB 12dB 12dB 48 48 44 44 40 40 27 27 17 17 11 11 52 3 4K 200 65 1 3K 52 52 3 4K 3 4K 200 200 65 65 1 3K 1 3K _ PROT POWER...

Page 26: ...6v 8 6v 2 2 1 1 DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 12dB 48 44 40 27 17 11 52 3 4K 200 65 1 3K 52 3 4K 200 65 1 3K _...

Page 27: ...1 1 DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO BATT REM GND POWER CONNECTIONS SPEAKER CONNECTIONS 1 1 2 2 BRIDGE _ 0dB 0dB 12dB 12dB 48 48 44 44 40 40 27 27 17 17 11 11 52 3 4K 200 65 1 3K 52 52 3...

Page 28: ...plifier with six channels and 150w per channel BUT it would be big heavy and expensive The expensive part has been eliminated with the higher efficiency obtained with class D and our power supply tech...

Page 29: ...nt into is in does not incorporate the load impedance measurement system owing to the fact that there are six channels and one power supply uses ultra fast MOSFETs in each channel rated at 29A The pow...

Page 30: ...115 360 1 8K 4K 80 115 360 1 8K 4K 80 115 360 1 8K 4K 17 27 40 44 40 240 50 63 110 180 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR BRIDGE BRIDGE BRIDGE POWER CONNECTIONS DESI...

Page 31: ...1 8K 4K 80 115 360 1 8K 4K 17 27 40 44 40 240 50 63 110 180 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR BRIDGE BRIDGE BRIDGE POWER CONNECTIONS DESIGNED AND ASSEMBLED IN THE U...

Page 32: ...6 1 2 3 4 5 6 11 48 80 80 115 115 360 360 1 8K 1 8K 4K 4K 80 115 360 1 8K 4K 80 115 360 1 8K 4K 17 27 40 44 40 240 50 63 110 180 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR B...

Page 33: ...5 6 11 48 80 115 360 1 8K 4K 80 80 115 115 360 360 1 8K 1 8K 4K 4K 80 115 360 1 8K 4K 17 27 40 44 40 240 50 63 110 180 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR BRIDGE BRID...

Page 34: ...6 1 2 3 4 5 6 11 48 80 115 360 1 8K 4K 80 115 360 1 8K 4K 80 80 115 115 360 360 1 8K 1 8K 4K 4K 17 27 40 44 40 240 50 63 110 180 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR BR...

Page 35: ...L LEVEL LOW PASS MODE MODE MODE LP BP 0 25v 0 25v 8 6v 8 6v 0 25v 0 25v 8 6v 8 6v 0 25v 0 25v 8 6v 8 6v SUB SONIC LEVEL LEVEL LOW PASS LP 1 4 LP LP 5 6 FLAT FLAT 1 2 3 4 5 6 POWER PROT CLIP 1 3 2 4 5...

Page 36: ...27 27 40 40 44 44 40 40 240 240 50 50 63 63 110 110 180 180 200 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR BRIDGE BRIDGE BRIDGE POWER CONNECTIONS DESIGNED AND ASSEMBLED IN T...

Page 37: ...27 40 40 44 44 40 40 240 240 50 50 63 63 110 110 180 180 200 200 BATT REM GND MINIMUM LOAD IS 2 OHM CHANNEL or 4 OHM BRIDGED PAIR BRIDGE BRIDGE BRIDGE POWER CONNECTIONS DESIGNED AND ASSEMBLED IN THE U...

Page 38: ...NEL or 4 OHM BRIDGED PAIR BRIDGE BRIDGE BRIDGE POWER CONNECTIONS DESIGNED AND ASSEMBLED IN THE USA by ZED AUDIO THE CONTROLS SHOWN IN GREEN ARE APPLICABLE ONLY LEVIATHAN with Chs 5 6 in low pass using...

Page 39: ...S MODE MODE MODE LP BP 0 25v 0 25v 8 6v 8 6v 0 25v 0 25v 8 6v 8 6v 0 25v 0 25v 8 6v 8 6v SUB SONIC LEVEL LEVEL LOW PASS LP 1 4 LP LP 5 6 FLAT FLAT 1 2 3 4 5 6 POWER PROT CLIP 1 3 2 4 5 6 1 2 3 4 5 6 1...

Page 40: ...his signal level the better the subjective S N ratio is Protection LED comes on Remove speaker connections from amplifier Turn amplifier off for 5 seconds Turn on again if LED is off the problem is wi...

Page 41: ...ced the warranty is null and void There are NO exceptions to this To obtain factory service under the terms of this warranty the purchaser must contact Zed Audio Corporation or an appointed service ce...

Page 42: ...with a copy of the original sales invoice The full purchase price shall be refunded less the original freight amount For any damaged or missing parts on the amplifier including packaging materials the...

Page 43: ...d and the power amplifier will incorporate tubes right up to the output stage The output devices will be high speed Sanken or Toshiba devices which in my opinion are the best bi polar devices around C...

Page 44: ...oduct purchased Serial number Name and address from whom this product was purchased Date of purchase Please do not forget to mail a copy of the retail invoice OR scan it an email to us If you are mail...

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