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Reference Manual

Macro-Tech

®

 24x6 & 36x12 Power Amplifiers

5 Technical Information

5.1 Overview

Your amplifier incorporates several new technological
advancements including low stress output stages, real-
time computer simulation of output transistor stress, an
advanced heat diffuser embodiment and a modular
system for signal input and processing. In addition,
Macro-Tech 36x12 models also have an articulated VZ
power supply in Channel 1.

Custom protection circuitry limits temperature and cur-
rent to safe levels while making the amplifier highly reli-
able and tolerant of faults. Unlike many lesser
amplifiers, it can operate at its voltage and current limits
without self-destructing.

Real-time computer simulation is used to create an ana-
logue of the junction temperature of the output transis-
tors (hereafter referred to as the “output devices”).
Current is limited only when the device temperature
becomes excessive—and just by the minimum amount
necessary. This patented approach is called ODEP or
Output Device Emulation Protection. It maximizes the
available output power and eliminates overheating, the
major cause of output device failure.

The amplifier is protected from all common hazards that
plague high-power amplifiers, including shorted, open
or mismatched loads; overloaded power supplies, ex-
cessive temperature, chain-destruction phenomena,
input

 overload damage and high frequency blowups.

The unit protects loudspeakers from DC in the input sig-
nal, turn-on and turn-off transients, and it detects and
prevents unwanted DC in the output. The amplifier is
also protected from internal faults.

The patented four-quadrant topology used in the
grounded output stages is called the grounded bridge.
The grounded bridge topology takes full advantage of
the power supplies delivering peak-to-peak voltages to
the load that are twice the voltage seen by the output
devices and twice the voltage generated by the power
supplies.

The grounded bridge topology is ground-referenced.
Because the required current exceeds the limits of pres-
ently available components, composite output devices
are constructed to function as gigantic NPN and PNP
devices. Each output stage has two composite NPN
devices and two composite PNP devices.

The devices connected to the load are referred to as
“high-side NPN and PNP” and the devices connected
to ground are referred to as “low-side NPN and PNP.”
Positive current is delivered to the load by increasing

conductance simultaneously in the high-side NPN and
low-side PNP stage, while decreasing conductance of
the high-side PNP and low-side NPN in synchrony.

A wide bandwidth, multiloop design is used for state-
of-the-art compensation. This produces ideal behavior
and results in ultra-low distortion values.

Aluminum extrusions have been widely used for
heatsinks in power amplifiers due to their low cost and
reasonable performance. However, measured on a
watts per pound or watts per volume basis, the extru-
sion technology doesn’t perform nearly as well as the
thermal diffuser technology developed for 

Macro-Tech

power amplifiers.

Our thermal diffusers are fabricated from custom con-
voluted fin stock that provides an extremely high ratio of
area to volume, or area to weight. All power devices are
mounted directly to massive heat spreaders that are
electrically alive. Electrifying the heat spreaders im-
proves thermal performance by eliminating the insulat-
ing interface underneath the power devices. The
chassis itself is used as part of the thermal circuit, and
this maximizes utilization of the available resources.

5.2 VZ Power (Macro-Tech 36x12 only)

VZ means Variable Impedance and is the name of
Crown’s patented articulated power supply technology.
This technology is what makes it possible to pack such
tremendous power into Crown’s 

Macro-Tech 3600VZ

and 

Macro-Tech 5002VZ amplifiers. The high-power

channel of the Macro-Tech 36x12 uses this articulated
power supply technology.

5.2.1 Background

A power supply must be large enough to handle the
maximum voltage and current needed by the amplifier
to drive its maximum rated power into a specified load.
To fulfill this require-
ment, conventional
power supply de-
signs produce lots of
heat, are heavy, and
take up precious real
estate. And it’s no se-
cret that heat is one
of a power amplifiers
worst enemies. Con-
sider the circuit that
follows in Figure 5.1.

According to Ohm’s
Law, as your power

Fig. 5.1  A Typical

Power Supply

POWER
TRANSISTOR

POWER
TRANSISTOR

SPEAKER
LOAD

POWER

SUPPLY

+

Summary of Contents for 24x6

Page 1: ...ifiers are produced by the Professional Audio Division of Crown International Inc Trademark Notice SmartAmp Grounded Bridge and PIP are trademarks and Amcron Crown Macro Tech IOC ODEP IQ IQ System and...

Page 2: ...nalpurchaser the warrantyperiod thatthenewCrownproductisfreeofdefectsinmaterials and workmanship We further warrant the new Crown product regardless of the reason for failure except as excluded in thi...

Page 3: ...RISK OF ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE Magnetic Field CAUTION Do not locate sensitive high gain equipment such as preamplifiers or tape decks directly above or below...

Page 4: ...ded plug does not fit into your outlet consult an electrician for replacement of the obsolete outlet 10 Protect the power cord from being walked on or pinched particularly at plugs convenience recepta...

Page 5: ...tion Systems 18 4 3 1 ODEP 18 4 3 2 Standby Mode 19 4 3 3 Transformer Thermal Protection 19 4 3 4 Circuit Breakers 19 4 4 Controls 19 4 5 Filter Cleaning 20 5 Technical Information 21 5 1 Overview 21...

Page 6: ...3 11 Wire Size Nomograph 14 3 12 Inductive Load Transformer Network 16 3 13 Loudspeaker Fuse Selector Nomograph 16 4 1 Indicators 17 4 2 ODEP and Signal IOC Indicator States 18 4 3 Input Sensitivity a...

Page 7: ...ect condition as most do save all packing materials so you will have them if you ever need to transport the unit NEVER SHIP THE UNIT WITHOUT THE FACTORY PACK 1 2 Features Here are some of the impressi...

Page 8: ...her IOC function is to indicate input overload If an input signal is too large the indicator for the affected channel flashes brightly with a 0 5 second hold delay to show clipping distortion D ODEP I...

Page 9: ...e they are electrically in parallel with the PIP in put connectors input signals should not be connected to the phone jacks when certain PIP modules are in stalled see Section 3 3 1 The phone jacks ca...

Page 10: ...ters etc to prevent rapid loading of the unit s own air filter When needed the unit s filter can be cleaned with mild dish detergent and water see Section 4 5 When mounting the amplifier in a rack cab...

Page 11: ...l eliminate any chance of loud blasts or damage to the loudspeakers Because each channel produces a different power level the Macro Tech 24x6 and 36x12 are dedicated to Fig 3 4 Wiring a Macro Tech 36x...

Page 12: ...ed Input Wiring Fig 3 7 Balanced and Unbalanced Phone Plug Wiring a standard tip ring sleeve TRS configuration the tip is positive the ring is negative and the sleeve is ground see Figure 3 7 Wiring f...

Page 13: ...t energy and can drive loudspeakers to levels which can cause permanent hearing damage Crown is not liable for personal injury or damage incurred when a transducer or component is over driven Fig 3 10...

Page 14: ...akers The latter problem occurs be cause the damping factor decreases as the cable Use Good Connectors 1 To prevent possible short circuits do not expose the loudspeaker cable connectors 2 Do not use...

Page 15: ...wires can be used for the same effect SOLVING OUTPUT PROBLEMS Sometimes high frequency oscillations occur that can cause your amplifier to prematurely activate its protec tion circuitry which can res...

Page 16: ...unless otherwise noted Speci fications were derived using a voltage that is accurate to within 0 5 with THD less than 1 0 under all testing conditions Performance variations can occur at other AC vol...

Page 17: ...re event that there is no re serve the indicators turn off and ODEP proportionally limits the drive level of the output stages so the ampli fier can continue safe operation even when conditions are se...

Page 18: ...dio output Possible reasons 1 There is no input signal 2 The input signal level is very low 3 The channel s level control is turned down ODEP SIGNAL IOC ON Normal Normal operation for a channel with a...

Page 19: ...is excessive heat The switch automatically resets when the transformer cools to a safe temperature It is very unlikely that you will ever see a Macro Tech amplifier activate transformer thermal prote...

Page 20: ...nly the phone jack inputs and has no affect on the PIP mod ule input connectors Sliding the switch to the left iso lates or lifts the grounds by placing an impedance between the sleeve of each input p...

Page 21: ...nd PNP devices Each output stage has two composite NPN devices and two composite PNP devices The devices connected to the load are referred to as high side NPN and PNP and the devices connected to gro...

Page 22: ...signed to prevent audible switching distor tion and yield the highest possible dynamic transfer function you hear only the music and not the amplifier You get not only the maximum power with the maxim...

Page 23: ...iescent voltage D309 D310 D311 and a trim mer resistor set the quiescent current point for the bridge balanced output stage The protection mechanisms that affect the signal path are implemented to pro...

Page 24: ...OWN NPN HI OUTPUT STAGE NPN LOW OUTPUT STAGE PNP LOW OUTPUT STAGE PNP HI OUTPUT STAGE OUTPUT Vcc Vcc TRANSLATOR LVA LVA Vcc Vcc BIAS CURRENT LIMIT TRANSLATOR BALANCE INPUT STAGE P I P BALANCED INPUTS...

Page 25: ...acro Tech 36x12 Channel 1 3600 124 6 1 12 or 41 9 dB 1 0 dB Macro Tech 36x12 Channel 2 1200 64 1 12 or 36 dB 0 5 dB Power Output Power The following are guaranteed minimums for standard 1 kHz power at...

Page 26: ...5 V and 1 4 V for rated output or a fixed voltage gain of 26 dB see Section 4 4 Output Signal Unbalanced two channel Output Connector A pair of color coded 5 way binding posts for banana plugs spade l...

Page 27: ...Page 27 Reference Manual Macro Tech 24x6 36x12 Power Amplifiers Fig 6 1 Typical Frequency Response Fig 6 2 Typical Damping Factor Fig 6 3 Typical Output Impedance...

Page 28: ...nual Macro Tech 24x6 36x12 Power Amplifiers TECHRON TEF 45 0 45 100 1 K 10 K 20 K FREQUENCY Hz Fig 6 4 Typical Phase Response Fig 7 1 Macro Tech 24x6 Power Draw Current Draw and Thermal Dissipation at...

Page 29: ...c is 20 Duty cycle of continuous speech is 10 Duty cycle of infrequent short duration paging is 1 Here are the equations used to calculate the data pre sented in Figures 7 1 and 7 2 AC Mains Power Dra...

Page 30: ...mplifier can be monitored and individu ally controlled from an inexpensive PC A total of 15 func tionscanbeeithermonitoredorcontrolled Memorybackup is also incorporated in case of power failure Requir...

Page 31: ...ssor but a circuit to preventanyoverload Itcanyieldupto13dBoradditional signal safety margin without noticeable program change P I P EDCbState of the artprogrammableerror drivenand signal driven compr...

Page 32: ...l Shaft Lock A security accessory the shaft lock can be used to secure your amplifier s level controls in situations where the front panel controls are subject to tampering One is needed for each chan...

Page 33: ...warranty service we will pay for ground shipping both ways in the United States Contact Crown Factory Service or Technical Support to obtain prepaid ship ping labels prior to sending the unit Or if y...

Page 34: ...________________ ______________________________________________________________________________ ______________________________________________________________________________ _________________________...

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