D'Amore Engineering A1500.2 User manual

A1500.2 / A1500.4
Mobile Audio Amplifier
Owner’s Manual

2
Table of Contents
About the design 3
Fuse it 4
Power Requirements 4
Balanced or Unbalanced 5
How do I know what type of source I have 6
The LED Meters 6
The LED Meters and fault conditions 8
How to remove the cover 10
Specifications 11
Dyno Test Results (Birth Certificate) 13
Limited warranty information 14

3
About the design
When you pick up the 1500.2 / 1500.4, you might realize
this amplifier is a bit different than most. The A series
amplifiers were originally developed from a Class A
home audio amplifier that our founders built for their own
personal use. They decieded to connect it to the front
stage of a car one day for fun back in 2012. The sound
of that system blew them away and drove them to
develop a mobile amplifier of the same exact circuitry.
They replaced the 120V AC power supply with a 12V DC
version and repackaged the amplifer into a mobile audio
amplifier chassis. The A series was born. High end
home audio for the car.
The A series amplifiers are based on a 3 stage Lin
design. This amplifier topology is the foundation for
some of the world’s best home audio hifi amplifiers.
They took the design, improved on it and made it
suitable for car audio by physically seperating the 3
stages for reduced noise; Input section, voltage
amplifier, current amplifier. They also made the voltage
amplification stage have two identical circuits, mirror
images of one another and run them in pure Class A for
the sonic characteristics generated by this topology.
Then added high current capability (1 ohm drive for
1500.2 and 2 ohm drive for 1500.4) and a high efficiency
DC/DC converter switching power supply.
The power supply uses MOSFETs, 12 of them rated for
75 Amps each. The output section uses high power bi-
polar junction transistors, 32 of them rated for 15 Amps
each in an emitter-follower design connected directly to
your speakers (direct coupled). This direct coupling is
partially responsible for the hard hitting dynamics and
lifelike realism these amplifiers deliver.

4
About the design (cont.)
The heat that MOSFETs and transistors create is sucked
out of them by using ceramic aluminum oxide wafers
between the devices and the solid aluminum billet
heatsinks. We want the heat in the heatsinks, not the
transistors and MOSFETs.
FUSE IT
These amplifiers DO NOT have internal fuses for the
battery connection to the vehicle. A 150 AMP FUSE IS
REQUIRED FOR EACH HALF of the amplifier. We
recommend high quality ANL fuse type. Please pay
close attention to B+ and GND Connections, accidentally
reversing these will cause irreversible damage to the
amplifier that will not be covered under warranty. Please
take your time and take care to ensure correct battery
connection polarity.
MOUNT IT
This is a very heavy amplifier. When it is mounted in a
car that is going 50 MPH and crashes the amplifier might
continue traveling at 50 MPH and cause destruction
and/or bodily injury if proper mounting techniques are
not used. Use #6, #8, or M4 machine screws in six
places to mount this amplifier to something very secure
in the vehicle. The bottom plate is electrically grounded,
so it is best to mount it to something not grounded to
avoid ground loops.

5
Power Requirements
Operating Voltage Range 10V –16V
A1500.2
Max current (sine wave, 14.4V B+)
4Ω X 2 resistive load, to clipping 40A X 2
2Ω X 2 resistive load, to clipping 85A X 2
1Ω X 2 resistive load, to clipping 145A X 2
A1500.4
Max current (sine wave, 14.4V B+)
4Ω X 4 resistive load, to clipping 86A X 2
2Ω X 4 resistive load, to clipping 147A X 2
Balanced or Unbalanced?
The A1500.2 / A1500.4 amplifiers have RCA inputs for
unbalanced or balanced (differential) analog audio.
Almost all audio source units / DSPs use unbalanced
audio output connections. As such the A1500.2 /
A1500.4 are shipped configured for unbalanced input
operation. If this amplifier is to be used with a balanced
output device, the top cover can be removed and the
unbalanced / balanced switches located on the Class A
voltage amplifier cards should be switched to “balanced”.
Do not switch these to balanced if an unbalanced source
is being used.

6
How do I know what kind of source I have?
Most likely you have an unbalanced source, in which
case no adjustment to the amplifier switches need to be
made. The easiest way to know is to use a digital
volt/ohm meter. With the RCA cables connected to the
source but NOT to the amplifier, measure Ohms from
the RCA outer shell to battery ground.
Unbalanced = 0 to 1000 ohms
Balanced = Over 1000 ohms
The LED meters
The LED meters on this amplifier are kind of special so
we thought they required their own section in the
manual.
Some history - VU meters and commonly called (albeit
incorrectly) “Power Meters” on audio amplifiers have
been around since the beginning of hi-fi audio. They
add a visual element to the music and they offer a rough
idea of how hard an amplifier is being pushed, or more
exactly how close the output signal is to being as big
(loud) as it can be without clipping. These meters are
just AC voltmeters that are calibrated in such a way so
that when the amplifier output voltage is as high as it can
be the meter is at its maximum position.
The problems with traditional meters –First, since they
are just voltmeters they know nothing about what the
impedance of the speakers being driven is, making them
not “power meters” at all. As such, most home audio
power meters are calibrated in Watts @ 8Ω, sometimes
they have additional markings for other impedances.

7
The LED meters (cont.)
This way the user has a rough idea of how much power
the amplifier is putting out IF the impedance was 8Ω or
4Ω. Since the amplifer is meant to drive various load
impedances, and the impedance of the speaker changes
depending on the frequency being reproduced, the
meters are never actually calibrated “power meters.”
Secondly, most audio amplifiers (including this one) use
unregulated power supplies. Unregulated power
supplies do not output a fixed voltage. Instead, the
output voltage of the power supply will vary based on the
input voltage to it. The output voltage of the power
supply will also vary based on amplifier load impedance.
These types of supplies are commonly used because
they are more efficient than a regulated power supply,
and arguably produce a more dynamic sound by offering
more headroom than a regulated design. This can be
problamatic for typical output meters. Example, an
amplifier with a unregulated power supply might clip at
42V RMS output when connected to a 8 ohm load, but
35V RMS when connected to a 4 ohm load. So a typical
output meter might indicate clipping when it is not, or
vice-versa (worse!)
The solution - In order to avoid the issues outlined
above, we have designed our meters with a dynamic
maximum. That is, instead of the maximum end of the
meter scale being set by a fixed voltage, our meter’s full
scale position is relative to the power supply’s high
voltage rails. In this way they will much better indicate
that the signal is close to clipping no matter the load on
the amplifier or the input voltage to the amplifier. An
industry first as far as we know .

8
The LED meters (cont.)
Our meters are calibrated in 3dB steps with the final
RED segment indicating the output is near or at clipping.
As such in normal use it is okay for the meters to flash
red on occasion but if they are solid RED for any length
of time the output is probably clipping and the output
level should be reduced to avoid speaker damage.
The LED Meters and fault conditions
Since our meters require some brains to run them (we
are using an Atmel ATMEGA microprocessor) we
decided to make them do some other useful things as
well. Meter special functions listed below.
Blue, 1st segment illuminated = Power On, condition
normal.
Blue, 1st segment blinking on and off = Low B+
Protection. This indicates that the battery voltage level
dropped below 9.5 Volts DC during use. The amplifier
will mute and flash the first segment of the meter for
approximately 10-15 seconds after which the amplifier
will unmute and continue provided the B+ is above 9.5V
Amber, 10th segment blinking on and off = Thermal
protection. This indicates that the temperature of one or
more of the heatsinks has exceeded 85C (185F). This is
still within safe operating parameters for the amplifier but
since the heatsinks are exposed we chose to shut the
amplifier down if this temperature is exceeded. Once
the temperature is below 78C (172F) normal operation
will resume.

9
The LED Meters and fault conditions (cont.)
Red, 11th segment blinking on and off = overcurrent
protection. This indicates that too much current is
flowing through the output devices. This can happen
because either the impedance of the load is too low, or
the speaker or speaker wire has a short circuit or is
damaged in some way. The amplifier will automatically
reset and try to play music once again after 20 seconds
or so. If it happens again, please shut the system down
and investigate the problem to avoid damage to the
amplifier or vehicle. Minimum load impedance for the
A1500.2 is 1Ωstereo or 2Ωbridged. Minimum load
impedance for the A1500.4 is 2Ωstereo or 4Ωbridged.
Red, 11th segment on solid = overvoltage protection.
This indicates that B+ exceeded 16.2V, the amplifier will
mute and reset after 20 seconds or so. Please check
the vehicle’s charging system and ensure the B+ stays
below 16V.

10
How to remove the cover
The cover can be removed for various reasons. One
reason may be to convert the amplifier from unbalanced
inputs to balanced (differential) inputs. DO NOT
OPERATE AMPLIFIER WITH COVER REMOVED AS
HIGH VOLTAGE EXISTS ON VARIOUS
COMPONENTS WHICH WILL BITE YOU IF YOU
TOUCH THE WRONG 2 THINGS AT THE SAME TIME
1. Start by removing all wires connected to
amplifier
2. Screw all set screws on speaker connectors and
battery connectors all the way into connector
3. Remove the nuts on the RCA jacks, and the
stepped washers
4. Remove the 2 screws from the sides of battery
connectors and one screw from above each
speaker connector
5. Remove 5 screws from front panel to top cover
6. Remove front panel, place aside
7. Remove 4 screws from perimeter of top cover,
one on each side and two on the back
8. Lift top cover straight up carefully as the fans
are still connected to it and the circuit
boards
9. Stand the lid behind the amplifier on the edge
the fans are on or disconnect fans from PCB to
completely remove cover
10. Reverse procedure to reinstall, RCAs should
have one washer behind front panel and one in
front of front panel.

11
Specifications
A1500.2
A1500.4
CTA 2006-C Power Ratings
4Ω
350 x 2
325 x 4
2Ω
650 x 2
500 x 4
1Ω
1000 x 2
----------
4Ω Bridged
1350 x 1
1000 x 2
2Ω Bridged
2000 x 1
----------
D’Amore Engineering Ratings
Power, 12.6V <0.05%THD
4Ω
275 x 2
250 x 4
2Ω
500 x 2
500 x 4
1Ω
800 x 2
---------
4Ω Bridged
1000 x 1
750 x 2
2Ω Bridged
1600 x 1
---------
Music Power Ratings 14.4V
IHF-202 Dynamic Standard
4Ω
470 x 2
400 x 4
2Ω
900 x 2
750 x 4
1Ω
1500 x 2
---------
4Ω Bridged
1800 x 1
1500 x 2
2Ω Bridged
3000 x 1
---------
Frequency Response
10 –40,000 Hz
+/- 0.4dB
+/- 0.4dB
5 –80,000 Hz
+/- 1dB
+/- 1dB
S/N Ratio A-wgt re: full power
>109dB
>107dB
Damping Factor 20Hz
>800
>700
THD ½ power 4Ω
0.025%
0.027%
Channel separation
>100dB
>80dB
Idle Current at 20C
3 - 4A x 2
3 - 5A x 2
Efficiency at CTA power 4Ω
> 67%
> 65%
Efficiency at hard clipping 4Ω
> 75%
> 73%
Input Impedance
10kΩ
10kΩ
Slew Rate
> 30 V/µS
> 30 V/µS

12
Specifications (cont.)
Dimensions, inches 23.25 x 11.0 x 2.25
Dimensions, mm 590 x 280 x 57
Weight, Lbs. / kg 27.7 / 12.6

13
TEST RESULTS DURING PRODUCTION
THIS AMPLIFIER SERIAL # _____________________
AD-1 Amplifier Dyno Test Results @14.4V
CH1
CH2
CH3
CH4
Certified Power 4Ω
Certified Power 2Ω
Certified Power 1Ω
Certified Power 4Ω Bridged
Certified Power 2Ω Bridged
Dynamic Power 4Ω
Dynamic Power 2Ω
Dynamic Power 1Ω
Dynamic Power 4Ω Bridged
Dynamic Power 2Ω Bridged
TESTED BY __________________________
DATE _________________

14
Limited Warranty
D’Amore Engineering warrants this product to be free of
defects in materials and workmanship for a period of one year.
This warranty is not transferrable and applies only to the
original purchaser from an authorized D’Amore Engineering
dealer. Should service be necessary under this warranty for
any reason due to manufacturing defect or malfunction,
D’Amore Engineering will (at its discretion) repair or replace
the defective product with new or remanufactured product at
no charge.
Damage caused by the following is not covered under
warranty: accident, misuse, abuse, product modification or
neglect, unauthorized repair attempts, misrepresentations by
the seller. This warranty does not cover incidental or
consequential damages. Cosmetic damage due to accident or
normal wear and tear is not covered under warranty. Warranty
is void if the product’s serial number has been removed or
defaced.
Any applicable implied warranties are limited in duration to
the period of one year beginning with the date of the original
purchase. No warranties shall apply to this product thereafter.
Some states do not allow limitations on implied warranties;
therefore, these exclusions may not apply to you. This
warranty gives you specific legal rights, and you may also have
other rights which vary from state to state.
If you need service:
All warranty returns should be sent to D’Amore Engineering
accompanied by proof of purchase (a copy of the original sales
receipt). Warranty expiration on products returned without
proof of purchase will be determined from the manufacturing
date code. Non-defective items received will be returned COD.
Customer is responsible for shipping charges and insurance in
sending the product to D’Amore Engineering. Shipping
damage on returns is not covered under warranty.
To obtain service worldwide please e-mail D’Amore
Engineering at
[email protected]

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D’Amore Engineering
A Series Amplifiers
Owner’s Manual Rev. 2
2020
Printed in
Camarillo, California USA