Precision Power MA1250 Owners Manual
CONTENTS
(click on a topic to view)
Congratulations Endpanel Layout
Features & Specifications Endpanel Layout
Installation Troubleshooting
Wiring Troubleshooting
Power / Ground Troubleshooting
Connections Troubleshooting
Connections System Diagrams
Inputs & Connections Block diagram
Inputs Warranty
OWNERS MANUAL MA1250
Thank you for choosing TUBE DRIVER. Tube Drivers musicality and absolute sonic
transparency allow accurate reproduction of recorded music enabling you to hear
as well as feel the music the way the artist intended. These handcrafted amplifiers
feature full differential “front ends” based upon a true instrumentation amplifier
topology . Tube Drivers utilize only the highest quality Svetlana tubes in our unique
configurations. All of the internal amplifier stages have been designed to have ultrawide bandwidth together with a high degree of linearity. The tubes used in these
amplifiers provide both voltage gain and current gain where they are connected in
Cascode and Cathode Follower configurations. D.C. servos are used to control any
D.C. offset. These servos are critically positioned in the circuit so that not only is
D.C. offset eliminated but also any subtle differences between tubes are internally
compensated. These tube stages are then connected to a high current BiPolar
output stage that uses the same audiophile quality Sanken output devices featured
in the PrecisionPower 2500F1.The output stages receive their power from a highly
regulated D.C. power supply which enhances their performance significantly. Very
little negative feedback is used. Low feedback designs have greatly improved sound
quality having an extremely warm and open sound with enhanced musicality
consistent with only the highest quality home tube amplifiers.
Service
Do not attempt to service TUBE DRIVER products yourself. Performing exploratory
surgery on your audio equipment yourself will void the warranty . Many parts of your
TUBE DRIVER gear are custom built to our specifications. Our factory parts are not
made available to anyone else nor are they for sale. Our goal is to make sure that
your TUBE DRIVER product will always sound as good as the day it was
purchased.Contact your authorized TUBE DRIVER dealer about obtaining any
warranty service through TUBE DRIVER. (See Warranty inside back cover)
FOR YOUR RECORDS
Model
Serial Number
Purchase Date
Caution!
The extended use of a high powered audio system may result in hearing
loss or damage. While TUBE DRIVER systems are capable of
Level"
volumes with incredible accuracy, they are also designed for you to
enjoy at more reasonable levels all of the sonic subtleties created by
musicians. Please observe all local sound ordinances.
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"Concert
Features
Fully regulated adaptive MosFET power supply
Balanced Mini-Din Input
High Voltage Input Capability with Input Attenuation Switch
Gold Plated RCA Input connectors
Three Year W arranty when installed by an Authorized
Completely Designed and Handcrafted in the USA
TD
dealer
Specifications
Power Bandwidth: 5 Hz -50 KHz
Total Harmonic Distortion: 0.2% or less (A-weighted)
Input Topology: Balanced Differential
Input Sensitivity: 500mV - 12 volts RMS
Input Impedance: 10K Ohms
Output Impedance: 2 - 16 Ohms
Continuous Output Power
MA1250
250 WRMS x 1 @ 4 Ohms
500 WRMS x 1 @ 2 Ohms
Dimensions
MA1250
Length = 17”
Height = 3.2”
Width = 9.25”
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Tools/Parts Needed for Installation
Small flat blade screwdriver
Phillips screwdriver (#2 or medium sized)
Wire cutters
Wire strippers
4 – #6 round head screws, and 1 – #8 sheet metal screw
(or nut, bolt, and star washer)
2 – Ring connectors (large enough to accommodate your method of grounding)
In-line fuse or circuit breaker — see fuse requirements below
Power and groundwire — see Power Wire Calculator on the next page
Speaker wire — 16 gauge or larger
Grommets (sized to work with the power wire you plan to use in your installa-
tion)
Tube of silicone sealant
(not supplied)
Fuse Requirements
Recommended Fuse Rating for MA1250 is 10 0 Amps
You will need to install an in-line fuse or circuit breaker in the power wire
within 18” of the battery. This fuse or circuit breaker protects your vehicle
from fire in case the power wire shorts to the vehicle body. If you are only using
one amplifier, use the recommended fuse rating. If you are using more than one
amplifier, add up the fuse ratings for all amplifiers, and use this sum for your main
fuse or circuit breaker. Use a power distribution block or fuse near your amplifiers
with the appropriate fuse for each individual power wire.
The information below is a basic formula you can use to determine approximate
current draw. A 50% amplifier efficiency rating is used as an average. This formula
is only a guideline. Using wire of a larger gauge can only improve the current transfer
of your system. Do not use smaller gauge wire.
Total 4-Ohm rated RMS output x 2 = Total Input Wattage
Total Input Wattage/Supply Voltage = Current Draw (in Amps)
Example:
Your
MA1250
(250 x 2 =500). You would use the formula below:
250W x 2 = 500W/12.5V = 40 Amps Total Current Draw
has 1 channel at 250 watts RMS into 4-Ohms
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Power Wire Calculator
Recommended MINIMUM Gauge
Total Current Dra w Length of Wire to Run (in Feet)
(in Amps) < 3 4 - 7 7 - 10 10 - 13 13-16 16-19 19-22 22-28
0 - 20 14 12 12 10 10 8 8 8
20 - 35 12 10 8 8 6 6 8 4
35 - 50 10 8 8 6 6 4 4 4
50 - 65 8 8 6 4 4 4 4 2
65 - 85 6 6 4 4 2 2 2 0
85 - 105 6 6 4 2 2 2 2 0
105 - 125 4 4 4 2 2 0 0 0
125 - 150 2 2 2 2 0 0 0 0
Warning!
Amplifiers Generate Heat!
You can mount the
must maintain proper airflow. Do not install your
MA1250
in any position, even upside-down. However, you
MA1250
under carpets or enclose
it behind airtight panels. In trunk-mounted applications, be sure to provide venting
for air circulation. Let the amplifier breathe. Without adequate air circulation, your
Tube Driver will turn itself down to protect itself.
Mounting
You need to mount your
may mount the system right-side up, on its side, or upside-down, provided there is
adequate ventilation.
MA1250
securely in your vehicle to prevent damage. You
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Warning!
To prevent a short to ground, disconnect the negative (-) terminal of the system’s
battery before you begin. If the power cable shorts to ground, current will continue
to flow until the short is opened, the main fuse blows, the battery explodes, or the
wire melts.
Reconnect the terminal only after you make all connections.
Grounding
Your
MA1250
electrical system. The ground wire should be the same gauge as the power wire
indicated in the chart.
The main power cable should run from the amplifier location, through or under the
vehicle, to the battery . Y ou must use a grommet wherever the cable passes through
a steel panel to prevent an eventual short to ground.
The ground connection is the most important part of any installation. If the
connections are poor and/or the resistance is high, the resulting drops in voltage
will rob you of amplifier power and may allow noise to enter your system. Your new
Tube Driver features a fully regulated power supply. It will make full power even if
the voltage changes. It will draw more current at lower voltages to make that power.
Lower voltage and high cable resistance means more total current draw. Using a
digital multimeter (DMM), try to get cable resistance as low as possible. If resistance
is too high, use a larger gauge wire. T ry to ground your system to a single point in
the vehicle. In larger systems, use distribution blocks and run both power and ground
cables directly to the system battery.
is designed to operate from a car’s positive 12 volt, negative ground
Remote Turn-on
IMPORTANT! Your new
circuit. When your system is turned on, The LED labeled “WARM UP” will
illuminate and full power is applied to the tube heaters for appr ox. 35 seconds.
The internal fan will then turn on and two seconds later the amp outputs will
be switched on. The system will then play as normal.
You must connect a wire to the remote (REM) terminal (located in the speaker
terminal plug) of your amplifier to power on your
provides a remote amp turn-on or power antenna lead that provides this +12 volts
when you turn on the unit.
MA1250
is equipped with our unique tube warm-up
MA1250
. The source unit normally
• Run a wire from the chosen turn-on lead to the REM connection
of your
MA1250
(See Endpanel Layout: Page 10)
• Tighten the connection
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