Owner’s Manual
Please read the Owner’s Manual completely BEFORE operating the unit.
Herron Audio M150 Power Amplifier
Troubleshooting
Troubleshooting
seven
Symptom
1. The output light is on (green) and there is no sound.
A. Check the speaker fuse on the back of the unit.
B. Check speaker terminations
C. Check the interconnect terminations at the M150 and
at the preamplifier.
D. Check the source equipment.
2. The power light is on, but the voltage light goes on and off
and the output light does not come on. No Sound.
A. Check input source for d.c. at its output. Note: It is not
uncommon for preamplifiers and other audio source
equipment to produce a d.c. offset for a short period of
time after being powered up. This condition will nor-
mally clear up after a few minutes. It is recommended
that the M150s be powered up after the preamplifier,
phono stage, CD player, etc. have been turned on.
3. The amplifier trips off while the output light and voltage
light periodically go out (the sound is interrupted) when
listening at high volume.
A. This condition occurs when the internal protection cir-
cuits detect an over-current condition. This is only
likely to occur if the unit is driven into clipping or if
the speaker load is less than 4 ohms.
six
Placement
Although the M150 power ampli-
fier runs relatively cool, it is
recommended that these ampli-
fiers are used in an open area for
best operation and prolonged life.
Each M150 contains an over-
sized toroid transformer wound in
a configuration designed for mini-
mum magnetic field radiation. It is
recommended, however, that the
M150s be placed at least a few feet
away from sensitive front end
equipment such as a turntable or
phono stage.
Power Connection
When possible, connect the same
power outlet used for the preamp,
phono stage, CD player, etc. This
configuration will minimize the
reactive currents from power line
RF that will be impinged on the
interconnect cables between the
audio equipment in the system.
Recommended Loading
We do not recommend using the
M150 with a 2 ohm load. As with
all audio amplifiers increasing the
load will increase the distortion
and defeat the purpose of having
a really clean amplifier such as the
M150. For this reason we did not
design the M150 to drive a 2 ohm
load to full power. The over-cur-
rent trip circuits will engage under
those operating conditions.
Speaker Fuse
The M150 is supplied with an
AGC 6 amp speaker fuse from the
factory. The user may wish to
install an AGC fuse with a lower
rating depending on the type of
speakers being used. Careful selec-
tion of the appropriate fuse is
recommended since the M150 is
capable of supplying power well
beyond the ratings of many
speaker systems.
Speaker Cable
Optimum performance from the
M150 will be obtained only with
careful selection of the appropri-
ate cables from the amplifier to
the speakers. Minimum capaci-
tance and inductance is preferred
in order to avoid over-shoot and
ringing in the cables. Here, simple
high quality cable is of utmost
importance.
Installation
Installation
