Luminance Audio KST-150 User manual

KST-150
Owner’s Manual

Setup Recommendations
Voltage Selection (Factory Wired For 115 Volts)
Two different 60 Hz AC operating voltages (115 or 230) can be selected by changing
jumpers on the power supply circuit board inside the amp. This must be done with the
power cord removed. We strongly recommend that this be done by a certified technician
to avoid damaging the unit. Please see the pictorial diagram below for clarification.
Fuse Selection (Rear Panel AC Fuse)
When wired for 115 volt operation, use a 15 amp slo-blo 3AG fuse.
When wired for 230 volt operation, use a 7 amp slo-blo 3AG fuse.
Placement
As the KST-150 amplifier relies on convection cooling, air flow is essential. We
recommend that you do not place the amplifier in a totally enclosed area and allow 3
inches open space at the top and back. Do not stack components above or below the amp
as this may cause overheating and impair the performance.

Connecting
Ensure that the positive (red) and negative (black) terminals on your KST-150 amplifier
are connected to the positive and negative terminals on your speakers. Tighten until snug
with a nut driver or other appropriate tool. Connect the right and left RCA outputs from
your preamplifier to the right and left RCA inputs of the amplifier. Make sure the power
switch on the front panel is OFF whenever making or breaking any connections. After all
connections are made, plug the power cord into the rear of the KST-150 amplifier, and
then insert the male end into the wall outlet. Power ON the preamp and all other
components before powering on the KST-150 amplifier. Power OFF the KST-150
amplifier first, before powering off your preamp or other components.
Break-In Period
Break-in is a fundamental part of conditioning an amplifier. You should consider the
first 100 hours of operation to be the “break-in” period. During this time, the sound will
improve noticeably as the capacitors “form” and other circuit components stabilize. It is
recommended that you turn the amp off for an hour or so several times during the break-
in period. After that, you can either leave it on, so it is ready to deliver peak performance
at any time, or turn it on at least 30 minutes prior to listening. A cold amplifier will not
deliver peak performance.

Specifications
Power Output:
150 watts per channel, both channels driven into 8 ohms from 20 Hz to 20,000 Hz with
no more than .4% total harmonic or intermodulation distortion. Power output into 4
ohms: 250 watts per channel, both channels driven simultaneously into 4 ohms with no
more than .4% total harmonic or intermodulation distortion.
Load Driving Capability:
Your amplifier can be used with no degradation in performance with loads having a
nominal impedance of 3 ohms or greater.
Frequency Response:
0 Hz (DC) to 630,000 Hz, +0-3db
Slew Rate:
250 volts per microsecond
(measured before passive output Filter network)
Damping Factor:
100 (20 Hz to 20 kHz)
Input Impedance:
20,000 ohms
Output Impedance:
.15 ohms at 100 Hz, .22 ohms at 20,000 Hz
Voltage Gain:
27 db

Power Consumption:
120 watts at idle, (no signal)
400 watts, with each channel delivering 150 watts
600 watts, with each channel delivering 250 watts
Circuit Features:
The input stage differential amplifier is followed by a fully complimentary symmetry
cascoded common emitter driver stage followed by a complimentary MOSFET output
stage. The number of amplifier stages is 3. No overall global loop feedback is used. All
linearity optimization is achieved through the use of cascoded circuit topology for the
front end and driver stage. The unit is upgradeable to 300 watt mono operation through
factory modification.

Circuit Description
The circuit is a three-stage design, with the qualification that a cascoded amplifier is a
single stage (although it employs two active devices).
The input stage consists of a differential amplifier pair, with a common mode rejection
ratio of 90 db. This differential amplifier is cascoded and biased with an active current
source for each of the differential pair. The next gain stage is a complimentary push-pull
cascoded common emitter amplifier. The final gain stage is a complimentary push-pull
source follower MOSFET output stage using 4 power MOSFETS per channel.
The feedback configuration employs a negligible feedback loop arrangement, where 28
db of feedback is applied at DC to provide DC offset stability. Negative feedback is
rolled off above that frequency at a rate of 12 db per octave, so that when the feedback
frequency is 20 Hz, the feedback applied is 7 db., at 1 kHz, the negative feedback
applied is .3 db.
This configuration eliminates the use of an integrated circuit operational amplifier and its
attendant signal colorations. Cascoding the voltage gain stages enables the extremely
wide bandwidth and high slew rate. The high damping factor of 100 is achieved by using
the ultra high current gain of the complimentary push-pull cascoded common emitter
amplifier driving the high-gain power MOSFETS. Since the driver and output stage
circuits maintain full gain over the 20 Hz to 20 kHz bandwidth, the damping factor is
maintained at all audible frequencies. This means that high frequency control of the

tweeter diaphragm is equal to low frequency control of the woofer cone. A passive
output filter eliminates unwanted RF signal injection into the active circuit.
Warranty Information
Your LUMINANCE KST-150 amplifier is warranted to be free from manufacturing
defects for a period of 1 year from the original date of purchase. This warranty covers
parts and labor but excludes any defects due to abuse, excessive wear and tear, shipping
damage, or failure to use the product in accordance with the instructions. The warranty is
also void for acts of God (refer to your home owner’s policy in such event) or units that
have been tampered with or modified by any other than factory authorized personnel.
Regulations on warranty may vary depending on your local laws.
Please keep the original box and all the internal packing material. You will require these
materials to ensure safe shipping in the unlikely event that you must return the unit for
service.
For return approval and shipping info, contact our customer service department below.
Contact Information
Email: [e-mail]
Luminance Audio
1611 S. Pacific Coast Hwy, Suite 100
Redondo Beach, CA 90277