Krell ksa 80 b owners manual

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Ra 7Lsifllsfls
ks Krefl Industries, Inc.

20 Higgins Drive
Milford, CT 06460, USA

KSA-BOB OWNER'S MANUAL: INSTALLATION E OPERATION INSTRUCTIONS

JUNE ll 1989

GENERAL INFORMATION

Thank you for purchasing the KSA-SOB Stereo Amplifier. The
KSA-8OB 'represents the absolute latest evolution in amplifier
technology and has many innovative design features. It is one of four
amplifiers in the new KRELL Programmable Series, the features of
which are are discussed below. There are several aspects of its
operation that require your special attention and understanding
before installation is begun. Also, this document contains general
information concerning audio system installation, in addition to
specifics of the KSA-8OB.

PURE CLASS A OPERATION AND POWER CONSIDERATIONS

The KSA-SOB is rated as delivering 80 watts of Class A power, per
channel, into 8 ohms. One inherent aspect of class A operation is the
need for a large amount of current from the Ac mains. The amplifier
at idle draws 8 amps. However, the Class A rating does not completely
reveal the true, overall power of the KSA-BOB, both in terms of
output power or AC power consumption. The amplifiers maximum output
into 8 ohms is 140 watts per channel.

That every KRELL product uses Class A circuitry in all gain and
supply stages is a foundation of our design philosophy. A second
design commitment that relates to amplifiers is that every unit be
capable of doubling its output into successively lower impedances.
The KSA-SOB will deliver 160 watts per channel into 4 ohms: 320 watts
per channel into 2 ohms and 640 watts per channel into 1 ohm. And
there is headroom over these figures! It is capable of driving
impedances below 1 ohm. Use below 1 ohm requires adjustment of the
Programmable Low Impedance Limit Set circuit on the Protection Board.
This adjustment is performed by the dealer or distributor.

Given the above, the AC power supplied to the amplifier is crucial to
getting maximum performance. The KSA-BOB should have a dedicated 20
amp line.

Telephone: (203] 8743139 I FAX: (203) 878-8373 I Teiex: 643924

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Amplifiers dissipate much of the power they consume in heat. The
KSA-BOB should be installed in a location that provides unobstructed
ventilation. If you have to install the unit on shelves or in a
cabinet, extra ventilation might be necessary. This can be easily
done with fans in a variety of ways. Generally, with the front and
rear open, 2 - 3 inches clearance each side and 8 inches above the
amplifier, ventilation will be adequate.

The dimensions of the KSA-soB are: 23" wide x 22" deep x 9 high.
The unit weighs 80 pounds; shipping weight is 100 pounds.

INPUT CONNECTIONS

The KsA-BOB has both balanced and single-ended inputs. The balanced
inputs use the 3-pin XLR connectors and the single-ended inputs use
RCA connectors. The pin assignment for the XLRs is: pin 1 = signal
ground: pin 2 = non-inverting input; pin 3 = inverting input. The RCA
connector is wired in parallel with pin 2, the non-inverted input.

iny ong pf these inputs shguld be connected to a preamplifier.

The input that is not connected to the preamplifier can be used as an
output to a second amplifier for power-biamp applications. Before

proceeding with such an installation you should consult your Dealer
or the factory.

INSTALLATION

After inspection of the amplifier for any shipping damage it is ready
for installation. The wiring to and from the amplifier, and all
components in general, should be arranged in a neat, organized
manner. Specifically, AC wires should be separated from audio wires.

This avoids hum or other unwanted noise from being induced into the
system.

It is always preferable to run long interconnect cables to the
amplifier and keep speaker cable length to a minimum. Speaker cable
does add impedance between the amplifier, regardless of its guage.
All KRELL amplifiers will drive the lowest impedances with ease. When
impedance is added in any significant amount, amplifier power is
literally wasted in driving the cable, thereby reducing the maximum
power that can be delivered to the speaker.

The feet on the KSA-eoB can be used two different ways. They are made
from machined aluminum and are supplied with separate rubber bottoms
and mounting screws. The rubber bottoms can be screwed into the the
feet for protection of fragile surfaces such as hardwood floors or

furniture. For use on rugs we recommend using the feet without the
rubber bottoms.

Once the amplifier is in place and turned off, connect the speaker
and interconnect cables. The preamplifier should be on at this point,
with level fully attenuated; all other sources should be off. The two
sets of 5-way binding posts for each channel's output are wired in
parallel. Connect the AC last.