KRELL KSA-150 (01) PDF Document

The KRELL KSA-150 will operate at its peak with a dedicated 20-amp line, although this is not a requirement. The amplifier should only be operated with the power cord supplied with the unit. Use of other power cords may damage the amplifier and void its warranty. Please consult your dealer before using any devices designed to alter or stabilize the AC power for the KRELL KSA-150.

Remove the unit, power cord and accessories from the shipping container. Store all packing materials in a cool, dry place for future use. Inspect the unit for shipping damage. If any damage is evident, contact your dealer immediately. If the unit is in proper condition, proceed with the installation.

• Do not connect the power cord into the AC mains before completing the entire installation.

• The unit must always be turned off while making connections.

• Krell XLR and custom RCA connectors are made to very exacting standards. Connectors of lesser quality may damage the amplifiers or cause poor connections. Please check with your dealer about the use of any other connectors.

Amplifiers dissipate much of the power they consume in heat. The KRELL KSA-150 must be installed in a location that provides unobstructed ventilation. If the unit will be installed on shelving or in a cabinet, extra ventilation is necessary. This can be accomplished with the use of ‘whisper’-type fans. Generally, with the front and rear of the installation shelving or cabinetry open, 8 inches of clearance on the sides and top of the amplifier should provide adequate ventilation.

The KRELL KSA-150 has both balanced and single-ended inputs. The balanced inputs use 3-pin XLR connectors and single-ended inputs use RCA connectors. The pin assignments for the XLRs are: 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. Only one of these inputs should be connected to the preamplifier.

The KRELL KSA-150 is shipped with shorting pins in the XLR inputs. These pins must remain in the XLR inputs if the unit is to operate in the single-ended mode. These pins must be removed to connect the unit for balanced operation. The shorting pin connects pins 1 and 3 and grounds the inverted input.

Yes, the wiring to and from the amplifier should be arranged in a neat, organized manner. Specifically, AC wires should be separated from audio wire. This ensures the avoidance of hum or the introduction of other unwanted noise into the system. It is always preferable to run long interconnect cables to the amplifier and to keep speaker cable length to a minimum to reduce the maximum power that can be delivered to the speakers.

The feet on the KRELL KSA-150 can be used three different ways. They are made from machined Delrin and are supplied with separate rubber bottoms and mounting screws.

1. The rubber bottom can be screwed into the Delrin for the protection of fragile surfaces such as hardwood floors or furniture.

2. For use on rugs or carpeting, using the feet without the rubber bottoms is recommended.

3. You may purchase a set of Acoustic Mass Dampers (AMDs) from your authorized dealer. AMDs are custom-machined stainless steel feet that thread into the Delrin feet to decouple the amplifier from vibrations present on the surface where the unit is installed.

Activate the system by turning on the source components and preamplifier with the volume fully attenuated (turned down). The amplifier must always be turned on last. Just after turn-on, a soft click will be heard, which is the main power relay closing. After the protection circuits detect that the unit has completely stabilized, the speaker relays will engage, and another click will be heard. The amplifier is now ready to use. The amplifier will be at temperature and sound its best after approximately 15 minutes.

When turning off the system, the amplifier should always be first. This avoids the possibility of a turn-off transient occurrence from some other component to the speakers.

Yes, care must be taken in the operation of the whole system in relation to the significant power output of the amplifier.

• Mistakes, such as switching between active sources without muting the preamplifier output or bumping/miscuing a phonograph cartridge, can generate large transients at low frequencies which can damage most loudspeakers.

• All switching of sources should be done with the preamplifier level either muted or fully attenuated (turned down).

• Inputs to the amplifier should never be changed while the amplifier is on.

• Because of their tremendous reserve of clean power, Krell amplifiers can safely drive speakers to higher sound pressure levels than other amplifiers. Always turn the volume level down at the first sign of distortion.

When the Input Protection is engaged the amplifier will remain on, with the front panel LED illuminated, but it will not pass a signal. This indicates a problem with the input signal caused by the preamplifier or source component, most often a DC condition. The amplifier will resume passing signal when the problem is resolved.

When the Output Protection is engaged the amplifier will turn off, with the front panel LED turning off as well. This usually indicates a problem with the speaker wires, their connection, or the speakers themselves. Once the problem is located and resolved the amplifier will turn on normally with activation of the front panel switch. The Output Protection will also engage if the amplifier fails. If the amplifier will not turn on with all inputs and outputs disconnected, please contact your dealer.

1. When the Output Protection circuitry has been engaged, allow at least 20 seconds before turning on the amplifier again. Repeated fast cycling of the On/Off switch can damage the amplifier and void the warranty.

2. If the amplifier does not come on following the procedure above, please contact your dealer.

3. There is a circuit breaker on the amplifier rear panel. This breaker protects the amplifier in the event of catastrophic failure. If the circuit breaker engages, contact your dealer. Do not attempt to reset the circuit breaker.