Amplifier Troubleshooting

HOW TO TROUBLESHOOT SYSTEM NOISE

AC grounding becomes critical when connect- ing high performance audio components. When you mix and match audio components, each with its own ground potential, a low frequency hum may occur in one or both speakers. This often occurs when introducing a new compo- nent into a system.

If a low frequency hum emanates from the speakers when you place the Full Power Bal- anced amplifier into the system, follow these simple troubleshooting steps:

Note

During these steps, the back panel power breaker switch remains in the on position.

1.Check all input and output connections, making sure they are of sound construction. With the amplifier in stand-by mode, remove the interconnect cables, then press the front panel power button. If the hum disappears, press the power button to return to stand-by mode, and reinsert one of the interconnect cables. Press the power button again. If the hum reappears with one or both intercon- nects inserted, there may be a defective cable. Have the interconnect cables checked before proceeding.

2.If the interconnect cables are sound, you may be experiencing a ground loop. This can often be easily eliminated. Please con- tact your authorized Krell dealer, distributor, or Krell for suggestions on how to solve this problem.

HOW TO EVALUATE AMPLIFIER OPERATION

The amplifiers are protected by a series of non- intrusive circuits that constantly evaluate the amplifier’s operation. This circuitry protects against damaging DC input or output and short circuits, see also DC Protection Circuitry, on page 14, and monitors regulator operation, ensuring constant voltage to the output stage. The protection circuitry in a Full Power Bal- anced amplifier is designed to prevent damage to the amplifiers or speakers caused by other defective components, faulty wiring, system mishandling, or amplifier failure.

In addition, when a Full Power Balanced ampli- fier’s DC protection circuitry senses a problem within the system, it identifies, then indicates the problem by illuminating the front panel blue LEDs, as described in the following table.

Notes

The Krell CAST LED illuminates only if a Krell CAST input is being used.

There are no output fuses in Full Power Bal- anced amplifiers.

Krell Full Power Balanced X Series Power Amplifiers

700cx, 400cx, 300cx, 750Mcx, 450Mcx, 350Mcx, 700cx, 400cx, 450Mcx, 350Mcx specifications

Krell Industries is renowned for its high-performance audio equipment, particularly its line of powerful amplifiers that deliver premium sound quality. Among these, the 450Mcx, 700cx, 400cx, 350Mcx, and 750Mcx models stand out for their robust capabilities and advanced technologies, making them popular choices for audiophiles.

The 450Mcx is a class AB power amplifier capable of delivering an impressive 450 watts per channel into 8 ohms. This model is equipped with Krell's signature current-mode topology, which ensures a high level of linearity and a dramatic reduction in distortion. With a heavy-duty construction, including a massive power supply, the 450Mcx offers deep bass response and engaging midrange clarity.

Next in line is the 700cx, which pushes boundaries with 700 watts per channel. This amplifier features Krell's Advanced Power Supply (APS) technology, enabling it to maintain stability even under the most demanding speaker loads. The result is explosive dynamics and captivating detail, delivering a listening experience that is both immersive and exhilarating.

The 400cx is designed for versatility, providing 400 watts per channel in a compact form. This model utilizes Krell's patented CAST technology, which minimizes signal degradation, ensuring that the audio signal retains its integrity from input to output. It is ideal for both home theater and stereo applications, allowing users to enjoy a rich sonic palette.

The 350Mcx, while delivering a powerful 350 watts per channel, is designed with a focus on reliability and heat dissipation. The dual-transformer design and sophisticated thermal management system ensure consistent performance, even during prolonged usage. It embodies Krell's commitment to sound fidelity and performance longevity.

The 750Mcx takes performance to the next level with remarkable output capabilities. This amplifier is built with multiple output devices in a high-current configuration, designed to drive even the most challenging loudspeakers. Its refined circuitry contributes to a soundstage that is both wide and deep, enriching the listening experience.

In addition to these models, Krell also offers the 300cx and the 350Mcx, both designed to cater to a variety of audio preferences and configurations. Each unit is meticulously engineered to deliver ultrasensitive dynamics and a transparency that brings recordings to life.

These Krell amplifiers not only emphasize power and performance, but they also showcase luxurious design and durability. The combination of advanced technologies, such as current mode and APS, ensures that users receive a premium audio experience that stands the test of time. Whether for professional use or high-end home listening, Krell amplifiers are truly an investment in quality sound.