S-550i
Integrated Stereo Amplifier


Building on the success of the award winning S-300i integrated amplifier, the S-550i boasts the sound quality and power output capable of driving any loudspeaker to its maximum performance. Delivering 275 watts of stereo output, the S-550i is a power source for virtually any speaker on the market while occupying a fraction of the space typically required for a system delivering this sound quality. The S-550i is outfitted with balanced and single-ended inputs, iPod dock, and Theater Throughput™ mode. Developed by Krell, Theater Throughput™ simplifies integration into home theater systems. For custom integration applications, 12 volt triggers, RS-232 connectivity and rack mount ears are included. Operational parameters can be customized via the menu system that is accessible from the front panel or the included brushed Aluminum remote control.


The preamplifier section features circuit concepts from Krell's flagship Phantom preamplifier. Krell Current Mode provides unequaled bandwidth for the most revealing playback of today's high resolution music sources. Direct coupled circuitry eliminates impact-robbing capacitors from the signal path and an elegant, custom-machined level control adjusts volume. Discrete circuitry, in a balanced topology, is afforded its own power supply regulation. All signal gain is realized using surface mount technology featuring proprietary current mirrors with nearly 500 times the open loop linearity of other designs. Negative feedback is not used anywhere in the preamplifier, nor is it necessary. Open-loop distortion is typically less than 0.003%. The volume control is realized with a balanced resistor ladder - bandwidth and transient response of the preamp circuitry are virtually unaffected by the volume setting.




The S-550i packs a massive 1,750 watt transformer and 68,000?F of capacitance into an elegant 5" high chassis. This power supply feeds classic Krell circuitry throughout the topology using only discrete circuitry. As with all Krell amplifiers, the S-550i design is an ideal voltage source. That is, the S-550i doubles its power output when a speaker's impedance is halved. For the S-550i, the results are 275 watts into 8 Ohms and 550 watts into 4 ohms. This capability is essential for realistic reproduction of a recording's dynamic content. Most amplifiers can't deliver this power doubling, leaving music sounding compressed and lifeless.




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S-300i
Integrated Stereo Amplifier


The S-300i is the first Krell integrated amplifier to feature iPod connectivity and extends the award winning tradition of audiophile grade integrated amplifiers.

A low profile chassis fronted by an elegantly finished silver Aluminum front panel hints at the potent circuitry hidden within its walls. Small in stature but big in performance, the S-300i integrated amplifier develops 150 W into 8 Ohms and 300 W into 4 Ohms. Employing a massive 750 VA toroidal transformer and 38,000 microfarads of capacitance guarantees huge power capability for maximum dynamic impact. Both balanced and single-ended inputs are provided, and the Theater Throughput™ mode, developed by Krell, simplifies integration into home theater systems. Robust WBT binding posts provide superior loudspeaker cable termination. New for the S-300i is direct connection for all generations of Apple iPods /iPhones with complete control of the iPod functionality via the included remote control. Unique for the category, the S-300i taps audio from the fully differential output included in the internal DACs of iPods/iPhones and maintains this balanced signal throughout the circuitry.


The S-300i features the latest Krell Class A, direct coupled design, and fully balanced preamplifier circuitry for the lowest noise reproduction possible. Krell Current Mode provides unequaled bandwidth for the most revealing playback of today's high resolution music sources. Direct coupled circuitry eliminates impact-robbing capacitors from the signal path and an elegant, custom-machined level control adjusts volume.


The included solid aluminum remote control replicates all front panel options as well as providing control for a connected iPod/iPhone. RS-232 is also included for inclusion in advanced control systems.





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