Krell KSA 300s – High End Stereo Equipment We Buy

McIntosh is one of the most dependable brand names when it comes to high-end audio systems. For years the brand has been recognized by audiophiles throughout the world as equipment that delivers clear and consistent quality in music. McIntosh is probably best known for its amplifiers and preamps, but the company produces many other components and parts for stereo and home theatre.

What are the specs for the Krell KSA 300s?

Solid-state stereo power amplifier.
Power rating:
300Wpc into 8 ohms, doubles with each halving of load impedance down to 1 ohm (24.8dBW).
Frequency response:
20Hz–20kHz, +0.0dB, –0.1dB; 1Hz–150kHz, +0.0dB, –3dB.
less than 0.1% at 1kHz, less than 0.3% at 20kHz, full power.
Slew rate:
Input sensitivity:
2.5V rms.
Damping factor:
greater than 120.
S/N ratio:
Input impedance:
47k ohms.
Power consumption, idle:
19"" W by 8.5"" H by 24"" D.
185 lbs (net)

What else to know about the Krell KSA 300s?

"The other aspects of the KSA-300S's design are more conventional, though by no means conventionally executed. The amplifier is direct-coupled; there are no capacitors in the signal path. Instead, electronic servos are used to eliminate unwanted DC. The circuit is fully complementary from input to output. Front-end driver circuits are high-bias, true class-A. First-rate materials are used throughout, from the anodized and hard-coated (a process said to be much harder than simple anodizing) front panel to the four-layer printed circuit boards. But exotic, expensive parts are not used where, according to Krell, they wouldn't have real benefits. Protection circuitry is provided for DC, short circuits, oscillation, AC power problems, high ground resistance, or out-of-phase ground. There are no fuses—only a single rear-panel circuit breaker.

Both balanced and unbalanced inputs are provided, and two pairs of output terminals are furnished to facilitate bi-wiring. The latter are superior-quality, gold-plated custom units optimized for spade lugs (they do not take banana plugs). They are also designed with a hex-head and may thus be easily tightened with a nut driver—unlike some of the otherwise excellent custom output connectors we have seen which omit this feature and therefore can only be hand-tightened. (A nut-driver is not a torque-wrench, and should be used only to ensure a secure connection, not a permanent one.)

But the KSA-300S's power supply is its most awe-inspiring feature. The 5kVA transformer occupies a huge portion of the amplifier's interior (and a large portion of its weight). The filter capacitance is 272,000µF (more than a quarter of a farad). Heavy bus bars connect much of the critical power supply and output circuitry. The supply is fully regulated. The net result is an amplifier rated to deliver power into loads down to 1 ohm, with a power supply so prodigious that the output is specified to continue to double for each halving of the load impedance below 8 ohms (300Wpc into 8 ohms, 2400Wpc into 1 ohm).

One might easily argue that the KSA-300S's design is engineering overkill. Do you really need, for example, its race-car–like performance into low impedance loads? Or a backbreaking weight that requires two strong people to move it? (footnote 2) Clearly, not all loads are difficult loads, and not all listening situations require enormous power reserves. Potential buyers of an expensive, bulletproof amplifier such as the KSA-300S should remain conscious of what they're buying and approach such a purchase with their eyes open. But the KSA-300S is an amplifier which is unlikely to be taxed by any conceivable load, now or in the future." - Stereophile (2010)

Brief History of McIntosh

Long mapped-to Binghamton New York – the current headquarters and manufacturing center for Krell Labs – not many people know the brand was originally launched outside of the Nation’s Capital in Silver Spring Maryland, in 1949. In 1956, the brand built their original facility in New York, according to the official brand website.

StereoBuyers has purchased tens of thousands worth Krell brand equipment since 2014, with individual buys ranging from $100 to well over $50,000. If you are moving, ready to upgrade, or have Krell equipment you do not or will not be using, why not contact us today to find out if it is worth good money?

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The following images show actual Krell equipment purchased by StereoBuyers.