Krell KRC Preamplifier with Separate Krell Power Supply

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Solid state flagship preamp from Krell dating back to the late 1990's when they made superbly reliable and innovative equipment.

Retailed for close to $7000 in 1997 ($12k+  in today's dollars).

This is a line stage only, capable of receiving an optional phono module sold separately, or you can use an external phono preamp like Krell's fantastic KPA.

Perfect working condition, fully tested in our lab and listening room.

Cool working motorized remote control does not degrade the sound quality.

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer. 

Summit Series Silver Streak Analog Interconnects (PAIR) - BALANCED XLR Connectors

Summit Series Silver Streak Analog Interconnects (PAIR) - RCA Ultraplate or WBT Connectors

Kimber Kable - Base Series PK14 Power Cord

SkyFi Service Notes
• Opened and cleaned volume control with F5 resolving the minor issue with scratchiness on the scope.
• Lubrication and realignment fixed the motor stalling issue. Necessary to lubricate the volume pot shaft and work the volume control with motor in small increments, retesting constantly. Resolved as entire range is smooth without stalling.
• Internal and External cleaning.
• Full function test PASS.
• Balance I/O PASS.
• Single Ended I/O PASS.
• Remote functions OASS. 
• No phono stage installed. Phono input is line level.

From the Krell KRC Preamplifier Owner's Manual:
Thank you for your purchase of the KRELL KRC remote control preamplifier.

The KRC combines refinements of the original KRC with a radical approach to volume control circuitry.

The HR designation signifies HIGHEST RESOLUTION due to the substantial improvement in sonic quality provided by our most sophisticated electronic volume control.

The unit also has a Theater-Throughput, which allows easy installation of the unit within a home theater system.

Specifications:
GAIN:
6 dB or 12 dB

SIGNAL TO NOISE:
96 dB unweighted

THD:
1 KHz less than .01%
20 KHz less than .01%

INPUT IMPEDANCE:
47,000 Ohms (47K Ohm)

OUTPUT IMPEDANCE:
5 Ohms

OUTPUT VOLTAGE:
14 volts R.M.S.

DIMENSIONS:
Unit Dimensions:
19.0" Wide
14.5" Deep
2.75" High, with feet

Power Supply Dimensions:
11" Wide
9" Deep
2.5" High

The SkyFi Testing Process for Preamplifiers:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.

We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.