Krell K-300p Phono Preamplifier
The K-300p is a high-performance phono preamplifier for moving coil and moving magnet phono cartridges. With separate moving coil and moving magnet inputs, the K-300p provides an optimal interface for each cartridge type.
- Separate MC and MM inputs, on-the-fly selectable
- Adjustable resistive loading for MC input: 10, 25, 47, 100, 249, 470, 825, 1k ohms (47k default)
- Adjustable capacitive loading for MM input: 10, 20, 47, 100, 220, 330, 470, 680 pF (0 pF default)
- Adjustable gain for MC input: 62, 56, 50, 44 dB
- Adjustable gain for MM input: 36, 30 dB
- Selectable infrasonic filter (14Hz)
- Selectable absolute phase
With adjustable resistive loading from 47k down to 10 ohms and up to 62dB of gain (at 1kHz), the moving coil input can accommodate a wide variety of cartridges, even low output models. The input is fed to a hybrid discrete-IC circuit using paralleled low-noise transistors and a Burr-Brown SoundPlus™ op-amp. This creates the low-noise environment necessary for high gain operation while taking advantage of the best audio features of each section.
The moving magnet input runs into a dual low-noise FET circuit that provides a highly stable input impedance of 47k ohms. With adjustable capacitive loading from 0 to 680pF and gain up to 36dB it is well matched to modern moving magnet cartridges.
The output from the moving coil or moving magnet sections goes into a passive RIAA EQ network featuring precision resistors and polypropylene film capacitors. This produces a highly accurate frequency response that has only a +/-0.2dB deviation from ideal.
From there the signal goes into a balanced output stage utilizing Krell Current-Mode topology. This circuitry has greater bandwidth than traditional voltage-mode designs for exceptionally transparent and effortless sound quality.
Power Supply Design
The power supply utilizes a custom designed linear tracking regulator that is extremely quiet and stable. This is important for high gain circuits in order to reduce the overall noise level and ensure symmetrical treatment of positive and negative signal excursions.
The K-300p is very easy to setup and operate. All the loading and gain settings are accessible on the rear panel without the inconvenience of opening the unit. Moving coil or moving magnet inputs are selectable on-the-fly from the front panel. There is also a default input switch on the rear panel so the commonly used input can be set to come up whenever the K-300p is powered on. The absolute phase button on the faceplate can correct for recordings that may be phase inverted. And the infrasonic filter button engages a 14Hz critically damped high-pass filter that can eliminate low frequency acoustic feedback problems.
The K-300p is packaged in an attractive black or clear anodized aluminum and steel chassis that will fit on a standard rack shelf.
Download the Krell “K-300p Owners Reference”
Download the Krell “K-300p Product Sheet”