Sondek LP12-50 marks the fiftieth anniversary of the most iconic product in hi-fi history. This limited edition turntable was designed with our friends at the creative collective LoveFrom.
Sondek LP12-50 produces the best vinyl playback performance Linn has ever achieved, alongside the immediately recognisable and iconic design language of Sir Jony Ive and his team at LoveFrom, applied in key visual and tactile interfaces.
The sonic improvement comes by way of Linn’s all-new Bedrok™ plinth technology; formed of orthogonal layers of beech placed under extreme pressure to create an entirely new, solid and massive material. The consequent ultra-dense wood has negligible resonance and offers a superior isolating housing for the turntable’s mechanism.
LoveFrom has applied their design expertise to the new, precision-machined power/speed control button and hinges – providing delightful and precise interaction with the turntable. Further aesthetic refinements to the classic Sondek LP12 form have been made with deep respect for the quality and integrity of the product.
The combination of performance, usability, and aesthetic improvements result in an historic piece with unrivalled sonic quality and beauty. Only 250 of these limited edition Sondek LP12-50s will ever be produced – with each bearing an embossed aluminium plaque celebrating this landmark collaboration with individual numbering.
The KMA-i800 is a state-of-the-art 800 watt monaural amplifier. It incorporates Krell’s most advanced circuit topologies and Krell’s proprietary technologies iBias, XD, and Sym-Max. This gives the KMA-i800 a warm enveloping three-dimensional sound with unparalleled detail, along with the rock-solid bottom end and effortlessness that Krell is known for.
Differential Output
The KMA-i800 is a differential output amplifier. This means it contains two identical amplifiers operating out of phase to produce an output signal twice as large as a single amplifier. The main advantage of this configuration is cancelation of common-mode distortion and noise components. The KMA-i800 also incorporates special compensation to maintain very low output impedance at the low end of the frequency range. This produces high impact extended bass that is felt as much as it is heard.
iBias
iBias enables the KMA-i800 to operate in Class A up to its full rated power of 800 watts with absolute accuracy but without the heat produced by a traditional Class A design. It does this by using a novel circuit to unobtrusively monitor the current flowing through the output stage. This is part of a closed-loop controller that makes sure this current never drops below a preset level (Class A means that it never drops to zero). This is what makes the amp both efficient and accurate.
The efficiency comes from the controller adjusting the bias to maintain that low preset current level as the signal and speaker load changes. Traditional Class A amplifiers set it for the maximum level all the time so they’re always dissipating the maximum amount of heat. iBias is like having a variable size Class A amplifier. If, for example, the signal and speaker are only requiring 10 watts, it’s like having a 10 watt Class A amplifier, all the way up to 800 watts in the case of the KMA-i800.
The accuracy also comes from maintaining that low preset current level. It doesn’t matter what the signal is doing or how the speaker impedance changes with frequency, by maintaining that preset current level the amplifier is always operating in Class A. Other variable bias schemes monitor the input or output signal to adjust the bias but that doesn’t take into account varying speaker impedance. This means they will sometimes apply more bias current than necessary or drop out of Class A operation.
XD
XD is a technique for lowering the amplifier’s output impedance. This results in better control over the speaker drivers which improves musical dynamics, depth, and dimensionality. It is very dependent on maintaining thermal equilibrium in the output stage so that all the output transistors are contributing equally to the signal output. The KMA-i800 uses a massive aluminum device bar to mount the output transistors and also employs special temperature compensation across the device bar to limit temperature variations.
Sym-Max
Sym-Max is short for “Symmetry Maximization.” The circuitry in the KMA-i800 is differential, meaning that there is a positive half and a negative half. The transistors in this circuitry are complimentary, meaning opposite polarity but with equal characteristics. In practice they are not so equal which means the circuit is operating asymmetrically. Sym-Max makes small adjustments in the circuit parameters to remove this asymmetry. The result is that 2nd order harmonic distortion is almost completely eliminated. This dramatically opens up the sound stage with more detail and a better sense of pacing, making for a more realistic experience.
Power
The heart of any power amplifier is the power supply. The KMA-i800 has a massive power supply consisting of 5800VA of transformers and 188,000uF of filter capacitance. Delivering this power to the output circuit is a combination of gold-plated circuit boards and silver-plated solid copper buss bars with a very short physical path for extremely low impedance. This, along with the audio circuitry enables the KMA-i800 to double its power from 800 watts into 8 ohms to 1600 watts into 4 ohms and even 3200 watts into 2 ohms. It can drive 1 ohm speakers and will deliver a peak current of up to 56 amps.
Circuitry
The KMA-i800 uses Krell Current-Mode circuitry with advanced current mirroring that is balanced, differential, and direct-coupled. Each stage is independently tuned and matched to the previous stage for optimal operation. The output stage consists of 16 pairs of 200 watt audio power transistors and 8 pairs of audio driver transistors. This results in a frequency response greater than 100kHz for effortless reproduction of the audio band.
Control and Protection
The KMA-i800 is microprocessor controlled and has Ethernet connectivity and a 12VDC trigger input for easy connection to a home controller. The Ethernet connection allows access to the KMA-i800 web page for status information and control. The KMA-i800 is protected against high DC on the outputs, output short circuit conditions, and power brown outs.
KMA-i800 Mono Amplifier Technical Specifications
800 Watt Amplifier feature Krell Ibias, XD, and Sym-Max technologies
Analog Inputs
1 balanced via XLR connector
1 single-ended via RCA connector
Outputs
2 pr. speaker outputs via gold-plated binding posts
Control inputs
1 Ethernet via RJ45
1 12 VDC trigger input via 2-conductor 3.5 mm connector
