Hello, Krell family,
From our Russian partners at Alcom, below is a review translated to English on the Vanguard Universal DAC, Illusion II Preamplifier and DUO 300 XD Amplifier.
Click
here
for the original version in Russian.
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Krell components with Legacy Focus SE acoustics
Posted by: Nikolay EFREMOV Placed: December 17, 2018
Suggest any audiophile to name the most reputable manufacturers in the field of High End Audio, and Krell will most likely be in the top three. The authority of the company has earned not only the uncompromising nature of its products, but also the active introduction of original engineering developments. We will get acquainted with some of them now.
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UNITY WITHOUT STRUGGLE
High End audio is not for nothing considered to be the most conservative area - its underlying principles were developed decades ago and are rarely revised on the merits. But there are exceptions to any rule. Krell Industries, founded by recognized audio guru Dan D'Agostino, being a high-end icon, constantly introduced various innovations into its products. Moreover, not only functional and ergonomics were improved, but also the principles of circuit design. The same applies to new components that we are preparing to listen to.
The source in our system will be the Vanguard Universal DAC, combining the “professions” of a tape drive, a digital-analog converter and a pre-amplifier. When connected to the Network, it provides access not only to the Spotify, vTuner, Tidal, Deezer and QoBuz music services, but television — Netflix, Vudu and Pandora. For switching the video signal, there are two HDMI input interfaces and one output interface — all supporting 4 K. Digital Audio can be supplied via optics, coaxial and Ethernet (for example, from UPnP servers and NAS), as well as through the USB A port displayed on the front panel. Built-in Bluetooth module provides wireless broadcast of music from various gadgets.
The audio path supports playback of AAC, ALAC, AIFF, FLAC, WAV, WMA formats with a resolution of up to 24 bit / 192 kHz and DSD (DoP), as well as files with the current MQA encoding.
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In addition to the standard, the control processor is protected by the Roon Ready program. This is a very useful option that can combine several different sources in one application, for example, a streamer, a computer on a local network and a smartphone with active Bluetooth. The application Roon in a visual form displays on the tablet the content available on each resource, and allows you to stream music from them to one or more playback devices. Ie, in fact, create an extensive multi-room with convenient and fast control.
The digital-to-analog converter in the Vanguard Universal DAC is built on an ESS Saber chip with balanced outputs. The subsequent analog section is discrete, with cascades in class A and a high-quality volume control. Accordingly, the signal can be fed directly to the power amplifier via the RCA or XLR line outputs.
"In addition to the standard, the control processor is protected by the Roon Ready program. This is a very useful option."
We used the updated version of the pre-amplifier Illusion II. Thanks to its unique circuit design, it was possible to obtain phenomenal linearity, the upper limit of the working range of 1.2 MHz and distortion in the audio range of less than 0.003%. And all this - without introducing general feedback. The signal path is fully balanced, the volume is controlled by an attenuator on precision resistors.
The preamplifier has the same DAC as the Vanguard Universal DAC with Krell’s Current Mode balanced analog stages. The power section includes a 95-watt transformer, a capacitor bank of 40,000 uF and a series of stabilizers.
Up to five analog sources can be connected to Illusion II, and two of them can be connected via a balanced line. There are also two outputs, RCA and XLR. The front panel has a headphone jack with the ability to optimize output parameters for their impedance.
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Dual-channel power amplifier Duo 300 XD - very fresh development. The abbreviation XD in the title symbolizes the expansion of three important parameters - Xtended Dynamics, Xtended Dimensionality, Xtended Detail, i.e. dynamics, space and detail. XD amplifiers differ from previous versions in their ability to control acoustics with impedance dips below 1 ohm. This is achieved by lowering the output impedance (less than <0.007 ohms in the entire audio range) and a serious improvement in power supplies.
In addition, the Duo 300 XD applied proprietary technology iBias, which allows you to get the sound quality of Class A amplifiers with the effectiveness inherent in the pulse terminals. With a power of 2 x 300 W at 8 ohms, the amplifier weighs almost 32 kg and is cooled by four silent coolers, so iBias is clearly not class D. The developers refused to passive heat sinks so that the amplifier would not overheat in a narrow niche or hardware cabinet. There are other pure installation attributes - a 12-volt trigger and a network control interface on RJ45.
"XD amplifiers differ from previous versions in their ability to control acoustics with impedance dips below 1 ohm."
The Focus model is the best-selling in the history of Legacy Audio. For more than 15 years of production of these systems, the design has repeatedly undergone changes, but the basis remained the same - 4 bands, a double bass section with a 6th order bass reflex and a rigid, solid body with impeccable finish. Model Focus SE (Silver Edition) - anniversary, released on the 25th anniversary of the company. Compared to the previous, basic version of HD, the proportions of the body have changed - it has already become deeper, due to which the resistance to vibrations has increased. Focus SE has no parallel walls, and the front panel is narrowed from above to avoid frequency dips due to interference of sound waves. Since 2013, the upper band has been voiced by dual Legacy Dual Air Motion Tweeter emitters (improved AMT design) with increased efficiency. All the speakers in the anniversary acoustics are the same as in the HD version, but are selected with an accuracy of ± 0.25 dB. The Solen polypropylene capacitors are used in crossovers, and the Kimber Kable silver cable is used for internal wiring.
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The jubilee finish includes 14 stages of applying lacquer with intermediate drying and hand polishing, so it takes about three weeks to cover one case. Of course, Focus SE are also produced in natural veneer of various wood species.
When listening, the signal was fed to the Vanguard Universal DAC over Ethernet from the NAS server, and we controlled playback from the smartphone through the Mcontrol application. Music - the most different, from classic to club electronics. The nature of the sound Focus SE is familiar to me - informative across the range, dynamic, with a linear tonal balance and a transparent top. It is clear that the other links influence the final result, but the most significant contribution is made by the speaker system with the amplifier - too many factors influence their coordination. Duo 300 XD - the oldest and most powerful model in the updated series, and its potential is immediately felt. And not in a thunderous sound (although the SPL record is easy to put here), namely, the ability to make a pair of 12-inch drivers naturally convey an instantaneous transition from a short pause to a sharp attack. Nor is the control so tight that the diffusers would not be able to reproduce the smoothly damped reverberations of the drum membrane. The bass is low, fast enough, with a well-readable structure. But to feel all its depth and energy, you need a room of 30-45 meters with a hard floor and capital walls. Plasterboard partitions - not for "Focus", in an alliance with the Duo 300 XD, they turn into a real battering rams.
"Nor is the control so tight that the diffusers would not be able to reproduce the smoothly damped reverberations of the drum membrane."
What is called dynamic contrasts, the system reproduces perfectly. High class is felt in the fact that the detail and intelligibility do not depend on the volume level. The merit of the amplifier and the purity of the upper range - in the sound is not noticeable neither transistor dryness nor the veil, characteristic of the powerful tips working in the class AB. And this is despite the fact that this band is entirely devoted to Hale emitters, mercilessly emphasizing any artifacts.
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However, this compliment applies equally to the source. It is in it, more precisely, in the streaming module and DAC, i.e. circuits that are very sensitive to jitter, and there are all sorts of troubles that tire the ear in the upper spectrum. Vanguard Universal DAC in this regard is extremely transparent, gives a lot of information, but does not shift the focus on the nuances of the sound picture. You can hear the difference between the hayresis and the 44/16 rips - mostly in terms of energy and the depth of the scene. But annoying stiffness is not in any case. It sounds quite comfortable and the music played from a USB flash drive - the spectrum is not simplified, small details are not enlarged. The software and user interface at the source are well thought out, everything is intuitive and works without glitches.
"Vanguard Universal DAC in this regard is extremely transparent, gives a lot of information, but does not shift the focus on the nuances of the sound picture."
And finally, the pre-amplifier. His task is formulated simply: without showing his presence in the system, to switch sources, adjust the volume of the slightly amplified signal and pump the cable to the end. As a rule, the snag is obtained with the first item, but the Illusion II - before the transparent. When changing the volume, the scene does not fall apart, the musical balance is not disturbed, the proportions of the virtual sources do not change. The corporate principle of the Current Mode (current output signal) minimizes the influence of interconnect cables - I have already mentioned this more than once while listening to Krell equipment.
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But in general, a modern system is obtained from components of such an equivalent level that it is perceived as a single whole with a classic combination of qualities that can attract extremely demanding music lovers.
SYSTEM:
- Krell Vanguard Universal DAC Converter / Streamer
- Krell Duo 300 XD Stereo Power Amplifier
- Acoustic systems Legacy Focus SE
Krell Vanguard Universal DAC
Manufacturer: Krell Industries, LLC (USA)
Analog outputs: XLR stereo, RCA stereo || Digital inputs: USB A, Ethernet, TosLink, Coax, 2 x HDMI, Bluetooth || Digital Outputs: HDMI || Supported formats: AAC, ALAC, AIFF, FLAC, WAV, WMA with a resolution of up to 24 bits / 192 kHz and DSD (DoP) || Streaming music services: Spotify, vTuner, Tidal, Deezer and QoBuz || Stream TV services: Netflix, Vudu, Pandora || MQA: yes || Roon Ready: yes || Bluetooth protocols: A2DP, AVRCP, HFP, HSP || Output impedance: 150 ohms || Maximum RCA / XLR output voltage (DAC mode): 2/4 V || Maximum RCA / XLR output voltage (Preamp mode): 5.8 / 11.6 V || Power consumption in operation: 26 W || Dimensions (D x W x H): 428 x 433 x 88 mm || Weight: 8.2 kg || Price: 339 000 rub.
Krell Illusion II
Maximum RMS output voltage at RCA / XLR / Headphone outputs: 8/16/3 V || RCA / XLR / Headphone output impedance: 155/310/3 Ohm || Nonlinear distortion factor (20 Hz - 20 kHz) at the XLR / Headphone outputs <0.003% / <0.09% || RCA / XLR / Headphone Gain: 6/12 / 5.1 dB || S / N ratio: -107 dBA || Input impedance: RCA / XLR 20/40 kΩ || Band of reproduced frequencies (+ 0 / -0.02 dB): 0.25 Hz - 1.2 MHz || Dimensions: 438 x 97 x 464 mm || Weight: 10.4 kg || Price: 673,000 rubles.
Krell Duo 300 XD
RMS output power: 2 x 300 W (8 Ohm), 2 x 540 W (4 Ohm) || Peak output current: 16 A || Frequency band (+ 0 / -3 dB): 0.5 Hz - 100 kHz || Amplification: 26.2 dB || Distortion coefficient (1 kHz, 400 W, 8 Ohms): <0.045% || The slew rate of the output signal: 40 V / µs || Dumping factor (20 Hz - 20 kHz, 8 ohms):> 1140 || Input resistance: 100/200 kOhm || Output impedance (20 Hz - 20 kHz): <0.007 Ω || Maximum power consumption: 1600 VA || Dimensions: 434 x 194 x 536 mm || Weight: 31.8 kg || Price: 918,000 rubles.
Legacy focus SE
Manufacturer: Legacy Audio (USA)
Configuration: 6 emitters, 4 lanes || Acoustic design: phase inverter and Butterworth 6th order filter || Frequency range: 18 - 300000 Hz || Sensitivity (2.83 V / 1 m): 95.4 dB || Nominal resistance: 4 Ohms || The frequency separation bands: 120, 2800, 8000 Hz || Recommended amplifier power: 10 - 500 W || Dimensions (H x W x D): 1400 x 356 x 390 mm || Weight: 63 kg || Price per pair:
1 360 000
rub.
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Walter Schofield
COO
Krell Industries, LLC
+1-203-298-4001 (Krell Direct)
+1-781-775-5650 (Mobile)
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Krell Industries LLC
45 Connair Road
Orange, CT 06477-3650
USA
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