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Reviewer: David Kan
Financial Interests: click here
Analogue Source: Denon DP-59L, Denon DL-302, Ensemble PhonoMaster
Digital Source: Marantz SA8260, Deltec PDM Two DAC, Restek Radiant, Assemblage D2D-1/DAC-3.1 Platinum
Preamp: Symphonic Line RG3 MkIII, NuForce P9, Audio Zone PRE-T1, KingRex PREference
Power Amp: NuForce Ref 9 V2 SE, Symphonic Line RG4 MKIII, JohnBlue TL66
Speakers: Dynaudio Facette, Apogee Centaur Minor, Mark & Daniel Diamond, Klipsch Synergy F2, Loth-X BS-1
Subwoofers: Yamaha YST-SW80, Mark & Daniel Maximus-Subwoofer
Cables: Clearaudio Silver Line interconnect, Deltec Black Slink interconnect, Luscombe LBR-35 interconnect, Artisan Silver Dream [in for review], OCOS speaker cables by Dynaudio, Aural Symphonic Digital Standard digital cable
Power Cords: Aural Symphonic Missing Link, Ensemble Powerflux, Symphonic Line
Power Line Conditioning: Tice Power Block IIIC, Monster Power HTS-3500 Mk II (modified by NuForce), Monster Power HTS-1000 Mk II
Room Size: 15’ x 13.5’ x 7’/8’ diagonal setup, carpeted concrete slab floor, suspended ceiling and all walls finished with drywall (basement with small window on one side, which is concrete foundation wall with insulation) / 12' x 24' x 9' opens to 12' x 17' x 9' L-shape, short wall setup, suspended hardwood floor, suspended ceiling and all walls finished with drywall, external wall finished with insulation inside and concrete on the outside.
Review component retail: $2,500 VL20, $ 2,650 VS70 (the flagship models retail at $4,600 for the VL10.1 and $5,200 for the VM60)
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JE is for je ne sais quoi. On first sight, the JE Audio gear had a certain je ne sais quoi about it that attracted me. After months of prolonged auditions, I now think I know. Let’s begin with the man behind the brand. John Lam, founder and chief engineer/designer, is a well-groomed and meticulously organized man who always keeps his home and office impeccable. Nope, I haven’t met John nor have I ever visited his home or office. These are mere assumptions based on his website and VL20 and VS70 creations. Audio palm reading if you like. For sure he’s the scholarly type as the website details: "John received a Ph.D in electrical engineering. Before he founded JE Audio, he worked in the semiconductor industries for over 11 years in various applications and sales & marketing positions. John developed a great interest in audio since his early teens. In recent years, his keen interest in vacuum tube devices led his design team to develop innovative fully balanced tube topologies. The dedication from the design team resulted in more than six international patents and various recognitions from the audio industry."
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When I asked John for a photo, he politely declined. Nonetheless he sent me one of his neat and tidy showroom, which did confirm part of my earlier notions. The audio components in the showroom include an Esoteric X-01 SACD player, Sony XA777ES SACD player and Sonus Faber Amati and KEF REF 205/2 speakers.
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If I could hand out a Blue Moon Award merely on the basis of visual statements, the VL20 and VS70 duo would have snatched one just like that. Only a handful of tube kit these days—Nagra, Hovland, Opera and the Luxman CL88/MQ88 spring to mind—pioneers a bold new look which not only defies tradition but defines a unique brand image. For a new Hong Kong player (JE’s inaugural product launched in 2007), it’s quite unexpected to join this league. Don’t pretend looks don’t matter.
In terms of build quality, the JE Audio components occupy the heavy-duty industrial class. Aesthetically, the VL20 line preamplifier and VS70 power amplifier adopt a clean modernistic approach to chassis design, a logical evolution of their stable-mate VL10 flagship preamplifier reviewed by Edgar Kramer. While the replacement VL10.1 retains the same straight-faced industrial aluminum alloy chassis with sturdy flat panels contrasting with black-anodized corner pillars [above right], the VL20 and the VS70 clean up the four corners and give the front and side panels a mild slant.
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The stylish laser-cut fascia of the preamp gallantly spells out Balanced Tube Amplifier. The most striking design feature is the square center opening through which the tubes insert horizontally. It’s not just open at the top. It’s also bottomless. This creates a chimney effect to facilitate heat dissipation. You still observe ventilation safety rules as with any tube component but this scheme contributes to the preamp’s distinctive look and a new kind of tube magic - now you see it, now you don’t.
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The stainless steel tube protection is secured by two screw-mounted brackets which are removable with the cage itself. Unlike that of the VL10, the cage removed leaves no trace of screws holes or mounting devices. Clean and tidy. Inside the opening, tube assignations are clearly marked in black silk-screen.
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Both VL20 and VS70 have their power rocker on the back next to the IEC receptacle for shortest power wiring and minimal interference. The front panels are sparsely populated – two knobs for the preamp (input and volume), one for the power amp (volume). The same tidiness applies to the backs. The preamp has four sets of line inputs both balanced and unbalanced, with a toggle making the selection. Outputs are balanced and unbalanced and may be connected simultaneously for bi-amping. Since the balanced output yields 3dB more gain, it’s recommended to connect that to the LF amp. The power amp also uses a toggle to switch between XLR or RCA inputs. There are two sets of binding posts for 8/4 ohms. Both machines measure 160 x 444 x 387mm HxWxD. The preamp weighs 15kg., the amp 24kg. Each piece is fitted with three aluminum alloy footers bolstered with Sorbothane triplet cushions. |
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VL20: The JE Audio motto is signal integrity from source to amplification, the modus operandi fully balanced. The VL20 line stage preamplifier employs the simplified version of the patented Wideband Unity Balanced Amplifier (WUBA) topology pioneered by the flagship VL10 now updated to VL10.1. A detailed description of the topology is posted on the FAQ/White Paper section of JE Audio's website. In essence, WUBA is a multi-triode single-stage as opposed to cascading-stage amplifier to reduce phase shift and distortion that would require global negative feedback. In addition to zero global negative feedback, the JE preamplifier eschews load resistors, buffers, followers, semiconductors, op-amps and transformers for signal amplification to net a 500kHz bandwidth. To improve the Common-Mode Rejection Ratio, a wideband Mosfet acts as constant input current source and improves accuracy in the differential circuit.
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What are the key differences between the affordable preamp and the flagship version? The VL20 uses two 6H30 dual triodes per channel instead of three as the VL10.1. It's essentially the same wide-bandwidth differential amplification circuit where the first pair of triodes amplifies the balanced input signal while the second pair presents the active load to lower the output impedance. The flagship is a true dual-mono design with two premium-grade R-core power transformers and two DC-regulated power supply boards with a price of $4,600. With the VL20, you get the majority of the more upscale stable mate in a more streamlined chassis with one premium-grade R-core power transformer and one DC regulated power supply board but one extra pair of balanced and unbalanced inputs - for only $2,500.
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VL10.1 - $4.600 |
VL20 - $2.500 |
| Circuit design |
Wideband Unity Balanced Amplifier |
Wideband Unity Balanced Amplifier |
| Tubes |
6 x 6H30 |
4 x 6H30 |
| THD |
< 0.05% (@ 2V/100k Ohm load |
< 0.08% (@ 2V/100k Ohm load) |
| Max output |
> 40V (@100k Ohm load) |
> 40V (@100k Ohm load) |
| Gain |
15dB |
14B |
| Bandwidth |
10Hz-500kHz +0/-3dB, volume bypassed |
10Hz-500kHz +0/-3dB, volume bypassed |
| Input impedance |
>47/94kOhm RCA/XLR |
>47/94kOhm RCA/XLR |
| Output impedance |
1.1kOhm per phase |
1.1kOhm per phase |
| Power consumption |
90W |
68W |
| Dimensions |
150 x 445 x 395mm HxWxD |
160 x 444 x 387mm HxWxD |
| Weight |
14kg |
15kg |
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The specs look frightfully similar. So I asked John what exactly the flagship was doing with its extra pair of 6H30s and if there were other extras I had missed."In the VL20, the top triode works as an active load for the bottom triode which is also referred to as a differential SRPP arrangement. In the VL10.1, the top triode again works as an active load. But if you look at the second and bottom triode together, they form the classic cascode amplifier with wide bandwidth and high linearity. With the top triode working as active load, the WUBA circuit offers low output impedance, wide bandwidth and high linearity all in a single stage. These are all desirable features for a preamplifier. If you want to know more, refer to US patent 7,482,867."
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So there you are. The VL20 is a differential SRPP. There have been many successful implementations of shunt regulated push/pull circuits including Leben's RE100 preamp and the Audio Space Pre-2. SRPP circuits are renowned for wide frequency response, high S/N ratios, superb EMI rejection, negligible phase shift and very low output impedance that can drive electrostatic speakers. A balanced SRPP was something to look forward to. When I asked John if the VL10.1 'cheated' with higher-grade parts, he assured me that they are "pretty much the same grade". I could see Rubycon, BHA and M-Cap Supreme silver/oil capacitors.
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As to the gateway into the preamp, the volume control of the VL20 is identical to that of the VL10.1 - a balanced shunt type around the popular Alps Blue Velvet 50K A-logarithm pot not connected in traditional fashion. In a single-ended preamp with shunt volume as in the classic Audio Note designs, a fixed resistor becomes the series element of the voltage divider and the logarithm pot the variable resistor for the shunt part. The JE Audio balanced shunt type volume control simplifies this since no ground connection is needed. The signal does not pass through the control which functions merely as attenuator and won't affect sound quality with deterioration over the years. (My Symphonic Line RG3 MKIII preamp featuring Alps pots for volume and balance had to have them either replaced or dismantled and sprayed with contact cleaner.)
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