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The 400Hz oscillators supply individual left- and right-channel isolation transformers, followed by rectifiers and discrete DC voltage regulators. The outputs supply clean, stable 400Hz power in the adjacent left and right "towers" capping the Controller. Each tower, machined from a solid block of aluminum, contains the power supply for its respective audio channel. An isolation transformer mounted inside the block further decouples the audio-regulation stages from the 400Hz oscillator amplifier. Soft-recovery diodes rectify and filter the transformer's output, which is then regulated with a…
Power and control connections
Each channel is connected to the Controller by a 10-conductor, heavily shielded DC cable. Four conductors deliver regulated DC power to the preamplifier's audio circuits; the other six carry DC control signals. More important, each channel's microprocessor is active only when receiving control signals—otherwise they're in "sleep mode" and entirely silent. A low-voltage, differential-drive control signal, buffered by optoisolators, issues commands. Except for the fraction of a second when the microprocessor is actually transmitting one of these commands,…
Each channel is connected to the Controller by a 10-conductor, heavily shielded DC cable. Four conductors deliver regulated DC power to the preamplifier's audio circuits; the other six carry DC control signals. More important, each channel's microprocessor is active only when receiving control signals—otherwise they're in "sleep mode" and entirely silent. A low-voltage, differential-drive control signal, buffered by optoisolators, issues commands. Except for the fraction of a second when the microprocessor is actually transmitting one of these commands,…
Volume control
The No.32 Reference introduces Mark Levinson's new active attenuator. The attenuator modules are constructed on their own four-layer Arlon boards, where local power-supply regulation and bypass capacitors make for clean power and optimum isolation. An array of precision resistors provides attenuation in 0.1dB steps down to -57.0dB, at which point the steps increase to 1.0dB. In total, this hardware provides for more than 65,000 steps, allowing the No.32's "stepped attenuator" to act—and sound—like a continuously variable control. Optimal volume was always a cinch to find…
The No.32 Reference introduces Mark Levinson's new active attenuator. The attenuator modules are constructed on their own four-layer Arlon boards, where local power-supply regulation and bypass capacitors make for clean power and optimum isolation. An array of precision resistors provides attenuation in 0.1dB steps down to -57.0dB, at which point the steps increase to 1.0dB. In total, this hardware provides for more than 65,000 steps, allowing the No.32's "stepped attenuator" to act—and sound—like a continuously variable control. Optimal volume was always a cinch to find…
Sidebar 2: Associated Equipment
Analog source: Rega Planar 3 turntable and RB300 tonearm, Grado Reference Master cartridge.
Digital source: California Audio Labs CL-20 DVD/CD player, Sony SCD-777ES SACD player.
Preamplification: Musical Fidelity Nu-Vista and A3CR preamplifiers, X-LP2 dual-mono phono stage; Blue Circle B3 Galatea preamplifier.
Power amplifiers: Musical Fidelity Nu-Vista 300 and A3CR, Mesa Baron.
Loudspeakers: Joseph RM7si, Celestion A3.
Cables: Interconnects (all Synergistic Research): Resolution Reference Mk.II, Designer's Reference with Discrete and…
Sidebar 3: Measurements
The Legend Starlet is about as basic an integrated amplifier as you can imagine: three inputs, a selector switch, and a volume control. There's no tape loop, so it wasn't possible to distinguish in the measurements between the active preamplifier section's contribution and that of the power-amp section. The significance of this will become apparent.
Maximum voltage gain into 8 ohms was lower than usual at 38.33dB; a sensible design choice, in my opinion, given that almost all preamps have too much gain for the power amps with which they'll be used. With…
Legend states in its literature that the Starlet's measured performance will be worse than that of a "$100 RadioShack amplifier." This was certainly the case when I examined the amplifier's levels of distortion. The literature implies that the Starlet's higher-than-usual THD number was deliberate and "contributes to the perception of power." But when you look at fig.3, which shows the percentage of THD+noise plotted against frequency at 2.83V into a variety of loads, including a simulated loudspeaker, it is difficult, for me at least, to sympathize with this design approach. Levels of THD…
Second-harmonic distortion is surprisingly euphonic; the ear can tolerate reasonably high levels of it, due to psychoacoustic masking and the fact that the second harmonic has a musically consonant octave relationship with the fundamental tone. But the same bent transfer function that gives rise to the harmonic distortion, if too bent will also produce high levels of intermodulation distortion, which is subjectively far more damaging to music. Fig.7 shows the spectrum of the Starlet's output while it struggles to reproduce a 1:1 mix of 19 and 20kHz tones at an indicated 6W into 4 ohms, just…
Sidebar 4: Manufacturer's Comment
Editor: Thank you for reviewing the Legend Starlet [in December 2000]. John Atkinson was exactly right about the testing result. When we put the Stereophile review sample of the Starlet on our test bench, we discovered that the preamp tube (the 5814A) was badly degraded, which did indeed make the Starlet a distortion machine. After we replaced it with a new 5814A tube, it worked beautifully again. We would like to send you a proper working unit to test again.—Ray Leung, Product Consultant, Legend Audio Design
THE SUBDUDES: Miracle Mule
Back Porch 70876-18410-2-2 (CD). 2004. Subdudes, Freddy Koella, prods.; Warren Dewey, eng. AAD? TT: 52:13
Performance *****
Sonics ***½
Back Porch 70876-18410-2-2 (CD). 2004. Subdudes, Freddy Koella, prods.; Warren Dewey, eng. AAD? TT: 52:13
Performance *****
Sonics ***½
Reunions are touchy things. Sometimes it's almost instantly obvious—no names here, but you know who they are—that it would have been better had a band stayed apart and allowed history to remember them fondly.
In the case of the Subdudes—a talented band that, after five albums, broke up in 1997—a reunion was a decidedly good thing. Dedicated to making heady, original music that touched most of the essential…
It may come as a surprise to relative newcomers to the field of audio, but some loudspeaker manufacturers are manufacturers in only a limited sense. They buy drivers, off-the-shelf or custom-built, from companies like VIFA, SEAS, Focal, etc.; cabinets from a woodworking shop; and crossovers from an electronics subcontractor. While the system design will have taken place in-house, actual manufacturing is restricted to assembling the components, perhaps tweaking the crossover, and final QC. Even some highly successful loudspeaker manufacturers use this approach, which can work well as long as…