The Vandersteen 2Ce's impedance curve in fig.1 indicates a load which should be easy to drive. The magnitude of the impedance never drops below 4 ohms. Though the 2Ce is said to function as a sealed box, the low-frequency impedance is reminiscent of the double peak response typical of reflex enclosures. But the upper peak is heavily damped. The box tuning appears to be about 41.3Hz—the minimum between the two peaks. The magnitude of the impedance at mid and high frequencies differs only slightly with the setting of the contour controls (the upper curve shows both…
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The anechoic response of the 2Ce averaged across a 30 degree window on the tweeter axis is shown in fig.4. The response below 200Hz is the complex sum of the woofer and acoustic coupler outputs. The response is virtually flat to 40Hz, with a -6dB point of about 30Hz—a little worse than the specified -3dB at 29Hz, but still very good. There is some elevation in the upper bass/lower midrange which is probably responsible for the slight warmth noted in the listening tests, followed by a broad but shallow depression in the upper midrange/low treble—the latter likely contributing to the somewhat…
The lateral response family of the 2Ce is shown in fig.6, normalized to the on-axis response. (That is, the on-axis response deviations are subtracted from all the curves, therefore showing only the changes which result from a (hypothetically) flat on-axis response as we move off axis.) The rolloff is quite smooth, the response holding up very well to at least 30 degrees off-axis. The vertical response, on the other hand, as shown in fig.7 (again normalized to the on-tweeter-axis response, shown as the straight line in the center), shows a considerable deviation above and below the optimum…
Manufacturer's Comments Vandersteen 2Ce
Editor: Thank you for Thomas J. Norton's review of our Model 2Ce loudspeakers and this opportunity to comment. We agree that the differences between our Model 2Ce and Model 3 fall into the realm of diminishing returns. Since both speakers share the same basic design, the only way to create a large, "Oh my gosh" type of difference between the two would be to intentionally make one or the other less accurate. The Model 3 was developed in response to the incredible number of people using our model 2 series speakers with preamp/power amp combinations…
Editor: Thank you for Thomas J. Norton's review of our Model 2Ce loudspeakers and this opportunity to comment. We agree that the differences between our Model 2Ce and Model 3 fall into the realm of diminishing returns. Since both speakers share the same basic design, the only way to create a large, "Oh my gosh" type of difference between the two would be to intentionally make one or the other less accurate. The Model 3 was developed in response to the incredible number of people using our model 2 series speakers with preamp/power amp combinations…
How much power do you really need? What does it do for you, anyway? Even before the single-ended renaissance, the prevailing wisdom was that you really didn't need that much power. When I had a pair of Met 7 speakers, even the "1 watt" indicator LED was hardly ever lit. Ditto for my time with a Threshold Stasis Two—all those cool power-indicator LEDs just sat there dark. Besides, everyone knows that power can be had only at tremendous cost, both monetary and in terms of other performance attributes.
And there's always been a mystique about small amplifiers—that, even regardless of cost,…
What is an MB-750?
The MB-750 shares its basic circuit configuration with all of VTL's amplifiers—a paralleled input stage driving a long-tailed phase-splitter driver stage, followed by the output stage. The basic circuit, designed by David Manley during his pre-VTL work in South African recording studios, is simple, tried, and true. Following the signal path, an MB-750 starts with a 12AT7 dual-triode input, either paralleled in single-ended mode or as a differential amplifier in balanced mode, with each half of the triode handling one leg of the signal. From there the signal is sent to…
The MB-750 shares its basic circuit configuration with all of VTL's amplifiers—a paralleled input stage driving a long-tailed phase-splitter driver stage, followed by the output stage. The basic circuit, designed by David Manley during his pre-VTL work in South African recording studios, is simple, tried, and true. Following the signal path, an MB-750 starts with a 12AT7 dual-triode input, either paralleled in single-ended mode or as a differential amplifier in balanced mode, with each half of the triode handling one leg of the signal. From there the signal is sent to…
The Leinsdorf/Boston reading of Bartok's Concerto for Orchestra (RCA LSC-2643) is another good example. This recording does a beautiful job of capturing the orchestra's huge size and layout within the ambient environment of Symphony Hall. A lot of amplifiers can pull this off at the softer end of the scale, but with the 750s, the perspective and soundstage held up even through the massive crescendos. The music simply swelled, without any hint of congestion or even the slightest flattening of the soundstage.
The dynamic punch and precision paid dividends on small-scale works as well. The…
Similarly, if you're coming at the MB-750s from the perspective of a more traditional triode amp, you may be unimpressed by their reproduction of harmonic structure and instruments' inner detail. In comparison, the MB-750s had less of that vivid harmonic "bloom," and could even sound (dare I say it) solid-state—or at least a lot less like a triode amp. Just as with the spectacular detail, as beguiling as the overly rich harmonic structures that some triode amps give you are, they're nowhere near reality. The MB-750s' portrayal was much closer to what I hear in the concert hall, and, if…
Summary
So what's the bottom line, and what about all those tubes? First, from an operational standpoint, other than their considerable weight and even more considerable heat generation, the MB-750s were a delight. One of the annoyances I've lived with in my Ichibans—transformer hum—was thankfully all but gone. The main power transformer on one of the 750s did hum slightly, but not loudly enough to interfere with the music. Compared to the Ichibans, additional chassis damping and a more rigid structure have reduced the MB-750's susceptibility to airborne feedback and microphony,…
So what's the bottom line, and what about all those tubes? First, from an operational standpoint, other than their considerable weight and even more considerable heat generation, the MB-750s were a delight. One of the annoyances I've lived with in my Ichibans—transformer hum—was thankfully all but gone. The main power transformer on one of the 750s did hum slightly, but not loudly enough to interfere with the music. Compared to the Ichibans, additional chassis damping and a more rigid structure have reduced the MB-750's susceptibility to airborne feedback and microphony,…
Sidebar 1: Specifications
Description: Vacuum-tube monoblock amplifier with class-AB-1, tetrode/triode-switchable, push-pull output stage. Rated output power: 20Hz-20kHz, 3% THD, 750W (26.7dBW) tetrode, 350W (23.4 dBW) triode. Small-signal frequency response: 20Hz-20kHz ±0.05dB. S/N ratio at 120Hz, 750W tetrode/350W triode: >95dB. Input sensitivity for full output power: 1.7V. Voltage gain: 31.3dB tetrode, 27.8dB triode. Input impedance: 130k ohms single-ended, 274k ohms balanced. Output impedance: approximately 1.5 ohms. Power consumption: 440W at idle, 1300W at full power. Tube…