The MB-750's roots lie in two very different VTL models: the 500W Monoblock and the Ichiban, both introduced around 1988. The 500W Monoblock was a growth version of the DeLuxe 300, reported to have grown out of a conversation between David Manley and Harry Pearson of The Abso!ute Sound, who were independently wondering how an ultra-high-powered tube amplifier might affect music reproduction. With 12 KT88 output tubes per channel run in ultralinear configuration and biased to run in class-AB-1, the Monoblock's 500W of power were targeted directly at…
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Sidebar 2: The Evolution of the MB-750
Sidebar 3: Associated Components
Listening tests were conducted in two systems (footnote 1), one built around Audio Artistry Dvorak loudspeakers, the other around Gershman Avant Gardes. Analog front-ends included a VPI TNT III/JPW Memorial tonearm combo and an Immedia RPM 2 turntable with RPM arm, fitted with Clearaudio Gamma S and Gamma "Gold" cartridges, respectively. Digital components used were a Parasound C/DP-1000 player as a transport paired with a Parasound D/AC-1500 converter, and the CAL Audio DX-2 integrated player. Preamps included a VAC CPA1 Mk.II, AHT-P, and Audire Nuance…
Sidebar 4: Measurements
A complete set of measurements was made on the VTL MB-750 in the unbalanced triode mode, with selected measurements repeated in the balanced triode and unbalanced tetrode configurations. If not noted otherwise, the result shown is for the unbalanced triode mode. Because of the amplifier's high rated power, it was warmed up at 50W in triode mode for one hour—the 1/3-power test is of limited usefulness for tube amplifiers, in any event. High-power tests were not run on our simulated real load.
The MB-750's input impedances measured 550k ohms and 440k ohms in…
The THD+noise vs frequency curves are shown in figs.4 and 5. The latter compares the unbalanced triode and tetrode configurations, which are relatively similar. The changes in the distortion curves from the unbalanced to the balanced configurations are insignificant—smaller than the differences in fig.5—and are not shown here. Fig.6 shows the distortion waveform into 4 ohms; it is primarily second harmonic. The waveform in the tetrode configuration, very similar, is not shown. The same is true with 8 ohm and 2 ohm loads (also not shown), though the latter shows clearer signs of higher…
The 50Hz distortion spectrum is shown in fig.7. The distortion level is relatively high, though not for a tube amplifier operating at such a high level. The second harmonic (100Hz) is at -35dB (about 1.7%), the third at -34dB (about 2%). The spectral analysis of the IM distortion resulting from the combination of 19kHz and 20kHz tones is shown in fig.8. Here, the IM at the 1kHz difference tone at 1kHz is -28dB (about 4%). Again, this is a relatively high figure, but the output power here is 122W.
VTL MB-750, triode mode, spectrum of 50Hz sinewave, DC-1kHz, at 178W into 4 ohms (…
When American architect Louis Henri Sullivan said "form ever follows function" (footnote 1), he was referring to the transition from the 19th-century view of architecture, driven by aesthetic concerns, to the bold new 20th-century approach of beginning with a building's functions, and letting the design flow from there.
Now, however, as we enter the advertising-defines-reality 21st century, it seems as if "form follows function" is being liberally applied to everything from cars to clothing to oddly configured European kitchen appliances. In most cases, it seems as if the phrase is used…
Rapping the rack directly did cause a slight ripple on the water's surface, but this is where the rest of the Bright Star isolation system comes in. When I set the water glass on an Air Mass/Big Rock combo, and the whole stack on the RoG, no amount of rapping, tapping, or even thumping was translated to the water's surface. In contrast, setting the glass of water and Air Mass/Big Rock setup on a light, rigid end-table provided nowhere near as much isolation; nearby footfalls clearly perturbed the water.
What does this all mean for your system? First of all, its exceptional stability and…
Sidebar 1: Specifications
Description: 6-shelf, sand-fillable equipment rack. Welded-steel construction with removable, nonadjustable MDF shelves.
Dimensions: Overall: 46" (1170mm) W by 35" (890mm) H by 19½" (500mm) D. Shelves: 21½" (550mm) W by 17½" (440mm) D. Vertical space between shelves: 17" (430mm) and 14" (360mm). Weights (unfilled): 202 lbs (92kg) net, 237 lbs (108kg) shipping.
Finishes: textured, powder-coated dark granite (medium gray), black granite (add $155).
Price: $1995. Approximate number of dealers: 95.
Manufacturer: Bright Star Audio, 2363 Teller Road, Unit…
Sidebar 2: Associated Equipment
Analog sources: VPI TNT IV turntable with JMW Memorial 12" tonearm, Immedia RPM-2 turntable with Well Tempered Reference tonearm; SOTA Cosmos; Grado Reference, Clearaudio Gamma Gold, Benz LO4 cartridges.
Digital sources: Parasound CD/P1000, Ultech UCD-100, Wadia 830 CD players.
Preamplifiers: VAC CPA 1 Mk.III, Adcom GFP-750, Sonic Frontiers Phono One/Line 3.
Power amplifiers: VTL Ichiban, Mark Levinson No.20.6, Sonic Frontiers Power 3, VAC Renaissance.
Loudspeakers: Magnepan MG3.6/R, Thiel CS7.2, Audio Artistry Dvorak.
Cables: Nirvana S-L,…
Richard Shahinian has been offering loudspeakers to music lovers for more than 15 years. I use the word "offering" here in its strictest sense, because Dick has never "sold" his products—by pushing them. Indeed, he is probably one of the worst self-promoters in the business. If we think of "soft sell" in the usual context of laid-back and low-pressure, then Shahinian's approach would have to be called "mushy sell."
Shahinian has less than two dozen dealers, does no advertising (aside from sporadic dealer newsletters), and only his first speaker system has been reviewed by a US…