search
During the time of the Native-American Comanches, a young brave had to undergo many trials by fire before he earned the respect of the tribe's adults. He was violently beaten by the men, humiliated by the women, and forced to endure physical torture such as the slow flaying of the foreskin with smoldering pine saplings drawn from the fire. Alienated from the tribe, exiled until he proved his manhood, he had to survive on wriggling cream-colored larvae and infrequent rainwater. Legend speaks of these Indian youths, dehydrated and disoriented, crawling around on their hands and knees and…
Well, this may sound absurd, but I actually had to replace the VTLs with another amp because I couldn't concentrate on writing their review! Every time I began to write, my mind would wander like it used to in algebra class, only now I was free to blow my work off and kick back without getting beaned in the head with an eraser. I tried putting on CDs I don't even like (Merry Christmas From Wayne Newton, Curb D2-77348. Seriously.) to try and focus on the review, but my attention kept snapping back to the music. As good as some of the other amps may have been, only the VTLs were able to…
Sidebar 1: Specifications
Description: 25W monoblock amplifier. No specifications given.
Dimensions: 9" W by 4" H by 6" D each.
Serial number of review sample: T25M399/400.
Price: $1200/pair (1991); no longer available (2006). Approximate number of dealers: 25.
Manufacturer: Vacuum Tube Logic, 4774 Murietta, Suites 9&10, Chino, CA 91710. Tel. (714) 627-5944. Web: www.vtl.com.
Sidebar 2: Measurements
The VTL's input impedance at 1kHz was a hair over 100k ohms, while its sensitivity was high, at just 71.6mV for 1W into 8 ohms, both factors making it suitable for use with passive preamps. The lefthand amplifier was 0.5dB less sensitive, however, as can be seen from the Tiny Triode's frequency response at 1W into 8 ohms (fig.1). This showed a slight rolloff in the extreme treble, reaching –0.4dB at 20kHz. The limited HF bandwidth can also be seen in the shape of a 10kHz squarewave (fig.2), which features a mild droop to the leading edges.
Fig.1…
Foreword by Sam Tellig: I wanted to like the Sci Fi Teslas. I originally heard these speakers at Dave Wolf's store in New Canaan, Connecticut—no longer in business, alas.
To say that the Teslas imaged like gangbusters would be an understatement. These speakers disappeared—particularly when used with a great tube amplifier, like the VAC PA90. With the VAC amps, the music just hung there, suspended in space. So what if the upper midrange was a little scratchy? So what if dynamics were somewhat limited and the bass was—well, not all there? These speakers were doing some amazing things.
…
The two bass-midrange drivers are mounted to the extended front fascia with what Sci-Fi calls "RIDS," for Resonance Isolation and Damping System. Mike explains that there are two ways to reduce driver basket resonances: mass-loading and decoupling. Mass-loading involves tightly securing the drivers to a heavy, inert cabinet; a good example of this is the deader–than–Andy Gibb Wilson WATT. However, this approach tends to be very expensive, so Mike has opted for the latter method; the woofer baskets on the Tesla are decoupled with two soft-foam gaskets, one between the driver basket and the…
Some weeks later, the third and final pair of Teslas arrived, along with the Trillium amps. Mike explained that the reason for the bass hump in the original review pair was that, unbeknown to him, his padding supplier had switched from polyester to Dacron; the padding wound up with only a third the fibers of the original stuff. A switch back to the original padding, plus more of it, plus a retuning of the port, was said to have gotten rid of the hump. Additionally, the tweeter was given a series 1 ohm resistor to bring it down a bit.
Mike said to just set up these Teslas exactly where he…
Jack English adds a postscript
Audio Dealer: Nice to see you again, Mr. Audiophile. Now that you've spent a couple of weeks with the Teslas, are you ready to buy them?
Audiophile's Left Brain: Well, they are gorgeous. They're large enough to look like a piece of modern furniture but not so big as to overpower our listening room. The slim look and curved ends make them unique and equally attractive. I've grown tired of all those big, rectangular boxes. Even the legs look good.
Audiophile's Right Brain: Yeah, they're easy to look at and priced right, too. There certainly…
Sidebar 1: Measurements
There were no surprises in the Tesla's plot of electrical impedance magnitude and phase (fig.1). The shape of the curve in the bass implies that the rear port is tuned to a low 22Hz, revealed by the dip in magnitude at that frequency. (I left the foam plug in place for all the measurements, though I did remove the grille socks.) The impedance drop to 5 ohms at 90Hz should not present good amplifiers with any drive problems, though as a great deal of high-power musical information lies in this upper-bass region, this impedance dip will also lead to a more limited…
Sidebar 2: Specifications
Description: Two-way, reflex-loaded, floor-standing, dynamic loudspeaker. Drivers: two 6.5" bass/midranges, one 1" aluminum-dome tweeter. Crossover frequency: 1kHz. Frequency response: 32Hz–35kHz ±3dB. Sensitivity: 88dB/W/m. Nominal impedance: 8 ohms.
Dimensions: 49" H by 8" W by 13" D. Weight: 52 lbs each.
Serial numbers of review samples: 00377, 00378.
Price: $1990/pair (1992); no longer available (2006). Approximate number of dealers: 45.
Manufacturer: Scientific Fidelity, 6301 Riggs Place, Los Angeles, CA 90045 (1991). No longer trading (2006…