The Diamante's impedance magnitude and phase are shown in fig.1. The single rise in the bass, to 15.5 ohms, suggests that the ATL loading does act as a true transmission line rather than as some kind of perverted reflex, though its frequency, 51Hz, implies limited low-frequency extension overall, as SS found during his auditioning. When the speaker is used with an amplifier having a high output impedance, this 51Hz impedance peak will result in an effective boost at this frequency. I suspect that this is why SS found his Atma-Sphere tube amplifier not to be a good…
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Manufacturer's Comment
Editor: I was very pleased that Steven Stone and John Atkinson were impressed with the Diamante. They heard what our many owners and retailers report: that this is a product which does not call attention to itself. My primary design goal is to be true to the music—our speakers must be revealing, yet always enjoyable. After several months of living with our loudspeaker, Steve reported that the Diamante "allows the music to come through, with very little editorializing." Some of the factors that make this possible are dynamic accuracy, dispersion, time coherence, and…
Looked at from one viewpoint, DVD-Audio and SACD appear to be exercises in sheer profligacy. In the case of DVD-A, why provide a maximum bandwidth almost five times what is conventionally taken to be the audible frequency range, and couple it to a dynamic-range capability far in excess of that achievable by the microphones used to record the sound? In the case of SACD, why provide a potential bandwidth in excess of 1.4MHz, only to fill more than 95% of it with quantization noise?
These questions have answers, and the topics they encompass are anything but trivial: they relate to…
Slope
The third graph in each set will be a complete novelty to most readers. At first glance you might presume it to be a plot of amplitude vs time, just as you would see if you were to view the track in audio editing software (albeit here with the left and right channels superimposed, blue and red traces respectively). But this is actually a graph not of amplitude vs time but of the rate of change of amplitude vs time; ie, of how rapidly the signal changes from one sample to the next. In less elegant parlance, it depicts the signal's slew rate.
The third graph in each set will be a complete novelty to most readers. At first glance you might presume it to be a plot of amplitude vs time, just as you would see if you were to view the track in audio editing software (albeit here with the left and right channels superimposed, blue and red traces respectively). But this is actually a graph not of amplitude vs time but of the rate of change of amplitude vs time; ie, of how rapidly the signal changes from one sample to the next. In less elegant parlance, it depicts the signal's slew rate.
Slew rate is usually specified in…
The Graphs
DVD-A
Tchaikovsky: Overture 1812
Telarc DVDA-70541
Duration: 15:43
Original recording: DSD
Bit depth/sample rate: 24-bit/44.1kHz
S/PDIF sample rate: 44.1kHz
Stereo track is only 24/44.1 but the rate of change results are not that different to the equivalent SACD, and the power envelope tests the same to within fractions of a dB.
DVD-A
Walton: Portsmouth Point Overture
EMI 7243 4 92402 9 2
Duration: 5:33
Original recording: analog
Bit depth/sample rate: 24-bit/48kHz
S/PDIF sample rate: 48kHz
Presumably the analog…
Conclusion
I empathize with those readers who have contacted Stereophile asking for some summary of the graphical evidence I presented in "New Media Metrics." I had planned to include a more rounded conclusion to the piece, but, with my word budget almost spent and a guilty conscience at asking John Atkinson to find space for more than 60 graphs, I put a perhaps premature sock in it.
So what messages did all those graphed wiggles convey? Well, let's first admit that, substantial though the exercise was, it can make no claim to represent a statistically significant sample of…
According to Cary Audio designer Dennis Had in this amplifier's documentation, "Countless hours were spent designing and voicing the CAD-280SA V12 stereo amplifier...It delivers high performance in a combination of class-A single-ended triode and true balanced push-pull technology."
Whew, I thought to myself. Push-pull. Thank goodness—it oughta measure pretty well. I read on.
"The new V12 is created by a stunning combination of the world-famous CAD-805 soundstage, the glorious midrange of the CAD-300-SE, and the supercharged power of the CAD-211-Ms."
Never above a little…
Then check each of the 12 red LEDs behind the tubes; they should not be lit, because you've turned the bias voltage all the way down. (When the amp is operating normally after bias is correctly set, the red LEDs pop on to indicate that the tubes are conducting and you're ready to play music.) After you've watched the output-tube filaments light up, grab a beer (or a V8!) and wait about five minutes for the tubes to warm. Then take a flat-blade screwdriver and slowly advance the bias pot clockwise until the red LEDs begin lighting up. "When you have reached equal brilliance on each tube's LED…
Triode mode was fine for 75-80% of my listening through the JMlab Utopias. On those occasions when I wanted to scare the neighbors, I'd go to 1/3 or all ultralinear, with an attendant loss of some air and delicacy. It all depended on the music and how deep I wanted to push the loud pedal.
Regarding really deep bass, try track 2 of Peter Kruder's Peace Orchestra 1999 (G-CD 004), the CD with the Band-Aid on the cover and the title printed on it—you can't miss it! The CAD-280SA V12 sounded like...a V12! Powerful, capable, with good roadholding that struck a fine balance with this CD's…
Sidebar 1: Specifications
Description: Two-channel, push-pull tube power amplifier. Tube complement: two 6922 input tubes, two SV83/EL84 driver tubes, twelve EL34 output tubes. Inputs: RCA or XLR, switch-selectable. Outputs: three five-way binding posts, red for 4 and 8 ohm transformer taps, black for ground. Specified output power: 50Wpc (17dBW) triode, 100Wpc (20dBW) ultralinear. Input sensitivity: 2V for full output. Input impedance: 150k ohms. Noise and hum: 84dB below rated output. Frequency response at full power output: 20Hz-23kHz, ±1dB. Power consumption: 420W Operate, 10W Standby…