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When it comes to amplifiers, ya gotcher tubes, yer solid-states, and yer hybrids. Although amplifier manufacturers would have you believe otherwise, the majority of designs within each category are variations on a few fairly-well-known themes. Everyone agrees that the power supply is extremely important. Most designers try to obtain the amplifier's desired frequency response and distortion characteristics with a minimum of negative feedback. It's also agreed—at least among designers of solid-state amps—that the ability to drive a variety of speakers, including those that present a low-…
I was ready for some serious listening. I went through the usual test pieces (Chesky, Reference Recordings, etc.), and also listened to some "ordinary" records that I just happened to feel like playing. The sound was impressively neutral, the amp doing little to call attention to itself—which is just what you want it to do. With the Lightstar in the system, I was content to listen to the music, and felt little urge to switch over to one of the other amps I had on hand (all of them more expensive). This, too, is a sign that an amplifier is doing something right.
Dynamics and a sense of…
Sidebar 1: Carver the Man & Carver the Company
For the benefit of those Stereophile readers who aren't fully up on industry scuttlebutt, here's the real scoop (or at least as much as I know) about Carver the Man and Carver the Corporation: Bob Carver founded Carver Corporation in the early 1980s and was its CEO for a number of years, eventually taking the company public. About two years ago, he left the Corporation on a year-long sabbatical, and ended up resigning in March 1994. There were suits and countersuits about financial matters, non-competition clauses, and patent rights.…
Manufacturer's Comment, March 1995
Editor: In spring of this year I wrote you to answer many questions which had been posed to us about the departure of Robert Carver from Carver Corporation, and the subsequent legal disputes that occurred. I am pleased to inform you that these disputes have now been settled, and in a manner that is very satisfactory to the company. The essential elements were reported in a letter to our shareholders as follows:
1) Both parties have mutually released any and all claims brought against the other party in the lawsuit.
2) Beginning in 1995…
Sidebar 2: Carver Research Lightstar Reference: Design
The Carver Lightstar Reference is a power amplifier whose ratings suggest that it is an ideal voltage source—meaning that its rated power doubles with each halving of load impedance (300W into 8 ohms, 600W into 4 ohms, 1200W into 2 ohms). That's difficult to accomplish with conventional power transistors, which operate safely only within a restricted range of voltage/current combinations. (The graph of this range is called the transistor's safe operating area.) Many amplifiers deal with this limitation by using several transistors…
Sidebar 3: Review System
Analog sources were the Linn Sondek LP12 with all the accoutrements (Lingo, Cirkus, QR/DNM Design 330 Mk.II Ringmat), Linn Ittok, and AudioQuest AQ7000nsx. Digital sources were PS Audio's Lambda transport, Sonic Frontiers' UltraJitterbug, PS Audio's UltraLink II, and Sonic Frontiers' SFD-2. The preamp used was mostly a Sonic Frontiers SFL-2, with some use also made of a Convergent Audio Technology SL-1 Signature. Reference power amplifiers were the Bryston 7B monoblocks, Krell KSA-100S, and Threshold T-200.
Interconnects, digital links (AES/EBU), and…
Sidebar 3: Measurements
A full set of measurements of the Carver Lightstar was made in its unbalanced mode, with selected measurements repeated for the balanced configuration. Unless otherwise noted, the results below are for unbalanced operation. Also, all measurements (except for the gain check) were made with the normal gain setting.
Following the 1/3-power, one-hour preconditioning test, the Lightstar's heatsink/chassis was too hot to touch comfortably for more than a few seconds.
The Lightstar is non-inverting in the unbalanced mode. Balanced, pin 2 is configured as…
Sidebar 4: Specifications
Description: Solid-state stereo power amplifier. Power output: 300W into 8 ohms (24.8dBW), 600W into 4 ohms (24.8dBW), 1200W into 2 ohms (24.8dBW). Frequency response: 20Hz–20kHz ±0.5dB. Full power bandwidth: 10Hz–20kHz. Channel separation: >60dB at 1kHz. Output impedance: ±0.04 ohms. Damping factor: >200, equivalent to an output impedance of less than 0.04 ohms. THD: <0.2%. Signal/noise ratio: low gain, 107dB; high gain, 98dB (A-weighted, referenced to rated power); low gain, 82dB; high gain, 73dB (A-weighted, referenced to 1W). Slew rate: >50V/µs.…
For a major, decidedly American change of pace from our usual fare of Prokofiev, Debussy, Xenakis, Berg, and Beethoven (for starters), let's lighten up with Reference Recordings' latest hybrid SACD, John Williams at the Movies? Also available as a 176.4/24 download—the format in which it was recorded and which I auditioned for this review—the performances by the Dallas Wind Band under Jerry Junkin are so vivid and color-saturated that RR has chosen them for their first hybrid high-resolution wind-band SACD.
The first thing you'll hear is that the team of Keith O. Johnson and Sean Royce…
Okay, we know that Humphrey Bogart didn't utter that immortal instruction in Casablanca, but we couldn't resist, given that this issue includes Jim Austin's adventures with Apple's HomePod, the first smart speaker with hi-fi pretensions, which is featured on our August issue's cover.
But wait, there's more! Reviews of ultimate power amplifiers from Pass Labs and Moon by Simaudio; an unusual but high-performing speaker from Tekton; Roon's fit'n'forget Nucleus+ server; a high-performance turntable from Merrill-Williams; and Herb Reichert comparing AC cords. (Yes, we know, that way madness…