Description: Two-channel, solid-state integrated amplifier with 1 pair CAST inputs via 4-pin bayonet connectors, 1 pair balanced via XLR connectors, 3 pairs single-ended via RCA connectors, 1 pair tape via RCA connectors. Speaker outputs: 4 on binding posts. Preamp output: 1 pair single-ended via RCA connectors. Preamplifier section: Frequency response: 20Hz–20kHz, +0.0/–0.05dB. Power amplifier section: Maximum output power: 300Wpc into 8 ohms (24.8dBW), 600Wpc into 4 ohms (24.8dBW), 1200Wpc into 2 ohms (24.8dBW). Maximum output voltage: 138V peak–peak. Voltage…
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Sidebar 2: Associated Equipment
Analog Source: VPI HW-19 Mk.14 turntable with JMW Memorial tonearm, Clearaudio Victory H cartridge.
Digital Sources: Krell Evolution 505 SACD/CD player, Simaudio Moon CD5.3 CD player.
Preamplification: Audible Illusions Modulus 3a (used only as phono-stage).
Loudspeakers: Verity Audio Parsifal Ovation.
Cables: Nirvana interconnects and speaker cables; Krell CAST interconnects.
Accessories: Bybee Technologies Signature Power Purifier, Monster Cable AVS-2000 voltage regulator; Black Diamond Mk.4 Racing Cones, Mapleshade pucks; VPI HW-19 record…
Sidebar 3: Measurements
Before performing any test on an amplifier, I precondition it by running both channels for 60 minutes at one-third the specified power into 8 ohms, which is thermally the worst case for an amplifier with a class-B or-AB output stage. At the end of that hour, the Krell FBI's entire chassis—not just the large vertical heatsinks on its sides—was too hot to touch. This is an amplifier that needs plenty of ventilation. The THD+noise percentage with the amplifier stone cold was 0.0142%; by the end of the hour's warmup, this had dropped to 0.0067%.
Without a…
Conrad-Johnson launched the all-tube Premier 7 in 1988 as an all-out sonic assault on the state of the preamplifier art. A great deal has happened since then. For starters, C-J has gotten a great deal of feedback from customers, dealers, and reviewers. None other than J. Gordon Holt (Stereophile, November 1988, Vol.11 No.11) concluded that: "It appears that nothing which could possibly have improved its sound had been omitted....It is, in fact, about as close as any tubed preamp has come to being perfectly neutral in sound—in nearly all respects." In the now-defunct Sounds Like... (issue 3…
• Replacing Tubes: While no other reviewer has mentioned this, I feel I must. Replacing tubes in the 7A is a big pain in the butt. The biggest problem is replacing any of the tubes in the right channel. Of the 7A's three chassis, both power supplies are in one box, the left- and right-channel circuitry in the remaining two. However, the left-channel box is fastened to and above the right-channel box. While getting at the innards of the power supply or left-channel circuitry is no big deal, access to the right-channel sockets is difficult enough that I advise having your dealer replace the…
Many tubed preamps can be described as being somewhere on the warm, musical, rich side of neutral. The 7A certainly isn't one of them. If anything, it sounds slightly analytical, favoring accuracy over euphonic colorations. Once again, what I heard through the 7A was very much what JA heard through the original 7. The midrange was phenomenally clean and detailed for a tubed product. With relatively simple music without a great deal going on, every little nuance is laid bare. A good example is Marianne Faithfull's Greatest Hits (London PS 547), which the 7A dissected surgically. Unfortunately…
Sidebar 1: Specifications
Description: Vacuum-tube dual-mono preamplifier. Inputs: phono (MC or MM), tuner, CD. Tape: 2 sets of inputs and 2 sets of outputs. Outputs: 2 sets, both phase-inverting, recommended for amplifiers with input impedance of 10k ohms or higher. Level control: 23-position stepped attenuators with front-panel LED level indicators. Tube complement: two 6CW4s and four 6GK5s per channel. Phono section: 40dB gain; overload in excess of 150mV at 1KHz; RIAA equalization ±0.25db (20Hz–20KHz); hum & noise 80dB below 10mV input. Line-level section: 29dB gain; 20V maximum…
Sidebar 2: Measurements
Before I began measuring, I noted that the mute switch on the Premier 7A's left channel was defective. It would stick in one position. Pulling it out manually would release it, but it would then simply stick at the next engagement. Fortunately it stuck in the non-mute position.
The gain of the Premier 7A's line stage—from input to main output—measured 29.6dB in the left channel. The right-channel gain was 0.2dB lower. The line input impedance depended to a small degree on the channel and the setting of the volume control, but ranged from just over 18k ohms…
I've been reading and sometimes participating in a number of Internet discussions that begin with something like "Is SACD (and/or DVD-Audio) Dead?" Regardless of your one-word answer, it seems that the issue is still quite lively. I won't address the question here (you know where I stand), but it almost doesn't matter. Many high-resolution multichannel recordings are still being made. It's just that they may be distributed in different ways.
I asked Robert von Bahr of BIS Records about the fiscal viability of making SACDs. I wondered if the small numbers of sales to audiophiles might be…
A case in point is Cary Audio Design's Cinema 11 surround processor ($3000). Last fall, when I first stumbled on a prototype Cinema 11 at the annual Expo of the Custom Electronics Design and Installation Association, I was impressed by its small size, sleek lines, and intriguing features. Although it lacked any video inputs or video processing, it was Dolby-HD compatible, and had room equalization (EQ) and a 7.1-channel analog input that could be bypassed or digitized. As it turns out, the production version contains all of these, though not exactly as I'd imagined them. In the broadest…