Description: Two-channel, tubed power amplifier. Tube complement: four KT77 (or EL34), two 12AU7, two 12AX7. Maximum output power: 55Wpc into 8 ohms (17.4dBW). THD: <0.1% typical, <1% at rated power. Input sensitivity: 1.0V RMS.
Dimensions: 18" (460mm) W by 5.5" (140mm) H by 17" (435mm) D. Weight: 50 lbs (22.7kg) net, 55 lbs (25kg) shipping.
Serial Number Of Unit Reviewed: ATL-0604.
Price: $1395. Optional cover, $100. Approximate number of dealers: 55. Warranty: 3 years (6 months for tubes).
Manufacturer: Rogue Audio Inc., 3 Marian Lane,…
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Sidebar 1: Specifications
Sidebar 2: Associated Equipment
Analog Source: VPI HW-19 Mk.4 turntable, VPI JMW Memorial tonearm, Clearaudio Victory H cartridge.
Digital Sources: Krell SACD Standard SACD/CD player, Simaudio Moon CD 5.3 CD player.
Preamplification: Audible Illusions Modulus 3a used as full preamp and as phono stage only, Krell KAV-280p line stage.
Power Amplifier: Krell FPB-400cx.
Loudspeakers: Verity Audio Parsifal Ovation.
Cables: Nirvana.
Accessories: Bybee Technologies Signature power purifier, Monster Cable AVS-2000 voltage regulator, Black Diamond Racing Mk.4 Cones, Mapleshade…
Sidebar 3: Measurements
Before performing any measurements on the Rogue Audio Atlas, I checked the bias of its four KT77 output tubes. All were running at around 40mA bias current, close to the 35mA recommended by the manufacturer. I tested the Atlas with its output transformer hooked up for 8 ohm operation, as usually supplied by Rogue, and also as wired for 4 ohm operation, as ultimately used by Fred Kaplan in his auditioning. To my surprise, the voltage gain into 8 ohms was the same from both output-transformer windings—26.5dB—despite the 8 ohm tap's greater intrinsic gain. This is…
Jeff Joseph always causes a stir at Stereophile's annual Home Entertainment Shows. No matter which speakers he exhibits, he invariably gets wonderful sound in his room. He's fooled more than one Stereophile writer who thought he was listening to Joseph's flagship Pearls when, behind a curtain, it was actually two of his in-wall models that were playing. And his competitors seem to envy his hi-fi show sound more each year.
My experience with Joseph Audio speakers had been limited to show demonstrations, as their prices have always far exceeded my self-imposed ceiling for "…
Sidebar 1: Specifications
Description: Two-way, reflex-loaded, stand-mounted loudspeaker. Drive-units: 1" Sonatex soft-dome tweeter, 7" metal-cone woofer. Frequency response: 42Hz–20kHz, ±2dB. Sensitivity: 86dB/2.83V/m, 4 pi (anechoic). Impedance: 8 ohms nominal, 7 ohms minimum.
Dimensions: 15" (381mm) H by 9" (228.6mm) W by 12" (304.8mm) D. Shipping weight: 55 lbs (25 kg)/pair.
Finishes: wood veneer.
Serial Number Of Units Reviewed: 70821 L/R.
Price: $2299/pair. Approximate number of dealers: 32.
Manufacturer: Joseph Audio, Inc., P.O. Box 1529, Melville, NY 11747. Tel: (…
Sidebar 2: Associated Equipment
Analog Sources: VPI TNT IV turntable, Immedia RPM tonearm, Koetsu Urushi cartridge; Rega Planar 3 turntable, Syrinx PU-3 tonearm, Clearaudio Virtuoso Wood & Aurum Beta S cartridges.
Digital Sources: Lector CDP-7T, California Audio Labs Icon Mk.II Power Boss, Creek Destiny, Creek CD53 Mk.II CD players; Pioneer DV-333 DVD player.
Preamplification: Vendetta Research SCP-2D phono stage, Audio Valve Eklipse line stage.
Power Amplifier: Audio Research VT100 Mk.II.
Integrated Amplifiers: Creek Destiny & 5350SE.
Loudspeakers: Amphion Helium2…
Sidebar 3: Measurements
My estimate of the Joseph Audio RM7XL Special Edition's voltage sensitivity on its tweeter axis was within experimental error of the specification, at 85.5dB(B)/2.83V/m—slightly below the average of 87dB for the 630 or so speakers I have measured over the past 17 years. Its impedance remains above 8 ohms at almost all frequencies, dropping to a minimum value of 7.15 ohms at 200Hz (fig.1). This, in combination with the generally low electrical phase angle, will make the RM7XL a very easy load for an amplifier to drive.
Fig.1 Joseph Audio RM7XL…
Frankly it's a bit nutty for me to be doing this review. First, as Publisher of this esteemed journal, my primary duties involve financial and personnel management, as well as a good bit of public relations; I don't need and am not required to perform the exacting tedium of product reviews. Second, Jim Thiel and Kathy Gornik of Thiel are friends of mine. So what, you ask? Well, if this were going to be a uniformly positive review, I would therefore be ruled out as the reviewer; if it's to be wholly or partially negative, it will surely put a strain on one of my best audio friendships.
But…
This is due to bass extension, loudness capability, and the generosity I referred to above. At the same time, the blending of drivers is just as good as with the CS2, and with greater difficulty since a significantly larger range is being covered.
Perhaps my focus on the "problem" in the CS2, now essentially cured, led me to pay inadequate attention to the high-frequency behavior of this tweeter. Its response is essentially flat out to 35kHz (according to information from Thiel), and sounds that way. The upper harmonics of triangle and cymbals are preserved with excellent detail. If I…
Sidebar 2: Specifications
Description: Three-way, sealed-box loudspeaker with line-level bass equalizer. Drive-units: 1" soft-dome tweeter, 4" paper-cone midrange unit, 10" plastic-cone woofer. Crossover frequencies: 400Hz, 3kHz. Frequency response: 20Hz–20kHz ±2dB. Sensitivity: 88dB/W/m. Nominal impedance: 4 ohms. Minimum amplifier power: 40W.
Dimensions: 41" H by 13" W by 13" D. Weight: 75 lbs each.
Price: $2450/pair (1989); no longer available (2007), replaced by the CS3.6 in 1993. Approximate number of dealers: 52.
Manufacturer: Thiel Audio Products Co., 1042 Nandino…