The Bryston B-60R was hot, but not alarmingly so, following its one-hour, 1/3-power preconditioning test. The B-60R's line input impedance measured 51.6k ohms at 1kHz, a comfortably high value that should be compatible with any consumer program source. The Bryston's output impedance is very low—under 0.04 ohms up to 1kHz, increasing to 0.06 ohms at 20kHz. The output impedance at the B-60R's tape outputs measured 49.5 ohms and was virtually unchanged with changes in source impedance, indicating buffered tape outputs. The output impedance at the preamp outputs…
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Sidebar 3: Specifications
Description: Solid-state line-level integrated amplifier. Inputs: Four gold-plated RCA line-level, one tape loop. Outputs: ¼" headphone jack, 1 pair 5-way speaker terminals. Pre-out/main-in RCA jacks.
Preamplifier section: Frequency response: 20Hz-20kHz, ±0.5dB. Maximum output: 15V. IM or THD at 3V output: <0.005%. High-level sensitivity: 500mV. Rated noise: 100dB below 500mV, 20Hz-20kHz. Input sensitivity: 500mV. Input impedance, 50k ohms; tape input impedance, 10k ohms. Preamp and tape output impedance: 100 ohms.
Amplifier section: 60Wpc into 8 ohms (…
Back in 2003, while auditioning the Burmester 001 CD player ($14,000, reviewed in the December 2003 Stereophile, Vol.26 No.12), I discovered that my system sounded much better if I bypassed my preamplifier and ran the 001 directly into the power amps. I concluded by suggesting that potential customers consider building a system around the 001 itself and forgo a preamp altogether. The response from Burmester fans was immediate and unambiguous: As good as the 001 was on its own, it sounded even better run through its stablemate, Burmester's 011 preamplifier ($15,999). The pair had, they…
Another component of the Burmester's sound was its huge soundstage, which stretched to well outside my Thiel CS6 loudspeakers and beyond the front wall of my room. Its height was also large, and varied as necessary to describe the venue. In some cases, that meant putting the front rows of the audience well below my Thiels—listen to Rickie Lee Jones' Naked Songs (CD, Reprise 45950-2) to hear what I mean—and in others, it meant locating a concert hall's ceiling high above them.
Individual performers were also large—arguably, in some instances, too large—but not distractingly so. The 011's…
Sidebar 1: Specifications
Description: Single-chassis, remote-controlled, full-function solid-state preamplifier with integral moving-coil phono stage. Inputs: 6 balanced line (XLR), 1 unbalanced line (RCA), 1 balanced phono (XLR). Outputs: 1 balanced (XLR), 1 unbalanced (RCA), 1 headphone (1/4" phone jack). Tape/processor loop: unbalanced (RCA) inputs and outputs. Input sensitivity: 250mV for unity gain. Input impedance, line: 10k ohms, all inputs. Input impedance, phono: 8 user-selectable levels, 10–1k ohms. Output impedance: 66 ohms. Frequency response: 0Hz–>200kHz. Line-stage gain…
Sidebar 2: Associated Equipment
Analog Source: VPI HR-X turntable & tonearm, Lyra Titan cartridge.
Digital Sources: Burmester 001, Ensemble Dirondo CD players.
Preamplification: VTL TL-7.5 line-stage preamplifier; Sonic Euphoria PLC, Placette Remote Volume Control passive line stages; Ensemble Fonobrio, Sutherland PhD phono preamplifiers.
Power Amplifiers: VTL S-400, Simaudio Moon Rock, Mark Levinson No.20.6 monoblocks.
Loudspeakers: Thiel CS6.
Cables: Nirvana S-X Ltd., Audience Au24, Nordost Valhalla, Silversmith Silver, interconnects & speaker cables. AC:…
Sidebar 3: Measurements
Looking first at the Burmester 011's phono input (assessed at the tape-monitor outputs, and set to RIAA), the input impedance was 886 ohms at 1kHz when set to 1k ohm, and it didn't invert signal polarity (with pin 2 of the XLR jack driven by the hot phase). The RIAA equalization was very accurate, with just 0.1dB of positive error apparent in the upper bass and 0.15dB of rolloff at 20kHz (fig.1). The ultrasonic bandwidth was sensibly curtailed, the –3dB point lying at 90kHz, though the low frequencies rolled off very slightly, the output at 20Hz lying at –0.5dB.…
A thorough exploration in a magazine article of such a pervasive and complex topic as vibration control in audio systems is next to impossible; vibration and sound are so intimately bonded that it would be very easy to extend this discussion to just about any area of interest in audio. My intention here is simply to lay a foundation for understanding the basic mechanical forces affecting our quest for improved sonic fidelity, and in the process provide the tools for anyone to achieve good, practical vibration control in his or her system.
The plethora of vibration-control products on the…
How does all this relate to mechanical vibration? I believe progress in audio design has reached a point that demands serious attention to these and other subtle interactions---along with the more obvious variables---if we are to further reduce the "electronic" signature in reproduced music and move toward a more convincing re-creation of the real thing. This is true whether one is dealing within the electrical, mechanical, or acoustic arenas. From a practical standpoint, the time and frequency domains are alternate frames of reference, and most real progress in sound reproduction is being…
A Road Map
In order to keep things in focus, I will explore the effects of vibration on audio systems by examining how resonances interact with each of the major elements---floor, stands, platforms or shelves, components---and the various means of connecting them. Throughout our discussion I'll be referring to large torsional, or twisting, forces on structures, as well as significant displacements vs small movements. However, these are only relative comparisons. On an absolute scale, all of the vibration interactions in a typical audio system are very small (except for some room and…
In order to keep things in focus, I will explore the effects of vibration on audio systems by examining how resonances interact with each of the major elements---floor, stands, platforms or shelves, components---and the various means of connecting them. Throughout our discussion I'll be referring to large torsional, or twisting, forces on structures, as well as significant displacements vs small movements. However, these are only relative comparisons. On an absolute scale, all of the vibration interactions in a typical audio system are very small (except for some room and…