Sidebar 3: Measurements
Despite its small size, the RA Labs speaker is surprisingly sensitive; my B-weighted estimate was around 89dB/2.83V/m. However, as its impedance (fig.1) drops below 6 ohms for most of the midrange, 8 ohm–rated amplifiers and receivers should be avoided. The tuning of the sealed box is revealed by the peak at 65Hz, implying only moderate bass extension.
Fig.1 RA Labs BG Mini-Reference, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).
Note the small wrinkle in the traces between 200Hz and 300Hz. These suggest the…
My first exposure to Burmester electronics was some years back at a New York Hi-Fi Show, where they were powering a pair of B&W 801s and impressed the hell out of me. But Burmester's distribution seemed sporadic and the prices beyond my consideration, so I put them out of my mind.
More recently, Burmester has been showing up at CES and in my local hi-fi emporium with a mind-boggling array of jewel-finished components and a no-holds-barred approach to design. Demonstrations were as impressive as that first one, and I leaped at the prospect of getting the 970 DAC and 971 transport for…
We can't usually know what the sound of the original event was, but I always got the impression that the 970 came closer than the others. In the case of the recent Chuck Mangione recording on Chesky [see "Quarter Notes" elsewhere in this issue—Ed.], I was present at a recording session and listened both to the live sound in the hall and to the live mix as it was fed to the disk recorder. I am not a big Mangione fan (sorry, guys), and I heard "Mountain Flight" at least eight times during the recording sessions. But while I can summon little enthusiasm for the music, I do know what it sounded…
Sidebar 1: Burmester 969 CD transport
Sitting on matching baseplates and carbon-fiber discs, the $27,500 Burmester 969 transport and 970 DAC look very much alike. On its front panel the 969 has fewer buttons and a larger, single display, and on the top, the central of its three armor plates can be slid back to reveal a top-loading, belt-driven CD turntable. I really got a kick out of hearing the subtle relay click as I slid back the cover. Indeed, the mechanism was so smooth that the relay was the only perceptible feedback to the operator.
Udo Besser gave me a demo transport…
Sidebar 2: Specifications
Description: Balanced digital/analog converter with 24-bit/96kHz DACs, HDCD capability, full remote control, five digital and two analog filter characteristics, and phase-inversion switching. High-precision master clock at the DAC with output to control Burmester transports. Digital inputs: ST, TosLink, AES/EBU, two RCA. Digital outputs: RCA, TosLink. Analog outputs, fixed volume: balanced and unbalanced. Analog outputs, variable volume: balanced and unbalanced. 60-step volume control. External power supply with 11,6000µF capacitor filtering.
Dimensions: Main…
Sidebar 3: Associated Components
Most of the extended listening for these reports was done with the California Audio Labs CL-20 CD/DVD player as the source. I made this choice to eliminate any possible bias from using a transport designed and constructed to mate to a specific DAC. As the common source, the CL-20 provided both S/PDIF (coax and optical) and AES/EBU outputs, as well as CD/DVD compatibility with up to 24/96 digital output. I did this also to maintain a level playing field without auditioning all the possible combinations of transport and DAC and interconnection. Let's see:…
Sidebar 4: Measurements
Because of the Burmester 970's large number of permutations of digital and analog filters, I performed most of the measurements at the fixed outputs and at the MaxRez/Sharp digital filter and Linear analog filter settings used by KR for most of his auditioning. I checked other settings as appropriate.
The Burmester didn't invert signal polarity from any of its outputs (the XLR jacks are wired with pin 2 hot). Its maximum output from the fixed-level outputs was 4.047V (balanced) and 2.025V (single-ended), sourced from 132.6 ohms and 66.5 ohms, respectively…
More than a decade ago, I bought a new pair of speakers and sought to find the most suitable cables for them. After auditioning a number of borrowed sets, I enlisted my daughter to confirm my selection. She grew up in a household where there was always good music playing on good equipment, but had no active interest in either. To placate Dad, she listened to a few of her own recordings with each of the various cables and then, lo and behold, reached the same conclusion I had. In fact, she described the differences almost exactly as I would have. I was ecstatic. Not only did it confirm my…
Three LEDs on the right side of the main panel monitor the frequency accuracy of the incoming digital signal. As we are all aware, digital signals often arrive at the converter in less than perfect condition. Not only can the transmission be plagued with jitter (short-term variations in data word-clock frequency) but the source (transport, DAT, digital broadcast, etc.) actually can be operating at a slightly different data/clock frequency than is specified for its type. Both of these factors can affect the operation of the phase-locked-loop (PLL) circuits, which are responsible for capturing…
Sidebar 1: mbl 1621 CD transport
Of all this marvelous hardware, I most enjoyed using the $14,900 mbl transport; I just couldn't keep my hands off it! Its massive black enclosure matches that of the 1611HR DAC, with its central, convex display module flanked by wonderful little gold buttons. Somehow, I wasn't bothered by the placement of the Play, Stop, and Pause buttons on the right—the display module clearly separated them from the track and search buttons. Operation, whether via the remote or the front panel, was straightforward, as were the display options.
The rear panel had…
