Boulder 1021 disc player
I saw a prototype of the Boulder player at the 2008 Consumer Electronics Show and was intrigued by the fact that its front panel is dominated by a large, 6.5" color display showing an album's metadata; ie, its artist, title, and track titles. Not unnaturally, I assumed the 1021 was a hard-diskbased media server, like the McIntosh MS750 reviewed by Wes Phillips in January 2008, with its transport used merely to rip CDs to the drive.
That's not correct, explained Rich Maez, Boulder's sales manager; the 1021 is still a disc player. But when a CD is loaded, it checks the CD Text data (if any), its own preloaded internal database of CD information, or the Internet (provided the owner has connected the player to his network router), in order to display the metadata. In the last case, it adds what it finds to its internal database for future reference. This is not your dad's dumb CD player.
Intrigued, and having just spent some enjoyable time with the sample of Boulder's impressive 860 power amplifier that Fred Kaplan had reviewed in December 2007, I signed up to be sent a review sample as soon as the 1021 was in production.
The innards of the hefty Boulder 1021 are housed in an elegant aluminum chassis that echoes the styling of other Boulder components. The panels are machined in-house from solid billets, and lock together to form a resonance-free enclosure. The top panel slides out on roller bearingsan impressive touch. Inside, the premium DVD-ROM mechanism is at the front right, behind which are two hefty toroidal power transformers, one each for the digital and analog circuits. Each transformer is magnetically shielded, encapsulated, and floated on a compliant mount"transformer hum is not permitted," declares Boulder.
A card frame occupies the left side of the chassis. The card adjacent to the transformer carries the primary power-supply circuitry, with a large number of reservoir capacitors and multiple stages of voltage regulation. Again, there is no connection between the analog and digital supplies.
The next card carries the digital signal handling circuitry, this making heavy use of an Analog Devices SHARC DSP chip running floating-point math to upsample the incoming data to a minimum rate of 705.6kHz with a 24-bit word length, perform digital filtering using what Boulder calls an Eigen-value algorithm, and adjust the volume if the user has selected Variable output level. The transport mechanism feeds data to this module as "packeted" data; ie, there is no timing reference, thus there is no downstream transmission of jitter. The transport also reads data from the disc faster than real-time (it's limited to 8x to minimize mechanical noise), and will repeat reading the segment if it encounters an errorshades of a PC ripping a disc with Exact Audio Copy! Only if the correct data are still unreadable does the software-based error correction interpolate the missing information. The use of a DVD transport allows audio data to be read with sample rates up to 192kHz and depths of up to 32 bits. Not only does the 1021 play CDs, it will also play data CDs and DVDs carrying high-resolution files (footnote 1). Definitely not your dad's dumb CD player.
The digital card sends the corrected, upsampled, and filtered data as a serial stream to the fully balanced, four-layer analog circuit card. This converts the data to analog using Analog Devices AD1955A converters, this a premium part with a specified signal/noise ratio of 120dB. The master clock for the conversion is sited adjacent to the DAC and, to keep jitter to a minimum, controls the timing of the data transmission everywhere else in the player. The output stage is built on Boulder's proprietary high-current, ultra-lowdistortion 983 gain stage, which is used in all their 1000-series products; the final low-pass analog filter is a six-pole Bessel type with constant group delay across the audioband.
Footnote 1: Though the 1021 will play the CD layer of SACDs, it will not play DVD-As. Nor will it play DVD-Vs containing high-resolution audio, such as Classic Records' 24/96 discs.