Digital Processor Reviews

I have owned the SE version of the Bricasti M1 D/A converter for several years. It's my reference DAC. When, recently, I became aware of the availability of the factory-installed MDx Processor Board upgrade, I packed up the M1SE and sent it off to the Bricasti factory, which is in Shirley, Massachusetts, northwest of Boston. The factory-installed MDx upgrade costs $1000—a lot less than the $10,000 it costs today to buy a new M1SE with the MDx board.

As ALF would say, "There's more than one way to cook a cat." We've been so overwhelmed with linear pulse-code modulation (PCM) recording, we forget there are other ways to pass from the analog domain to the digital.

One of these is delta modulation. The Greek delta (which in its upper-case, block-letter form, looks like an equilateral triangle) is the mathematical symbol for the difference between two quantities; accordingly, in delta modulation, we record not the absolute value of a signal sample, but the difference between successive samples.

In 1978, when I reviewed Sony's first audiophile-type PCM-1 converter, I earned the undying scorn of a large segment of audiophilia by reporting that, on the basis of a rather short testing period (which did however include some live recording), I was unable to hear anything the matter with its sound. Four years later, but after substantially more testing, I am obliged to report the same thing about the PCM-l's son, the PCM-Fl.

With the furor over the launch of DAT (digital audio tape), it is worth remembering that commercial digital recorders have been with us for some time now: it is now nearly a decade since studio PCM converters were first successfully used for audio recording in conjunction with a VCR (which uses a helical spiral recording via a spinning drum to achieve the high writing speed).

I have reported on exaSound DACs since the introduction of the e18 in 2013, but those reports were in my Music in the Round column. This is Stereophile's first full review of an exaSound product and the first time one has spent time on JA's test bench.

What I categorize as mainstream, dealer-based, fancy-pants streamers and big-speakers audio is actually only the gold-plated tip of a gigantic asteroid-like monolith that extends (underground) from New York to Hong Kong, from the Arctic Circle to Antarctica.

For his review of the Pink Faun 2.16x music server in the December 2020 issue, Kal Rubinson needed to use a Linux-compatible multichannel D/A processor. A little Googling uncovered the 8-channel dac8 PRO from Okto Research in the Czech Republic, so Kal borrowed one from the manufacturer. He found it to be a great-sounding DAC with an intriguing feature set. He purchased the sample.