DS Audio Master1 Optical Cartridge and Master1 Equalizer

A New Benchmark

Equipment report
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Cartridges
DS Audio Master1 Optical Cartridge and Master1 Equalizer

Weighing in at a hefty 53 pounds, the Master1 EQ uses thick, solid copper plates (one of the reason for its mass) as busbars to connect its twelve 120,000µF electrolytic capacitors. Each of its three sets of RCA and XLR outputs (there is only a single set of RCA inputs) runs on a separate power supply via fully discrete, dual-mono circuitry mounted on hand-made circuit boards. The Master1 EQ employs different bass eq curves for each output: a first-order roll-off at 30Hz with Output 1; two first-order roll-offs at 50Hz and 30Hz with Output 2; and two first-order roll-offs at 50Hz and 30Hz, followed by an additional second-order roll-off at 25Hz with Output 3. (With the multi-ported Børresen 05 loudspeakers I preferred Outputs 2 and 3.) 

Judging from what I hear from the Master1 (and the previous DS Audio carts I’ve reviewed), I’d say these bass filters aren’t just latter-day “rumble filters.” They are also correcting for the Master1’s inherent rising response in the bottommost octaves. (Though DS Audio doesn’t comment on this, one would think that reading the amplitude of a signal rather than its velocity should accentuate higher-amplitude vibrations—i.e., bass signals—in the same way that reading velocity accentuates higher-velocity treble signals in an mm or mc. It is a fact that the Master1 EQ provides bass filtration of various orders on all three of its outputs—and no filtration of the treble—which suggests an inherently elevated low end.) The Master1 also has another little measurable and audible quirk in the upper midrange and treble, which we will come to.

What’s New About the Master1?
DS Audio made some changes in the DS-002 that are carried forward in the Master1. The LED and photo sensors have been moved closer still to the stylus, as has the thin opaque plate that serves as the vibrating system, so the amplitude of vibrations can be transmitted and read with greater precision. The use of a traditional suspension, where the cantilever is held rigidly in place via a tension wire secured by a setscrew, has also been retained, where other things, such as the stylus rod and the stylus itself, have been outright improved. The DS 002’s Shibata stylus has been replaced by a micro- ridge type mounted to a sapphire cantilever. The cartridge body, once aluminum, is now constructed of light, strong, vibration-resistant ultra-duralumin.

The Master1 EQ is also improved over the DS-002 EQ. Where the 002 EQ offered two sets of RCA-only outputs (and two levels of bass filtration), the Master1 EQ has, as noted, three sets of RCA and XLR outputs (and three levels of bass filtration). And where the 002 EQ had a power supply with ten 33,000µF electrolytic caps, the Master1 EQ has, again as noted, twelve 120,000µF electrolytic caps, thick solid copper busbars, dual-mono circuitry, and handmade boards.

Setup
Fundamentally, setting up a Master1 optical cartridge is no different than setting up any high-quality moving-coil, moving-iron, or moving-magnet cart. Initially, you adjust overhang via a double-null-point grid; you dial-in azimuth via a Fozgometer or similar device; you determine SRA/VTA (stylus rake angle and vertical tracking angle) as per your usual method (more on this in a moment); and you set tracking force with a meter (and anti-skate to taste). 

Would this were all there was to it. But it is not. Whether the cartridge’s unusual sensitivity to set-up adjustments results from the unique way it generates current (for which, see above) or from the absence of mechanical and magnetic damping (ditto), the Master1 does seem to need more coddling than most to show its considerable best. You certainly don’t have to throw the book away when it comes to setting it up, but you may have to rewrite certain chapters when fine-tuning SRA, anti-skate, VTF, etc. 

For instance, with SRA, the “textbook-correct” solution of 92º or thereabouts (customarily dialed-in via a USB digital microscope and computer software) may not be the right height for the Master1, which (at least for smoothest treble and bass with the ribbon/cone Børresen 05 loudspeakers I’m also currently testing) tends to prefer something closer to 90º, i.e., parallel to the record surface. (Then again, with another speaker, the theoretical and the actual may coincide, and 92º could turn out to be right.) The cartridge, once again in my current front end (Acoustic Signature TA-9000 tonearm mounted on an Acoustic Signature Invictus Jr. ’table), also seems to like a VTF closer to 1.8 grams rather than to the 1.7 grams that DS Audio recommends, with anti-skate set below that.