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Balance on the remote is adjusted by pressing the balance button. The status LED will blink rapidly and you can use the left/right arrow keys to facilitate adjustment. Hitting enter locks in the offset. Reset returns to perfect balance. Internal construction is described as "high-grade components embedded in premium cool-blue nickel-immersion gold-plated printed circuit board with lead-free solder. All power and i/o connections are hand-wire point to point to PCB using high-grade Teflon insulated silvered copper wire. Heavy 12-gauge solid copper ground rod links audio signal common to circuit board. The audio signal passing through the LRD6 is both electrically and optically isolated from the power supply and the control circuitry. The audio signal only sees purely resistive LDRs. There is also a common signal ground physically isolated from the power supply ground. Isolation between the incoming audio signals is well in excess of 5MΩ."


The rear panel is an array of high-quality gold-over-brass RCAs as 6 inputs and one output. There is also an input for a 12V trigger and a power supply input. The LDR6 operates with an outboard 12V wall wart. For those concerned about that, remember that this a passive pre and does not use power for the traditional active circuitry. Aesthetics fall on the functional side with subtle embellishments. Front and rear panels are black with silver metal exposed on the edges for contrast. All lettering front and back is engraved with the front lettering finished in azure blue. The control knob is a black enamelled solid brass knurled Fender Telecaster. The cheeks are flat black with horizontal surface contours. Exposed connectors are black Allen bolts. Oversized trapezoidal rubber feet mount to the bottom. Some of the competition offers heftier carved metalwork but Tortuga’s package is small, subtly attractive and unobtrusive enough to accompany its electronic ancillaries and not visually overpower them.

The Tortuga LDR6 had the luck of a wide variety of equipment thrown into its path. The 98dB Casta Model C was a horn-based statement piece born of live music and studio requirement. The 86dB Apogee Acoustics Duetta represented the nastily inefficient end of the spectrum to explore how far our passive hopeful could be pushed. The Casta ran full range, the Apogees added a Paradigm Servo 15 to gauge if bass would be a problem. Despite the large discrepancy in efficiencies, neither was a problem. The worst-case scenario of Apogees was never an issue and available volume levels were equivalent to what I would normally use with an active pre and in fact somewhat higher. The systems never ran out of gas and proved effective over a wide volume range.


Amplification was via Bel Canto Evo 200.4 and briefly with the succulent Audio Valve Challenger 250 tube powerhouse. Sources were the Wyred4Sound Music Server with its companion DAC2 through optical and I²S connections as well as the Audio Space CDP8A running with tube and SS outputs and utilizing its digital outputs into the DAC2. The visiting AURALiC ARK MX+ DAC also logged some time and showed its addictive abilities.


Choosing some music to soothe and invigorate. "Don’t Stop the Dance" from The Jazz Age: The Bryan Ferry Orchestra [BMG 53800759 2] has Bryan Ferry excel at the unexpected. Here he dons the producer’s hat with a namesake Bryan Ferry Orchestra doing 1920s Jazz interpretations of Roxy Music hits. If that weren’t unusual enough, the style of recording certainly is. It's essentially monophonic with a restricted tonal balance to emulate a feel for recordings of the period minus the crackle and hiss. Pick any cut and find it surprisingly dynamic and involving despite the obvious imposed restrictions. A real test for how much can be extracted from less.
"Bel Air" from Paradise: Lana Del Ray [Polydor B001766702] has delicacy and depth refer to multiple parameters of lyrics, intonation and recoding quality. No big swings here, just exploration of complex layers with a vocal talent that takes on the material with unusual ease. Evokes memories of Kate Bush and Tori Amos taken in different directions. A good piece from a strong collection of material.


"Nobody Knows the Trouble I’ve Seen" from Antiphone Blues: Arne Domnerus/Gustav Sjokvist [Proprius PRCD 7744] is a classic cut from the classic album that turned heads with its unusual pairing of sax and organ in a lively church setting. Air, reverberation and heartfelt emotional power in the saxophone performance were all beautifully captured and recorded by the Proprius team.


"Petit Fleur" from Chansons: Jill Barber [Outside Music] is a clean recording that concentrates on accuracy of tonal color minus gimmicks or effects. Piano, percussion, bass, trumpet and sax accompany Ms Barber in an intimate little walk down memory lane with some very effective covers of various French chansons. Her articulation and purity reveal real vocal talent. In shared listening sessions the name Edith Piaf arose and that certainly is good company to be mistaken for.

"Night on Bald Mountain; Mussorgsky" from Mephisto & Co. Eiji Oue/Minnesota Orchestra [Reference Recordings RR-82CD] is a lovely little collection of sonic spectaculars to gleefully test dynamic verve and detail as expertly engineered by Keith Johnson to capture the intricacies and power. A familiar piece given a great workout here.

Listening for the details. Character in a passive preamplifier of this caliber is less about what it contributes and all about what it allows the components around it to reveal. In all its matchups this proved true of the Tortuga Audio LDR6. Noise was non existent for the pre and source dependent. Tonal balance was chameleon-like where a change of cable or component shifted what the system was doing. What remained consistent was a solidity in the midrange and lower midrange that allowed objects an extremely natural weight of tone. High frequencies could be pushed from sweet to bright but stayed grain free in any combination I could muster. Clean without inherent character. Bass was passed through with no alteration in level or detail. Overall the LDR6 was essentially dead neutral as befit its passive nature. Which brings us to the handling of detail and dynamics. Again this description is less a catalogue of character and more a list of what to expect given suitable ancillaries. The passive could unravel an extraordinary amount of information without exaggeration or editorializing. The little Tortuga had the capability of differentiating noise floors on different recordings which had varying resolution levels with uncanny clarity. Deep rich low-level noise floor or premature digital dark were revealed without prejudice.


The LDR6 also demonstrated exemplary preservation of transient behavior, allowing the system to reproduce leading and trailing edges with unusual fidelity. There was steep rise and fall on appropriate material to contribute to high articulation with extreme clarity. The LDR6 mustered impressive dynamic gradation and uncompressed range that could (depending on the recording) combine the subtle and explosive without losing individual lines. It differentiated dynamic steps with precision to reveal a richness of information that combined with its matter-of-fact tonal character gave the music a liveliness that was one on one with the recording. Direct and intense.