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Finally, we received the integrated model of the Moon series from the manufacturers of Celeste electronics. Celeste components were introduced about six years ago and are manufactured by Simaudio, named for its founder Victor Sima. Current company president John Poulin bought Simaudio about five years ago and since then has developed the Moon series for the audiophile market. Moon components are sold by specialty dealers around the world selected for their credentials and experience in high-end audio. The Moon i-5 amplifier was introduced about two years ago; we however, couldn't get a unit because Simaudio had sold every i-5 amplifier and none were available for review.
Appearance:
The Moon offers one of the industry's most elegant looks. Its aesthetic appeal marries modern architecture with common sense and functionality. The clean lines are complemented by an elegant faceplate which offers a small display widow on the left followed by three buttons for monitor, mute and input selection. On the right, a large volume control completes the unit's appearance. The Moon's electronics are placed on an extremely rigid chassis to minimizes the effects of outside vibrations, thereby diminishing mechanical colouration of the music. The chassis rests on four height adjustable cylindrical cones which screw into the base. While the mechanical aspects of the chassis serve a purpose, to be sure, the design shapes up as a remarkably attractive audio component. Speaker outputs are heavy gold-plated WBT binding posts. A toggle on the unit's rear serves as the main power switch; five inputs plus a tape loop accommodate source components and a detachable power cord and fuse complete the unit's rear panel. The unit's shipping weight is 25 lbs and it measures (W x H x D) 19" x 7.5" x 19"; large enough to accommodate the electronics and small enough to place on a shelf. A large remote control comes with the amplifier and will accommodate Simaudio source components and other designs. All switching is done electronically and with the help of the remote control. The tape output is switchable for more flexibility; the preamp output can be used to control another amplifier or sub.
Technology:
Simaudio engineered the integrated amplifier based on the design of the Moon preamplifier and power amplifier. The technology is based on what Simaudio calls "Advanced Renaissance" employed in all Moon series components. The fundamental design philosophy typifies the omission of overall feedback and the utilization of a precise differential circuit. There is only one step of local feedback in the output stage to maintain low total harmonic distortion. According to Poulin, intermodulation distortion, far more damaging than THD, is virtually non-existent. This engineering method results in an exceptionally fast amplifier without phase errors (resulting from feedback). More importantly, with this circuit, the speaker cannot return its counter-reaction after a musical impulse, which usually results in reduced clarity of the music and diminished tonal accuracy. Poulin claims that the design offers a less forced sound as a result of a feedback-free circuit in the gain stage, but hurries to add that there is a small price to pay&emdash;the unit has to be fully burned in and operated for at least 3 days to reach optimal performance. This should not be considered an inconvenience as this integrated amplifier is designed to be powered up constantly. Another relevant Moon arrangement is to maintain the shortest possible signal path and to eliminate all potential sources of signal erosion. In the case of the Moon i-5, the signal path measures fifteen inches in length (from input RCA to output binding post). Poulin decided to minimize signal path obstacles by using a passive circuit for the preamplification section. This circuit is void of both carbon-based parts (resistors, pots, etc.) and capacitors which adversely affect the signal by introducing coloration and a nuance of inaccuracy.
The Moon i-5 gain stage results from an intensive research and development program. Poulin settled on an electronic component manufactured by Crystal. This device functions in a slightly different way than an M-DAC, but it basically reproduces the RBG circuitry in a single chip configuration. RBG stands for Richard Benoit Gain&emdash;the engineer who developed this circuit&emdash;and this circuitry is found in both the Moon integrated amp and the Moon P-3 preamp. By applying more or less impedance (using a network of relays) in a shunt-to-ground mode against the input signal, gain can be increased or decreased without degrading the quality of the audio signal, regardless of the selected level of gain. Poulin opted for the Crystal devise to save space inside the Moon i-5. It was assigned the name RBG-cy to make a distinction between it and the company's other gain control circuits.
Finally, there is the Simaudio-designed 500VA toroidal transformer used in the power supply and complemented by quality components with low resonance characteristics. The parts are made by well-known quality conscious manufacturers such as Vishay Dale, Phillips, Ero, Wima and Thompson, Nichicon, United Chemi-con and Cornell.
Output section wiring is done with custom proprietary silver plated OFC copper with Teflon insulation. All other signal path wiring uses silver plated copper with Teflon insulation. 2% silver alloy multicore solder is used throughout the circuitry. Input devices are J-FETs; the input impedance is 14Kohms and the power rating is 70 watts per channel into 8 ohms, 110 watts into 4 ohms. Output impedance is 0.04ohms, damping factor is >200, gain is 30dB. Max. output volts are 23.5; slew rate is 20 volt/micro sec. Maximum peak current is quoted as 15 amps, bandwidth is from 10Hz-75Khz +0-3dB, crosstalk @ 1Khz is 85dB. Intermodulation distortion is unmeasurable and THD is (from 20-20Khz) <0.15%.
The Sound:
For our auditioning sessions we used the Gershman Avant Garde, Coincident Technology Millenniums and Dalquist speakers, all reviewed in this issue. A pair of our Editor's Ethera Vitaes, a pair of Swans and a pair of Polks, also reviewed in this issue, were also used. This rather large selection of loudspeakers was used to establish the Moon's sonic signature, its compatibility with loudspeakers and its ability to handle different loads. An Alchemist CD transport/DAC (reviewed in this issue) was our source component and the system was wired with Nordost SPM cables and interconnects.
To everyone's astonishment, the Moon maintained a steadfast sonic disposition throughout every listening test and communicated its sonic distinctiveness to all connected loudspeakers. One word might best describe the unit's sound: enlightening. Of all the integrated amplifiers we have auditioned, this one got everyone's attention the moment the first bar of music hit their ears. The Moon's all-round sound is spirited&emdash;not laid back, not mushy, not mollifying, but grabbing and captivating and believable when it come to sonic refinements. When listening to this amplifier you can't help but get involved with the music. We noted that loudspeakers with an efficiency rating of 87dB&emdash;more if possible&emdash;fared best as the amplifier didn't need to work excessively, resulting in a melodious and effortless flow of the music. The best match was achieved with the Gershman Avant Garde and the Ethera Vitae speakers. The Coincident Millenniums sounded full-bodied and accurate but couldn't quite achieve their apex, determined by us when we evaluated the speakers. The Polks were a surprisingly good match and sounded great across the audible frequency range. A slight edge at the upper bass can be attributed to the Polk's built-in amplifiers and a possible input/output discrepancy. Nevertheless, the Polk/Moon system must be considered an undeniable bargain and ranks high when budget restrictions prevent further spending. The Swans sounded rather impressive and revealed the Moon's stunning imaging proficiency. We considered these loudspeakers a good match and a viable system configuration for those with space restrictions. All in all, the Moon i-5 manages to reveal the character of loudspeakers, cables and source components&emdash;which is to say that it's sound can be considered candid and musical, a unique blend of performance and entertainment.
Synopsis & Commentary:
This is going to be short and sweet, but allow us a moment to comment on perception versus predilection of reproduced sound. Perceived sound quality relates to the process of (our) understanding and the method of becoming immediately aware of something&emdash;an elevated degree of sound, in our example. Predilection, however, describes preference&emdash;a partiality toward a flavour, a colouration, not necessarily the correctness of sound, but a choice of the auditory end product. This said, we are going to tell you that the Moon is what we perceive to be one of the best integrated amplifiers we have auditioned up till now. We feel that it belongs in the category of those few exceptional components that can achieve high-resolution sound comparable only to separate amp and preamp systems. We aren't going to tell you that it's the only one, but it certainly can be grouped with any of the other high-end, high priced components of which we know. So, we have awarded it with four musical notes&emdash;short and sweet!OCM Amplifier
