Musical Surroundings MM/MC Phonomena Phono Preamplifier

Musical Surroundings MM/MC Phonomena Phono Preamplifier
 

Paul Szabady

4 January 2001

Specifications

American made using discrete transistor topology
Dual mono circuit layout
Class-A operation
Matched low noise input transistors
Adjustable gain: 40 – 60 dB in 16 steps
Adjustable loading: 30 ohms – 100 k-ohms in 128 steps
Adjustable capacitance
Remote AC Power Source
Constant ON feature for thermal stability
Coming soon: Optional battery power supply
Introductory price: $600

Distributed by Musical Surroundings
5856 College Ave
Suite 146
Oakland, CA 94618
Phone: (510) 420-0379
Fax: (510) 420-0392
Web: www.musicalsurroundings.com

Distributed by Musical Surroundings (purveyors of Basis, Benz-Micro, Koetsu, Graham, and Aesthetix) and designed by Michael Yee, the Phonomena offers unprecedented cartridge-loading flexibility at its $600 price. There are 16 steps of gain, ranging from 40 to 60 dB, and 128 load impedance settings available, ranging from 30 to 100 k-ohms. Two capacitance choices are available for loading moving magnet cartridges. Removing the metal top plate of the 12″ by 5″ by 2″ chassis, with the thoughtfully supplied Allen wrench, allows access to the small DIP switches, which allow the user to set the gain and impedance for virtually any cartridge. A group of 8 DIPs (4 for each channel) control gain and another group of 16 (8 for each channel) set capacitance and impedance, resulting in a choice of 2,112 possible combinations.

A transparent plastic fascia saves the unit from the typical generic black-box appearance.

There is no power switch, but a blue LED indicates that the unit is turned on. The circuit is a class A design, incorporating discrete, matched, low-noise input transistors and a dual mono layout. A smallish detachable wall-wart supplies power. An optional rechargeable battery power supply will be available shortly but was not ready at the time of this evaluation.

The manual is straightforward as to the unit’s operation, but only names cartridges distributed by Musical Surroundings as examples for gain settings. There are no specifications listed, nor is absolute polarity mentioned. Settings can be changed with the unit powered up and require about 60 seconds to settle. The factory settings are 40 dB gain, and 50 k-ohms impedance.

Casual introductory listening at the standard settings hinted that the unit might have better been named “Chameleon,” as its sonic signature hid behind the output of 4 different turntables and a slew of interconnects. Consistent through all this, though, was the sense of a wide and deep soundstage, extended high frequencies, and general unflappability of high-frequency transients—things never got hard, edgy, or nasty. So the Phonomena passed my basic Hippocratic requirement for all components: “First, cause no pain.”

Pondering the plural form of its name and then considering the 2,112 possible setting combinations of gain/impedance/capacitance, I realized that the Phonomena moniker was appropriately selected. Close listening to the new Series 2 Benz-Micro Glider L2, set at 60 dB gain and 1000 ohms, and then changing the load impedance to other settings, revealed a very different sonic signature with each change. These results were repeated with the other moving-coil cartridges I used: the 47 Labs’ Miyabi, the Goldring Eroica LX, Audio Technica AT OC9ML, and the Sumiko Talisman Boron. Changing gain levels further complicated the issue. The amount of possible settings opened up a labyrinth that could lead to confusion, if not despair and madness. What IS the right setting? And what are the chances of ever finding it?

Most of us look to sufficient gain as the primary requirement to run a given moving-coil cartridge, but since most phono preamps offer little if any load impedance selection, one hopes that the setting supplied is the right load for the cartridge we’re using. As I understand it, the load impedance will affect the damping of the cartridge’s electrical signal and each cartridge will have an optimum, or correct load impedance, where the signal will rise in time with the transient and stop when the transient stops. It will be critically damped. Under-damping a cartridge by using a load impedance too high will allow ringing, or the continuation of the signal when it should stop. Conversely, under-loading a cartridge results in over-damping, where the signal is “slower” than it should be. Finding this correct impedance loading is not always easy. Most cartridge manufacturers recommend a general range of loading, but one is never sure if the recommendations reflect this critical damping or not. The Phonomena owner’s manual mentions this only briefly, referring to the lower impedance settings as providing “increased focus and tighter bass” and the higher impedance settings as sounding more “open.”

Translating these variations in electrical damping into sonic and musical terms is more complex. Although I did not try all 2000+ possible combinations with each moving-coil cartridge, (I got excellent and consistent results with the various moving magnet cartridges I used, including the Shure V15 xMR, Grado Signature TLZ-5 and Reference Sonata at 40 dB gain and 50 k-ohms of impedance) I systematically tried a wide enough range of them to have a feel for what occurs. One could assume that the manufacturer’s suggested “correct” loading is the one to go for and IS the obvious place to start, but the context of the system and one’s tastes bear consideration. For example, an over-damped woofer and a dead-sounding tweeter might benefit from a bit less damping, and conversely, a loose-sounding woofer and ringing tweeter might benefit from a greater amount of damping. In addition, the tonearm/turntable’s sonic signature can be accounted for. Using the Glider L2 in an older Linn LP 12, a Rega Planar 3 and the Origin Live Basic turntable required different settings, as did changes in arms from stock RB300s to OL RB300 and OLRB250s. A safe procedure would be to set the Phonomena according to the cartridge manufacturer’s recommendation, and then to systematically lower (or raise) the impedance until transients, bass articulation, and soundstaging are the most natural. Did I nail the exact settings for each cartridge I used? Probably not, but with most I felt that I was in the ballpark.

The potential advantages of this enormous capacity to tune the sound are, unfortunately, equally matched by the potential to totally screw things up. One could say that the Phonomena offers a wide, deep, and focused soundstage and, if set improperly, say that its soundstage is flat, amorphous and ambiguous. Depending on the settings one could conclude that vocals sound focused in the back of the throat, or that they include the chest also. The bass could be described as recessive and compressed, or as dynamic and a bit loose in control. So, the Phonomena can exhibit sonic characteristics that are totally opposite, or any shading in between; and a bit of experimenting may be needed to find the optimal settings.

It becomes clear then that the true sound of the Phonomena is highly subjective and elusive. Trying to assess its ultimate sonic signature is fraught with qualification and the potential for error. But at its best, it offers a wide, deep, and coherent stereo image with very good ambience retrieval. There is no sense that two instruments are occupying the same position in space, thus allowing easy orientation to and placement of instruments within the soundstage. Detail is excellent and reveals musically relevant information rather than mere extra-musical minutiae. Compared to the best available phono stages, timbre of the instruments is only fair and not as harmonically rich as it could be. Tonal colors are on the pastel side, and there is a slight pale-grey cast to the overall sonic palette. Ultimate transient capacity is slightly blurred and lies on the softer side of absolute neutrality. Bass dynamics, power, and authority are somewhat lacking, though musical expressiveness in the smaller gestures is quite good. Silence and timing between notes is only so-so, leading to a slight lack of vividness, sometimes diminishing the emotional impact. High frequency reproduction is pleasing and extended, but the ultimate resolution of complex percussive sounds, such as cymbals, is somewhat diluted. But the piano is free from clang, and violins don’t shriek. Although the Phonomena falls short of the absolute, its sins are mainly of omission and are quite forgivable considering the unit’s very reasonable price.

Aggressive and somewhat harsh systems may find the Phonomena heaven-sent, and mellow, laid-back systems may not reveal its ultimate weak points. Compared to entry-level phono stages, say, those below $400, the Phonomena offers a far more accurate soundstage portrayal, much finer articulation of detail and nuance, and a more linear frequency balance. The only area that might be lacking in comparison to some is that of bass drive and weight.

Throughout my listening to the Phonomena, I couldn’t help wondering about the product’s simple wall-wart AC transformer, and what sonic benefits would result from using the more sophisticated, battery supply that will soon be available. Will the silence and space between notes and sonic events improve, will transients resolve more clearly, will the bass tighten and deepen, and will tonal colors move away from pastel and closer to neutral (if not the Technicolor)? Will the Phonomena then live up to its name and become a totally satisfying, musical product? I eagerly await the arrival of the new power supply, and hope to write a follow-up report. Stay tuned!

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