Review: Soundsmith SG-410 Strain Gauge Cartridge Cartridge

Category: Analog

This is a review of the Soundsmith Strain Gauge cartridge and its dedicated SG-410 electronics. I ordered the cartridge with both the standard nude contact stylus (SGS-5) and an additional optimized contour contact stylus (SGS-6). The SG-410 electronics is the remote control version of the basic model with an alternate line input enabling it also to be used as a CD or other source input or even to accept the output from a separate preamplifier.

The workmanship of both the cartridge and the accompanying electronics is outstanding. The cartridge body is a precision-milled piece of aluminum, and the stylus is a delicate ruby cantilever mounted onto a milled piece of aluminum that can easily be attached to or detached from the cartridge body, which enables the stylus to be easily changed or replaced. The photos below show the cartridge mounted on my Triplanar Mk VII tonearm as well as the bottom of the cartridge body and each of the separate stylus assemblies; the SGS-5 is the black one; the SGS-6 is the orange one. This user-replaceable stylus feature is, I think, unique – it obviates the need for retipping cartridges, and makes it both easy and inexpensive to change the stylus.

The SG-410 is a relatively small, low-profile unit (15.5” wide x 15” deep x 3.5” high), which is built on a 0.25” thick aluminum chassis that is wrapped on the sides and front with a hardwood exterior. Soundsmith offers a number of options in terms of the wood that is used; I ordered the standard walnut, and had it finished with an ebony stain so that it appears black with some wood grain showing through the finish. There is a separate power supply in a small aluminum enclosure (6” wide x 8.75” deep x 3” high). I asked Soundsmith to install a DPDT (double-pole double-throw) switch on the power supply to accommodate my usage of 120 volt balanced power – 60 volts of potential between ground and each of the “hot” and “neutral” contacts.

Unlike traditional moving magnet (MM) or moving coil (MC) cartridges, the SG cartridge does not produce a voltage or current. Instead, it responds to mechanical movement in the grooves by changing resistance. As a result, it requires the use of a separate dedicated piece of electronics to generate a direct current against which the changes in resistance can then be converted into an analog signal. This is supposed to have several advantages. First, it should provide for a relatively flat frequency response over a wide range that exceeds the audible range. Second, the SG cartridge is a high compliance cartridge that has a much lower effective moving mass than MC cartridges (which generally have a lower effective moving mass than MM cartridges). The substantially lower effective moving mass should mean, at least theoretically, that there is a substantially lower level of stored energy which could be reflected back down the cantilever and stylus and give rise to mistracking and distortions. All of this should enable the SG cartridge to maintain a better contact with the groove walls and to extract more detail with greater accuracy than either MC or MM cartridges. These advantages were confirmed, as explained below.

One other advantage – which I noticed immediately – is that, even with the gain all the way open, the SG cartridge is dead quiet. I have never experienced any other cartridge that is this quiet. I believe this is due to two key facts. First, the signal flowing in the tonearm cable is derived from a non-inductive source. That is to say, unlike every MC or MM cartridge, there are no coils or other windings that are susceptible to picking up hum or RFI. And second, the SG 410 electronics are exceptionally quiet; this may be due, in part, to the fact there is a much smaller level of gain needed or to the fact that the design and execution are superb. The bottom line, for whatever reason, is that the SG cartridge is just dead quiet with no hum or background noise at all. Period.

I have used the SG for several months now along with the following equipment. The cartridge is mounted on a Triplanar Mk. VII tonearm on a TW Acustic Raven AC-1 turntable. This sits atop a Symposium Svelte Plus platform which lays on a 2” thick slab of Pennsylvania black slate. The slate rests on four Symposium Rollerblock Jrs., which are attached to the tops of 4 posts of a homemade turntable stand constructed out of 3.5” square Ipe wood and braced at two different levels through mortised and tenoned Ipe cross supports. The stand has four 2.5” aluminum cones that rest on a carpeted suspended wooden floor.

The associated electronics are a VAC Renaissance Signature Mk II preamplifier and a VAC Phi 300 amplifier, which drives Verity Audio Lohengrin speakers. Power is fed through a large 350 lb EI-style Topaz 10 kVA transformer that sits in my basement and is hard-wired to provide 60-0-60 volt balanced power with an isolated technical ground. This power is fed directly to the amplifier; all other components are fed this power through a Shunyata Hydra 6. Power cords are Stealth Dream, interconnects are Stealth Indra and M-21, and speaker cables are Stealth Ultimate Ribbon in a bi-wire configuration. All equipment, other than the turntable, the Hydra 6 and the SG-410 power supply, are mounted on Sistrum stands or racks. The SG-410 power supply is mounted on 2” thick Pennsylvania black slate that sits across the lower cross supports of the turntable stand. The dimensions of the room are 21.5 feet wide by 29 feet long; ceiling height is mostly 10 feet.

So, after all of this description, how does the SG cartridge sound? The SG cartridge performed exceptionally well right out of the box, and after about 25 to 30 hours of break-in, improved another 15% to 20% to its current level of outstanding performance. Let me just say that this cartridge far surpasses the best of cartridges I have heard in my system from Benz, Koetsu, Lyra, Miyabi and ZYX. It is the most revealing, three-dimensional and involving cartridge that I have ever heard anywhere. It is extraordinarily detailed, and yet, it marries exquisite detail with a wonderfully layered and lush sound. It provides the fastest transients I have ever heard – nothing else comes even remotely close in this area – and it has a delicacy and purity of decay, sustain and harmonic depth that I have heard only at a live performance in a setting with excellent acoustics. It effortlessly reproduces the lowest and highest frequencies (as well as everything in between) with a depth and clarity like no other cartridge I have ever heard. Precise imaging and a wide, deep and tall soundstage all add to the creation of an astounding and intimate three-dimensional image of an actual performance. To put it bluntly, the SG cartridge is in an entirely different league from every other cartridge I have ever heard.

I might add that you cannot appreciate what the SG cartridge is capable of doing if you have heard it only at audio shows. Quite aside from the usual limitations at shows, the SG cartridge, to my knowledge, has been demonstrated only with small monitor speakers. While very good as far as small monitors are concerned, they are no match for serious full-frequency reference-level speakers with an extended range on both the low end and the high end. Demonstrating the SG cartridge with those limitations is like driving a Ferrari F430 Scuderia on a small track built for go-karts.

The Verity Audio Lohengrin speakers are essentially flat from 15 Hz to 60 kHz, and they are very fast. I now realize that I had never heard the depth of bass and the clarity of higher frequencies that these speakers were really capable of producing until I used the SG cartridge. The SG extracts more bass detail, with lightning-fast speed and more natural decay, than any other any other front-end device I have ever heard. This was immediately apparent on Rimsky-Korsakoff’s Scheherazade, Op. 35, performed by the Chicago Symphony (Reiner), (Classic Reissue of RCA LSC-2446), which is a serious test of any system or component. It has extensive dynamics ranging from delicate ppp violin and harp solos to powerful fff full orchestral movements. The SG cartridge effortlessly handled those dynamic extremes with total ease. I heard details – from the vibrations of bows against bass, cello, viola and violin strings to delicate bells in the background – that I had never even known were there. This is one of my favorite classical pieces, and I know it like the back of my hand. So to hear many new details from the same LP that I have played many times over was just remarkable. But that was no less remarkable than the soundstage that this cartridge was able to produce – it is the most lifelike reproduction I have ever heard. This cartridge effortlessly reproduces the deepest rumbling and strikes of the timpani, the crash of cymbals and the most delicate notes from the violins simultaneously, just as you would expect in a live performance. The fourth movement is just an astounding experience.

Patricia Barber’s “Companion” (Premonition Records 1999) is one of my favorite Jazz LPs with its excellent material and high quality of recording and mastering. I never really appreciated how superb the bass was on “Use Me” until I played it with the SG cartridge: rich and detailed with lightning-fast transients and the most natural decay I have ever heard. At the same time, the cartridge’s ability to layer Barber’s voice with an intimacy, an honesty and realism against the deep and fast bass is just remarkable.

Hugh Masekela’s “Hope” (Analogue Productions APJ 82020) is my favorite LP purchase over the last 12 months. The SG cartridge reproduces “Stimela,” a particularly moving piece on side 4, with more detail, intimacy, dynamics and speed than I have ever heard. The brassiness of the flugelhorn is reproduced with a realism you won’t hear anywhere other than in a live performance. The combination of crisp cymbals with deep fast bass, crystal clear triangles, a lush and detailed midrange and the magnificently textured voice of Makela makes for a presentation of sheer beauty.

I much prefer the optimized line contact stylus (SGS-6) over the standard line contact stylus (SGS-5). The SGS-6 stylus extracts more detail than the SGS-5 stylus (which in turn extracts more detail than any other cartridge I have ever heard), but there are several caveats one must keep in mind in using that stylus. First, it must be aligned with painstaking accuracy, and VTF and VTA are highly critical in optimizing performance from this stylus. Second, the SGS-6 works extraordinarily well on high-quality recordings which are in pristine shape. In the case of a lower-quality recording or a high-quality recording which is not in excellent shape, the SGS-5 stylus will produce a better result because it will integrate out some of the noise or other adverse elements in such a recording that would otherwise be retrieved in all its inglorious detail by the SGS-6 stylus. The good news is that these styli are easily changed, and the SGS-5 is much less demanding from an alignment perspective than the SGS-6. So, in my experience, once you have optimized your setup for the SGS-6, changing to the SGS-5 for a particular recording does not require any other adjustments.

I was particularly interested in how the SG-410 would sound directly into my VAC Phi 300 amplifier as opposed to going in as a line-level input into my VAC Renaissance Signature Mk II preamplifier. After a great deal of comparison, I concluded that it sounds better going directly into the amplifier. There is marginally more detail, without any sacrifice of that legendary VAC holographic sound. This is admittedly a close call.

The excellence of the SG-410 electronics when listening to vinyl made me curious as to how it would sound as a preamplifier when using a non-vinyl source such as my digital front-end (Zanden 2000P transport and 5000S DAC) through the alternate line input. In this case, though, I preferred the sound of my Zanden separates being fed through the VAC Renaissance Signature Mk II preamp over being fed through the alternative line input on the SG-410. This preference, though, was only a marginal preference tilting slightly in favor of the VAC preamp just as the preference for the SG-410 over the VAC preamp was only marginal in the case of vinyl. Perhaps the difference is that, with vinyl, using the VAC preamp with the SG-410 means that there is an additional component placed in the signal path whereas with the CD input there is no additional component placed in the signal path. The bottom line is that the SG-410, even as a stand-alone preamp, is an exceedingly good performer that will give even the highest reference-level preamps a run for the money.

In summary, the SG cartridge is the most revealing, musical and realistic cartridge I have ever heard. Anywhere. It effortlessly extracts the full range of frequencies with superb detail and extraordinary speed, decay, neutral richness and three-dimensional realism that places it in a class by itself. When matched with a high quality amplifier and speakers, the SG cartridge and SG 410 will reproduce music in a manner that is just jaw-dropping staggeringly good.

Associated gear
TW Acustic Raven AC-1 turntable
Triplanar Mk VII tonearm
VAC Renaissance Signature Mk II preamplifier
VAC Phi 300 Amplifier
Verity Audio Lohengrin Speakers
Stealth Dream power cords
Stealth Indra and M-21 interconnects
Stealth Ultimate Ribbon speaker cables