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
Hi, Spiritofmusic. Sorry for the delay in responding, but I don't log in to AudioGon as much as I used to. I feel the same way about the SG-410 as I did when I wrote the review; I have never heard any cartridge that comes even close to its performance. I would caution you, though, that the SGS-6 stylus is very demanding in terms of setup. That is no surprise given the very small point of contact. So, if you are auditioning a strain gauge cartridge system, you should make sure that the tonearm is properly set up and that the cartridge is properly aligned, especially if you are using the SGS-6 stylus. Let me know how it goes.
Vac_man, I've been running the SG200 for a good 6 months now, and it never fails to amaze. Have decided to stick with the '5' stylus, the '6' just looks too much trouble.
I've taken it's performance to a whole new level by scrapping the 24v dc wall warts, replacing them with a bespoke Red Wine Audio Black Lightning twin battery psu for the cart.
I have tried to read everything available on the internet about Peter's SG cartridge and am very close to buying one because of their obvious design advantages.

I just have one simple question that I can't get answered.

I understand that a strict adherence to RIAA is not critical to SQ (i.e., +/- .1db is beyond audible and probably over-kill).

I understand the speed, coherence, sound staging,(et. al.) of the SG is well worth a mild response variance from RIAA. Peter has publically disclosed this variance as +/-1db between 50hz and 14khz.

What I don't understand is why there is no disclosure about the magnitude of roll off from 50hz down to 20hz and the magnitude of upward tilt from 14kz up to 20kz both of which are in the audible range and generally not disputed?

I understand that a displacement sensitive design will not require any where near the equalization of a velocity sensitive design and will thereby stay fairly close to flat with no phono-stage equalization; but on the ends of the sonic spectrum Peter admits the tolerance exceeds +/-1db but refuses to quantify this variance. He seems to prefer simply tell us it doesn't matter. Peter is beyond brilliant, but I just don't get this approach.

This technology is phenomenal and the RIAA variance has spooked many an audiophile unnecessarily only because it diverges slightly from what is considered the norm. In turn, many technocrats in the industry cant get their perfectionist minds around what they perceive to be a deficiency.

The best speakers in the world have several dB humps and troughs at their cross-over points that are measured and then viewed as "character" by the audiophile community. (Think if an archaic manufacturing practice led to a strict linear response definition at the expense of speed, coherence, sound staging and so on in the speaker market. Seems pretty silly right?)

I don't get why Peter doesn't quote the rest of the audible spectrum variation, own it for what it is, take away the big mystery, and rule the world.
Peter admits the tolerance exceeds +/-1db but refuses to quantify this variance. He seems to prefer simply tell us it doesn't matter. Peter is beyond brilliant, but I just don't get this approach.
I can't speak for Peter, but keep in mind that if a phono CARTRIDGE actually measures +/- 1dB from 50Hz to 14KHz . . . this is quite flat, for any design. While it's true that a properly-designed RIAA phono PREAMP can (and IMO should) itself be better by at least a couple orders of magnitude, once you add the cartridge and measure the two of them together, then the tolerances are entirely different. The Soundsmith strain gauge cartridge is sold as a cartridge/preamp system, so if you want to compare it's response flatness with other products, then you have to compare it to other complete cartridge/preamp combinations, not simply to a preamp on its own.

This reminds me of recent article by Bruce Hofer (founder of Audio Precision) about the difference between "adjustment" and "calibration" of test instruments. His main point was that in order to be considered "calibrated", an instrument needs to have absolutely ironclad documentation of exactly how the accuracy of each adjustment was verified, back to international standards organizations. The maximum possible tolerances of each step are added together to ascertain the accuracy of the calibration process.

I've personally measured a enough cartridges to make quite a tidy little pile. Simply swapping between three different pressings made from the same lacquer can change results one way or the other by more than 1dB at the top octave of the spectrum. The same cartridge mounted on different tonearms can change the bottom octave much, much more. The temperature of both the cartridge and the record makes a noticeable difference. And then we have to add the tolerances of the cutterhead and cutting amplifier EQ to the mix.
I don't get why Peter doesn't quote the rest of the audible spectrum variation, own it for what it is, take away the big mystery, and rule the world.
Well, it's very difficult to play the "specs game" rationally in the audiophile market, and if I was in his position, I would probably come to the conclusion that there's very little to be gained from it anyway.

Thank you very much for your insightful, empirically based perspective. While I haven't measured cartridges, arms, and vinyl deltas as you have, my intuition is exactly as you described. I feel your observations (to me) serve to bolster the point I was trying to make about the SG in comparing its variation to the response variations that are inherently present in speakers.

I feel a simple expansion of Peter's quoted tolerances range to cove the complete audible spectrum from 20hz to 20khz would help the audiophile community embrace the SG more openly given the somewhat irrational RIAA controversy that is regularly debated on these forums. I think the fear some in the community have (Rauliruegas in particular) is that the roll off and tilt up on the ends may be a large number (say even in excess of 10db to 15db per octave) and they fear this is why Peter refuses to state a spec beyond his currently quoted range. If the role off and tilt up beyond this range are as I suspect, in the 6db per octave range, no one will care as that is de minimis given the points you so aptly make and given what I have said about speaker crossovers.