March 2000

Taking a Spin With The Clearaudio Sigma Gold MC Cartridge
Review by Oswaldo Martinez

  What we have here is the latest entry level offering from renown German cartridge maker Clearaudio Electronic GmbH. Clearaudio’s designer, Peter Suchy, has managed to pack a very impressive punch with his new moving coil baby -- The Sigma Gold (just “Sigma” for the rest of the review). 

To those who are familiar with Clearaudio is one of the most striking new features of this cart is its new wooden body. This special wood indigenous to the German Black Forest, Fernambuk, is the very same wood utilized to make violin necks. This wood is very tight in grain structure, it has very little resonance and it is reported to sport a sweeter top end than its lead body cousins. In addition, its coil windings are 24kt gold and there’s even use of a new special solder called Indium. Its stylus shape is the proprietary Trigon II as with previous Clearaudio designs.

Setup
Because of this cart’s much lowered mass it’s recommended tracking force (at least for my sample) is of 2.8grams! This obviously took me by surprise but a call to importer Joe DePhillips helped appease my initial reservations.

One thing is for sure, this cart has made me work like no other in order to achieve final calibration. I found this cart ultra-sensitive to all parameters due to its uncanny resolution. Vertical tracking force and azimuth deserve special attention in my opinion. Needless to say, if your arm does not allow for azimuth nor VTA calibration then you needn’t sweat it out as I’ve recently discovered while trying out the Sigma on my Rega Planar 3. I am speaking strictly about those tonearms like my beloved Syrinx PU3 whose azimuth may have been slightly off from a prior cartridge’s set-up.

The VTA I finally settled on was with the cart a little higher in the rear as opposed to perfectly parallel but I highly recommend that you experiment as to what works best in your particular scenario. If I recall correctly, this “slightly higher in the back” setting may have been Mr. DePhillips' preference way back when. Also, make sure that you properly dial in anti-skating as you will easily hear distortion on either channel. Even the slightest deviation from spot on will stick out like a sore thumb.

WARNING!!! Do not be surprised if in the first few hours the cart sounds a bit congested or distorted during musical peaks. Oddly, this is what I experienced but it surely went away after 20 hours or so just as Joe DePhillips suggested. Incidentally, this cart starts to hit its stride at around 50 hours of break-in and it goes on to become a positively "orgasmic” sonic experience as it nears 100 hours.

The Sound
I’ve had the pleasure of road testing the Sigma now for well over a year. IN FACT, this review has been a long way coming but changes in my analog playback chain forced me to re-evaluate my original thoughts on the matter. Additionally, as absurd as this might seem, the Sigma has also managed to keep improving over time not unlike a rare fine bottle of wine.

In my system the Clearaudio Sigma replaced previous price champ (and still is under 1K) Benz Glider which serviced me admirably for nearly two years. But now I’m sorry to say that as good as the Glider is -- and make no mistake about this, good it is *specially* for the money -- the Sigma is on a whole higher plateau or two.

Perhaps one of the most appealing characteristic of this cartridge is its ability to make beautiful sounds no matter the musical genre. Listen gang, I’d like to think I have a fairly wide-ranging musical taste, and no matter what type of music at threw at the thing, it never failed to amaze. Be it the raw power of MFSL’s Led Zep II or Aqualung, the supreme beauty and humanity of Anner Bylsma’s Bach Six Cello Suites on ProArte/Seon, the amazing booty-shaking feel good rhythms of Classic Records’ Buena Vista Social Club -- the Clearaudio Sigma always delivered the goods. To say the least, the Boogie-Factor is quite high with this product.

For those of you stepping up to the Clearaudio experience for the first time you will be shocked to discover exactly how much more information exists hidden within those precious grooves you thought you knew all too well. Trust me, it will happen. While the amount of information/resolution that the Sigma manages to coax is quite astonishing, the cart never sounds overly etched or analytical. In fact, while I believe this cart to be quite neutral from top to bottom, if forced to choose, I’d say that it leans towards the sweeter side of the sonic spectrum than the analytical. Uhmmm... does this have to do with its wooden housing? Maybe.

Soundstaging is another trait in which the Sigma excels like so very few components in my experience. The sonic images that it paints with good symphonic recordings are so real, so convincing that... well, case in point, Classic Records’ reissue of the Ravel/Ibert on Mercury. Wow! Talk about beautiful and expansive soundstaging in all its glory! Instruments are perfectly laid out in their proper place and perfectly “locked” -- no wavering instruments here, uh uh! The other amazing thing about the Sigma’s presentation is that all the instruments seem rendered in their right size/proportions (program permitting of course) and with a level of “you-are-thereness” that is a little hard to put to words.

Soundstage depth and width are quite impressive as well. Ariel Ramirez’ Misa Criolla featuring José Carreras on Philips 420 955-1, for example, throws an unbelievably deep soundstage. And while this is a digital recording, there’s an uncanny sense of the sheer volume (space) at the Spanish sanctuary where it was recorded back in 1987. Throughout its sonic spectrum, the Sigma seems extremely well balanced top to bottom. Bass is VERY extended and controlled and the upper bass has the right amount of snap. Its midrange performance is quite divine if I may say so. It oozes tonal richness and a sense of intimacy (if this intimacy is in the program) that it’s quite extraordinary. Oddly enough, one of the Sigma’s features that really took me by surprise is its spectacular high end/treble performance. Upper frequencies are so far extended and airy that’s is quite unlike anything I’ve ever heard (and which is exactly where lots of acoustical cues reside). Air galore!

The last aspect of the sound I will comment on is the Sigma’s excellent portrayal of harmonic textures. Zowie! Harmonics ‘R’ Us man! Whether it is Michael Hedges’ awesome guitar work, Miles’ trumpet, or Ella’s glorious voice, any and all instruments are portrayed harmonically correct and true to the real deal. I love that.

If the are any glaring faults with this product I have yet to discover them. The only thing I will say is that on rare occasion there might be a tiny bit of upper mid/lower treble grain hidden somewhere in there -- but even so -- I’m not completely sure the Sigma is to blame here since it seems to be more of a software dependent thing (sometimes I seem to forget that lots of today’s music is digitally recorded and/or mastered so perhaps the cart is just ruthlessly revealing of this). But heck, even if the cart is to blame, then it is allowed a tiny imperfection, right? After all, we are only talking $1100 buckaroos here!

(I must amend the above statement with the fact that this tiny bit of upper mid/lower treble grain was mostly experienced with my old solid state ARC PH-1 phono/LS7 tubed line stage and has now virtually vanished with my new Herron VTPH-1/VTSP-1 combo).

Final Thoughts
I must stress that it is of utmost importance to keep checking and re-checking all the set-up parameters over the span of the break-in period as to make sure the cart is perfectly dialed in. But the good news is....once this is accomplished, you just leave it alone and forget about it.

In my humble opinion, the Sigma’s performance is far beyond that of any of the under 1K cartridges available today -- including the venerable Benz Glider which is the cart it replaced in my system. And the thing is gang, not for a lot more dough! In fact, I would even go as far as to say that in the proper “hi rez” system the Sigma will more than hold its own against any and all carts in the lofty 3K to 5K region. Uhmm... I now have to wonder, if this is how good the Sigma is (mind you, Clearaudio’s MC entry level), I can’t even begin to fathom what Clearaudio’s top models can accomplish.

Bottom line: If you are looking to pump new life and excitement into your analog playback system, and are willing to put forth a little bit of effort and patience, the money spent on this Clearaudio Sigma may very well be the best money you’ll ever throw at your system.

Needless to say... an unquestionable bargain at $1100 and WAY RECOMMENDED!

Specifications
Design Principle: Moving Coil System with 24 Karat gold wires
Housing Material: Handcrafted special Fernambuk wood
Total Mass: 4 grams Stylus TRIGON II. diamond orientated (tip radius 5x40 nü/m)
Cantilever: Clearaudio boron
Coil array Symmetr. to pivot point (Clearaudio-patent)
Compliance hor./vert. 15/15 nü m /mN
Minimum Tracking Force: 1.6 grams
Recommended Tracking Force: 2.2 grams
Maximum Tracking Force: 2.8 grams
Channel Separation: >35 dB
Channel Balance: <0.5 dB
Output Voltage: (ati 5 cm/sec peak) 0.6 mV
System impedance 50 Ohms
Recommended Break-In Time: 50 hours or more

Manufacture
Clearaudio
Graefenberger Strasse 15
91054 Buckenhof
Germany

Voice: +49 9131-59595
Fax: +49 9131-51683
Website: www.clearaudio.de