THE STORY

The Strain Gauge cartridge is not at all like any other cartridge. All other cartridges, whether moving magnet, moving coil, or moving iron, are "generators" - that is, you put motion in, and you get energy out.....a tiny voltage that you amplify and send to your speakers. The key here in describing all other cartridges is in the word MOVING. All other cartridges need to move a mass around - a magnet, and iron core with wires (moving "coil") or moving iron. They are all magnetic generating systems, which require a mass to be constantly moved to generate a voltage.

When you move any mass, it has stored energy, just like your car when you get it going. When you need to turn, or slow down, the mass tries to keep you from doing so. Imagine a stylus in the groove of a record that must make lots of changes in direction to follow the groove walls. Imagine how the mass of the generating parts must restrain the stylus as it tries to move.

Now, imagine driving a car where you and the car have NO MASS. If you can, then you can understand only one reason why the Strain Gauge is so exciting; it has almost no "stored energy" in the moving system - there IS no large amount of "mass" to move around - it does NOT have to move around a magnet, or wire coils, or iron. This means that the stylus stays in much better statistical contact with the groove walls of your records because there is no large mass trying to keep it from doing so. Imagine how different that sounds.

Inertia (the law by which mass tends to stay at rest or continue in the direction in which it was moving) makes all styli "jitter" or jump about in the groove of the record, and not stay in intimate contact with the groove wall. If a stylus can't follow the groove wall, you cant hear what's on the record. Its that simple.

So how does it work if it doesn't generate a voltage???

The SG cartridge has two Strain Gauge elements, pieces of silicon crystal that when compressed or expanded by tiny amounts, change resistance. The cantilever suspension, a necessary part of any cartridge, is coupled to these elements. The energy that is usually always "lost" into the suspension of all cartridges is used to create the signal in our Strain Gauge cartridge. It is also a purely "resistive" system, with no coils of wire to alter the high frequency performance, or pick up hum, noise or radio stations! Our preamp supplies it a flow of electricity, which it varies, and that gets amplified.

Because it has ultra-low moving mass, and because it uses no wire coils, it has a high frequency performance to beyond 50 Khz. Because it goes all the way down to DC, we can use that DC information to display tracking forces, forces on each groove wall, record eccentricity and "AC" component of the tracking force (record warp). Because it does NOT have to move around a large mass, and has little stored energy, it can track at one gram without "jittering" or chattering down the groove walls, and therefore stays in intimate contact with the record groove. And because we engineered it carefully, our Strain Gauge has user replaceable styli, a first for high end cartridges.

THE TECHNICAL:

Instead, the cartridge contains two identical elements of a device originally developed as an extremely accurate scientific measuring tool. The device is called a “Strain Gauge”. Strain Gauges come in many forms, but the type used in our cartridge is a specially created solid silicon beam. As pressure is applied to the beam, it changes its resistance to a flow of electric current applied to it. Essentially two silicon beams are used in our cartridge, one for each stereo channel, and each change resistance in an extremely linear manner when pressure is applied via the stylus and cantilever assembly. The Soundsmith specialized preamps supply a “current”, or flow of electrons into the cartridge strain gauge elements which vary the current.

Because this design eliminates a large mount of “moving mass”, (no magnets, coils, iron, etc…) the stylus does not have to “fight” that mass to stay in intimate contact with the groove walls. The INERTIA of the moving system is dramatically lowered, therefore, there is far less “jittering” or bouncing of the stylus – just smooth, consistent contact with the record, even with very high frequencies. Only when the stylus is able to stay in perfect contact with the groove walls can one truly hear what has been recorded on the vinyl.

Low moving mass means that it is very easy to “damp” the movements of the moving parts to keep them from ringing like a bell. This also allows one to design the compliance of these parts very high. (Compliance is the ease with which the stylus and cantilever are moved or can “comply” with the changes in direction of the record groove walls). High compliance cartridges enjoy the advantage of being able to use much less downward force, and can track very lightly, often below 1.4 grams. This results in less record wear and less stylus wear. It also allows a wider choice of tone arms or greater tolerance for any tone arm it is used in.

Because the stylus does not have to be an inseparable part of the moving system, it means our cartridge can and does have user replaceable styli, a feature that is never found in high end cartridge systems. We will offer varied cantilever/styli configurations and compliance for those who wish to “fine tune” the cartridge’s performance to the mass of their tone arm, or use different types of stylus/cantilever assemblies such as 78 styli, or lower cost/rugged types. Our standard supplied cantilever/stylus assembly is a high-end type; Ruby rod, with nude Contact Line Diamond.

There are also many other advantages to using Strain Gauges instead of other types of sensing elements. The elimination of coils means that the high frequency response is greatly extended, and the phase rotation (time distortion) is dramatically reduced. It also means that there is complete elimination of the tendency to pick up hum, or RF interference. Because the Gauge elements only change when they are compressed or expanded, the movements from one channel into the other (which happens on all cartridges) causes a "sideways" bending of the Gauges. The good news is that because of our unique Gauge design, they do not change resistance when bent sideways, meaning that the Strain Gauge cartridge has inherently excellent channel separation, even extending up into the higher frequencies where most cartridges suffer from poor channel separation. This is important, as imaging and depth are largely dependent on accurately reproducing information contained in the higher registers of the audio spectrum.

The other advantage occurs at the low end of the audio spectrum. A strain gauge has no lower frequency limit – in fact, it responds all the way down to DC ! If you deflect the stylus and hold it there, the cartridge and circuitry says so. We can therefore use that information to display vertical tracking force, force per groove wall, record eccentricity, record warp and tone arm/cartridge resonance. At all times you can “see” how the stylus is behaving in the record groove, with great definition.

A HIGH compliance cartridge with a low compliance arm??? Normally, this would cause severe problems with magnetic cartridges; the type of lack of compatibility would be due to extreme low frequency signals generated by possible record eccentricity. These signals would normally overload the input of a MM preamp, or worse, a MC preamp or input step-up transfomer. These issues are not relevent to the SG cartridge because a passive, low frequency shunt rolloff filter at 14 Hz. is used before any amplification. Therefore, no overloading of the one and only FLAT gain stage. It is important to state that unlike any other phono preamp, since there is no EQ (flat gain) - no low frequency BOOST that is always required as part of the RIAA - low frequency overload is totally avoided in the Strain Gauge sytem, opening up the range of tone arms that can be used.

Electronics:

The preamp’s first and primary electrical stage is a ultra low noise, extremely linear current-to-voltage converter, and is comprised of carefully chosen high grade components to provide which allows it to reproduce an exact replica of the audio signal. Additional RIAA filter compensation circuitry is not required for the Strain Gauge; it is "automatic" due to the fact that the Strain Gauge cartridge is a displacement controlled device, as opposed to a "magnetic" cartridges, which are velocity controlled devices. The signal is then presented directly to the “fixed” level + output connectors. The signal path from cartridge to output is as short and clean as one can make.

We also provide a variable set of outputs, using an extremely linear amplifier to supply as much as a 10 dB signal boost for those systems that require volume control, or a boosted signal level.

Both our fixed and variable outputs are present in + and – RCA jacks; this allows both balanced and/or unbalanced outputs to be used. It also allows driving multiple systems at once. Balanced lines can be used for long cable runs without hum problems.

Our higher end models (SG-810, SG-610, SG-600) provide detailed information on tracking force, AC component of the tracking force, force per groove wall, and record eccentricity. They also feature front panel lighting control, automatic or manual.

Our top of the line unit, the SG-810, offers full input switching allowing it to function as a system preamplifier.

Our entry level units, models SG-410 (with remote) and SG-400 (without remote) offer the same sonic characteristics as all other models, but do not feature performance displays or lighting control.

Features:

• Ultra low moving mass (no coils/magnets or iron used to generate the signal)
• Frequency response, DC to 50 Khz
• No "RIAA" filter circuitry is required or used in our preamp - just one super clean gain stage
• Compatible with standard "4 wire" tone arm wiring
• User Replaceable Nude "Contact-Line" stylus w/Ruby Cantilever (varied stylus types avail)
• System Price includes Strain Gauge Cartridge and Soundsmith SG Preamp
• Line level (& +10dB) outputs, fixed and variable, Balanced and Unbalanced (via RCA jacks)
• High Compliance suspension allows compatibility with any tone arm

More Features:

• One gram tracking with extreme precision
• Compatible with any 1/2" mount headshell
• Frequency response DC-50kHz with only 10° of phase shift in the audio band (rumble filter built in @ 12 Hz - passive type before single flat gain stage
• Front panel displays for tracking force (digital readout), AC component of the vertical tracking force, force balance per groove wall, and record eccentricity! (on models 810, 610,and 600 only)
• Fixed and variable, balanced and unbalanced outputs via RCA jacks. Our variable output will provide up to +10dB level, and may be used DIRECTLY into any amplifer, balanced or unbalanced inputs.
• Automatic Cue -Up muting (works with any turntable, and is user defeatable), manual muting control, and fault-sensing auto-mute to allow "hot plugging" of the tone arm or cartridge with the volume up, thus eliminating buzz or transients (allows stylus cleaning, adjustments, etc....)
• User replaceable styli available in varied compliance and configurations (Ruby & Aluminum cantilever, Nude Contact Line &, Elliptical Styli - 78 Styli) Styli replacement Costs from $150-$650
• IR Hand Held Remote controls volume, mute, power (and input switching) on the SG-810 model
• All models feature front panel finger "light-touch" control switches for power, manual muting and front panel lighting control (on models 810,610 &600) allowing adjustable front panel lights from "automatic room lighting level" to variable intensity - full bright to off. Our lucite volume knob changes color to indicate the state of operation: RED (standby); Yellow (auto-mute); flashing yellow (manual mute); Blue (unmuted - playing)

Our Strain Gauge cartridge requires specialized preamp circuitry, and is sold with any of five models of Soundsmith's preamplifiers:

All models are line output - can be used directly into an "aux" input on your preamp, or used DIRECTLY into any power amplifier.

All models have identical sonic characteristics and vary only in features:

• SG-400 - Dedicated SG Preamp only - Manual Volume, mute & power - without remote, performance displays and auto/touch lighting control
• SG-410 - Dedicated SG Preamp only - Remote & Manual control for Volume, mute & power - without performance displays and auto/touch lighting control
• SG-600 - Dedicated Preamp for Strain Gauge - Same as 610, no remote
• SG-610 - Dedicated Preamp for Strain gauge - as 810 but without input switching
• SG-810 - Full function preamp system featuring the SG input plus 4 line inputs & tape monitor, Front panel "touch" & Remote control input switching, volume, mute and power with full Strain Gauge performance displays and lighting intensity control (auto room adjust or manual "linear control" from lights off to full bright)

Pricing:

• SG-400 - $5,999.95
• SG-410 - $6,999.95
• SG-600 - $10,999.95
• SG-610 - $11,999.95
• SG-810 - $14,999.95

Strain Gauge Ordering Options and Spares:

• Line Input Option (Option A) $750 - On models SG-400/410/600/610 - This option allows the owner to switch between the Strain Gauge source and one unbalanced line input DIRECTLY on the SG preamp via touch switches. (This allows the users who connect their SG preamp DIRECTLY to their power amp for the cleanest signal possible, to be able to easily switch over to another source, such as a CD player or output of another preamp)
• Light Intensity LED Adjusting Option (Option B) $150 - On models SG-400 and SG410 - Rear panel adjustable LED light intensity control - adjusts from full bright to off. (White LED volume dot is not varied, to always show volume position and power-on mode)
• Lights OFF switch (Option C) $100 On models SG400/410 - Rear auto mute switch becomes able to turn LEDS OFF when in the AUTO MUTE OFF mode

Extra/Replacement Styli cost:

• SGS-1 $149.95 Bonded Shibata/Aluminum Cantilever
• SGS-2 $199.95 Nude Elliptical, Aluminum cantilever
• SGS-3 $199.95 Special 1 mil radius conical (for vintage 48-49 records)
• SGS-4 $199.95 78 RPM stylus – special Soundsmith EQ in line circuit must be used
• SGS-5 $399.95 Nude Contact Line/Ruby Cantilever (Our "standard" that is supplied with the cartridge)
• SGS-6 $499.95 Nude “Optimized Contour” Contact Line/Ruby Cantilever

All preamplifier models are 16" deep by 16" wide; external power supply is 8" deep, 3" tall, 6" wide; shipping weight is 32 Lbs.