Strain Gauge details

Strain Gauge Cartridge

preamplifier

system

preamp close-up

cartridge close-up

The Strain Gauge on

a VPI HRX turntable
* * * * *
The Soundsmith is proud to be a VPI turntable dealer, and will be glad to perform a custom set-up with any VPI turntable of your choice. We offer the Strain Gauge cartridge system, as well as a variety of ultra-low moving mass "moving iron" cartridges, including "The Voice", our recently developed and acclaimed
"MM input" compatible cartridge.

“Now, with one giant leap, your strain gauge cartridge has leapfrogged the finest moving coil cartridges..... I was completely stunned....”

(Ijaz Khan, M.D.)

"The area in which the strain gauge system really excelled was in its ability to project a three dimensional image. It was surreal. The openness and air around the musicians was like nothing I have ever heard."

(Stephen Kaufman, M.D., Ph. D.)

IT'S OFFICIAL - WE WON ANALOG PRODUCT OF THE YEAR!!

From the review by the director of the Italian Magazine Fedeltà del Suono ~ the most popular Italian magazine for hi-end 2 channel

"Discover what may be the Phono Cartridge of the III Millennium.."

"True technical innovation in a stagnant sector..."

"The systems' linearity...may be considered virtually perfect....virtually free of distortion"

"We can’t refrain from crying for joy, and shout for this miracle."

..Unconditional applause to the creator and designer of such a “good monster”

click here to download PDF of article (Italian & English translation)

click for more testimonials!

The Strain Gauge

patents pending

Why, How & What:

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... they generate a tiny voltage that you amplify and send to your speakers.
The key here in describing all other cartridges is in the word moving......because all other cartridges MUST move a mass around - a magnet, and iron core with wires (moving "coil") or iron.
All other cartridges are all magnetic generating systems, which require a mass to be constantly moved to generate a voltage. The Strain Gauge does not; the effective moving mass has been reduced by over 80%....allowing the stylus to stay in intimate contact with the goove walls.....and allowing the stylus to stop jittering - or "bouncing" in the groove as it now is not trying to move a "large" mass back and forth....

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Features:

Frequency response, DC to 70 Khz
No "RIAA" filter circuitry is required or used in our preamp - just one ULTRA clean gain stage (this is because the Stgrain Gauge is a "displacement" device, not a "velocity" sensitive device like magnetic cartridges - see below).
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 of your choice
"Fixed" Line level & +10dB variable outputs, both Balanced and Unbalanced (via RCA jacks)
High Compliance design and feedom from low frequency saturation assures excellent tracking ability and performance with any tone arm
All preamp models now feature toggling between the Strain Gauge function and single or (multiple) line inputs for maximum hookup flexibility to your equipment

Low tracking forces with extreme precision
Compatible with any 1/2" mount headshell - uses STANDARD 4 wire tone arm wiring
Frequency response DC-70kHz 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 with balanced or unbalanced inputs.
Advanced muting features: 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 $249.95 - $599.95
IR Hand Held Remote for remote controlled models controls volume, mute, power (and input switching on the SG-510 and SG-810)

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. (All other models have rear manual control for lighting intensity) 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 seven models of Soundsmith's preamplifiers - All models have both fixed and +10 dB varialbe outputs - and 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:

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About:

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.

Why no RIAA required??

The Strain Gauge cartridge does not use or require an RIAA playback filter because it inherently plays the RIAA recording EQ curve used on the record correctly. This is because the RIAA recording curve used to make the original master recording with a magnetic cutter head COMPENSATES for that cutter head velocity response and results in a groove of basically equal “displacement” for an amplitude flat input signal. How does that happen? Simply. Without RIAA, the "velocity" response of the magnetic cutter head would normally cut a large displacement groove for low frequencies, and less so as the frequency rises. Using RIAA, which LOWERS the amplitude as the frequency lowers and raises it as the frequency increases, it "COMPENSATES" for the natural displacement differences of a magnetic cutter head's response and RESULTS in a basically equal displacment groove, for a flat input signal. Since normal mangetic cartridges are velocity sensitive devices (whose output is sensitive to velocity), they need the RIAA inverse filter to result in a flat playback response of a groove cut with an RIAA recording curve. However, since the Strain Gauge is a DISPLACEMENT sensitive device, it automatically produces a basically flat response from a RIAA encoded groove, which as stated above, is a basically equal displacement recorded groove.

The Strain Gauge cartridge is a displacement device, producing an output that is dependent and directly proportional to the amount of displacement of the stylus, NOT the velocity, like magnetic cartridges. It therefore inherently plays the RIAA encoded groove correctly. If one inspects the RIAA EQ, one will discover that there are discrepancies that occur where a displacement type cartridge deviates from a perfectly flat playback of the recorded RIAA grooce, and therefore will not produce a perfectly flat response.

Attempts made in the distant past to absolutely correct Strain Gauge cartridges for any amplitude anomaly have required equalization circuits, which not only add circuitry, but also introduce phase or time shifts. It is the Soundsmith’s belief that human hearing is much more forgiving of amplitude errors than time errors, so we have made minimal efforts to correct for any amplitude deviation from absolute flatness.

Because it has ultra-low moving mass, and because it uses no wire coils, it has a high frequency performance to beyond 70 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.

That's a lot of "because's". And there's more.

I will be glad to consult with those who are seriously interested in owning this system. All cartridges are individually hand-made by me, and I take great care in doing so.

Below is some anecdotal and additional technical information on our Strain Gauge Cartridge and preamp systems......

Thanks for your interest - Peter Ledermann/President & Chief Engineer

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The Strain Gauge is available in:
SG-810	Our top model is a multi-function preamp and full function Strain Gauge Preamp; It features the SG function 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
SG-610	Dedicated Preamp for Strain gauge - Front panel "touch" & Remote control for volume, mute and power; full Strain Gauge performance displays; lighting intensity control (auto room adjust or manual "linear control" from lights off to full bright)
SG-600	Dedicated Preamp for Strain Gauge - Same as 610, no remote control
SG-510	Dedicated Preamp for Strain Gauge and full function preamp - SG input plus 4 line inputs & tape monitor; Front panel "touch" & Remote control for input switching, volume, mute and power, no displays
SG-500	Dedicated Preamp for Strain Gauge and full function preamp - same as SG-510, but no remote control
SG-410	Dedicated SG Preamp - Remote & Manual control for Volume, mute & power
SG-400	Dedicated SG Preamp only - Manual Volume, mute & power
SG-210	Dedicated Strain Gauge preamp with both fixed level and +10dB variable outputs via front panel volume control
SG-200	Dedicated Strain Gauge preamp with fixed level outputs
Replacement Styli
SGS-1	Bonded Shibata/Aluminum Cantilever
SGS-2	Nude Elliptical, Aluminum cantilever
SGS-3	Special 1 mil radius conical (for vintage 48-49 records)
SGS-4	78 RPM stylus - special Soundsmith EQ in line circuit must be used
SGS-5	Nude Contact Line/Ruby Cantilever (Our "standard" that is supplied with the cartridge)
SGS-6	Nude "Optimized Contour" Contact Line/Ruby Cantilever

More Information:
Technical Specs Performance Features Full Product Brochure (.pdf)
Additional Options: Wood Front available in Walnut or Mahogany other woods can also be special ordered Available in 120 or 230/240 volt power
The Strain Gauge : SG-810 through SG-400 preamplifiers are 16" x 16" x 3.5" high; external power supply is 8" deep x 3" tall x 6" wide.
Prices-Systems: NOTE: SG -400 through SG-810 are available as FACTORY DIRECT only products SG-810 - $15,999.95 SG-610 - $12,999.95 SG-600 - $11,999.95 SG-510 - $11.999.95 SG-500 - $10,999.95 SG-410 - $8,499.95 SG-400 - $7,499.95 SG-210 - $7.499.95 SG-200 - $6,499.95 Prices-Styli: SGS-1 $249.95 SGS-2 $349.95 SGS-3 $349.95 SGS-4 $499.95 SGS-5 $499.95 SGS-6 $599.95