The strain gauge
For some strange reason, I have been thinking about the strain gauge phono cartridge. And, here’s the weird thing. I have never heard one.
What’s interesting to me about this strange beast is how different it is from your conventional phono cartridge.
I am always fascinated by truly different.
Most phono cartridges are generators. They rely upon movement to induce a variable magnetic field which in turn generates a voltage. The movement occurs in response to the needle in the record groove. Attached to the needle/cantilever arrangement is either a small coil of wire (moving coil) or a small magnet (moving magnet). As the disc spins the needle moves and we generate a tiny electrical signal which we first amplify and then pass it through an EQ network called the RIAA curve.
A strain gauge does not generate a voltage. Instead, it disrupts either a small voltage or impedance which is then converted to what we need to play music.
Interestingly enough, strain gauges don’t work into phono preamplifiers. Instead, they require a special analog input that is more closely related to a standard analog aux in. This is because strain gauge cartridges don’t need the EQ correction normally applied through the RIAA curve.
I see that Soundsmith is offering their version of a strain gauge cartridge and input box for $10K.
Why are we going down this road in today’s post?
Perhaps the most difficult technology to wrap one’s head around is digital.
Analog? Not so much. Consider that it’s not that hard to understand how the quality of a tape head or a phono cartridge has a direct and obvious impact on sound quality. It has to.
Digital is a whole different can of worms. 1’s and 0’s should be easy to maintain quality. It’s far more difficult to try and understand how bits on a hard drive or, for that matter, bits sent across millions of miles of space can be affected.
Inviolate performance. Perfect sound forever. That was the promise.
And yet, DACs and transports sound different. One USB cable vs. another makes the difference between good and great.
Over time we’ve been learning what makes digital audio sound different. We’ve come to recognize and own up to the fact bits are not just bits. That the timing, noise levels, and quality of those bits changes that which we hear in music.
We never perfected analog and I sincerely doubt we’ll ever perfect digital.
But, we’re moving forward in positive ways and music is getting better for it.
That’s got to be a good thing.
Pickup and playback
In yesterday’s post, I riffed on the difference between the broad strokes taken by recording engineers and the fine polishing we as audiophiles expend to enjoy all that the recording captured.
That line of thought can take us in a few directions. Among them is how very different our views of reality are.
Take for example the differences in sound quality between loudspeaker and microphone types.
It should be no surprise that music played through dynamic loudspeakers sounds very different than the same played through a planar ribbon design—the two transducers are built from radically different technologies.
It should also be no surprise that music captured by a ribbon microphone sounds very different than the same music as captured by a dynamic or a condenser microphone. Again, very different transducer technologies offer us very different sound.
The same can be said for most transducer types. Compare a record played back with a MC or MM phono cartridge.
The point here is that transducers used to either capture or reproduce sound are so radically different as to make one’s head spin.
How, with all these differences, do we ever get close to the real sound as if the musician were playing in the room with us?
Are any of them accurate?
If you double the input impedance of your power amplifier from, say, 30kΩ to 60kΩ you’re not going to hear a difference.
Yet, double the input impedance of your phono amplifier and you’ll hear a change.
What’s different between the two?
In the first case of the preamp feeding the amplifier, we won’t hear any difference because nothing in this chain affects frequency. The amp’s input impedance must be high enough to not load down the preamp, but aside from that, not much else matters.
That’s not true when it comes to a device such as a phono cartridge. Here the small coil generating the voltage feeding the phono preamplifier is part of what we refer to as a tank circuit—a tuned inductive network where the frequency response is a function of impedance and capacitance.
Think of it like a filter where the resulting output is dependent on the values of the elements that make up the network: coil, cap, resistor.
It is natural to assume that if the impedance setting of one element within our system matters, then it stands to reason all must.
Hopefully, it helps to have a short little explanation like this to set the record straight.
Labels are necessary for communication yet offered without thought of consequences they can be destructive.
There’s no harm in labeling sodium chloride as table salt. In fact, labeling a shaker of white crystals as “salt” is extremely helpful at the dinner table.
But what happens when we label stereo equipment with opinions? For example, labeling a particular phono cartridge as wooden or tight-assed can destroy a product’s reputation. Imagine taking home an expensive moving coil cartridge and on your audio system, it doesn’t sound right. You label it with your opinion and it is forever tainted—even if all that might have been wrong was your ability to set it up properly.
I remember the first time I heard about Cambridge Audio products. Asked what their shtick was I was told it earned the label: cheap gear. Good, but cheap. It wasn’t until I spent the time to audition their products myself that I realized the label was not only unwarranted but unfair. Not because it wasn’t inexpensive gear (it was) but because that label assigned it a low value in people’s minds. I began to support the brand by telling people it was an exceptional bargain.
PS Audio products were for years labeled as “The poor man’s Audio Research”. I guess that’s a compliment, though I probably could have picked a better label.
I guess my point is we should be careful about the labels we assign products and certainly people.
They have a habit of sticking.
Coils, magnets, and compromise
There’s no free lunch when it comes to engineering. Every design is fraught with compromises to make it work.
One great example is the differences between moving magnet and moving coil cartridges.
A moving magnet phono cartridge places a tiny magnet atop the stylus. In close proximity are two big coils of wire. As the magnet moves in concert with the vinyl grooves, an electric field is generated and we hear sound. The advantage of this design is high output signal level. The compromise is that the magnet has a lot of mass for the stylus to move.
A moving coil phono cartridge is the opposite of a moving magnet. Instead of the heavy blob of magnetic material atop the styles, we instead mount two tiny coils of wire in close proximity to some big magnets. As the coils move in concert with the vinyl grooves, an electric field is generated and we hear sound. The advantage of this design is less mass on the stylus. The compromise is that the coils must be very tiny, resulting in less output (which is why we must add a head amp or step up transformer).
Neither of these schemes is perfect, but the moving coil is considered the better option.
We live with compromise on a daily basis. It’s just part of the deal.
The trick is to choose what best fits your system from among the choices.
The sound of skill
The first high-end turntable I owned was a second hand Linn LP12.
I don’t remember the year but I do remember the era. Turntables had been elevated from utilitarian necessities to essential components. The story we were told through magazines and brochures was if you hoped to achieve great sound you started with the turntable, arm, and phono cartridge. Everything else followed.
The notion that sources were the most important piece of the audio chain was new. A brilliant piece of marketing.
Hoping for instant gratification I took possession of my new table and, like a kid at Christmas, plunked it down and fired it up with an expectation of miracles. I was disappointed. The music wasn’t much different than I had achieved with my trusty AR. In fact, on some recordings, I swore it wasn’t as good.
I shared my frustrations with several friends who also had given thought to upgrading their turntables. They clucked and counseled me not to be too disappointed. After all, the idea that the quality of a spinning platter mattered to the sound was kind of silly. Then, I ran into a fellow who asked an interesting question.
“Have you set up the table and arm?”
45 years ago I was a newbie. I had never heard of turntable setup as anything other than just getting it to play. My friend brought with him an arsenal of strange tools: protractors, scales, levels. He spent an easy hour performing a strange ritual fussing with the table and arm. I half expected him to sprinkle holy water across the device.
Finally satisfied with his incantations and machinations we played one of the albums I thought had sounded worse. I was stunned. The transformation from ugh to ahh was complete. It was to me a miracle.
The hype was right.
The setup skill and knowledge were missing.
The color of music
I often think of music in shades and hues: a light amber sheen from the delicate bowings of a string section, the fat gold honeypot of the double bases, the trombone’s bright blaring blat, the reed’s cold blue honk, or the unwanted glare of a misaligned phono cartridge. These are not just sounds, but complex gatherings of frequencies that evoke colors, emotions, and images.
What I so love about having at the touch of a button or the drop of a needle, music from the masters, is this wealth of imagery. When I watch film or television I am led by the nose where the director and cinematographer wish to take me. No room for added senses and emotions.
But music…. Music in my home evokes far more than almost any other form of emotional stimulation I can think of. And the better my stereo system, the more I get out of the experience, a rarity indeed. I don’t enjoy art more with cleaner glasses, nor do I delve deeper into the story with a finer copy of a book. But the better reproduced music is, the closer I can get to that wealth of emotional stimulation.
If your stereo system isn’t enhancing the color of music, perhaps you’re missing out.
When is too much enough?
I am often asked if a certain this or a certain that is overkill.
“I have a small room, would a subwoofer be overkill?”
I am tempted to turn the question around and ask what size room benefits from a rolled off speaker? Seems to me I always want to get everything on the disc.
Or, “is this DAC too good for my system?”
I get the sentiment of not wanting to “waste” expensive high quality. When I first got into the drinking of good wine I’d share an expensive red with my mother Sue who would proceed to plop a few cubes of ice into it to get the temperature right.
But I think asking the question of how good something needs to be before its goodness is wasted is misguided. Why wouldn’t it make more sense to always do the best you can: the widest frequency response speakers, the highest DAC resolution possible, an unrestricted dynamic range phono cartridge.
I think it should be turned into: What’s the best I can do?
Little things add up to bigger things. And often, we pay so much attention to the big items like loudspeakers, power amplifiers, and power regenerators, that we ignore the little things.
Yet, it is the little things that often matter most. Audio system setup; phono cartridge tweaking; turntable leveling; anchoring racks; proper grounding; dedicated lines; musical selections. Setting the perfect volume levels.
For me, it often depends on my mood. If I am in my critical zone—where everything has to be just so—I’ll use CleanWave, I’ll dial the level to match the number of people, I’ll make sure the lighting is just right.
The next time you want perfection, remember it’s often the little things that matter.