Tag Archives: preamplifier

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Good article explaining phono stages. I’m writing the next one about the audio business!!

Perilous journey

Imagine the tiny signal coming out of a moving coil phono cartridge: 30,000 to 50,000 times smaller than what comes out of your preamplifier. It has come a very long way and through much amplification to become that much bigger. Like a weary long-distance traveler who struggles to stay intact along the way, its journey is a difficult one with detours, traps, pitfalls and dangers aplenty. But sometimes a designer is so adept at navigating the perilous journey that what comes out the other end shines.

The trick to making a successful phono preamplifier that honors and preserves this tiny signal is two-fold: make sure the vanishingly low output from the cartridge is perfectly preserved, then keep the progressively louder signals away from any limiting agents.

The first challenge is often the most difficult. Interfacing with and amplifying without adding noise can often be more art than textbook solvable. For example, most phono preamplifiers use bipolar transistors to interface with the cartridge because they are low noise and easy to work with. Unfortunately, bipolars and their non-linear diode inputs are not the best at working with tiny signals like those coming from moving coil cartridges. A pure voltage device, like a FET or a tube, is a better choice, yet getting these devices to be low noise can be a challenge. In the new Stellar Phono, engineer Darren Myers solved this problem by lining up multiple FETs in parallel. Each added device reduces noise. The greater the number, the lower the noise.

If one manages to get the tiny signal through the input it’s off to the races, though not without challenge. As the signal grows exponentially larger, it begins to approach the power supply limitations of the circuit. When this happens, linearity suffers—which is why Darren uses high voltage throughout Stellar.

It’s often tempting to just meet spec and call it a day, but then you probably won’t get Stereophile’s Michael Fremer to write: “The midrange on this phono preamp is as open, uncongested, transparent, and revealing as that of any phono preamp I’ve heard at any price.”

It’s a rare treat when a designer maps with care the perilous journey of a signal, then clears a free path for it to arrive at the other end unscathed.

 

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Feels wrong

I remember how proud I was upon learning the trick of screwing a stubborn lid onto a jar. Though it feels wrong, my father counseled, you first unscrew the lid until the threads are aligned, then turn the opposite direction and tighten ‘er down.

There’s plenty we do that’s seemingly incorrect to get things right: increasing the length of the audio chain with a preamplifier to improve sound quality. Or adding another speaker cable in parallel with an existing one to get tonality in line. Or powering small speakers with big amplifiers so as not to limit dynamics.

Doing what feels wrong to get things right is the inflection point where experience trumps intuition.

When we know enough to pull ourselves out of the rigors of standard practices and leap into the chaotic, we can confidently say we’ve arrived. And that’s a great feeling in whatever endeavor we hope to succeed at.

The circle of experience and knowledge is actually a spiral that is never in the same place at the same time, yet repeats itself in slightly different form as we each share what knowledge and wisdom we’ve accumulated over the years.

It made me feel good when years later I was able to return my father’s lesson. As I watched his face scrunch up as he tried in vain to open a stuck jar lid, I shared my own experience. I turned the jar upside down and demonstrated how a stuck lid needs only a couple of sharp bangs on the countertop to free itself for the turning.

As audiophiles, we have knowledge about music and its reproduction that not many others do. If we can share that wisdom and experience, we lift up those around us.

Just as music was always intended to be shared, so it is with our knowledge. It might feel wrong to speak up in the presence of bad sound, but I’d lean in the opposite direction.

There are few gifts better shared than properly reproduced music and the knowledge required to achieve it in our homes.