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.

Can work either way..

Subwoofer connections

For more than three decades I have strongly advocated the high-level connection of subwoofers—where we connect the output of the power amplifier to the input of the subwoofer.

What amazes me is that still to this day, that viewpoint is considered radical.

The vast majority of subwoofer manufacturers would have you connecting their subwoofers through low-level inputs as supplied by your preamplifier. Their reasoning is simple. The output of a preamplifier is cleaner and more direct than what happens after a power amplifier has processed it.

My good friend, John Hunter of REL subs is one of the few subwoofer manufacturers agreeing with me.

And here’s the thing. The majority of subwoofer manufacturers are correct. There’s no argument that the output of the preamplifier is cleaner, purer, and more direct than the output of a power amplifier.

So why the debate?

Because they are missing the point. Subwoofers should not stand out in the system. The whole point of a subwoofer is to augment the performance of the main loudspeakers. We don’t want to hear the subwoofer. We want to pretend as if it were a perfect appendage to the main speakers. To make that happen we need to do whatever we can to get closer to matching the sound of the main speakers—a perfect pairing.

We want the characteristics of the power amp to color the output of our subwoofer in an effort to more closely integrate it.

Hope that helps.

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.

Mechanical vs. solid state

When we need to switch inputs on an analog preamplifier we use a switch. The kind of switch we use affects stereo sound quality.

For years we had only mechanical switches from which to choose. Standard switch contacts in those days were nickel or tin-plated while the more expensive and better-sounding styles were either silver or gold.

These worked great and sounded excellent, but they had a problem. They were nearly impossible to remote control.

The customer’s desire to control their systems from their easy chairs drove us designers to replace mechanical switches with electromechanical relays. Relays were available with the same contact materials though because they weren’t self wiping (like mechanical rotary switches), their slap and connect operations produced a slight degradation in sound quality.

Relays are expensive and cumbersome.

Along came silicon switching. Low cost, quiet, reliable, and without the problems of contact degradation. Sonically, they fell into third place, but not too far behind relays.

Engineering is always a matter of compromise. We give up one thing and in exchange get something else.

In most of PS Audio’s PerfectWave series of analog audio products, we rely upon a combination of electromechanical and electronic switching.

Common sense, practical, excellent performance.

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.

Shortening wire length

In yesterday’s post, we posed the question of what might happen if we were to lower or even eliminate the impedance inherent in the AC power wires feeding our home.

The answer is simple. Dramatically better sound.

Something we all want!

But, how best to eliminate or significantly lower the impedance of hundreds (often thousands) of feet of connecting power cables shared by our neighbors?

Traditionally, lowering impedance inherent in wire can be handled in two ways: shortening its length and/or increasing its thickness.

Increasing wire thickness from the standard of 14 gauge copper, which is about 0.06″ thick, to something ridiculously heavier like 0 gauge wire, which is nearly ten times the thickness (times 3 conductors), would help but wouldn’t solve it. Only thickening and shortening the wire to mere feet would get the total impedance where we would want it, to perhaps 0.01Ω or lower.

The problems with taking these steps would be one of practicality (or the lack thereof). Let’s start with thickening the wire. 3-conductor 0 gauge wire is about 1.5″ thick and weighs in at about 1.5 lbs per foot. That’s going to be a bear to install in the walls (never mind the impracticality of typing that wire into an AC receptacle). But, let’s say we managed all that copper. We still need to shorten it to mere feet. To do that we’d have to move our home next to a noisy, stinky, coal-fired power generating station.

We might get some spousal pushback.

Fortunately, there is an alternative. A power amplifier.

Let’s back up a moment.

If you want to power a pair of loudspeakers you won’t get very far connecting the output of your preamplifier to them. Preamps can’t drive speakers because their output impedance is too high.

To lower a preamplifiers output impedance you need to add energy, something a power amplifier is very good at.

Power amplifiers have high input impedance and low output impedance.

Does this sound like something that might interest us in our quest to reduce the impedance of the power line from high to low?

Methinks, maybe.

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.

Systems

Each of us produces a liter of mucus per day. Snot, actually, and we use it to keep our esophageal system working smoothly. And here’s the thing, despite the fact that’s a lot of snot, unless there’s a problem we never notice it.

And that’s the way most systems work, seamlessly and in the background until something goes wrong or we yearn to make something better.

It’s the fringes we notice, not the main system.

It is good and proper we focus our time and energy getting our core audio systems functioning properly, but it’s almost never what we think about.

I have for many years been a proponent of stepping back from the pieces in my system I interact with like the transport, preamplifier, or streaming interface, and pay homage to my silent partners that make it all happen: the AC power, amplifier, audio cables, and rack system.

Central systems are easy to ignore until something goes wrong or we wake up to the fact we can make improvements that matter.

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.

Who’s on first?

Making a decision as to which model of loudspeaker, amplifier, phono stage, or preamplifier can be daunting. There are more brands than one can count and, within those brands, many models.

In the days of dealers, we relied upon their curation skills to narrow the field. The only problem with that model is that most times big dealers carried not what they believed you needed most (after all, how could they?) but what worked best for them.

Fortunately, that wasn’t the norm in our small high-end industry. The dealers we loved and honored were those that stocked what they loved and eschewed brands and products that didn’t meet their standards. Those were the good guys in our industry. Personal pride and a love of audio drove their interests and formed their opinions.

Sadly, many of those heroes are gone. (Lyric HiFi recently announced the closing of its New York City store)

Despite the shrinking number of honest and heartfelt curators, it is still possible to cut through the cruft to narrow down the field to a few choices.

That happens through trust. Trust built through a magazine, an advisor, a reviewer, a manufacturer, or a friend.

Who’s-on-first gets less confusing when we’re working with people we trust.

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.

I’ve got a few of these VPI bricks and have for over 20 years. I use them on my Furman Power Conditioner, which has a giant isolation transformer and does buzz a little and it seems to help with that. I’ve never compared them with, and then without. Too much trouble and if they do no harm, I’ll keep using them.

The VPI Brick

Years ago, when Harry Weisfeld was running VPI and probably before son Matt was yet born, there was the Magic Brick.

The Magic Brick isn’t all that complicated. Essentially a transformer without windings. Underneath the wood exterior are steel laminations like those in a transformer. The idea is to redirect and focus magnetic fields in an amplifier or preamplifier away from sensitive internal components.

The Brick was the first tweak I refused to even consider auditioning. At the time, its innards were a mystery, its name used the word “magic”, and it was offered without any explanation as to its workings other than, “I don’t know what it does, but dang! it works!”

A mystery cube. That was enough to make me not want to try it.

What were my fears? Aside from feeling like I was perhaps being made a fool, I was more worried about it actually working. Magic bricks placed atop high-end audio equipment that somehow improved sonics was a frightening prospect.

Unanswered mysteries.

I did finally give in because of Harry Weisfeld—the guy is so genuine how could I not?

Fortunately, it worked and my reward was finally learning its structure and why it worked.

Seems making sense goes a long way towards acceptance.

 

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

I use vintage Urei 539 EQ’s, which are all analog and they sound great. So, while I get what Paul is saying, there are exceptions, like the Urei 539!

Conflating D and A

In yesterday’s post on tone controls, there were a number of comments about the use of DSP, yet few about the differences between analog and digital controls.

There is no question that if one is happy staying entirely in the digital domain, DSP EQ and correction is a near-perfect solution. We can design extensive tone controls that have zero phase shift and are sonically neutral.

The same cannot be said for analog. And therein lies the rub.

If you’re going to add tone or EQ controls to an analog preamplifier you are going to suffer added circuitry, phase shift, and sonic degradation. That’s just the cost of doing business in the analog domain.

As a manufacturer, we have to be sensitive to all our customer’s needs. We can’t, for example, produce an honest analog-based preamplifier with DSP for EQ. To do that would require the analog signal to first be converted to digital and then back into analog.

Which is why blanket statements about EQ and tone controls are difficult. We first need to set the ground rules of the playground before making blanket statements.

Just sayin’.

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

AC receptacles

For those of us with long memories here’s a flashback. Remember when preamps sported rear-mounted AC receptacles to power the rest of the stereo system?

The first memory I have of the rear-mounted AC receptacle was on my father’s McIntosh C28 preamplifier.

Note the use of switched and unswitched outlets. The idea was that unswitched outlets were for the power amp and switched outlets for tuners and tape decks.

What a grand idea. Run your entire stereo system including your power amplifier through a skinny 16-gauge 2-wire zip cord.

What was it Red Fox used to put his hands up towards the heavens and cry out?

“Elizabeth! They’re coming for me.”

Some innovations are better left in history’s dustbin.

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.

Moving forward

When Stereophile Magazine awarded Stellar Phono its coveted Analog Product of the Year award we were, of course, ecstatic. What an honor.

That award got me thinking about the near-impossible job of a phono preamplifier: to amplify without noise a tiny signal 30,000 to 50,000 times smaller than what comes out of your preamplifier.

I remember from 40 years ago my struggles to design without noise PS Audio’s first moving coil preamplifier. It felt impossible. How does one add, without additional noise, 30dB of gain in front of an already high gain moving magnet phono stage? Everything I tried came with unacceptable levels of noise. I searched, I studied, I consulted with experts. At the time, the general consensus was it couldn’t be done and we should instead do what everyone else was doing: use a step up transformer.

I own up to being a stubborn mule. Dammit! I was going to figure out an active solution and so I continued to slug it out with various schemes. Finally, after a year of constant failure, I succeeded. Low impedances and a single common base BJT amplifier were the answer.

One of the industry’s very first active moving coil amplifiers, the PS Audio MCA, was born.

That was four decades ago. Today, innovative bright young engineers like Darren Myers are blazing trails I couldn’t have imagined.

Progress. Breaking new ground. Moving forward. It’s what gets me up in the morning.

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.

Who knew? Not me!

Audiophile Day #5

Just a reminder that today, October 2nd, 2020, is Audiophile Day.

On this day of celebration for what we all love—perhaps through our comments section—we can share some of our stories and thoughts about what it means to be an audiophile.

I’ve told the story many times of my first experience with a high-end audio system. I even wrote about it in my upcoming book The Audiophile’s Guide.

“I had yet to grasp stereo sound’s true potential. That revelatory moment came in 1971, on a hot summer’s day in Santa Maria, California. I was working as a disc jockey and program director at a local FM radio station, and the station’s chief engineer, Jim Mussell, invited me to his home to hear his stereo system. He’d heard I loved music and knew I bragged about my home audio setup. Given that my rig played loud rock, impressed my friends, and had two tall loudspeakers, I felt pretty confident that I was in the upper echelon of stereo aficionados. I was soon to learn otherwise.

Jim lived in a modest three-bedroom track home on the east side of Santa Maria, near the noisy 101 freeway. His home was a hoarder’s dream, filled with stacks of papers, test equipment, and piles of boxes kissing the ceiling. From the front door we wound our way through the chaotic maze and into a surprisingly neat and orderly living room. Wedged into each of the room’s two far corners was a 4×4’ dark mahogany speaker cabinet. In their center was a two-foot-wide and three-foot-tall panel of dark wood, flanked on each side by black grille cloth. Near the very top of the center block was what looked to me like window louvers. These two cabinets, explained Jim, were his pride and joy: an original pair of JBL D30085 Hartsfield corner horn loudspeakers. On the table to the left side of the room sat a fancy looking turntable, with an unusual arm that moved straight across the album instead of the typical pivoting tonearm. And next to that was an ancient looking Audio Research preamplifier with vacuum tubes (of all things). I remember quietly snickering at the use of these ancient fire bottle vacuum tubes—my dad had used them, for Pete’s sake, but I had long since graduated to the newer transistor models. All Jim had was an ancient pair of loudspeakers coupled with old amp technology…and I was supposed to be impressed?! Harrumph. As I sat in the single overstuffed chair facing the speakers, Jim lowered the needle onto Edgar Winter’s Frankenstein. I did my best to be polite, pretending I was going to be impressed.

Holy shit. Suddenly, the musicians were in the room! No sound came from those two ancient speakers—instead, standing before me were Edgar Winter, Ronnie Montrose, Dan Hartman, and Chuck Ruff. Winter’s synthesizer was alive and in three dimensions, while Ruff’s drumbeats smacked me in the stomach and dropped my jaw to my chest. It was as if neither the room nor the speakers even existed. I was there, on a holographic soundstage. I could “see” where each musician stood on that stage and I could picture Winter’s fingers gliding over the ARP keyboard he slung across his chest and played like a guitar. Hartman’s bass notes went lower than I ever imagined possible, at least outside of a live performance.

When the final synth note died away in the reverb chamber, I turned to look at my friend. Jim seemed unfazed by what we had just experienced—as if it were just an everyday occurrence—and launched into some engineering techno-babble we two nerds had previously been chatting about. I cannot remember a word he’d said, though, because I was still digesting the life-changing experience.

I had gone from flat monotony to three-dimensional color in the four minutes and forty-four seconds it took Edgar and his group to play that song. The idea that two speakers could disappear from the room and in their place live musicians might appear to play music was so mind-bendingly new that I struggled to wrap my head around it. What made this magic? Was it those speakers? That odd turntable? The vacuum tubes? His room? All of it? I had to know. 46 years later, after a lifetime of designing, building, and helping audiophiles around the world achieve what I experienced on that hot summer’s day, I feel pretty confident I can help you achieve that same sense of wonder and amazement that forever changed my life.”

What’s your story?