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

Paul is getting technical here, but what he is beginning to describe today  are different ways to make an amplifier make music through speakers via solid state amplifiers, as opposed to tube amplifiers, although tube amps also have different ways to operate. Today, he describes something called a Class B circuit, which nobody I know uses exclusively. Class A/B yes, but Class B, on its own, no.

There are no hard or fast rules as to which type of amplifier sounds best. So far, in my 35 years in this audio hobby, the best solid state amp I’ve heard is the one I’m using now, which is a class AB amp, but has a speaker compensation network built in, which take most of the speaker cables out of the sound equation. Unfortunately, it is a Pro amp, built in the early 80’s, has fans, albeit quiet enough to not bother me…much….. and is pretty ugly. Still, it sounds great.

I’ve had Class A amps, Class A/B, Class H and Class D amps and sound wise, they are all over the place. I’ve recently taken in a pair of  Class A Aragon Palladium II monoblock amplifiers on consignment and they sound pretty darn good,

Here is Paul.

How much is enough?

We’re familiar with the common terms describing amplifier bias levels: class A, AB, and B. And we generally want more bias for better sound—which means we like class A better than the lower bias settings of AB and B. But how many of us really know what all this means? How much is enough?

Let’s start at the beginning to help our understanding.

First things first. These classes of amplifiers generally apply only to solid state designs. With few exceptions, we don’t worry about tube amplifiers and their output bias schemes. For simplicity sake let us just avoid the subject of tubes and agree that when we refer to the classes of an amplifier we are talking solid state.

Modern solid state power amplifiers split the output signal in two—one for the top half, the other for the bottom. Here’s a picture.

The two bluish circles labeled NPN and PNP are the transistor output devices. The squiggly lines are resistors that you can ignore. Note how the top transistor (TR1) handles what’s labeled as the “positive half-cycle”, the bottom transistor the “negative half-cycle”.

The input signal in this illustration is a simple sine wave. The circuit breaks the sine wave apart and divides the reproduction duties between the two devices.

What you are looking at is a Class B circuit. No Class A’ness to it at all.

More tomorrow.

 

 

 

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

Recordings or equipment?

Most of us weren’t present when recordings were made. We listen to the work of bands, performers, recording and mastering engineers without reference to what it sounded like in the first place. When we play these recordings back, how should we know whether they are correctly reproduced?

Commonality and consistency.

If there’s a consistent bass hump in most recordings—or a problem in other areas of tonality or imaging—you can be confident it’s the equipment or the room rather than the recording. That’s the basis we use to ferret out problems in recordings or electronic equipment.

I have posted partial lists of the tracks I use to determine problems, like this one. I’ll post more as time and inspiration happen.

Once you develop your personal baker’s dozen tracks, be rigorous in their use when auditioning a new component.

We can’t know how recordings sounded live because we weren’t there. But we do know a dozen tracks from different artists can’t all be the same.

Takes a bit of effort, but the results are worth it.

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

Humility

I am happiest when I am humble, yet humility and I are often at odds. I wonder why that is. My maleness? My ego? I bristle when a kind soul offers directions to a known location. “As if I didn’t know!”

I often stop to offer my services as photographer when I see a tourist capturing their family without them in the picture. And, inevitably, they tell me how to use an iPhone camera. My first reaction is to correct them. “Yes, I know it’s the little white button on the screen.” Do they think I am ignorant?

In a quieter moment, I understand they want only to help, not to criticize. I need to take a deep breath. Smile. Thank them for their kind advice—even though I didn’t need it.

When a customer explains to me the basics of stereo—offering an unwanted lecture—I do my best to listen and thank them for the information so generously offered. I find far more reward from this activity than the opposite.

Yet change is hard for me. My instincts are self-serving—to set my turf, establish my credentials.

My greatest joy is serving others, but making this behavior a habit is challenging.

Of all the souls I know, I find the battle with myself is the hardest.

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

Relaxing the load

First-time listeners to the IRS V in Music Room One are typically impressed with its effortless presentation of dynamics. I have no music in my thousand plus library that challenges it. Whatever is played—from drum whacks to cannon blasts—the system easily sails through it without compression or distortion.

The same cannot be said for most high end systems and for obvious reasons: their single driver’s linear excursion is often exceeded (even in a 3-way).

The IRS V is a line source of multiple drivers: 12 midranges, 36 tweeters, all sharing the duties normally handled by just one per frequency range. That’s important. Put another way, the cumulative output of 12 drivers is the same as a single driver with 12 times the linear excursion—and that driver does not exist.

Does this mean that you have to own an IRS to enjoy linear, unhindered dynamics? No. But, what it does mean is that you want to focus your next speaker purchase on a system where the designer has taken the challenge of linear excursion into consideration. Most don’t, though a few do in the all-important midrange area where critical dynamics occur.

There are other means of accomplishing this feat of distortion-free dynamic range without resorting to load sharing, but most I am familiar with employ compression drivers or ultra sensitive horns and—well—they have their own limitations when it comes to tonal neutrality.

You don’t need a beast like the IRS to get good dynamics, but it’s also true you’ll never get there with most conventional loudspeaker designs.

It can be done. I hope someone takes the time and effort to do it.

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

Things that jump out at you

If I am watching a scary movie and the music becomes ominous, I steel myself for the inevitable. Something’s going to jump out and scare the pants off me. Even forewarned I still jump.

The same sort of thing happens in a very different way with a new hifi system. Problem areas stand out from the music. This often happens to me at audio shows where I am listening to many new systems.

Depending on the music, I might notice the sudden blat of a trumpet breaks free of believability and crosses into the “wince” zone. Of course, trumpets blare, but they still sound like trumpets unless something’s amiss in the system.

These audio cues that jump out of the music’s reality fabric are clues we should pay attention to. In the trumpet example, it might just be the amplifier is underpowered, or perhaps the speaker drivers have exceeded their maximum linear excursion.

Whatever the cause, it’s instructive to pay attention to those elements of performance that routinely jump out and make themselves known.

Taming them is the challenge on the well-traveled road to audio nirvana.

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.

Stubbornness

My favorite audio company of all time is Audio Research, back in the day when William Zane Johnson ran it.

Bill Johnson was a passionate man—stubborn too. For many years, he had every right to be firm in his beliefs. In those days, Audio Research made the best-sounding audio equipment in the world. If you’ve never had the opportunity to hear a vintage Audio Research system on resolving speakers, you’ll have difficulty understanding the passion and reverence for that lush, rich, warm sound washing over you. It was so juicy you could just fall into the music.

Change was hard for Bill Johnson. The idea of balanced inputs or detachable power cords just chapped his buns. He and I sparred over such newfangled ideas but I was never able to sway him—particularly about power cords (though someone must have). Years later all Audio Research products sported detachable cords.

Bill’s stubbornness about power cables came from two areas: “bullshit!” and “what we have works.”

The first is obvious if you knew Bill. I could never persuade him that power cables mattered. He was too much of a diehard engineer to swallow any of that.

But what hurt Audio Research was the last bit of reasoning: what we have works.

Sometimes it’s alright—preferable even—to acquiesce to what your customers want as long as it doesn’t violate your core principles.

Bill Johnson’s core principles were simple.

Make great music.

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.

Format wars

Whatever happened to the format wars? We lost sleep over FLAC , WAV, DSD vs. PCM, MQA in competition with everything else.

Did our playback equipment suddenly get so good that these various formats now perform with varying degrees of excellence rather than acceptability?

I can tell you that playback of 44.1kHz through DirectStream is so close to higher resolution formats that one has to question the need to purchase higher resolution media. But that’s just us in a sea of other DACs.

Have we, as an industry, elevated playback quality to such a degree that the wars are over? Is there a white flag flying that I missed?

It’s hard to know if the most vocal among us got tired of the battle, or found peace in the improved performance.

I do appreciate a lull in the battles.

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.

Skeptics

You don’t have to look too far to find skeptics. It’s our nature to question that which does not fit our worldview.

Take audio equipment fuses for example. I first scoffed at the notion of a fuse impacting sound quality. After all, it’s a half-inch glass tube passing AC power. It’s hard to imagine that tiny object affecting the sound quality of an 80 pound beast like the BHK amplifier. Yet there’s little argument it does (which is why we went some lengths to upgrade our stock fuses).

A skeptic might say “it’s impossible! I cannot believe this has any impact on sound.”

Someone who has just heard the improvement might say, “Hard to imagine how it couldn’t impact sound quality. You’re squeezing hundreds of Watts through a wire no thicker than a whisker.”

The role of skeptic in the grand scheme of things is important. In fact, skeptics are critical to furthering understanding.

If we don’t question what seems wrong, we’ll never understand what is right.

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.

Honest sound

Before first-time visitors get a chance to experience sound that’s unlike anything they’ve yet heard—the performance of the PS Reference System played back on the mighty Infinity IRS V in Music Room One—their anticipation level is high. Most hope to get the thrill of a lifetime: a one-hundred voice choir and pipe organ, perhaps blasts of the 1812 Telarc cannons, or subterranean low frequencies that flap pant legs.

But when the thrill is gone (as B.B. King once crooned), we’re left with hopes of honest sounds: music so real that we not only buy the illusion of instruments in the room but that each voice is real—tonal, timbral honesty.

Honesty isn’t as exciting as the thrills and chills big music presents in all its dynamic full-range glory, but it’s more valuable over the long term.

Honesty is the most difficult quality for any stereo system to achieve—so difficult, in fact, that very few approach the ideal.

How’s the honesty in your setup?

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.

Transparent sound

We sometimes use odd terms to describe what we hear. Transparency in audio reproduction is one of them.

What does it mean to see through something when we listen to our stereo systems? Do we mean that clarity is at such a level we cut through the gauze of the speakers? Or, do we mean that we can see deeper into the thicket of musicians on stage?

In my case, it is the latter. When I switched from PS Audio designed round speaker cables to the MG Audio flat ribbon designs, a whole world of transparency opened for me. Where once the musicians crowded together on a smaller stage, the new cables opened up the stage and spread apart the players on that stage—creating a sense of greater transparency, providing enough room to hear the instrument’s ambiance.

There are many more examples of what I mean referring to transparency, but it’s one of those things best understood when it happens to you.