Tag Archives: amplifiers

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.

Parallel vs. series

There is a fundamental difference between projects worked in parallel or in series yet both have their merits.

In the former, multiple tasks and projects are tackled at the same time while with the latter, every step follows the next.

Each of us operates at different levels with respect to how we handle projects. Some are most comfortable focusing all their efforts on a series project: dig in, push everything else aside, focus on seeing every step in the process completed to fruition. Others work effectively on multiple tasks and projects by commutating in small spurts their time and energies into many projects. Still others operate in a combo between both series and parallel.

Neither method is better or worse than the other. It’s up to each individual to figure out the most efficient path for their particular skills.

Take PS Audio as an example. At any one time, we have multiple projects being worked upon: loudspeakers, streamers, amplifiers, DACs, recording studio, Octave music, etc. Yet, within each of these parallel endeavors, we find a dedicated group of engineers working tirelessly in series: the beauty of having a team.

Me? If I don’t have ten projects percolating in my head I am bored. My greatest joy is commutating between projects and diving into each with all the zeal and passion I possess until exhausted, then moving on to the next and repeating.

What’s glorious about our differences is recognizing within each of us what works and doesn’t.

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.

Valves

We’re all familiar with the terms amplifiers and valves. We use electronic valves like vacuum tubes and transistors to amplify audio signals. Yet, even writing those words makes me a bit nervous because I can see how they might be misunderstood.

When we talk of amplifying the input signal it sounds like we are taking a small signal and somehow boosting it. Maybe a good analogy can be found in an airport and its moving sidewalk. You’re walking along at your pace and then step onto the moving conveyor belt, boosting your speed. That’s amplifying your walking.

That’s not what’s happening in an amplifier.

In fact, the input signal never reaches the output. It does its work and then is discarded, never to be seen or heard again.

We don’t amplify the input signal in the same way a moving sidewalk amplifies our forward motion. Instead, the input signal turns a virtual valve up or down to release more or less voltage and current from the power supply. What gets passed on to our loudspeakers and headphones is not the input signal, but voltage and current straight from the power supply.

It’s more than semantics.

Our input signals are but instigators.

Once they do their work they are gone forever.

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.

The FET

One of the most important secret weapons available to the high-performance stereo equipment designer is the Field Effect Transistor, better known as the FET.

Originally envisioned by Austrian physicist Julius Edgar Lilienfeld in 1925 and then again by Oskar Heil in 1934—yes THAT Oscar Heil, the inventor of what is still to this day one of the best tweeters ever made, the Heil Air Motion Transformer—it was little more than a pipe dream because they couldn’t get it to work. It wouldn’t be until another decade later when, in the course of trying to understand their failure to build a working FET, Bell Lab’s scientists John Bardeen, Walter Brattain, and William Shockley would instead build a point-contact transistor in 1947, followed by the bipolar junction transistor (BJT) in 1948. It would take another decade of work to produce the first practical FETs, and another decade after that to enter the general marketplace.

The fundamental difference between a BJT and a FET is that BJTs are at their inputs excited into operation by current while FETs rely upon voltage. This fundamental difference—current vs. voltage—is what has such a profound effect on sound quality differences between the two structures. A FET is more closely related to another voltage amplifying device, the vacuum tube.

So it should be no surprise to find that FETs sound remarkably closer to vacuum tubes than do BJTs.

Great food, like great power amplifiers, depend on the quality and nature of their ingredients.

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.

Power calculations

One of the most common questions I cannot answer is about matching power amps to Power Plants. It seems such an obvious question and you’d think the answer would be straight forward. But, you’d be incorrect.

The problem with matching power amps to Power Plants happens because we don’t have the complete story. What we’re missing are the speakers and your listening habits. An M1200 monoblock pair is capable of delivering massive amounts of power to speakers, yet in many cases, the pair can be powered with the smallest of our Power Plants, the P3. It all depends on what the amplifiers are being asked to do.

The easiest way to visualize what’s happening is to view the power amp/speaker as a pair. A power-hungry speaker will demand the same amount of wattage from any amp regardless of that amplifier’s rating. And conversely, even power-hungry speakers take less when not being played loudly.

I don’t mean to make this difficult. I bring this up merely to point out that what we might view as a straight forward calculation is, in fact, a bit more involved. If you’re confused, it’s always worth a call to us.

Here’s an easy rule of thumb you can use. If your power amplifier is a standard bias class AB or class D amplifier, and your speaker’s sensitivity hovers close to the 90dB/Watt/meter, then, on average, you’re likely not pushing much more than 100 watts even on peaks. Thus, any of our Power Plants would work just fine for you.

Just remember, amps and speakers should be thought of as pairs.

 

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.

With my Daedalus Ulysses loudspeakers that weigh around 120 lbs with their custom bases and tube amplifiers that weigh 100 lbs each, and racks full of heavy stuff, I’m not moving anything. However, unplugging audio cables and cleaning contacts might be worthwhile. Otherwise, an exercise like this sure isn’t for me.

However, if you feel the need, this certainly won’t hurt, except the disconnecting from the wall part, and here’s Pauls recommendations.

Spring has sprung

Terri and I make a point of walking three times per day: morning, noon, and evening. We traipse around our neighborhood or, if the weekend and the sun’s being cooperative, on the few trails we can access. Fellow walkers are increasingly respectful of keeping their distance as are we. And, we wave and smile at each passerby, thanking them for their courtesy. We may have to keep our physical distance, but we’re determined not to get divorced from connecting as people.

A smile can be powerful medicine.

While outside it’s hard to miss that spring weather is encouraging a hint of green and budding trees.

Spring also means it’s time to roll up your sleeves and get to rearranging and rejuvenating your stereo system.

A major teardown and rebuild of the system is cathartic—tension relieving—because when you’re in the thick of it the rest of the world isn’t pressing in on you.

Here are the steps I recommend:

  • Shut the entire system down by powering off all equipment from the mains.
  • Remove all interconnects and power cables, stacking them neatly away from the main system.
  • Use a piece of tape to mark exactly where your speakers are on the floor.
  • Pull all equipment off the shelves, rack, stands, etc.
  • Grab a bottle of Windex glass cleaner and go to town. Get down not just on the rack or shelves, but then clean every inch of the equipment itself. If you have tube gear pull out the tubes, make sure the insides of the gear is clean, and reinsert them. (When’s the last time you replaced those tubes?)
  • Reassess the symmetry of your setup. Using a tape measure, get the rack and stands straight and orderly. Recheck the speaker placement.
  • Grab the vacuum cleaner and with its hose detached from the head, get every corner and crevice of the room cleaned, then mow down the balance.
  • Carefully reassemble your system ensuring symmetrical placement of each piece of kit (for me, at least, ensuring symmetry helps imaging – probably because I can relax more).
  • If you’re into DeoxITKontak, or other potions to improve connectivity, go to town. Me, I stay away from them figuring the in and out disconnect and connect are enough.
  • Turn back on everything and play a setup recording to make sure you have left and right channels correct and then the proper phase between channels.

Finally, turn the light on low, play your favorite tracks of music, and enjoy a renewed connection with what brings you pleasure.

Your HiFi system.

 

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 have owned plenty of tube amplifiers with high second harmonic distortion that sounded great, so a little different take on this than Paul.

Does distortion matter?

If we have two amplifiers under consideration, and one has twice the THD as the other, does that matter? Would we choose one over the other because of its distortion spec?

I can recall years ago when Halcro trotted out their vanishingly low distortion power amplifier, setting the world back on its heels with triple and quadruple zero percent distortion levels—levels that challenged even the most advanced measurement equipment of the day.

And yet, the difference between an amplifier with 0.1% THD vs. another with 0.05% may not only be hard to hear, it’s entirely possible the higher distortion model might sound better. Or not.

The point of this is simple. When distortion and frequency response measurements exceed audible limits there’s an obvious result when we listen. When the measurements get below a certain threshold, those measurements mean less and less on their own.

To a design engineer, they might give clues as to the underlying circuits producing them, but used as a measure of sound quality, relative to others with very similar results, they are next to worthless.

Below a reasonable threshold, distortion measurements do not 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.

Paul is introducing a new amplifier from PS Audio. It’s based on a B&O Ice Power module, which is a lot better sounding Class D module than any Hypex based amp I’ve heard and is very powerful, efficient and probably sounds very good, if not excellent.

Myth busting

Just about everything in our lives goes back to a story living in our heads. Perhaps it’s the story of your childhood, or maybe how you learned to drive, or your first stereo system. When we think back over our experiences we come to understand we’ve built stories around them, stories that help us navigate the world.

When those stories are incorrect we refer to them as myths.

One of the most common audio myths is the need to match a power amplifier’s output wattage to the connected loudspeaker. It’s been taught to us we don’t want to overpower a speaker. Connecting a 1,000 watt amplifier to a bookshelf speaker just feels wrong, yet that’s only a myth.

The facts of the matter are pretty clear. All power amplifiers deliver only the number of watts they are told to by the preamplifier. The speaker’s role involves only its impedance. A 4Ω speaker draws twice the 8Ω power needs for a given volume level.

Of course, most myths have their roots in truth. A 1kw power amplifier has the potential to fry the crap out of a small speaker just like a 500 horsepower engine has the potential to slam your car into a cement abutment at 100 miles an hour. But, potential should not conflate to will.

I bring this to your attention because we’re just now making public the webpages for our new 1.2kw monoblock amplifier, the Stellar M1200.

We’ll be beta testing the Stellar M1200s this month, and I can tell you that it is a stunning achievement. Rarely have I ever heard dynamics as uncompressed and open as what the M1200 provides. I mean, I’ll go so far as to suggest that in my 50 years of HiFi listening I have yet to hear anything as dynamic as these new monoblocks.

When the going gets tough, when the orchestra revs up, the trombones blat, the 32 violins get rippin’, the double basses get bowin’, the tympanis are poundin’, and the horn section blares, I swear I’ve never experienced anything quite like it. The crescendos seem to just soar outside the room with zero hint of compression.

Until you hear 1.2kw driving the system you simply do not know what’s been holding things back. You can’t. Not until it’s been removed can we know what we’ve been missing.

 

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 totally agree with this one and don’t listen to any of my systems until its been playing for around one hour.

Is burn in real?

I had to chuckle to myself. Sitting in our weekly meeting, where production engineers meet with design engineers, the topic of discussion was how to build a new burn-in rack and system for the upcoming M1200 monoblock amplifiers.

What made me laugh is all the time and money we’re spending setting up a rack whose only purpose is to make sure when owners first turn on their new amplifier it sounds right. That’s a bunch of needless expense if burn-in weren’t real.

In fact, the new M1200s require more burn-in time than any product we’ve yet manufactured. We’re still debating not the number of hours, but rather the number of days. The discussions even include what track of music to use for best results. Sound silly? Not really. The average energy level of reproduced music has a direct impact on the improvements we desire to make. A quiet musical piece wouldn’t be nearly as effective as a loud one.

Since we’re not in the habit of needlessly incurring expenses, those who doubt the efficacy of burn might be well served to take notice.

Burn-in matters.

 

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.

Tails wagging dogs

It’s sometimes good to take a step back and widen our views because it’s easy to get mired in the classic tail wagging the dog syndrome.

Take for example our audio and video systems and how we improve them. Too often I have seen people add tweaks and potions to correct for fundamental problems.

It can be difficult to know when you’re efforts at polishing are what’s needed. Often, it’s a new paint job that will get the job done.

Just today I am working with a fellow that’s struggling to hear differences in amplifiers. Try as he might, the obvious changes between a good amp and a bad one are not apparent. It’s not because they aren’t there, it’s just because his loudspeakers and setup aren’t up to the task.

One of the best ways of identifying if you have a core problem or a modification challenge is to ask yourself where you are in the magnitude scale. Does your audio system get you 90% of where you want to be? If so, you’re likely to benefit from small tweaks and modifications. But, if you’re a few miles from home base, your best bet is to instead work on identifying the weak link (or links) in the chain.

A wide angle view is often more illuminating than zooming in to see which part of the dog is moving.

 

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.

This is correct and that is why I use and sell Computer Audio Design products. They filter this noise Paul is talking about, out!!!!

The sound of noise

Ultrasonic noise should have no sound to it. It is, after all, “ultra” sonic which means it is beyond our hearing.

Yet, we know removing ultrasonic noise riding on the music reduces glare and brightness. So, if we cannot hear noise how does it add to the brightness of sound?

Here’s my unscientific guess as to why that’s happening. High-frequency hash and noise upset the amplifier’s circuitry and that’s adding a degree of harshness.

We know from years of experience in circuit design that feedback circuits struggle when challenged with higher-order frequencies. Circuits without feedback sound much more open and are more tolerant of square waves and other high-frequency events that can trigger ringing. (One might then ask why anyone would bother with feedback at any level and that’s a discussion for another day. Let’s just suggest engineering is all about the best compromises for a given result).

The point of this post is simple. Cause and effect are not always 1:1. In other words, it would be easy to argue the logic that ultrasonic noise cannot be bright since we cannot hear the noise. Yet, our experience shows us something very different.

Just because it’s logical doesn’t make it right.