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.

Technical stuff.

From the tiniest beginnings

Of all the questions we are asked by customers, finding and fixing hum is perhaps number one. Ground loops would be our first suspect, but a close second is hum and noise from turntables.

Ground loops occur when two pieces of interconnected equipment find themselves grounded at different levels (one slightly higher or lower than the other). The difference in ground potential permits a tiny noise current to flow and we hear hum or buzz. The biggest source of ground loops we see is happily supplied by the cable television companies whose grounding schemes differ from our home’s. It doesn’t take much to introduce a nasty buzz in the system—a problem solved with either an isolation transformer on the cable television or disconnecting it altogether. We have several tutorials in our How To section of the website if you need.

Turntable hum can be much harder to solve if you’re unfortunate enough to have a noticeable amount. That is because the task of amplifying tiny signals from phono cartridges to the relatively huge voltage swings necessary to power loudspeakers is impressive, to say the least. Gains of 1000 times are needed for moving magnet and 30,000 times for moving coils—and these gains are just to get it to the preamp where it is further amplified up to 10x by the preamp, and 30x more by the power amp. Considering these gobs of gain you get an idea of how difficult a task it is to quietly amplify the tiny currents from small coils of wire in the phono cartridge to the massive coils of wire in your speaker drivers.

In fact, it’s actually quite amazing just how little hum and noise we get in a phono setup. My latest video covers some of those issues in more detail. You can watch it here.

One of the earliest head-scratching design challenges I faced in the late 1970s was designing our first moving coil head amp. Every amplification device has noise. How does a design engineer build a device with a gain of 30x without adding more noise? Seems rather impossible and it’s one of the reasons engineers turn to step up transformers instead (they haven’t extra noise to speak of). However, I was determined to design an active head amp with little to no more noise. What I wound up with, for those among you that care, is called a common base transistor. Here’s a simplified schematic.

Instead of the input going into the transistor’s base (the “B” middle pin similar to the grid of a tube), the device’s “E” emitter is used instead. This is a very low noise configuration with one serious downside for most applications—the input impedance is quite low (it’s essentially set by the emitter resistor). But, guess what? That’s perfect for a moving coil which wants a low input impedance in the first place. Voila!

This simple circuit became the basis for our first moving coil amplification product, the MCA.

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.

Demanding more bass

I was in the process of posting today’s Ask Paul video on the difficulty of designing power amplifiers when I was reminded of the lengths some speaker designers were willing to go for bass.

I was thinking of Arnie Nudell’s Infinity Kappa series, the terror of solid state amplifier manufacturers the world over (though he wasn’t alone). Our power amplifiers of the mid-1980s had minimal overcurrent protection in an effort to not sound squeezed or to trip the unit’s circuit breaker every time a bass drum was struck. This worked fine for most speakers, but not the Kappa 9s and their siblings. Soon, PS amps with blown output stages came back for service in alarming numbers. All had been connected to Infinity Kappas.

Clever crossover design can force a power amplifier to deliver more watts where it is needed most. In particular, the bass regions. And that’s exactly what the Kappa series did. By lowering the input impedance of the speaker to below 1/2Ω, greater power could be squeezed out of amplifiers and converted to robust low frequencies. Tube amps didn’t care because of their output transformers, but many solid-state designs gasped for air when faced with such outrageous demands. Infinity (bless their hearts) included a “safe” switch on the rear of the speaker that limited impedance dips, but customers hated the switch because it robbed them of bass.

In the end, we were forced to redesign the amplifier’s protection circuitry to accommodate the Kappas—something we did on the fly in production—but for a while there it was touch and go depending on what music and volume levels users were at.

Ahhh. The good old days!

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.

Land of the rising sun

Not more than a few weeks ago I returned from a great trip to Japan where I toured multiple cities and high-end audio dealers. I put together a ten-minute video you might enjoy. Click here to play it.

We know the high-end audio industry is in a state of flux—many suggest it’s being turned upside down by major changes: the way products are sold, the companies that are coming and going, and certainly the internet. Japan seems no different. Where once Japan was the far east Mecca for ultra expensive high-end products, I have noticed a clear shift to the more affordable.

Most of the uber-expensive products I saw at dealers were in their used equipment departments.

One thing that hasn’t changed over the years is the Japanese penchant for perfection and their obsession with simplicity. The last dealer I visited while in Osaka had the simplest of all systems but it sounded the best by far—a single pair of Magico S1 (their little 2-way), Spectral power amp, DirectStream DAC, MIT cables. He had followed all the rules of good setup I would have recommended—the rule of thirds, diffusion through absorbers and diffusers—but one was missing. No subwoofer. In fact, I don’t think I saw the likes of even one subwoofer while over there.

You know me, I can’t resist offering up an opinion—not when everything else in the setup is so correct. When I asked him why no subwoofer (through our interpreter), he just smiled and put on Telarc’s 1812 Overture. Indeed, I was surprised at how well it sounded—especially with only a 2-way. Only…the canons were still pale representations of the real deal.

He shrugged his shoulders in a way that I understood. Though neither of us spoke the other’s language, I knew he was telling me it was perfect for him.

Indeed. I could have lived with that system for a good long time.

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 20 amp question

On my recent visit to Japan, I was working with a high-end dealer who had a beautiful set of Dan D’Agastino’s monoblock amplifiers on display. He and I both wanted to pit the BHK monos against these copper-beauties which we did. Helping him disconnect the D’Agastinos from the wall I noticed the amps sported 20 amp IEC inputs that needed a special power cord. Tracing the cable back to the wall socket I had to laugh. An adapter was in use. A 20 amp to 15 amp “cheater plug” because the dealer hadn’t a bonafide 20 amp AC receptacle—not only defeating the purpose of the 20 amp inlet—and limiting power cable selection—but also adding an unwanted layer between the wall socket and amplifier.

I see these 20 amp to 15 amp cheaters in a lot of installations and it raises several questions, one of which I address in this video.

The 20 amp connector does indeed permit greater current to flow into the amplifier. With a 15 amp connection, you can theoretically draw about 1800 watts, while a 20 amp connection affords about 2400 watts. Do we need that greater current? How many loudspeakers are using anywhere near the rated wattage available through a 20 amp connector, relative to the 15 amp?

I cannot think of many (actually any) loudspeaker systems that approach even the lower of the two numbers. So, I often wonder why 20 amp connections are used.

There are applications where it makes sense to me. Our newest Power Plant, the upcoming P20, is a good example. Here, we have a situation where multiple large power amplifiers might be plugged into this single P20 regenerator and the increased wattage potential offers greater headroom if nothing else.

How did we solve the practicality issue I reported from my Japan trip? By clever means. Our chief engineer, Bob Stadtherr, designed both a 15 amp and 20 amp IEC receptacle into the new P20. A foolproof door slides over the unused inlet so users can attach whichever power cable they wish.

We’ll be unveiling the new P20 beasts at RMAF in a couple of weeks.

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.

A bit technical, but I agree totally with this!

Power supply madness

The story behind PS Audio introducing the high-end world to the oversized external power supply is a good one that I cover in this video.

But that was more than 40 years ago. Is power supply “overkill” still a factor after four decades? Indeed it is. And for good reason.

In the early days of audio design, the power supply was considered secondary to the amplifier itself: a necessary hassle designed to meet the minimum requirements and not much else. The magic of sound was thought to be in the amplifier itself, not the lonely power supply converting the wall voltage to something useful.

Over the years it became apparent that changes to the power supply had unexpected benefits to the quality of music’s reproduction. The first I ever heard about power supplies affecting sound quality was in early 1974 when it was suggested that placing a small 1/10th of a microfarad capacitor in parallel with a large electrolytic capacitor made an immediate improvement to sound quality. Transients were quicker, the music more open and alive—as if a veil had been removed from the speakers.

This first technique, known as bypassing, is still in use today. Look at any one of our circuit boards and you’ll note that every single electrolytic on the board has been bypassed with a small capacitor—the type and size chosen for the specific circuit application. Bypass capacitors improve the high-frequency performance of their more sluggish electrolytic mates. Bypassing is but the tip of the power supply iceberg.

Today we understand the power supply is as important to the circuit’s performance as the circuit itself. In fact, some designers (including myself) often place a greater level of importance to the power supply than the amplification circuit it feeds.

After all, an amplifier’s only job is to modulate the power supply in cadence with the music. Get the power supply perfected and everything else has a better chance at getting the music 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.

Built in head amp?

Head amps are devices used to separately amplify moving coil cartridges to the same level as moving magnets. They can be built from active electronics with power supplies or simple step-up transformers. They are needed because moving coil cartridges typically have outputs thirty times lower than their moving magnet brethren. Why they are separate has always been intriguing to me.

Moving coil cartridges have been around for many decades. I think it was in the late 1940s that Danish company Ortofon started selling moving coils, but for the most part, turntables and records were played primarily on moving magnet cartridges. From my memory, it wasn’t until the 1970s that moving coil cartridges like the famous Koetsu made their presence known and the need for head amps became the hot ticket for manufacturers.

PS Audio made its first head amp, the MCA, in the late 1970s. Not long after its introduction we also outfitted our preamplifiers with the ability to play moving coils without aid of a separate head amp, but that was rare.

Ron, from Hayes, Va., asked me a good question about head amps in this video about reducing vibrations. “Why don’t they just build head amps into the turntable’s headshell?”

This is a great idea because it eliminates the need for separate boxes, power supplies, connecting cables. But that’s also the problem. Unless the head amp is a passive transformer, you still need most of that stuff to make the circuitry work. Moreover, most head amp manufacturers aren’t the ones building turntables, arms, and headshells.

But the notion of miniaturizing the sensitive electronics that provide gain to these low output moving coil cartridges is certainly food for thought. Perhaps a better place to put a head amp is at the base of the turntable itself—where the tonearm mounts to the table. There we can have power and space to make this happen.

What’s stopping us? I suspect if you ask most turntable manufacturers why they don’t include a built-in head amp I’ll bet you’ll get one of two answers: we don’t do electronics or, the more practical of them all, audiophiles don’t want any sort of built-ins.

Separates are, after all, what distinguishes many of us from the crowd.

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 general tips for loudspeaker placement, although I don’t necessarily agree with all Paul is saying on the subject. Much has to do with size and shape of room and type of speakers.

Optimal distance between loudspeakers

Before we get started on today’s subject I wanted to offer an apology as well as an explanation about the hats. I love these hats and wear mine proudly. I’ve been approached three times now, asking just what an audiophile is and the conversation is always a pleasure. Those of you that have sent me pictures wearing your audiophile hats have warmed my heart. Thank you. It’s a level of awareness we want to support. That said, I want to apologize for messing up.

In my original post to you about the hats, I told you they were hand-crafted by Legacy Athletics of Hannover, Pa. American made. That’s not entirely true. The hats themselves, known in the industry as “shells”, come from one of three approved manufacturing plants around the world: China, the Philippines, or Taiwan. The “decorating” embroidering work, bill forming, inspection, and packaging happen in the United States. My bad. Please accept my apologies for the misinformation. If you want a refund or wish to cancel your order just email me. Again, I am truly sorry.

It’s an unfortunate truth that few of us have the freedom to place our speakers where they sound best. Instead, we pull them out from the front wall as much as our living situations afford and call it good.

We need to know three basic things: how far out into the room is best, how close together they should be, and how much toe in.

With respect to the first question, we’d like to use the rule of thirds. This simple formula places the speaker pair 1/3 the way into the room as measured from the front wall (the wall behind the loudspeakers). The listener is then placed 1/3 the way into the room as measured from the rear wall (behind the listener).

The second question is how far apart should the pair be? Here, we want to form an equilateral triangle: the left and right speakers at two vertices, the listener at the remaining vertex.

Toe in (pointing the speakers at the listener) is really dependent on the type of speaker you have and its off-axis response. My advice is always start with the speakers facing straight ahead and toe in to solidify the center image without sacrificing stage width and depth.

These are great starting points for system setup. Depth of soundstage is controlled by front to back movement of the speakers (away from the front wall increases depth). Tonal balance changes with distance between the left and right channels (closer together increases midbass coupling giving a fuller sound).

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 kind of a funny post, although more technical than most would want to read about.

I use PS Audio’s DSD DAC and it is a fantastic sounding digital player, made even better by the occasional updates to it that PS Audio offers for free.

Simply, the player takes our digital music, say music that we have copied onto a hard drive of some sort (computer, phone, iPod, etc) and then makes real music out of it that we can listen to.  At some point, the digital file is turned into music we can listen to and that is called a digital to analog conversion, or DAC.

Is no DAC the best DAC?

I’ve been answering a lot of great customer questions on Ask Paul. One of them was a simple misunderstanding, but it sparks good dialog.

On the DIY forums, a poster suggested he was converting digital audio to analog without the benefit of a DAC and the question posed to me was, “Is that possible?” The answer should be a simple “no” but then it’s never quite that simple.

Let me first explain what the poster on the DIY site was doing: converting DSD to analog with little more than an output transformer. Thus, he didn’t need a “DAC” to make music, he needed only a single part.

DSD is very different than traditional PCM. If you were to try the same technique of decoding PCM with a simple capacitor, you’d get nothing but noise (if you got anything at all). This is because PCM isn’t anything close to analog, while DSD is as close to analog as any digital format can be. Look at PCM on a scope and you see nothing recognizable as music (it’s a code, after all). Try the same thing with DSD and you can actually see the music.

This difference is one reason why our digital guru, Ted Smith, converts everything to DSD in our DirectStream and DirectStream Junior. Their output stages are essentially simple low-pass filters (like the transformer I mentioned earlier). DSD is already close to analog and requires very little post-processing.

In direct answer to the reader’s question whether it’s possible to play digital music without benefit of a DAC, I would answer, no. Anything used to convert digital to analog is, by definition, a DAC.

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 heard these, along with my wife and son,  at the PS Audio factory and they are very good speakers, although limited by the small room.

With all the drivers and 4 very large cabinets, their most amazing quality to me was how well they could image, especially in such a small room, However, image, they did.

The best ever? I’m not going there, but they are really good speakers.

The IRSV for peanuts

The mighty IRSV in PS Audio’s Music Room One. 1.2 tons of elegant overkill in 4, seven and a half foot tall columns wrapped in Brazillian Rosewood. The speaker system remains unmatched even to this day. Its multitude of drivers in a floor to ceiling line source produces breathtakingly effortless music at any listening levels.

There were only 58 pairs of the IRSV produced, and lucky owners of this classic rarely sell them.

Does this mean that you have to have an IRS to get close? Or, is it possible to put together an affordable modern day equivalent of this reference standard loudspeaker?

I believe the answer to be a qualified yes.

Newer driver technologies, like the AMT style of folded ribbons that can be used for tweeters and midranges, exceed the performance of the original Infinity planar ribbon drivers. Modern amplifier and servo technology betters that of the original IRSV and cabinet advances are readily available too. In fact, just about every aspect of the IRSV can be bettered with today’s technological advances and found in speakers magnitudes less expensive.

But there are two qualities of the IRSV that have yet to be conquered in a single loudspeaker: the effortless sound and the craft of its original designer, Arnie Nudell.

Very few speakers can claim effortless sound like the IRSV and for good reason. The vast majority of speakers rely upon small numbers of drivers to do the work of many. There are 108 separate speaker drivers in an IRS. Even today’s biggest behemoths rarely have more than one or two drivers handling any one frequency range. It certainly is not out of the question to build something like this again but at an economical price? That’d be a real challenge.

Certainly, today’s speakers can duplicate or even exceed the IRS in terms of tonality, imaging, and full frequency response. What’s lacking is the effortless I just mentioned.

You can get close – really close – but no one has yet figured out how to make it affordable or (for that matter) available.

If you’d like to see more of my thoughts on the question, go to this video Is it possible to get the same sound as the IRS for less?

 

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.

Wimpy internal wiring

Take a look at the back of most high-end audio systems and you might notice the fat speaker cables connecting the amp to the speakers. Or, as in my case, the massive flat ribbons. Whatever means you employ to connect the amp to the speaker, it no doubt looks like massive overkill compared to what’s inside the speakers you’re driving.

From the speaker binding posts to the internal crossover and then on to the driver, the type of wiring can be anything from the mundane to the exotic—but nearly always of smaller gauge than the cabling between the amp and loudspeaker. Take a look at this example.

You might be wondering how this makes sense and why speaker manufacturers don’t use thick speaker cabling internally. Of course, every speaker company has its own philosophies and design ideas, but for the most part, I would wager to suggest the reasons are more for practicality than anything else. One look at the tiny terminals found on speaker drivers will give you an idea of the challenges speaker designers face.

Many of the higher end speaker companies I am familiar with go to some lengths as well as expense to use special cabling, like from Cardas, but even these solutions are almost always thinner gauge than what’s feeding the speakers.