So many choices
Have you ever considered how many choices we have in just our small niche of the market? The number is so great it makes my head spin. I write this because while attending the Montreal HiFi show we had a wonderful sounding room using Neat SX1 loudspeakers from the UK and Kimber Kables from the US: one brand I know nothing of, the other I am quite familiar with.
The little SX1s were smooth, open and easy to make disappear in the room and the Kimbers were like they weren’t even there; a greater compliment one can’t receive.
We all have our favorites and I am no different. But the problem with favorites is it precludes using all that is available and thus we narrow our field of vision to the point of near-blindness to what else is around us. With so many choices available I don’t know what else to do, but it does trouble me.
Tiny vs. huge
One of the worst and best things that’s happened to passive components used in stereo equipment is the surface mount part. These tiny bits of silicon, plastic and metal are used to form the transistors, diodes, capacitors and resistors used in modern equipment. Before surface mount there were through hole parts and the differences between the two can be summed up simply: through hole parts have legs, surface mount do not and as a result, can be much smaller.
Here are two pictures:
The differences are obvious.
And when I first heard about surface mount they appealed to me because their lack of legs meant fewer junctions and the potential for a purer part. What I learned was not so simple.
Turns out the best choice between the two technologies depends greatly on the application they are used in. Surface mount makes products like the DirectStream DAC possible. Without the small size and direct connections the DAC would not be as good. Yet, those same small parts in the power amplifier or a preamplifier don’t perform as well. And this has to do with both the amount and type of material used in them and what we are doing.
2400 year advice
Every piece in an amp, preamp, DAC or link in the music reproduction chain matters; even the chassis itself. To believe otherwise ignores Aristotle’s insight the whole is greater than the sum of its parts. For more than 2,400 years we have known that everything matters and the passive bits in our hifi products are no different.
I first learned this lesson designing the original PS Audio phono preamplifier forty one years ago. Our design used a passive RIAA curve consisting of two capacitors and two resistors of exact value; their tolerance should not exceed 0.1%. Precision resistors are easy to find, capacitors are a different story. One of the capacitors was an odd value; 0.0233mF when the standard is 0.022mF. The difference between the two is small but ignoring the 0.0013mF meant a deviation from the RIAA standard we were unwilling to consider. Capacitors can be stacked together to form new values: a 0.022 and a 0.001 might get us close, but the easiest method of finding what we wanted was to hand-measure from selected bins of lower tolerance parts instead.
Every designer has boxes of parts accumulated over years and ours proved a treasure chest for building prototypes during the initial design phase. The problem we kept running into was consistency of sound; even seemingly identical designs sounded different. Building matching pairs of phono preamplifiers was at a standstill until we could figure out what affected differences in sound. Each of the reference designs were identical from the viewpoint of the schematic, differing only in the parts themselves: in one we used polystyrene capacitors for the curve, the other polypropylene and in a third, ceramic; and each had a sound different from the others.
It took a lot head scratching to determine the cause of sound differences between units; each measured identically. But once we settled on a common capacitor type, unit-to-unit differences vanished. This bit of insight proved invaluable as we moved forward with the design process and remains a hallmark for those building with the ear as the best piece of test equipment owned.
It all matters.
I nearly forgot
Today is the start of the Montreal hifi show and I neglected to let you know. Room 2417 will be my home for the next two days and if you are attending please give a listen to the BHK Signature amplifier and DirectStream DAC in our room. Travis Townes and I will play music from my new Mac Mini.
Bill Ernst, who has taken charge of my Mac Mini server, is a magician. The improvements to this unassuming white box are nothing short of miraculous. And before you ask me what he has done know that I cannot speak of the sorcery within, even if I fully understood it, which I do not. And if I forget, ask to hear a few tracks from the new PS Audio music release stored on that same server, played in DSD.
I hope to see you there.
It is said you are what you eat and there is truth in that statement. We could also make a similar observation of our equipment’s sound quality: performance depends on passive components.
Within each piece in the music reproduction chain are hundreds, perhaps thousands of building blocks called passive components that are not unlike the cells we are made of. From input to output music travels through these tiny components that collectively produce the music in our homes. Along the way each passive affects the sound; some more, some less, and their contributions cannot be ignored.
The master designer of homes pays close attention to the bits that he chooses as building blocks and tomorrow I will begin to expand on some of the observations and reasoning behind the types of bits and pieces that make up the audio equipment we love.
Measuring with our ears
As I write today’s headline it seems obvious to me this is how it is done. The headline could just as easily read Tasting with our mouths had this post been about food. It’s obvious this is how it is done, yet we continue to attempt to quantify that which we hear, in the hopes our opinions are validated.
It’s a tough battle, this listening and striving for better with our ears and our equipment. During our presentation to the Colorado Audio Society last Saturday, speaker Arnie Nudell said: “I am always searching for something better, a way to get even closer to the music.” And it is the same for most of us. Our ears seem restless if we are always striving to hear something better; and the better is that which we have been unable to measure.
Why are we not content to trust our ears? Why do we demand better measurements and reasons to explain what our senses are telling us? For me the answer’s easy; because I cannot move forward with better sounding products without this insight.
I am a vegetarian and have been so for a quarter of a century. Eating crow is not on the short list of delectable menu items for people like me. Admittedly it was a tofu construct of the black bird I ate, but down it went.
I did not sit at the table lightly when asked about placing a vacuum tube in front of the new BHK Signature amplifier. But here’s the thing, it is perhaps not the first plate of raven I have eaten and it probably won’t be the last. Over the coming weeks, and with scattered frequency, I will do my best to explain the tough decision; but the simplest is the sound. Like being squeamish when asked to taste food I am convinced isn’t good, it’s the trying of things that’s often most difficult. I never tried vacuum tubes in one of my designs because I did not want to like them. Liking them opened a can of worms I was never ready to deal with, but now I relish the challenge. And I feel I owe it to you to explain why.
I perhaps should have chosen instead to have eaten my hat or even my words, but crow seemed fitting given the magnitude of the decision.
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 long way and through much amplification to become this much bigger. Like a weary long distance traveler who struggles to stay intact along the way, the journey was a difficult one with detours, traps, pitfalls and dangers aplenty. Bruised and somewhat battered, the signal is ready to meet its next challenge, getting through the gates of hell where it will be suddenly transformed from a pristine voltage to a powerful one-eyed cyclops with a high-wattage club, ready to do battle with the loudspeaker.
The point of entry for our beleaguered signal is a critical juncture where solid state amplifiers fail to meet the challenge without loss. And once musical details are lost they can never be regained. Whatever shape our signal at the output of the preamp, it is critical we lose nothing more, and that is the first task of every power amplifier. Unfortunately most fail. Can it ever work? Yes, but not with the current-centric attributes of solid state. For this task we need a pure voltage amplifying device with many electrons, and there is only one of those. It is called a vacuum tube.
Now, many of you no doubt think “oh, this is just Paul trying to sell an amplifier” and you would be right. But! Here’s where logic does not properly extend. If my only goal were to sell you an amplifier it sure as heck would not be by adding a vacuum tube to its input. No, it would be far easier to place what we have always done; a transistor. But it would not be right and I would forever be listening to significantly compromised sound, which I am not. And this admission is from a person who has sworn an oath to never make products with tubes inside; an oath I have successfully clung to for 40 years.
They say with age comes wisdom, but in my case abandoning my oath came not from wisdom but letting my prejudice go so I could observe the truth, even if it violated my belief system. Trial after trial between all manner of solid state devices convinced me of the tube’s amazing abilities, so superior to that of a FET or bipolar there was no contest. None at all.
But tubes are not good at much else in a power amplifier and we will examine that next.
The Greeks prefer their yogurt with less water and so we name it after them.
Loudspeakers need large signals to drive them but sources of music produce only tiny ones, and so we name the interface between the two by its task; amplifier.
Amplifiers have a nearly impossible task: taking in the tiny, delicate music signals from our source and connecting them to a massive power supply controlling the movement of our speakers with brute force, hoping never to overwhelm or lose anything in the process. Nothing else in the chain of music-making equipment has such a difficult task except the loudspeaker itself. And power amplifiers haven’t the necessary tools to complete their tasks perfectly. They are like an artist trying to create the Mona Lisa with a paintbrush the size of a novel. None are perfect, all are noticeably flawed. Which means, of course, what you have in your home is robbing you of the potential buried in your music.
It is instructive to breakdown the tasks of an amplifier into three main categories of work:
• Acting as the interface between the tiny signals fed to it
• Using those delicate signals to control a huge knuckle-dragging power supply
• Sending the output of the Mona Lisa to the speaker and making sure it does what it’s told
Tall challenges and we’ll look at each one starting tomorrow.
Loudspeakers and movie stars
When’s the last time you went to the movies? Since my home theater was installed I haven’t gone once, but I have seen a number of films. And watching those films fools you into believing the only ones that matter are the actors. If the director and crew have done their job then the stars of the film are all you see. The press and fans fawn over actors while the film crew go home and prepare for the next bit of work with little recognition.
Loudspeakers are like movie stars. We stare at them when listening to them. We fawn over them, we show them to our friends, we belong to their fan clubs, we read their latest reviews we eager anticipation, and we position them just so. Our favorites are the ones wearing the latest fashions: once natural wood, now shiny black dressed with a sock to hide what’s beneath, and before that thin was in: panels with magnets, and tall, nearly bulimic, with see-through high voltage dress. Our love affair with loudspeakers is legendary and for good reason; they are the most important link the the music chain.
But like a great film with actors we adore, built by a crew of hundreds, the loudspeaker’s a jealous starlett hiding behind the real masters of the craft responsible for its performance; those pieces that drive it.
No actor in Hollywood stands alone, and they know it, just as no loudspeakers performs without the second most important piece in the listening chain, the power amplifier; who humbly does its job day in and day out without proper recognition of its role in the making of music.
Let’s work on bringing this shy ‘second best’ to center stage. Stay tuned.