Fine Tunes #12
How do components breathe? Well, for starters, let's understand that the end table, that pile of books on the floor, and m'lady's ètagére are poor places for your system. Rigidity and mass are the name of the game, although Linn and others have successfully espoused low mass as long it's coupled with high rigidity. If you absolutely can't manage an audio rack, here are a few basic precepts to follow.
Place individual components on the sturdiest shelving or tabletop possible, especially the record player. . . hellooo! If your turntable sits on a springy, sagging, poorly supported shelf, expect it to sound that way. If footfalls send the tonearm wildly skipping, news flash: that's not the best place for it. And the same can be said for the other front-end components, especially CD players and separates . . . or even (perish the thought) receivers.
If you must site your components on bookshelves, knuckle-rap the shelves to find the most solid and inert spots, and place your components there. You'll find the best location near whatever vertical supports there may be. If the shelves are held up with metal brackets, you're in trouble. Don't even dream of putting speakers on such a shelf, or your books'll jump around with every tune you play.
If you must hide your components in the bowels of an ètagére or sideboard, do the knuckle-rap test. But first, beg and plead to be allowed to place the components atop whatever piece of furniture you're considering. Failing that---hey, shit happens---if the shelves within droop, sag, and rattle like loose dentures, consider adding brackets to make a more solid support. Go on---no one will notice them.
Watch out for heat buildup in closed cabinet spaces. I know one experienced audiophile in a worst-case situation: leaving the cabinet doors open to ventilate the equipment blocks the direct sound of his speakers. He's got a tube preamp and a hot-running DAC---it's a heat wave when you open the doors. That's not really good for the equipment. Fortunately, the power amplifier, also tubed, sits behind a couch between the speakers. And let's not even discuss the glass-topped coffee table sitting between the speakers. Sigh.
But say you're lucky, like me, and your mate adores music---you can get away with a little more than the average long-suffering audiophile. Audio-specific racks come in many forms, from the most basic to multiple air-supported platforms like the new Townshend to sculpture created by Volkmar Drubbisch at pARTicular Contemporary Design in San Francisco. Remember, you're looking for high rigidity and whatever mass you can afford to purchase. As shelf systems increase in cost, they often themselves comprise vibration-damping materials.
If, like several of my audio buds, you're working with an entry-level Salamander rack, two shorter ones will do you better than one tall (and swaying) rack. Place your rack in a location with a low probability of inducing feedback or acoustic breakthrough. Corners are the worst places, which is why I always recommend the corners behind the speakers as the right places to begin using room-treatment products.
Another absolutely crummy place to set up your rack is to either side of the outside or inside edges of the speakers, especially your LP player and phono preamp. You don't want the sound from your speakers to address itself quite so directly to your low-level and most thoroughly microphonic equipment. (Microphonia is the tendency of objects to vibrate or resonate.) While most audiophiles are aware that tubes can be microphonic (footnote 1), circuit boards---and the individual components mounted on them---can vibrate and adversely affect the signal. That's not just audiophile paranoia, by the way. On an oscilloscope, you can readily see the disturbances created by resonances in solid-state components. In fact, Balanced Audio Technology's manufacturing process includes checking circuit boards for their resonant characteristics so that vibration-sensitive parts can be located at the boards' null points.
The same thing goes for your room: Place your equipment rack at an acoustic null point and you'll experience fewer problems with external structure- or air-borne resonances that affect the sound. An easy way to home in on the right place is to take a stroll through the area you're planning to use while playing material with strong bass and dynamics. You'll know the ideal location right away---there'll be no bass bloat, and no high frequencies will jump out at you.
Now that you've found a good place for your rack, how should you arrange the components within the rack? This depends on how many shelves you have, but in general, whether placing components on a rack or shelf or hiding them away in a sideboard, avoid stacking such items as preamps atop power amps. If you've been reading "Fine Tunes," you'll understand the evils of induced 60Hz hum, and there's no better way to get it than this. For the same reason, it's best to keep components that generate low-level signals---like a phono stage--- well away from power supplies, amplifiers, or digital components, which also radiate spurious high-frequency signals. If the phono stage is integral to the preamp, apply the same rule to the entire unit. In fact, in almost every respect, line-level signals should be treated the same way as a phono stage's more minuscule output.
Next month: the ins and outs of audio shelves, materials to place under front-end components and amps, and footers and equipment supports and how they relate to internally generated resonances.
Footnote 1: Especially, in my experience, some of the more prized and costly NOS (new old stock) items.