It has been awhile since my last column. Truth be told, I was suffering from a mild form of writer's block. I had more than a few pieces of gear sitting around waiting to be reviewed, but nothing I felt passionately about. My solution to the conundrum was to return most of the equipment to manufacturers and do some cogitating. After awhile I realized a retreat back to basics was just the creative colonic I needed.
For the past month my nearfield desktop system has been rather simple by audiophile standards. All AC power goes through the PS Audio Quintet power device, which I'll write about in detail later in the column. Input sources include an EAD 8000 Pro CD/DVD player, Pioneer MJ-D707 minidisk player, and i-Tunes via my Intel MacPro quad computer. The EAD and Pioneer digital signals go through a Monarchy Audio DIP box so that I can switch between the Pioneer's Toslink and EAD's coaxial feeds and convert them to an AES/EBU digital output. The Mac's USB feed goes into a Trends USB audio dac UD-10 that converts the USB feed to a Toslink output. The Trends also supplies an analog output for my Stax headphone system. The AES/EBU and Toslink digital feeds then go into a Meridian 518 which upsamples the 16-bit digital signal to 20 bits and feeds a Meridian 561 via digital coaxial. The Meridian's main single-ended analog output is split via a Monster L-connector into two single ended outputs which go to both the Bel Canto S-300 amplifier and Earthquake Supernova Mark IV 10" subwoofer. The Bel Canto drives a pair of ATC SCM-7 loudspeakers. As I said, it's simple by audiophile standards.
After my last column, regular readers might suspect that I would never willingly go back to a system that employs a preamplifier with an analog volume control. I wasn't planning to, but when I snagged a Meridian 561 controller off eBay for a very low "buy it now" price I figured the least one could do was try it out in my nearfield system. At the time I was running the 518 directly into an Apogee AD-1000E, which fed the Bel Canto amp via XLR, balanced cables. The Apogee supports 24 bit Pro word lengths, so I was upsampling everything via the Meridian 518 to 24 bits and using the Meridian as my volume control. The sound was exactingly detailed with exceptionally good depth and image focus, but ergonomically less than ideal. Every time the Meridian lost signal lock the system would emit a loud electronic burp. The periodic sonic rudeness was great for torture-testing speakers, but not so good for my nerves.
When the 561 arrived, figured I'd try it out temporarily yet wasn't expecting much. Was more than a little surprised to discover that the 518/561 combo surrendered surprisingly little compared to the 518/Apogee rig. Not only did the 518/561 combo produce an extremely accurate dimensional image, but also inner detail and dynamics were nearly identical to what I'd become accustomed to from the Apogee AD-1000E. Rude noises vanished and the added features, such as DSP modes, channel balance adjustments and, as soon as I break down and beg, borrow or buy a portable windows PC so I can run the Meridian software program, the ability to configure the system as a 2.1 with digital crossovers makes it hard to go back to the more primitive 518/Apogee hot rod system. Ergonomics do matter.
About 99 percent of the time I use the 561 in "direct" mode, so the unit doesn't do any digital signal processing and merely passes the signal directly onto its D/A section. The 561 ranks as one of the most musical and least colored analog preamps (if you can consider anything from Meridian with the exception of the 502 or 541 preamps to be analog) I've had in my nearfield system. It has the ability to make even 320 MPS encoded MP3s from i-Tunes sound involving to the point where it's become hard to tear myself away from my computer when the system is playing. I have, for the past month, been exceedingly delinquent at emptying cat boxes and doing other chores that require traveling more than a couple feet away from my computer. Consider yourself warned.
PS Audio Quintet
I've never been a big proponent of the wondrous sonic healing powers of AC line conditioning. For me line-conditioning devices serve primarily as prophylactics to protect gear from the dangers of spikes, surges, brown outs, and lightening strikes. But I have finally seen and heard the light. Specifically, the PS Audio Quintet has earned a permanent place in my nearfield system. What caused this sea change? Settle in because this might take a while...
About two months ago I reviewed a well known, highly regarded, and very pricy AC filter and power cables. The review was up on the site for maybe 24 hours before it was pulled because I had not had it "fact-checked." In the end it was agreed that the review be scrapped. At the time I wrote the review, was not overly impressed by the filter. But before I returned the unit I did some additional testing and discovered, much to my chagrin, that it worked far better at removing AC noise than I had previously thought.
The main problem with reviewing AC filter devices is that they are designed to reduce or eliminate AC noise, and you need to have AC noise before they serve any earthly purpose. Oh sure, AC filter manufacturers will tell you that all AC power has noise all the time. But how can we be sure this is really the case? And how can a reviewer determine that an AC filter device actually works?
There have been very few consumer-level devices available for measuring AC noise (hint, hint, if AC filter makers were really sharp they'd make just such a device). One product that was on the market for a couple of years was the Audioprism Noise-Sniffer. You plug it in, turn it on, and if its built-in speaker makes noise, you have AC noise in your line. It's simple enough that even a reviewer can make it work properly. But how can you make AC noise? My favorite AC noise creator is an old Pioneer LD-704 laser disk player. When I plug it into an AC outlet and turn it on the Noise-Sniffer does a perfect imitation of a Geiger counter that's just been thrown on top of a nuclear pile. My testing procedure is very simple; connect the Noise-Sniffer, check the base noise level, plug in the LD player, turn it on, and compare the difference.
After running a series of tests on this AC filter system whose name-will-not-be uttered I discovered several interesting things. First, it did an excellent job of filtering AC noise coming from the mains. When the LD player was plugged into the wall, the filter eliminated all the noise generated by the player. The filter also did an excellent job of filtering noise between its two filter banks. When the LD player was plugged into one bank and the Noise-Sniffer into another the Sniffer was silent, but when the LD player was plugged into the same filter bank as the Noise-Sniffer, the device didn't do squat in reducing noise. This is perfectly normal since the device has no way to filter the AC between outlets in the same filter bank.
Just for the heck of it I tried isolating the Noise-Sniffer from the LD player by using one of the firm's fancy AC cords. I have a power strip, which accepts standard AES power cords so I used one of the firm's special AC cords to connect the strip to the same filter bank as the LD player. I then plugged the Noise-Sniffer into the power strip. Suddenly, near-silence. Their power cord alone proved to be almost as effective in reducing AC noise when both units were plugged into the same outlet as the AC filter box had been when the LD player was plugged into the wall. Hmmm. Naturally I tried other AC power cords. Most of them had little or no effect, but a few older and long discontinued specialty cables produced similar results. I put them in my "good" AC cord pile.
Because I was already scrabbling around on my knees under my desk I tried plugging in various components from my regular desktop system to see which ones added noise to the line. The Meridian 518 and 561, Bel Canto S-300 and Monarchy DIP were all silent, but the Earthquake Supernova produced almost as much noise as the Pioneer LD player. By giving the Earthquake its own private filter bank I was able to eliminate most of the noise it introduced into the AC line. Using the right AC power cord on the Earthquake further reduced the noise to below audibility.
What were the sonic effects on the entire desktop system when it was reconnected? The overall sound seemed less mechanical and more relaxed. I also noticed greater depth and dimensionality even on MP3 sources. Ok, so I was wrong about this AC filter – it did make a sonic difference. Too bad you're never going to know who made it...
Just about the time I finished discovering the error of my ways, PS Audio introduced their new Duet and Quintet AC filter devices. Since I had to return the unidentified filter device to avoid incurring further wrath I trotted on down to the PS Audio facility, which coincidentally is located in the same town I live in, and picked up a bright shiny new Quintet.
Ran the same tests on the Quintet as I had with the previous filter device, and the results were identical. It does a wonderful job of isolating noise between its four filter banks. The Quintet also protects against spikes and surges (something the previous filter bank did not) and has an easily replaceable protection module so if your domicile does receive a lightening strike you can easily get the Quintet back up and running. Another nice feature included on the Quintet is turn-on delays. You can set up one filter bank to stay on permanently while the others can be turned on and off sequentially. Since the Apogee AD-1000E puts out rather loud turn-on and turn-off noises, being able to turn on the Bel Canto S-300 after the Apogee and turn it off before the Apogee was very comforting. The Meridian 518 has an annoying habit of changing its type when it looses power, which causes it to power up at full volume. This can be pretty darn LOUD. With the Quintet I keep the 518 on all the time, which avoids this little problem.
Sonically the PS Audio device also achieved the same repeatable and noticeable results as the other AC filter device. The overall sound of the system was less mechanical, more refined, and more musical. MP-3's from i-Tunes especially benefited from the PS Audio Quintet's ministrations. Depth, which was usually lacking from mp3s, increased to the point where some of them almost matched the CD originals. Also, inner detail was improved. Granted MP-3s still aren't universally indistinguishable from CD's, but with the Quintet in my desktop system the quality gulf has been clearly reduced.
If I had to choose between spending $500 on more premium cables or on the PS Audio Quintet, I'd choose the Quintet in a heartbeat. Sure, cables matter, but in my humble opinion clean AC power and reliable spike protection matters more.
I've been using this versatile little box for a couple of months now. It took me all that time to fully appreciate its charms. It performs more functions than any under $110 device I've ever seen. Not only does the UD-10 allow you to convert a USB audio signal to multiple Coaxial, Toslink, or AES/EBU digital outputs, but it also delivers an analog signal. Either a USB connection or an external battery can power the UD-10. In my system I use the USB connection because my Intel Mac doesn't like the battery and will not recognize the UD-10 when it is powered that way. No big deal since it works perfectly via USB.
In my system the UD-10's primary function is to isolate the computer from the rest of my nearfield system. After all the time I've put into cleaning up the system's AC it would be silly to connect any non-isolated device. Computers are notorious for generating tons of AC noise. By running the USB sound into the UD-10 and then sending a Toslink connection to my nearfield system I can completely isolate the computer from the system.
When I first hooked up the UD-10 I didn't give its analog output much thought. After all how good can the D/A in a little box be? Recently I needed a way to use my Stax headphone system because the Apogee AD-1000 didn't have enough analog outputs to handle the Stax system. I remembered that little mini stereo connection labeled "headphone" on the front of the UD-10 and connected a stereo mini-plug to RCA adapter to it. I then ran a meter length of ancient AudioQuest diamond to my Stax SRM-1/MK-2 headphone amp, and surprise, surprise, it not only worked but also sounded more than acceptable. The sound was clean, detailed, and harmonically well balanced. When I compared an analog feed from the Meridian 561's tape outputs to the Trends UD-10 I discovered just how amazing the UD-10 really is – I couldn't tell any difference. This is one very good little D/A!
For $110 I dare anyone to find an audio device that does so much so well. The Trends UD-10 is simply a must-have for anyone with a computer-based recording or playback system. For more info here's a link to Trends Audio website.