The Fifth Element #44
Ars-Sonum is a Spanish audio company that, as far as I can tell, makes only one product—but it's a doozy (footnote 1). The Filarmonía SE is a tube integrated amplifier that is, in many ways, an homage to Dynaco's iconic Stereo 70 power amplifier of 1959, but the Filarmonía is by no means a slavish copy. Get down to specifics, and it's actually more of a clean-sheet-of-paper design.
I first saw the Ars-Sonum Filarmonía some years ago, in a hotel-room bathroom at a Home Entertainment Show in New York; perhaps it was 2004. (That venue was not chosen for its acoustics, I can assure you.) Bobby Palkovic, of loudspeaker manufacturer Merlin Music Systems, wanted to give journalists a quick, eyes-only sneak preview of the amplifier.On the basis of its drop-dead-gorgeous looks alone, the Filarmonía seemed to justify its (at that time) $3500 price. However, an audition would have to wait until the order-backlog situation improved—which, owing to the Filarmonía's essentially hand-built nature and robust word-of-mouth sales, turned out to be some length of time. The relevance is that the Filarmonía SE is now a mature and successful product that has been in production for some years, and that has been improved (hence the SE designation) in the course of its marketplace development.
Bobby Palkovic sent me a new unit with minimal break-in time on it in early 2007. At Home Entertainment 2007 in New York City, he included the Filarmonía in a system showcasing his own Merlin speakers. That system won plaudits from other Stereophile writers at the "Ask the Editors" panel discussion, as well as from a broad cross section of e-zine writers covering the Show. A bonus at HE2007 was the avuncular presence of Ars-Sonum's genial factotum Ricardo Hernandez.
For those of you not in the hobby during the relevant years (1959–1990), a few words about Dynaco's Stereo 70 are in order. David Hafler's first company, Acrosound, which he founded in 1950, was dedicated to making audio-output transformers. Although Acrosound's products were well respected, the company was reportedly not very profitable. So perhaps it's not unfair to infer that Hafler turned to selling audio kits as a way to sell more audio transformers. He founded Dynaco in 1955.
Dynaco's first product was the Mk.II, a 50W monophonic tube power amplifier. I could not locate any source explaining why their first product was called "Mk.II." Perhaps Hafler wanted people to think that all the bugs had been worked out. With the advent of commercialized stereo, Dynaco offered a one-chassis stereo power amplifier of somewhat less power, and, to indicate that it was not a mono unit, included stereo in its name: the Stereo (ST-) 70.
While the Stereo 70 employed Hafler's basic amplifier-circuit design, which itself consisted of refinements to earlier designs by D.T.N. Williamson and Alan Blumlein, the Stereo 70 was actually designed by Bob Tucker and Hafler's partner Ed Laurent, while Hafler himself was away on a business trip.
The ST-70 originally cost $99 for the kit version, which included a preassembled and tested circuit board; the builder need only wire the chassis and assemble the hardware. The fully assembled version cost $129. The original ST-70 design had an open area toward the front of the chassis, through which the audio circuit board stood proud. I dimly (and perhaps incorrectly) recall the brown metal tube cage as having been optional. People were less touchy about product safety back then, or perhaps society expected parents both to put electronics where children could not mess with them, and to teach their children prudent avoidance—or at least buy the tube cage. This memory of the tube cage is from an early-1960s Allied Radio catalog that was my audio "wish book" when I was a tyke.
The cultural relevance of the tube cage is this: With the cage installed, the ST-70 looked like a cinderblock someone had painted with a brown crinkle finish. But with the cage off and music playing, the ST-70 had the look that, for millions of people, for decades, said "hi-fi." That iconic ST-70 look was two pairs of power tubes in front, one pair on each side of some juice-can–sized thingies, and three transformers at the rear: a larger power transformer, with smaller output transformers on either side. This is the look that the Ars-Sonum Filarmonía SE pays tribute to, and updates and improves on. The Stereo 70's audio performance was good enough to make it known as "the poor man's McIntosh."
Owing to the large numbers in which it was produced—reportedly more than 300,000 units—and the comparatively low prices that built kits that were only average in build quality fetched on the used market, the ST-70 became a popular "mule" for experimenters and modifiers from the 1970s on. Audio Research Corporation and Audio by Van Alstine were two of the many companies that have offered ST-70 modifications. I had not been previously aware, however, of a commercial firm's offering a from-scratch designed and built ST-70 "tribute" amplifier (footnote 2).
Suddenly, it's 2007!
The first thing to get out of the way is that the Ars-Sonum Filarmonía's suggested retail price is now $4000, which I attribute not to venality or cupidity on the part of its builder or importer but to the weakness of the US dollar against European currencies. That price will be good at least through the end of 2007.
The Filarmonía SE arrived in a sturdy corrugated carton plus inner carton, with several inches of resilient foam padding all around. No worries on that account. The tubes came in a wooden box with a brass clasp. In addition to a complete and well-written (and well-translated) owner's manual, there is a microfiber dusting cloth, and a single cotton glove to wear while installing the tubes. US importer Bobby Palkovic feels so strongly about the need for a high-quality, well-chosen power cord that he includes a hefty Cardas Golden Reference AC cord with the units he sells; I used that for most of my listening.
Setup and operation were trouble free. The Filarmonía runs somewhat hot, so proper ventilation is a concern; this is no amplifier to shut up in a closed cabinet. The power tubes are in complementary pairs with a claimed 98% matching factor, and therefore are numbered corresponding to their sockets on the chassis. (Bias is not user-adjustable.) The Filarmonía is another amplifier, similar to the darTZeel NHB-108, whose owner's manual warns in the strongest possible terms of extremely dire consequences if the unit is operated without loudspeakers connected.
The Filarmonía does have one quirk. For best break-in results, Ars-Sonum strongly recommends that, for the first 50 or so hours of operation, the amplifier be used for a period of three hours, then turned off for one hour, then turned on again for three, etc. This is claimed to optimize the curing of the paint on the transformer laminations. The unit I received had some time on it, and I followed the three-hours-on/one-hour-off regimen until at least 50 hours had passed. The owner's manual cites 100 hours as the point when you're out of the woods, but also cautions that completely stable operation will not be reached until 500 hours.
That was my experience, in that there was a small amount of transformer hum at the outset, inaudible when most music was playing. I hasten to assure that this was a mechanical hum from the unit itself, not through the speakers. The hum stayed around and stayed around, and then, suddenly, one day it was more than half gone—not a linear process at all. A few more discrete ratchets-down and it was totally gone.
Palkovic reports that a hum not occasioned by power-line problems that has taken that long to work itself out had happened only once or twice before with the Filarmonía SE, and further, that when he put the first couple of dozen hours on the amplifier on my review sample at his factory, it was dead silent.
As you can tell by looking at the photo, the Filarmonía SE is quite handsome. The quality of the chassis work is extremely high, but it is a retro or nostalgic quality, not the modern high-tech feel you get from Nagra or Sound Devices. The Filarmonía looks like what a Stereo 70 might have looked like had Dynaco had an exceptional industrial designer on staff—and an open checkbook. I rate its fit'n'finish one step above 1960s McIntosh, so how's that? You can spend quite some time looking at the chromed chassis corners and edges, wondering how they got them so uniform.
I won't recapitulate all the information on Ars-Sonum's website, www.ars-sonum.com. Briefly: the front panel holds a slim toggle switch for power on/off, a small deep-blue pilot light, a volume control, and a source selector. There is no balance control. The knobs for volume and source selection are made, exclusively for Ars-Sonum, of very highly polished solid aluminum, and have a wonderful tactile quality (the volume potentiometer is an Alps Blue Velvet). And many opportunities to appreciate that feel you will have, because remote control is not an option. There are three line-level source inputs and no phono input. The front panel is available in silver or gold finishes; the review unit's was gold.
The chassis top plate holds a 6922 (E88CC) double-triode input driver tube, flanked by two JAN5814-A (E82CC/6189/12AU7/ECC82) double triodes for phase inversion, behind which are a large capacitor and two pairs of E34Ls (a special version of the EL34/6CA7 output tube). The transformers have chrome caps, and are mounted on Delrin standoff insulators. The transformers are designed by and made exclusively for Ars-Sonum.
The rear panel holds four pairs of RCA jacks, for three inputs plus a tape output; a pair of Cardas copper EC-compliant speaker binding posts; and a hefty IEC power inlet. (The binding posts do not allow the use of banana plugs, which are verboten in the EC.) The Filarmonía weighs 29 lbs and sits on three, not four, resilient feet.
The two-year guarantee excludes the tubes, which are anticipated to have a working life of 4000 hours. I didn't open up the unit, but internal construction is stated to be a combination of circuit-board traces and point-to-point wiring, and to include such premium parts as cryogenically treated Hovland capacitors.
The Filarmonía departs from Dynaco's design in several important ways: The input is screened and transformer-coupled, the circuit design is not Ultralinear, global feedback is a low 6dB, and the Filarmonía operates in class-A for most of its rated 30Wpc output. Loudspeaker impedances should nominally be 6 ohms or greater, and should not fall below 4 ohms at any point.
In short, the Filarmonía is a handsome 30Wpc integrated amplifier reminiscent of a Dynaco ST-70 but with an arguably more ambitious circuit design and a laundry list of premium or exclusive component parts—and which costs 40 times what the original kit did, nearly 50 years ago (not allowing for inflation).
As I idly awaited word that the time was ripe for me to evaluate this individualistic amplifier, I was full-on primed for a nostalgic wallow in classic Stereo 70 "butterscotch" sound: rolled-off highs, flabby bass, a candlelit midrange—a single candle, in fact. Think again, pilgrim. On firing up the Filarmonía SE, I was taken aback at how "modern" it sounded. I'm not about to say that it didn't "sound like a tube amplifier," but it certainly didn't sound like any Stereo 70 I had heard. Golly. Time for a reappraisal. Don't judge a book by its cover.
With the Wilson Benesch Arcs
Wanting to assess the Filarmonía SE with a familiar loudspeaker that I thought would be a likely match in the marketplace, I asked US importer Steve Daniels of the Sound Organisation to again lend me a pair of Wilson Benesch's entry-level model, the Arc, which I wrote up in November 2002 (Vol.25 No.11). The Arc currently retails for about $4500/pair, including integral stands. Finish options determine the final price.
Well, isn't this nice? Just about a match made in Heaven. The Arc's ported enclosure made no demands that the Filarmonía couldn't effortlessly cope with, and its soft-dome tweeter made for an ensemble that was beguilingly smooth and easy to listen to. Compared to my aural memory of the luscious Unison Research S2K single-ended triode amplifier, which I'd used with the Arcs five years before, the Filarmonía was somewhat more robust in dynamics and somewhat more (for lack of a better word) orthodox in frequency response and freedom from euphonic coloration (or special pleading on behalf of acoustic instruments and human voices)—but there were more similarities than differences. Just as was the case with the Unison Research S2K, the Filarmonía-Arc combo was one I could imagine many discerning music lovers deciding was ample reason to get off the upgrade merry-go-round.
For all of my listening, the source was Grace Design's m902 DAC/line stage/headphone amplifier, fed by a digital signal from Oppo's DV-970HD universal player. For cables, I swapped between Cardas Golden Reference (power cord supplied with amplifier; speaker cables and interconnects lent by Cardas) and Nordost Blue Heaven (lent by Nordost). I slightly preferred the Nordosts with the Wilson Benesches; with the Verity Audio Rienzis (see later), I slightly preferred the Cardases. The Nordost Blue Heaven's bracing clarity brought focus to the Arcs but went too far in that direction with the Rienzis, while the Cardas Neutral Reference's, erm, neutrality left the Arcs a bit uninvolving but was just the ticket for the Rienzis.
With both the Arcs and Rienzis, and with both the Cardas and Nordost wires, the Filarmonía SE sounded more like unto than different from most of the other excellent amplifiers I have heard. Good audio sounds more like good live music than does bad audio. And even different varieties of good audio sound essentially more similar than different.
Over months of intense auditioning that included more hours than I care to count of listening to alternate takes for my Pipes Rhode Island organ project (CD, RIAGO CD101), the Filarmonía SE proved itself extremely coherent, and to have wide bandwidth, exceptional low-level resolution, and nonexistent fatigue factor. Positively engaging.
In some audio judgments of mine I have extremely high confidence; in others I am confident, but I wouldn't stake my life on them. Among previous high points of certainty were my first experiences with the Nagra-D recorder, Wilson Benesch's A.C.T. One speaker, and darTZeel's NHB-108 power amplifier. I can say with that level of confidence that I am sure that the Ars-Sonum Filarmonía SE is an absolutely superb amplifier that will make many owners happy for years. The limb I am not quite ready to climb out on (though I'm tempted) is to say that the Filarmonía—detailed yet oh, so sweet—is "the poor man's darTZeel NHB-108." I'm not there yet, but the temptation is there, and that says a lot.
However, the Filarmonía SE is not the integrated amplifier for all seasons. Based on its specifications alone, I anticipate that it will pretty much give up if asked to drive a speaker whose impedance falls to 2.75 ohms while presenting a –45° phase angle, and that has gallons of air to push around in a large enclosure. Good intentions plus craftsmanship do not repeal the laws of physics. Careful system matching and, ideally, an in-home audition will determine whether this marriage is made in Heaven or somewhere else. If you blindly buy a Filarmonía SE and pair it with the wrong speakers, you'll be wasting a lot of money.
The other side of the coin: Despite the many fine qualities of a more likely candidate for "integrated amplifier for all seasons," Audionet's excellent SAM V2 (see this column, June 2006, Vol.29 No.6), it did not excite in me quite the same emotional response as the Filarmonía SE.
I had been curious for some time to hear a speaker from Verity Audio. US representative John Quick, of Tempo Sales & Marketing, lent me a pair of the upper modules from the Rienzi system ($3200–$3600/pair and up, depending on finish). My intention was to try a different pair of speakers from a price tier likely to be shopped in by those putting together a system that included the Ars-Sonum Filarmonía SE.
The Rienzi Monitor is half of the full Rienzi model (the bass module costs ca $4800/pair), and it is handsomely made. My review pair was in the highest-quality piano-black lacquer finish I have ever seen. The cabinet is 13.5" tall, 8.5" wide and 10.5" deep at the base, and 7.5" wide and 9.25" deep at the top—gently tapering but not really pyramidal. The drive-units are a 0.75" recessed soft-dome tweeter and a 6.5" midrange. The front panel is covered in a black felt-like fabric. The review pair arrived in the extra-cost ATA transit case, with fitments not only for the speakers but the binding posts (the cabinet rear has threaded inserts for them), owner's manual, isolation platforms, and magnetically attached grilles. A first-class presentation all around.
The Rienzi is a sealed-box design. Sealed-box bass loading has the advantages of better group-delay performance, a smoother impedance load, and more uniform low-frequency rolloff. The disadvantage is that ported enclosures, despite drawbacks that are mirror images of the virtues of sealed-box designs, are more efficient at getting more bass out of a small box.
The good news is that the Rienzi was blindingly electrostatic-fast, yet not harsh or brittle—at least not with the Filarmonía SE. Although I think that, overall, the Verity Rienzi and the Wilson Benesch Arc have more in common than not, the Rienzi came across as a "clarity" speaker, the Arc as a "warmth" speaker. Listening through the Rienzis to John Coltrane's "Acknowledgement," from A Love Supreme, I couldn't remember hearing as clearly before that the vocals are overdubbed.
A friend gave me a surprise gift of a CD-R made from a legal download of Anna Netrebko's achingly beautiful Russian Album (Deutsche Grammophon 000815302). The (apparently) download-only bonus track of the soaring duet "O Soave Fanciulla," from La Bohème, played back through the Filarmonía SE and Rienzis, engendered a case of whole-body goose bumps. This was all to the good—the Rienzi is a wonderful speaker.
But you hear a "but" coming: The two-way Rienzi Monitor is intended to be the upper module of a complete three-way system. The combination of the Rienzi's speed, lean or muscular tonality, and sealed bass loading added up to a speaker that could be a tad frustrating for its bass reticence—at least with the Filarmonía SE. And I approve of the uncompromising choice of sealed-box loading in the interest of greater transparency, even if the bass response of the Rienzi Monitor does somewhat suffer.
The bright side of all that is that you can buy the Rienzi Monitors, and then, when your circumstances permit, add the bass modules, and you'll have a complete, nearly full-range system. However, if your plan is not eventually to add the bass modules, I recommend careful audition, and selection of an amplifier well-matched to these speakers and to the size of your room.
Furman Sound IT-Reference 20i
When my listening to the Ars-Sonum Filarmonía SE had passed the 100-hour mark and the amp continued to emit a slight hum, Bobby Palkovic suggested that I try a balanced power conditioner. Balanced power separates the usual 120V hot leg of wall current into plus and minus 60V legs.
The IT-Reference 20i ($3499) is Furman Sound's top-of-the-line power conditioner. It weighs 81 lbs, and provides four duplex outlets offering balanced and power-factor-corrected power, as well as two duplex outlets offering unbalanced power, for high-current-draw power amplifiers. The 20i is protected from ground faults and offers connections for protecting telco and cable lines from surges. The industrial design is understatedly handsome. Unlike some other power conditioners, the IT-Reference 20i does not offer a front-panel convenience outlet. Given its comparatively small current draw, I plugged the Filarmonía SE into one of the 20i's balanced power outlets.
The IT-Reference 20i is built like a tank, and worked flawlessly. It brought a slight lowering of the noise floor without any reduction in dynamics. To my annoyance, the Filarmonía kept on hummin', though that problem eventually solved itself over time, and it was hardly the Furman's fault.
Furman claims that the 20i can handle virtually any instantaneous voltage surge from lightning or commercial power. Owners of ambitious systems, especially A/V systems that connect to the outer world through phone or cable lines or satellite dishes, are well advised to invest in a high-quality power-management solution such as the IT-Reference 20i.
