Todd Warnke and Mike Fenech

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October 1996

Audio Synthesis Passion Preamp - Sneak Peek

When I come across an exceptional performer I can’t keep my mouth shut. So, even though I’m not ready to fill you in on everything, I wanted to let you in on the secret. It’s Passion, and I’m in love. Now before you call my wife you need to know at least some more of the facts. The passion I’m referring to is the Audio Synthesis Passion passive pre-amp.

As soon as you heard the word passive I know some of you, out of concern for me, started saying, "Todd, give up this affair! Passives are picky. High maintenance. They will greet you with a rush of excitement and then let you down as soon as anything around them changes. Seductive yes, but they just can’t cut it in the long run." Well, let me tell you that while some passives do indeed fit that description, I’ve got reason to believe that my personal Passion doesn’t, at least not entirely. This Passion is steady, reliable, good looking, well-built, and has an adaptable personality. Sure, she won’t fit in just anywhere (what true Passion can?), but if you put out a little effort, she’ll met you half way.

As a sneak, I can report that after several weeks the Passion is working very well in my system. It combines breath-taking accuracy with excellent dynamics (even though dynamics are supposed to be a weakness in passives). Bass is tight, controlled and powerful. Highs are absolutely transcendent. Now, before I give it all away, I better stop. I’ve got a new amp to check out with the Passion, but, based on what I’ve heard so far, this piece is excellent. To quickly sum up, according to the German philosopher G. C. Lichtenberg, "Man is to be found in reason, God in the passions". I can’t claim that Audio Synthesis had this particular idea in mind when they named the "Passion", but it certainly fits, as it truly excites the passions with it’s exacting performance. God-like performance? Well, for the answer to that question, tune in next month.

...Next month look for the Passion Full Review

November 1996

Audio Synthesis
Passive Pre-amp

Price: $1495 USD

The Nearer Your Destination ...

Think back to college physics. Remember the "Uncertainty Principle"? In case you've forgotten, simply stated (and no doubt poorly as well, perhaps Dick Olsher will correct me if I'm grossly wrong), it says that when dealing with sub-atomic particles you can measure either a particle's position or momentum accurately, but not both at once. It seems to me that the High-End has adopted it's own version of this law. I'm gonna call this High-End law the "Slip Slidin' Away Principle". See, everywhere I turn people will call a particular component musical, or in reference to another piece, they'll say it's accurate, but never is a single component described as both at the same time. Before you say that this principle obviously and necessarily affects entry level gear, keep in mind that the SSA principle shows up at the very highest reaches of the High-End. Think about it, when's the last time you heard someone call the Wilson WATT "musical"? How about a Krell superamp? Is anyone willing to call the Audio Note Kassai accurate? I thought so.

The odd thing about this principle is that in the non-audiophile world, in the world of live music, we are never faced with the musical/detail trade-off. I mean, who's willing to call a live jazz quartet amusical? How about inaccurate? Oh, the bass may be mushy, but that's due to room acoustics. The group may be uninvolving, but that's a matter of their skill or our taste. But at home we are still faced with this choice - and since our goal is to recreate a musical event, to do so correctly our systems must deliver both musicality and accuracy, seamlessly. In other words, we need to transcend the Scylla and Charybdis of Detail vs. Musicality and find the place (or more correctly those components) where details adds to the musical event.

When looking for such components I'd say that certain classes of components will have a far more difficult time with this task than others. Speakers, for example, which have the Herculean task of converting an electrical signal into mechanical motion and then into acoustical pressure, are nothing more than a series of design trade-offs with no real way to win. Like the talking dog, at times I marvel not at what they say, but that they speak at all (I mean no disrespect to speaker designers by this, but rather I mean to indicate my awe at their tremendous successes). But, some components would seem to be disposed to a purity of reproduction that would allow them to pass on all the detail they receive without obscuring it, or adding to it, all while preserving the musical message. Wire would be one obvious category. Another, not quite as obvious category would be the pre-amplifier.

"THE PRE-AMPLFIER", I can hear you scream, "he's just nuts! I knew he didn't have a clue what he was talking about and now he's shown it for everyone to see". Well, not so fast. Traditionally a pre-amp has had 3 tasks. The first is to provide source switching. The second is to give us some way to control volume. And the third, especially with phono, is to provide additional gain. The decline of vinyl coupled with the advent of CD, as well as amps of greater power and sensitivity means that today most pre-amps spend the vast majority of their time performing only the first two of those tasks. And to do that all you need is a selector switch and a good attenuator. Or, in other words, a passive pre-amp.

A Straight Wire Without Gain

Correctly called passive control devices, passive pre-amps combine just source selection and attenuation. Circuit topology and parts quality are what set passives apart from each other, and in my opinion, play a greater role in determining sound quality with a passive than with an active pre-amp simply because that is all they are composed of. A poor design has no place to hide, nor do inferior craftsmanship and parts selection. With its tasked limited, a high quality passive has a chance to be a true straight wire without gain.

While this sounds like such a boon that we all should have a passive and use an outboard phono pre-amp if needed, the Audio Gods never give us anything for free. Since a passive has no active parts ( - I can hear you "I got that part already", but bear with me), which means no power cords, no buffering circuits, no gain stages, your source component(s) must supply all the signal drive to the amp. This can lead to impedance mis-matches, cable mis-matches as well as possible volume problems. To work well, a passive needs to be placed into a system that takes these possible problems into account. That said, let's look at a special passive from Merry Ole England.

Passion Is No Ordinary Word (with apologies to Graham Parker)

Just across the pond Audio Synthesis manufactures a line of passive control devices. The $1495 Passion is little black box of simple beauty. Measuring only 4 1/4 inches wide, 2 3/4 inches high, and 6 inches deep from the two brassy control knobs to the back of the polished input jacks, little is the operative word here. On the front panel, one knob selects from 3 possible sources, plus a mute position, while the other knob controls attenuation in 31 steps, from -60 dB to unity gain. On the back, all high quality WBT RCA jacks are used. One set is for the output to your amp, while three sets are for inputs. A fifth set offers a "Direct" input. When used, instead of offering a fourth source, this input bypasses the selector knob entirely, giving an slight increase in sound quality, while effectively limiting you to one source since there is no way to de-select the direct input source. Attenuation is performed using Vishay resistors, and all internal wiring is silver. So, while the box is little, it gives you a lot in parts quality for price.

Hook up is easy, as long as you pay attention to wire type and lengths. Audio Synthesis cautions against using wire runs longer than two meters, or with total capacitance in excess of 300pF as this will roll off the treble. Keeping that in mind, I dropped the little black and brass beauty into my system and let 'er break in for about a week before attempting any serious listening.

As for my system, the Audio Alchemy DDE v3.0, with a maximum output level of 3.6 volts, and output impedance of 100 ohms (slightly higher than the recommended 25 ohms, but still within reason) matched nicely with the Passion. The 100kohm load of my McCormack DNA-0.5 Deluxe and its input sensitivity of 1 volt also mated well with the Passion. The Sound-Lab Dynastats proved to have enough sensitivity as well. They are spec'ed at 88dB, and while I'm not sure they hit that, in my room I was able to hit 95dB peaks with the Passions attenuator at -18dB, as high as I wanted to go.

Perhaps this is the place to cover total system gain, as anyone looking to use a passive must be aware of all the electrical implications of a passive. A typical pre-amp supplies anywhere from 12 to 24dB of gain. However, in actual use most active pre-amps spend the majority of their time attenuating the signal rather than boosting it, never using their gain stage even though the signal is passed through it. What this means is that if your system is capable of max spl's of 115dB with the knob at the proverbial 11, the rest of your system is putting out at least 91dB, and perhaps as much as 103 dB before the pre-amp has to add its gain. If the attenuator is accurate on the Passion, in my system I can get up to 113 dB using the passive! On the
other hand, many tubes amps have input sensitivities of 2 volts, and some digital processors put out less than 2 volts. If these are coupled, and then added to insensitive speakers or a large room such a system's total gain would not be sufficient to deliver adequate volume. To make a passive work you must pay attention to this, as well as the aforementioned impedance matching. When you do, magic can happen.

The Truth, the Whole Truth and Nothing But the Truth

I started this review talking about the difficulty of combining detail and musicality. I have to confess that until the Passion showed up I secretly subscribed to the "Slip Slidin' Away Principle". It seemed that every time the detail dial was increased some of the life in my system slipped away. And moving to a "warmer" more "emotional" set up felt too much like throwing the baby out with the bath water. To be honest, I have been able to combine both detail and musicality with some success, but always in a two steps up, one back manner. The Passion, by appearing virtually invisible, had a 4 step up and no step back effect on my system.

Tracks such as the title cut from Cowboy Junkies' "Lay It Down" yielded up a wealth of detail, but each new wrinkle, rather than distancing me, served only to lead deeper into this songs devastation (not to mention make me appreciate Margo Timmins voice even more). Bass, a supposed weakness of passives, was quick, articulate and powerful. The staging was the best I've experienced in my room, and tonality was spot on. The natural warmth of the recording came across as an intentional artistic choice, and was indeed welcome in the bleak emotional landscapes this album often presents .

Moving on to Shawn Colvin's "Steady On", the Passion showed that it could handle bright recordings with equanimity as well. "Diamond in the Rough", a beautiful track, but one mixed almost jalepeno hot, was served up without diminishing any of its brightness. Yet the emotional hope and complexity was fully ntact. On some systems, when presented with as much "accuracy" as I felt the Passion was giving me, I have been forced to turn the song off. Not here. The message was reaching me fully intact, it was simply enjoyable.

Tonality was also excellent. James Carter's version of "Round Midnight", from The Real Quietstorm, is a duet for baritone and piano. My uncle, a sax player himself, sat mesmerized listening to it. When James demonstrates circular breathing at the 2:45 mark, Uncle Leo just about fell off his chair! The detail was enough to convince him that James was really in the room. Deadly accurate, silently emotional, it was a moving experience.

To test staging I dropped Richard Einhorn's "Voices of Light", by the Netherlands Radio Choir and Philharmonic in the JVC and sat back to absorb it's beautiful and novel telling of Joan of Arc story. I must confess that classical vocal music is not to my usual liking, but this album is transcendent, in all the meanings of the word. Anonymous 4, singing the part of Joan, bring a passion to Joan that nearly resurrects her in my room. And Susan Narucki! Oh my goodness. Her voice is simply celestial. She conveys the mystical and the earthly with equal power - and the Passion delivered her and the orchestra uncontaminated to my life. Front to back, right to left, they were all there. Detailed as hell, but supremely musical as well.

Into The Fire

As a final test of the Passion I decided to see what my system sounds like without a pre-amp at all. I use a JVC XL-Z1050 as my transport, which, besides it fine ability in that capacity, has variable analog outputs. So, to bypass the pre-amp I spent some time listening to it hooked directly to the McCormack. In absolute terms the Audio Alchemy DDE v3.0 through the Audible Illusions L-1 clearly bested the JVC's output (due no doubt to the better quality output stage in the DDE, among other things, more than making up for the added componentry), but the sound did take on an appealing immediacy. After several days I put the Passion between the JVC and the McCormack, with the gain set at unity, and continued to use the analog outputs on the CD player to control the volume. The differences I heard, or rather didn't hear, were the final proof of the Passion's power. What little editorial affect the Passion had was so minute that I spent hours chasing one little wrinkle or another, never quite convincing myself that I captured it. What difference I did find is more than easily chalked up to the additional interconnect needed to add the passive to the set up. Impressed? Damn Right!

Mercy, Mercy Me

So, how do I wrap this up. Simply. The Audio Synthesis Passion is one serious piece of equipment. In the right system it can take you places no active pre-amp can (I tried it paired with the Warner Imaging VTE-200 amp where it was, if anything, a better match than the McCormack. And the Passion, McCormack, Martin-Logan CLS combo went beyond musical reproduction to almost literal music re-creation). Detail is presented with purity, but in a musically consonant manner. And while breaking the "Slip Slidin' Away" principle may not bring a Nobel prize like breaking the "Uncertainty" principle would, in my world it's nearly the equal achievement.

....Todd Warnke