The Thor Crescendo Monoblock Amplifier

The Thor Crescendo Monoblock Amplifier
Bringing down the thunder from Connecticut


June 2006


The god of thunder via Paul Marks?
I know according to mythology the god of thunder’s name is Thor, but only because in the minds of the Norsemen, it sounded cooler than, say Kevin. But the god of thunder, as we audiophile types know it, is Paul Marks, the owner and chief designer of Thor Audio. I have been a fan of Thor Audio since the late 90’s when renowned deer hunter, Green Bay Packer fan, and former proprietor of Wisconsin-based Salon One Audio Bruce Jacobs, raved to me about these new “donut shaped” electronics that I just had to hear. Luckily, not long after told me about them, one of my favorite local audio shops, Holm Audio, picked up the line. Well needless to say, it only took one listening session and I was hooked. I started stopping by the shop on a regular basis (make that an even more regular basis) just to listen to the wonderful sounds these electronics could generate. And when shop owner Mike Holm allowed me to take the preamp home, I was in Audio Heaven. To this day, I still own a Thor TA-1000 preamplifier and Thor TA-3000 phono stage, both of which I’ve had upgraded to the MKII version.

As much as I liked the preamp, I was very curious to see what this company’s amplifiers had to offer. I couldn’t fathom Thor keeping the same circular shape and then try to figure out a way to insert an amplifier into it. No way, no how. Shortly thereafter, Thor came out with the TPA-30 (which would eventually evolve into the “Capriccio”), a 30-watt monoblock amplifier. Much to my surprise, Thor maintained that unique, round shape and built an amplifier into it; a darned good one at that though while listening to it, I became intrigued by the thought of what a more powerful amplifier might be capable of. So I checked out Thor’s website and saw that they indeed had come out with two more amps that offered more power and could possibly give me that extra little piece of musical weight that I felt might have been missing from the smaller amp.

I absolutely had to hear what the larger Thor amps could do. So, at the 2005 CES/T.H.E. Show in Las Vegas, I had my chance to hear one up close and in person. It was the TPA-60, now known as the Crescendo. I was not disappointed by what I saw or heard from these amplifiers.

Thunder that can be seen and felt
As I mentioned above, the Thor amplifiers maintain their distinctive shape, but the width, height and weight increase as you go up through the amplifier line. From an aesthetic point of view, not many components can match the look of the Crescendo power amplifier. On the top plate of the amplifier, sitting directly in front of the output tubes, a clear 1/4″ thick tempered safety glass is sitting on a row of blue LEDs and tinted gel. The blue light shines straight up inside the center of the glass. This not only illuminates the bottom edge of the glass with this really slick blue color, but it extends upward and outward giving both the top and sides of the glass the same look. An acid-etched Thor logo in the center of the glass creates a nice three-dimensional image and looks like it’s floating in mid air. The output tubes glow behind the glass to give it an even more elegant look. As with all Thor products, the lettering, knobs, and wall behind the output tubes are available in either chromed silver (standard) or the 24k gold (optional).

The Crescendos are the result of a painstaking process taking over three years to bring to production. Like the rest of their line, they reflect a ‘no price point’ approach to circuit and component selection, and are built using hard-wired point-to-point construction techniques. Paul Marks feels this approach retains all the sonic characteristics of any source, leaving their original signals intact. Small wattage power amps are notorious for their inability to handle loud, deep bass. The power supply in the Crescendo has more than twice the current capability found in most small wattage amps. The audible result is an amp that delivers a very controlled bass that is tight and deep. It never runs out of steam – even at maximum output!

The Crescendo was designed into a 16″ diameter chassis with careful thought to every aspect of circuitry, customer safety, and ease of use. All circuitry and transformers are mounted inside the chassis. Only the tubes, fuses, bias pots and meter are visible. The end result is a simple and extremely elegant appearance. Both power and output transformers in the Crescendo are custom wound to Thor’s demanding specifications and are proprietary to Thor Audio. Unique to the Crescendo are features including top-loading fuse replacement, bias adjustment controls, and built-in bias meter. Bias settings are very user-friendly and made using a combination of toggle and rotary switches that automatically shunts the input to ground while turning on the bias circuit and powering up the built-in meter and circuit. With this approach there is no need to turn off the amp, unplug the interconnect cable, and place a shorting plug in just to bias the amp. The amps can be biased “on-the-fly” while the music is playing, and takes only seconds to accomplish. Most importantly, all controls are accessed from the top of the unit for safe, user friendly operation. There is never a need for you to open the unit and expose yourself to the high voltages present inside. Besides, as with the rest of the Thor line, the Crescendo comes with a Lifetime Warranty.

Describing the sound of thunder
This could almost be taken literally. The first attribute I noticed in regards to the Crescendos is how dynamic they are. It’s more than just something subtle that you happen to notice. Dynamic information, such as percussion, bass, synthesized music, etc., is very explosive when the music calls for it. This is not at the sake of the Crescendo’s transient response, which is also very good. The dynamic capabilities of these amplifiers will take hold of your attention and make you sit down and wait for the next volley. Though the amplifier is grainless, it will also sound unforgiving of the source material if there are any anomalies that reach it from upstream. Equipment changes were easily identifiable and made cable and preamp evaluations easy to accomplish. The high frequencies have nice extension, with a large amount of air and ambience retrieval that good vacuum units are known for. Brass instruments come through with a goodly amount of tonal textures, triangles sparkle and cymbals shimmer as they do at live events. Tonally, the Crescendos are neutral with maybe a slight hint of tube warmth. Trust me; most vacuum tube electronics are not as fast or dynamic as the Crescendos. They throw a stage that is wide and deep and had no problem extending past the outer edges of each of the speakers I used during this review. The midrange performance is very palpable, to say the least. Performers seemed to be magically transported into my listening room with lifelike presence. Micro details from my recordings were clearly evident and easy to pick out. The bass response of these amplifiers is tight and extended with a lot of low frequency information and detail. The amps are coherent and balanced with no one area of the performances standing out. 


One of the musical experiences that I want to share with you include Muddy Waters’ Folk Singer [Mobile Fidelity] which was a perfect example of the dynamic range of the Crescendo. This entire CD is simply wonderful. From the very beginning of the track “My Home Is In The Delta,” Waters captivates you with his heartfelt, bluesy style. What struck me was the way Muddy phrases his notes, and ends some of his verses a whole lot louder than when they started out. I had always noticed this in the past but with the Thor in place, I could get a better sense of the emotion he was conveying through his songs. On the Wynton Marsalis CD, The Magic Hour [Blue Note], the title track contains a veritable cornucopia of percussive sounds, with both soft and strong attacks. The Crescendos just breezed through these sections with accuracy and detail and with no confusing sounds or blurring of notes. Male vocals were also convincingly rendered. Andy Bey’s rich, velvety baritone voice (which is reminiscent of Johnny Hartman) on his American Song CD [Savoy], is effectively communicated with the emotion with which he sings. From his heartfelt, “Never Let Me Go”, to the swinging, “Speak Low”, Bey shows why he deserves to have a much larger following. Female vocals, as well, were reproduced with a heightened sense of realism and that cool feeling that the singer was in the room while I was listening to music. On Jane Monhiet’s CD, In the Sun [N-Coded Music], I was able to appreciate the subtleties of her vocal inflection and tone. Another favorite of mine is Malcolm Arnold’s Overtures of Malcolm Arnold [Reference Recordings], in which he conducts the London Philharmonic Orchestra. The Crescendos had no problems delivering the dynamic extremes presented by this work.

Putting it all together
The Crescendos were well behaved while in my possession as there were no pops, turn-on thumps, tube issues, or strange noises. I made a lot of cable and interconnect changes as well as plugging lots of different equipment in and out during the review but the Crescendos remained in control of themselves. For those who may feel that you can get Thor’s Capriccio and still get the sound of the Crescendo but at a lower price, please don’t because you will be disappointed. I lived with the smaller Thors for a week and though there is a familial resemblance, it’s just not in the same league as its larger sibling. The Capriccios were meant as Thor’s alternative to the single ended tube crowd. I have heard the Capriccio paired beautifully to the Coincident Total Eclipse at Holm Audio, and can tell you it’s a wonderful little brother to the Crescendo. With that being said, the Capriccio “played” my Martin-Logans (note that I did not use the word “drive”) well enough, but not with the same authority and verve that the Crescendos did. I played all kinds of music with the Crescendos driving the Martin-Logans and it was consistently musical across the board. It handled music that was heavily synthesized or that had prominent bass lines (such as Prince’s Musicology), as well as it handled chamber music and violin pieces (Mark O’Connor’s Appalachian Journey). The Crescendos drove the dynamic speakers I had on hand with ease. Any dynamic speakers, except for those with an esoterically designed load, it should have no problems with. For the really difficult loads, the Thor Consonance, at 150 watts per monoblock, should do the trick. In terms of how the Crescendo compares with what I have been listening to recently, I have to put them up there with the best that I have heard. Comparing it with the solid state TIDAL Impact, which cost’s almost $9K more, the Crescendo would appear to have slightly better dynamic performance and a slight nod in the midrange. While the Crescendo’s bass performance is very good, the Impact’s bass performance had better extension, drive and impact, pardon the pun. Neither amplifier would leave you feeling like you were missing out on anything bass-wise. The high frequency performance of both is excellent, with the Impact having a touch more information, detail and air, while the Crescendo was slightly more life like. They both are highly communicative and allow the listener the opportunity to connect with the performer for a more satisfying listening experience. The Crescendo throws a bigger stage but the Impact appeared to have slightly better focus on some music. There are a lot of similarities in the excellence of performance of these amplifiers, especially when you get into this level of performance. As in most cases, it comes down to a matter of your individual tastes. I would be elated to own either.

I have been blessed to be able to get a glimpse into what the more expensive class of amplifiers are capable of doing. It started with the TIDAL Impact ($26K) and continues with the Thor Crescendo ($17.5K). A year or so ago, I would have told you that performance at these price points do not get you a significant amount of improvement. After living with amplifiers with the level of performance of the Crescendo for a couple of months, I have a better appreciation for the effort that goes into producing these components and the level of musical enjoyment the listener is exposed to. The Thor Crescendos are not only electronics you can look at and admire as they sit in your listening room, but they sound wonderful as well.

You really owe it to yourself to find your local Thor dealer and give these amplifiers a serious listen. If there is no dealer near you, you need only contact Paul Marks at Thor’s headquarters located in Asgard, er uh I mean Fairfield, Connecticut. These amplifiers are most highly recommended.

Michael Wright

Output: 60 watts into 4/8 ohms (6 ohms nominal) ultra-linear and should handle loads from 2-16 ohms
Input sensitivity: 1.2 Volts RMS +/– 2% for 60 Watts into 4/8 ohms
Input impedance: 100K
Input Connectors: Single-ended, non-inverting RCA jack or pseudo-balanced, non-inverting 3 pin XLR connector 
Tube Compliment: 12AT7 (1), 12AU7 (1), 12BH7A (1), EL34 (4-Svetlana)
Frequency Response: 10Hz – 60KHz +/- .1db
Dimensions: 16” Round
Weight: 65 lbs.
Price: $17,490

Thor Audio
315 Palmar Drive
Fairfield, CT 06825
(203) 373-9264

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