July 2002

  
Surfin' The Audio Waves With
Wavelength Audio's Cardinal X-1 Monoblock Amplifiers
Review By Steven R. Rochlin

  It is no secret that Gordon Rankin of Wavelength Audio garnishes respect of vacuum tube aficionados worldwide. From Japan to England, from Australia to Canada... The critical eyes of the DIY community also covet Rankin's amplification designs. While being outspoken at times, Gordon Rankin has earned the respect of "those in the know," and there is good reason for this. Wavelength Audio employs some of the highest quality parts with top-notch engineering. When you have loudspeakers that are 103dB/W/m sensitive, an amplifier needs to be dead quiet. Not 80dB signal-to-noise ratio, not 86dB either as those pesky buzzes, clicks and humming can easily be heard through such highly sensitivity hornspeakers. Add to that the sheer microscope-like ability of such a system to hear every detail -- both good and bad -- you need top-flight equipment.

Many years ago before the United States and much of the world was enlightened in single-ended tube amplifier i had the fortune to acquire the prestigious Audio Note Ongaku stereo integrated amplifier. This nearly $90,000 integrated amplifier resided with me for quite a few years. It is basically an ultra-tweaky virtually 100% silver wired (including output transformers) design employing a single VT4C/211 output tube. As time passed i decided to get yet another single-ended tube amplifier... this time one that would use a single 300B in the output stage. Enter the Wavelength Audio Cardinal monoblock amplifiers circa 1994.

Wrapped in elegant dark Walnut finish, the simplicity of the design intrigued me. While the Ongaku used no less than ten tubes, the Cardinal needed only six (three per channel). As i was using good sensitivity loudspeakers such as my then fave KEF 104/2 (92dB/W/m) or Audio Note's own AN-J/SP silver wired offering (93dB/W/m). Back then there were few choices, though good ol' Klipsch and some Altecs were obviously options. While many loudspeakers have come and gone within my humble abode, i am proud to say that both the KEF and Audio Note are still here singing sweet sounds from time to time. And speaking of time, it marches on...

Grab Your X-1 Board, Dude
Months ago i felt it was time for some system updates. While my main rig had been improved upon since 1994 with new wire (Kimber and Nirvana), loudspeakers (Avantgarde Audio Duos), pre-amplifier (cj Premiere 17LS)... the Wavelength Audio Cardinal was like a lone adult surrounded by "new comers". After hearing many great comments concerning the updates that have been made to the Cardinal, it was decided to send my units back to their maker for complete updates to X-1 status. While i was extremely happy with the Cardinals, there are times when in faith you feel an upgrade will improve things. After all, change may neither be good nor bad, it just is. My main fear was that the magic enjoyed for many years might be destroyed through "upgrading". Throwing caution to the wind in came FedEx to take my precious babies away. This is comparable to when i sent in my fave custom made skim board for refinishing... Would it improve the ride or destroy all those years of being "as one" with it. Fortunately for me, both the skim board and the amplifier update were beneficial.

Paddling Out For Better (Audio) Waves
The details of Wavelength Audio's Cardinal monoblock evolution to X-1 status come directly from an e-mail received by the owner of the company, Gordon Rankin. He writes "The Cardinal amplifier was first designed in late 1988. The first unofficial version was a 5693 Pentode driving a 300B using the 5AR4 rectifier. The first one went out to an avid customer who pirated the design and two of his friends called and asked about buying the proprietary parts I used, chassis, wood etc. I could not believe what I was hearing.

I quickly looked at what I had and what this pre-production amplifier was sounding like and thought it needed some more top end. I designed an augmented SRPP 6SL7 circuit that had less gain, but better drive, less noise and much better overall sound and it was easier to build. I had put several variables into my copy of Groilers Encyclopedia one of which was three. The reference for the cardinal number came up and so it was named.

The only change from 1988 to 2001 was the XS model in 1995 that featured a proprietary output transformer and the change from HOLCO to Shinko resistors. A customer who was interested in the Triton but wanted to resolve a weak point in that technology asked me what I could come up with. I told Steve Guttenberg that I had an idea for a new amplifier that may become the new Triton or something else.

I built Steve Guttenberg's amplifier on a Cardinal XS chassis was the WE437A input tube used in the original Triton and still used in the Napoleon. The Circuit was the WE437A plated loaded cap coupled to the 300B in self bias mode. Something new though... I used a grid choke instead of a resistor for the 300B. See in the Triton, which uses interstage the coupling between the driver and the 300B, is very tight. But, the scale of the music is diminished, I think also because of the interstage transformer. What the Grid Choke does is this; AC wise this 1500H choke looks like a 188.5Kohm resistor at 20Hz. The DC resistance is just over 3,500 ohms. When the 300B goes into clipping it starts to draw DC current through the grid which re-biases the tube and cuts off the signal Since the DCr of the choke is very low the voltage applied across it is very low making the clipping region much larger which results in a 20% increase in power, without the lose of scale.

The power supply was made with Black Gate WKZ filter caps and the venerable 5AR4/GZ34 tube rectifier. The results where very nice but the WE437A is very expensive and hard to come by. I decided to make the new amplifier using the 6C45PI instead, it is almost the same as the WE437A, who knows the KGB may have stolen the plans to the WE437A and the Russian engineers felt that a standard 9-pin socket was cheaper than the expensive Noval-type custom Western Electric socket. Since I made the original idea on the Cardinal platform and this stayed with the Cardinal number of tubes 3, I decided to declare this the new Cardinal X1, because in my book this is the best circuit for 300B. Other nice things where also added such as Yamamoto Teflon sockets with solid silver pins for the 300B and a new more modern layout and chassis."

So there you have it from the (proverbial) horse's mouth. All this reads well and good, though the proof is in the pudding... or the sound. Of course in my home there is always room for Jell-O too.

The new units arrived and my ever-eager hands went to work unboxing them. Upon first inspection was the new rear plate that featured more sturdy female RCA jacks and two new Cardas loudspeaker binding posts (all three pieces are gold-plated). The top of the unit had the same Magnequest transformers for power and output, though the Yamamoto Teflon sockets with solid silver pins appear more substantial and of higher quality then the previous parts. While a GZ34/CV1377/5AR4 for rectification and 300B output tubes were used, gone was the 6SL7 in favor of the 6C45PI tube.

Surf (Sound) City Here We Come
After a few hundred hours of settling in time for both the newly updated Cardinal X-1 and the Sophia Mesh Plate 300B, it was time to go back to my old fave JJ Electronic 300B (to keep the same basic setup before upgrading the monoblocks). The difference was a mix of subtle advances with a god dose of overall improvements. When your music reproduction system reaches a certain plateau, small improvements are hard to come by at times. With the original Cardinal being so great, the X-1 version was up against some stiff competition! Of course no one wants to spend $2,500 for upgrades and get nothing in return, or worse, declining sound quality. There was no disappointment on my side of the loudspeakers.

Those of you who remember my rave review of the Silbatone C-102 battery powered pre-amplifier will remember my immense praise for it's ability to "flow endlessly... not a hint of anything other than silky smoothness yet with plenty of meticulous intelligibility". This aptly describes the improvements from the older Cardinal to the new X-1 status. This is analogous (pun intended) from the digital sampling of 16-bit/44.1kHz CD to vinyl replay. This is not to say that the original Cardinal lack flow and seamless cohesiveness. Far from it! it is to say that whatever type of "beat frequency" that is heard with some equipment was now completely gone. In its place was a smooth, flowing like a stream musical bliss! What saddens me is that it took the Audio Note Ongaku, to some extent, and the Silbatone, to a larger extent, for me to truly realize the problems with many other products in a signal chain. Those who have gone from solid-state amplification to a proper single-ended tubes system may be realizing this type of benefit. The notes below are mainly using the Sophia mesh plate 300B as it seemed to add a touch more high frequency smoothness while bass was more defined. During moments of weakness, the Western Electric 300B was inserted for romantic interludes. Ah, the joys and ease of tube swapping. (Try to do that you sand-based amplification lovers!)

The overall frequency response seemed to be the same, yet there was a slight bit of added clarity. This is especially true in the frequency extremes. Imaging and soundscape ability was the same as it is always great to hear stereo music truly surround you. With great recordings, musical instruments are easily capable of appearing far outside the loudspeaker plane. Furthermore, there is great front depth and, at times, sounds from behind the listener! Yes, you read that correctly, from behind the listening position. How can this be? Without going into vast details, it mainly has to do with phase and timing factors as the sound arrives to your eardrums. Of course what really matters is the music...

Taking out my prized 1970's Direct Master Series 45 rpm direct to disc vinyl Beethoven Piano Sonata No. 23 in F Minor, Op. 57 Appassionata by Ikuyo Kamiya (pianist) on a Bösendorfer Imperial (RCA RDCE 4), there was some slightly improves speed and clarity. The real improvement came with the way notes hung in the air and subtle intricate string interactions and harmonics off the piano and its sounding board. Furthermore, the way notes seamlessly flowed gave the feeling of improved musicianship! While i have always felt this recording and performer are in the uppermost echelon of captured musical performances, the small improvements brought about a deeper understanding into the music and its presentation.

The monophonic reissue of Miles Davis' Young Man With A Horn [Classic Records/Blue Note LP 5013, reviewed here] reminded me how little we have truly progressed in musicianship and recording technology. Ok, so this is mono and not stereo, or surround sound, yet if you can not get one channel right, who the hell would want five more channels like it!?! SACD, DVD-Audio... What really matters is finding truly talented musicians and capturing their performances in the best possible way. Alas, we music lovers/audiophile truly have too few newly released packages to choose from. A few hundred is not enough! This is one of the main reasons why vinyl will be around for a long, long time.

Young Man With A Horn is a must-have for vinyl junkies. Not just for sound quality, which is there in spades, but in the ability for us to experience what truly talented musicians are capable of doing. The Cardinal X-1 brought forth this talent with added vigor. The sweet sounds filled my room to enchant my soul. Make no mistake about it, it is love at first listen! Of course no review by yours truly is complete without some Pink Floyd and/or Roger Waters....

On my vinyl copy of Pink Floyd The Division Bell [Columbia C64200] the opening piano notes with synthetic hall ambience were the single most graceful i have ever heard. When my mood is just right, as it was at this moment, it almost gives me the same feeling as being, said with tongue in cheek, high. Yes, you read that correctly. While this feeling was also achieved with the Audio Note Ongaku, once it was gone so was the feeling this recording was capable or producing. This is not to say the Wavelength Audio Cardinal X-1 is better or worse than the Audio Note Ongaku. Simply put, it produces a different, yet still extremely enjoyable experience. While i have heard this recording in other system, only my very own has had the ability to truly bring about euphoria. Why? i have asked myself that questions more time that i care to admit. As a grateful recovering alcoholic/drug addict, there are times to simply take things on faith. This is one of those moments.

Music recorded in "Q-Sound" such as Roger Waters Amused To Death on vinyl [Columbia 468761 0] were, as always, completely encompassing with their well synthesized 360^o soundscape. Kraftwerk's "The Mix" on CD [Elektra 9 60869-2] occupied more three-dimensional space from in front of the loudspeakers to behind them. On the first tack "Robots", the frequency sweeps upward also came from slightly back of the loudspeaker plane to in front of them more than usual. The same can be said for "Pocket Calculator" where the synthesized piano notes climbed upward. It was the unnatural ambience that floated with more ease into my listening room. Furthermore, the phase shifting found in the electronic drumming on "Trans Europe Express" was more evident and more easily perceivable (and more three dimensional). All in all a musical feast for the ears!

As The Sun Sets Below The Ocean...
To say i was impressed with the upgrade from regular Cardinal to X-1 standard would be an understatement. For those who have never have the opportunity to experience either amplifier, the X-1 is now "standard" form and should bring many years of musical bliss. The use of a single 6C45PI as drive tube, Black Gate WKZ filter capacitors, tube sockets and other changes has made a relatively small, yet overall more coherent package. it is these small improvements in top-echelon products that make for one amazing end result. To say i highly recommend the Cardinal X-1 would be an understatement! Another one of Enjoy the Music.com's reviewers, Ian White, went gaga over the Wavelength Audio Duetto stereo amplifier in May of 2001. In fact i found the Cardinal X-1 more enjoyable than either version of the Mercury monoblocks i reviewed for Ultimate Audio magazine nearly two years ago. Of course in the end what really matters is that you...

Enjoy the Music,

Steven R. Rochlin

Specifications
Tubes: 6C45PI input/driver, 5AR4 rectifier, and 300B output
Connectors: Heavy-duty gold-plated female RCA jack,
   Cardas five-way gold-plated loudspeaker binding posts, detachable IEC power cord
Input Impedance: 47 kOhms
Output: 4 or 8 Ohm switchable
Power Output: 12.5 watts
Bandwidth: 5Hz to 35kHz (-3dB at one watt output)
Finishes: User choice of solid cherry, curly maple or walnut. Custom wood finishes available
Dimensions: 8" x 12" x 14" (HxWxD)
Weight: 38 lbs. each monoblock
Price: $7,500 (or $2,500 upgrade from older Cardinal)

Company Information
Wavelength Audio 
3703 Petoskey Avenue
Cincinnati, OH 45227

Phone/Fax: (513) 271-4186
Website: www.WavelengthAudio.com