17 June, 2011

Overview: WAVAC

Overview: WAVAC Part I
Wavac MD-300B and PR-X2
Overview: 300B amps

As you may have known, I am a Wavac fan, but I have never directly written on the subject. Recently, my ever-expanding SET inner circle is moving so fast that I must catch up. But it is best to start from the beginning. There is so much going on, I just hope I have the time and means to do this brand justice.

History of Direct Heated Single-Ended Triode Amplifiers (DHT, SET)
Although the direct-heated triode was invented early in the twentieth century, it is a common misconception that it once saw wide usage. The limited power and inefficiency meant little commercial viability and its use as power tube vanished very soon after the development of push-pull technology. Connoisseurs would agree with me that it was a case of an inferior topology driving out a superior counterpart, just as the solid state almost drove tubes out of existence, or, if you would, just as digital technology pushed analogue reproduction to the brink. But the superior always survives, albeit residing in a minority.

If the comeback of the vacuum tube can be termed a miracle, then the revival of the direct-heated triode as amplification device borders on a second-coming. There is little doubt the Japanese played the most pivotal role in the revival, before Frenchman like Jean Hiraga etc. Read this Enjoy the Music article for a brief history of SET.

History of Wavac and Nobu Shishido
When it comes to Wavac, one must mention Nobu Shishido, one of the pioneers in SET design. Despite a devotional following in the West, including the late Dr. Gizmo, there is surprisingly little coherent information on the man on the internet. It would be easier to find a schematic of his (especially the Loftin-White 2A3, likely the most famous SET design ever, first published in 1970!) than even a picture of him. The man lives on in his design, as all great men do.

Shishido is an even more important figure than Kondo, and his relationship with Wavac can be glimpsed from the following passage (from Positive-Feedback, link):

WAVAC Audio Labs come into being in 1994 when Yasuo Yoshizawa, the executive director of the former Yoshiki Industry Co., stumbled upon the book "Production of Single Amplifier" written by the late Nobu Shisido. Mr. Yoshizawa was so taken by the read that he sought out Mr. Shisido at his home, and the two rapidly developed a friendship, one that blossomed into a project to develop and produce tube amplifiers.

Though the circuit was the brainchild of Mr. Shishido and the chassis was the result of the efforts of Mr. Yoshizawa, the company eventually grew to include a development staff which included Yuzuru Ito, a stage, sound effect, and recording engineer, Yasunori Matsuki and Masakuni Kudo. One of the earliest identified goals of the company was to create a large output tube amplifier to drive today's modern, more moderate to low-efficient loudspeakers easily, not just to recreate yet another good nostalgic tube amp.

In March of 1998, when Mr. Shishido abruptly passed away, Yuzuru Ito took up the reins of the company and followed his tradition, continuing to develop fine tube based products.

In October of 1999, Sigma Co., Ltd, the large Japanese industrial firm where Mr. Ito is a Vice President, took over the development, production, and sales sections of WAVAC Audio Lab from Yoshiki Industry Co., and the sale/joint venture provided additional funds for growth and expansion. However, by 2004, as soon as was practical for WAVAC to financially stand on its own, Mr. Ito was able to make that a reality, which it is to this day.

Today, Wavac's products, especially in the use of Interstage tranformers, are faithful to Shishido's originals. It should be said that the amplifier product line comprise triodes that Shishido had worked on, including the 805 and mammoth 833.

There is even less on the internet on Yuzuru Ito, Shishido's successor and currently head of Wavac (an interview in Chinese,專訪Wavac社長伊藤讓). I find it re-assuring that the man is a recording engineer and has broad experience in stage amplification. On this note, no less a recording engineer than Steve Hoffman has great words on Wavac. I wonder if there's another example of DHT being used in a recording studio? Is there better evidence of the triode's ability to faithfully reproduce the event?

My Wavac Experience
Unlike Audio Note and Kondo, Wavac has not had much of a presence in Hong Kong. Although I had followed the brand for a long time, aside from the occasional sighting, there was not much opportunity to hear it for oneself.

As chance would have it, a year or two back, just before I was due to return to the USA, I sighted a set of Wavac in a second-hand shop. Although the shop had no big horns, the sound was still quite good with conventional speakers. I quickly decided on the amp, but had great hesitation on the odd-looking preamp, which took me longer to decide on. Here, thanks to my friend whlee for handling the stuff for me. When I returned from NYC I began my Wavac journey.

MD-300B Official Info
MD-300B Soundstage review
MD-300B Enjoythemusic review
MD-300B dagogo review

I'd refer you to the above links for details about this amplifier. Wavac makes several levels of amps. The MD-300B is really entry level. Although it is well built and well-finished, the chassis is really quite light. Underneath, however, the most important transformers are substantial, though stacked. The higher level 300B amps have much classier chassis but are largely the same amp underneath, but built with higher-grade components (like larger transformers).

Like all Wavac amps, there is no coupling capacitor. The 12AT7 is directly coupled to the 6Y6, which drives the 300B through an interstage transformer. I don't have the circuit diagram, but at the very bottom of this article there is a schematic for the very similar 811 amp (now discontinued, but more on that in Part II).

As you know, I have quite a few SET amps. For 300B, I still have a Sun Audio (using VT-25 kit, hence the transformer is a deliberately mis-matched 5k impedance, with resultant smaller power output), the Elekit 8300 and the ICL Model 1-300B. Don't forget, I have had many 300B amps before, including Audio Note Kit One, Audion Silver Night and AES SE-1 and have heard even more (I refer you to my ancient big 300B report).

Note the interstage transformers

I would not mince words, the MD-300B is the best 300B SE amp that I have heard, bar none. It is hard to speak of its virtues, as it is such a many-splendoured thing. Its awesome performance is all-encompassing. It is easily the quietest amp (as one review had noticed, quieter than transistor) and the most potent of all the 300B amps I have tried, a testament to superiority of the Wavac interstage transformer.

A word on interstage transformer
Long time readers know I do not necessarily like interstage transformers. I have heard just too many DIY samples that sound deficient in one way or another, even when supposedly good trannies are used. It is not just a question of restricted bandwidth (a problem that plagues lesser ones), as much about implementation. Of course, when it is done right, as in old WE amps, it can sound superior.

The MD-300B is also easily the most transparent and full bandwidth 300B amp I have heard, another testament to the superiority of their interstage. It is also a fast amp, with excellent portrayal of the leading edge and transients. Tonally, although very neutral, it is in no way aseptic, just a faithful reproducer of music.

The effect of tube-rolling is easily heard. The supplied 6Y6 is a late straight glass GE that sounds the most revealing and driven. I marginally prefer the much earlier ST RCA black glass, which gives a little more body at the expense of a little detail. I use Shuguang 300B.

In view of the sonic achievement, any reservations are reduced to quibbles. The chassis can be stronger and the volume pots can be noisy occasionally (turning it a little makes the problem disappear). And yes, the amp runs quite hot.

click on pics to enlarge

PR-X2 Preamplifier
PR-X2 Official info
Some remarks on Audiogon

Despite my amassing quite a few Japanese SET amps, I had previously never thought of buying their preamps (aside from dreaming about Kondo). One reason is I already have too many super-preamps (EAR 912, ARC SP-10, SP11, Melos 222, MFA Magus, to name a few). The other reason is these classics all have superior phono sections. During the years I spent with Sun Audio, I never tried out their preamp.

But this time, I bit the bullet and decided to get the Wavac PR-X2, and it proved an important decision. There is virtually no information on the internet about the Wavac PR-X2; and the official info lacked specs. The website does not even have a pic of the separate power supply, which is a long and heavy gold box with the same wood trim in front. As with the flagship PR-T1, it is a solid state supply. Inside, there are 3 substantial transformers, no wonder the weight! The main chassis is lightweight. Inside, each channel has its own circuit board and utilizes 2x 12AU7. The tube shields are awkward to remove due to the narrow gap. Curiously, this entry model sports remote control facilities, which adjust the main volume and select channels. The remote, however, does not control the two separate gain knobs, a useful feature (some say indispensable; found on classic preamps such as ARC and MFA) that enables you to tailor to source input level (useful when using high-output sources like my Audio Note DAC-2; I no longer have Wadia) and provides the function of balance. Curiously, there are 3 inputs marked "digital" and another 3 marked "analogue", the latter having lower input level (500mV as compared to 2V).

It took me quite some time to get used to its looks, and its quirks. The design is of extremely high gain (I wonder if this is SRPP). In my system, the gain knobs don't go beyond 12 o'clock, and the volume knob spends most of its time between 7 and 9 o'clock. Although this is really more gain than I'd like, sonically it was a revelation from the word go. Despite the high gain, it is quite refined and highly detailed, and with its gain control partners even high output sources with ease . Most importantly, it has wonderful rhythm and pace, imparting a lively presence to the proceedings, which after all is what SET is all about. In this respect, it trounces one of my reference, the EAR 912, which I had mostly used till then. The preamp drives everything I have equally well. Since I acquired this, my interest in the preamps of Japanese SET manufacturers have grown in leaps and bound. The best indication of love and bondage is the fact that I have even begun to like (but not adore) its looks!

You'd think such a clean preamp would not necessarily be the best match for the same company's clean 300B amp. Wrong. It is a synergistic match, as one has a right to expect, the combo delivering the highest level of detail I have heard from SET in my home, yet never at risk of lapsing into over-etched and anti-septic terrain. Two events shall illustrate the synergy.

1. One day my friend icefox (who has slowly evolved into my taskmaster and my motivator) came by and we compared the full set of Wavac against the full set of Verdier (reported here). It is his opinion that the JCV imparts a richer and more soulful character 幸福指數高點, while the Wavac tends to be etched in more details and perhaps more alert. For myself, I prefer the Wavac combo for its higher level of lucidity (but as a firm believer of polygamy and non-absolutism, I'd like to own both). Now this is followed by an even more seminal event...

2. One day Danz came by to audition. Remember him, a fellow Canterbury user (reported here)? My link is woefully out-of-date, as Danz had moved fast. At the time he came, he was using a full set of Verdier, Control B + 2A3. He was interested to hear the Wavac 300B amp because he just felt he needed a little more power than 2A3 could provide. He was dumbfounded by the performance of the MD-300B, which was first connected to another preamp, and we tried the Control B too. But true epiphany came when I installed the PR-X2. A puzzled look came over his face, and it took a while before he spoke. Friends, don't under-estimate a moment's import. In one moment, earths can shake, dynasties can change, we can live or die, and I could go on...

Like me, Danz preferred the Wavac combo over the Verdier combo. He astutely pointed out then that he thought the preamp even more of an achievement than the amp. Like me, he had never thought of buying another preamp before stepping foot in my house, but that moment changed him. A short while later Danz made a momentous decision. He decided to acquire a full set of Wavac, but at a higher level.

Gentlemen, in the next installment I shall detail on Danz' flagship preamp PR-T1 and the MD-805, only second to the 833 in hierachy.

More pics


  1. Hello doc,

    Would you care to comment on the differences between Wavac and Kondo? As a user of Wavac (Ec300b) I am very curious.

    Kondo is often referred to as a "holy grail" by many people online, but very little people comment about Wavac, as they are far less known.
    I assume this has a lot to do with the fact of the ongaku price/set condition/bass+power when it was first released and most reviewers where still using low or medium efficiency speakers (?).

    Could you please spare a few minutes with us and explain us the differences in soul between them?
    I can't personally imagine a better 300b amp than the ec300b, but I haven't listened to the kegons or ongaku as you have.

    Many thanks and gongratulations for the blog!

  2. I am not sure how to answer this. With the highest end, description is difficult. Even the best writers in the trade magazines (they are very good writers, though one may or may not trust what they write) have a hard time. Usually they would point to things being more real, palpable etc. But when you talk about difference, that is even more difficult, which is why you don't find much comparison in this blog, not to mention A/B "shootouts".

    It is easier to delineate the difference in preference of the 2 companies: 1) Unlike Kondo, Wavac eschews capacitors for interstage transformers; 2) Kondo uses silver whereas Wavac does not. These are important sonic consequences.

    The use of Inter-stage transformers is definitely a plus with complex music and higher volume playback. In this, Wavac is the perfect example. Watt for watt I think Wavac has the better driving ability. Wavac's aim has always been for wider compatibility with different speakers, whereas Kondo definitely is only for higher efficiency speakers. The downside (for me, a horn user) is that sometimes too many trannies result in too forceful/brute a sound, which is how I would characterize the PRT-1 and MD-805.

    On the other hand, the use of silver, including caps, in Kondo gives it a sheen and sinuous quality that is more "ethereal" (though it can easily become too bright in lesser hands) that can be rather addictive with high efficiency speakers. This quality eludes some Wavac products.

    You sound familiar, do I know you?

    1. Hi Doc,

      I live in northern Spain. We don´t know each other, I haven´t had the pleasure yet.
      I travel almost every 1 or 2 years to NYC , so I will try to ping you next time in order to give you some nice spanish wine :)
      (you are based in HongKong and NYC, right ?)

      My impression about Interstage Transformers has allways been very similar to yours. I allways found the sound to improve in easily cuantifyable aspects of music reproduction (ie dynamics), but I allways found them to sacrifice a bit of the poetical tapestry that some capacitor coupled amplifiers are able to weave.

      That was until, based on a recommendation, I arranged an audition of the Wavac Ec300b power amplifier. This audition completely knocked 2 misconceptions I had, both about ITs and the 300b valve. Together with my loudspeakers (AN-E Spe Signature), the amplifier is incredibly natural, and I talk about natural in the best possible way: the tone is natural, no ss grain and no valve sheen or exagerated tone, natural as in live. Dynamics are natural, no artificial fireworks or slowish sound. Nuance is excellent, very natural. Inflections are clearly portrayed, again in a very natural manner. And most importantly, my foot taps big time: I have already found myself standing up and dancing in the living room quite a few times. Such is the adrenalin rush I often get while listening to my favourite tracks through the Ec300B. Its a raw emotional rollrcoaster that I am trully enjoying. It seems to be only limited by the quality and character of the source used . Forceful is certainly not a word I would use to describe how it weaves music in the context of my system.

      I have only listened to the M7 KSL out of the Kondo range in a couple of systems at Scalford 2013, so it is literally impossible for me to draw any valid conclusions. The systems where not bad by any means (they where very good and very enjoyable in fact), but they were still "hifi" sounding for my taste.

      I am still very curious about the Kondo amps, so I will try to arrange an audition. I am not sure however, of the best place to audition the amps, as I have the impression that a huge horn system would be the ideal setup to better understand their potential.

      Maybe a trip to Hong Kong or Japan ?
      Unfortunately, this will have to wait ....

      Many thanks again Doc

      Best regards,


    2. Hello b_online:

      I completely agree with you and your Spanish Soul!

      Spain is wonderful! Maybe I should not say that, as the only place I have been to is Barcelona. But what a place! Great food and warm people!

      Please do not misunderstand me. The Wavac amps are FANTASTIC. the MD-805 I have no use for, as it has too much power. But I do have doubts about their flagship preamp PRT-1. I am sure the EC-300B is great, as a friend of mine sold his MD-805 after he got the EC-300B.

      We have similar views. Can you send me an email so you can visit me in NYC or I in Spain? My email is doctorjohn@myself.com

      BTW, I like Spanish wine, jambon, tapas, etc....

  3. Hi Doctorjohn,

    Good news regarding your comment "I wonder if there's another example of DHT being used in a recording studio? Is there better evidence of the triode's ability to faithfully reproduce the event?", please check Dr Ed Pong's (from Toronto, Canada) link: http://ultraanaloguerecordings.com/wpsite/home/ for more details and listen to his music samples. Additional info on Ed from Dagogo's interview: http://dagogo.com/interview-with-dr-edward-pong-of-ultraanalogue-recordings.

    You and your readers will be surprised at how well his recordings are.

    Best regards,

    1. Thank you for the surprise arrival of the Ultraanalogue Recordings CD of Beethoven/Rachmaninov Cello Sonatas. Excellent sound; enjoying it now!

  4. Hi Doctor John, being an happy owner of the Wavac EC-300B, I'd like you to share your experience regarding tube rolling on this amp. I have tried the Elrog -300B and they play simply stunning on the Wavac. What is your experience about 6L6GC and WE 435a tube rolling; have you ever tried the Nec 6rr21 to replace the WE435a? ANy thought or suggestion about 6l6GC? Your insights and experience will be hghly appreciated. Thx Ugo

    1. This comment has been removed by the author.

    2. Hi Ugo, if you see this message, please contact me by email (see right sidebar). b_online is keen to get in contact with you.

  5. Hi Ugo, as mentioned in another article, it is my friend Karma who has the EC-300B, not I (mine is the MD-300B). So, I don't have tube rolling experience on this amp. I am not sure if Wavac specifies that 6L6GC has to be used (stock tubes use modern tubes, which only have high rating GC and equivalents). If any 6L6 would do (likely), I myself would try out the ST shaped 6L6Gs or GAs. WE350B is too expensive but certainly can be substituted. For WE435A, I'd think WE is the best.

  6. Hello Ugo,

    I was thinking about ordering a pair of Elrog 300bs myself. Could you let me know how they are performing with your Wavac and how you feel they compare to other tubes you have tried so far?

    Also, could you please send me an email (Doctorjohn can provide my @ to you) ?
    I'd like to be able to keep in touch, so we can share our findings on the Wavac.

    Many thanks and best regards,

  7. Hello Ugo ,

    I was thinking of purchasing a pair of Elrog 300b valves myself :)
    I would appreciate it if you could further comment on your experience with them in the EC-300B.
    What other valves have you tried before the Elrogs in the EC-300B ?

    I would appreciate it if you could provide me with your contact details, so we can exchange our findings with the EC-300B in the future (Doctorjohn has my contact email address).

    Many thanks and best regards,

  8. AnonymousMay 28, 2015

    Hi DoctorJohn,
    Recently I bought a used MD300B and has since paired it with a pair of WE755a speakers with 4 ohms impedance.
    From the info that I have gathered, the MD300B speaker output is on 8 ohms tap. I am now toying the idea if I should change the 8 ohms tap to 4 ohms to get better sounding or just leave it as it is if the change improvement is not significant.
    Would be happy to hear your opinion. Thanks in advance.


    1. First, the MD300B should have an 4 ohm (and 16 ohm) tap (as the MD-811 does from the circuit diagram).

      The sonic difference is likely audible but small, especially since the small WE755A full-range does not have much bass output. However, it is a worthwhile pursuit since your WE is priceless and one should squeeze every bit of performance out of it, no? Opening the chassis and re-solder should not be that difficult. Good luck!

    2. AnonymousMay 29, 2015

      Hi Doctorjohn, thanks for your prompt response.
      Just yesterday evening I managed to ply open the chassis and top casing. I saw the output transformer but there is no output taps with any marking. However each transformer has 4 cables from the secondary windings coded with different colors. The arrangement of the cables start from Red (left most)--> White-->Green-->Grey (right most).
      Here is the cables connection details:
      1. Red cable from output tranformer wired to -ve speaker terminal. There is another red cable from -ve terminal wired to center main PCB board ( i guess this is GND cable. Just my guess..)
      2. White cable from output transformer is held floating with cable lug at the terminated end nicely wrapped with heat string insulator tube. Is this 4 ohms tap ???
      3. Green cable from output transformer wired to +ve speaker terminal. I guess this is 8 ohms tap.
      4.Grey cable from output transformer wired to main board. I assume this is 16 ohms tap but have no idea why it is being wired in this manner.
      Just want to seek 2nd opnion whether the White cable is indeed meant for 4 ohms connection. Again looking forward to your expertise advise.


    3. This is really strange. Your assumptions and logical and I have no idea why the the grey cable is also connected to the circuit board. Maybe I shall open my MD-811 in due course to see what is going on.

      One possibility is the 16 ohm tap is used for feedback?