HK THE TUBE WORLD MONTHLY on Feb. 2016 Editor Notice: PSVANE WR50


      RCA 250 triode amplifying tube (or UX-250 & 50) from United States has been awarded as one of the most fair-sounded amplifying tubes rare to be seen since it came out in 1920s. From my personal listening experience, RCA 250 features so subtle and charming sound that even greater than 300B of Western Electronics, yet has been rare to be found especially the well-conditioned 250 in the antique market after 80 years of market changes. Amplifying tube fanciers know the good reputation of 250, yet have no idea about how fair its sound really is. Recently PSVANE of our country has introduced WR50, the triode amplifying tube re-created according to the structure of 250, can be compete with 212-the tube king, with its so strong and beautiful sound, a fact ensured through my putting it into 250 audio going through the listening test. The two tubes are equal in the depth of their emotions, yet have some difference, that is, WR50 has a relative fine output, a bright tone and a strong sense of “amazement”, whereas PSVANE WR50 gives me an astonishing feeling with its extraordinary fair sound. It wound be reckless waste if the contemporary audio manufactures do not select it as the post-amplifying tubes!  

Actually, RCA 250 has gained a legendary good reputation among tube fanciers over the past half of the century. As one of the two largest tubes in USA, RCA never gave way to Western Electrics with its exquisite design and perfect sound quality. Till now, the design of RCA has still been adopted by many tube manufacturers, among which the most reputed are 2A3, 6SN7, 6L6 etc. However, there are different futures for the development of different famous tubes. Though a delicate design, it easily has the problem of adapterization due to its not enough stable tube shield which is easy to tilt with a slight crash of tube’s body, influencing directing to its sound performance (a case similar to that of famous 205D of Western Electronics). And the main cause of its astonishing fair sound may be its structure with valve in every part. However, the concept of FAIR SOUND IS EVERYTHING doesn’t accord to the volume production demanded by many Hi Fi audio manufacturers with Practicable Ones as their principles, so that 250 has been rare to be adopted by manufacturers despite its good reputation. In the past one decade, 250 capable of opening sound were those DIY made by senior fanciers. Currently, 250 audios that can be purchased in the market only from two stores, P&C of Japan and HK WELLPAK, where audios are manufactured limitedly and with payment first. 250 audio of P&C can be a work with volume production in the prospective of its structure and relatively cheap selling price. 250 audio of WELLPAK (ML-6S as its model) can truly be the one percent delicate work with black sanders as its appearance and with dual C transformers, all of these have been designed by the professional designer Chen Shengxiao on his own. The first 250 audio, actually, has been designed for me (more details in AUDIO FANCIERS OCT. 2015), and it is one of the most fair-sounded triode audios. After I finished my listening test report, it has been broadcasting in my house, now since the come out of WR50, its sound performance and wonderful design can be fully be tested in the masterpiece made by Chen.

250 Audio of WELLPAK has adopted the push-pull design, with four amplifying tubes used by two post degree single tracks, among which the RCA 250 is the counter one I have found for many years on the Internet. Because now the perfect conditioned 250 antique tube is rare and is easy to get destroyed, I choose two pairs of RCA250 that is selected among 20 antique tubes over the past years with many efforts and time. The outcome of WR50 of PSVANE gives me an unexplainable sense of astonishment, turning out to be shock if I find the sound performance is not good as RCA and be a surprise if its sound is better than RCA. Therefore, in the following days, most land of China may see more unparallel and fair sounded 250.

Because PSVANE only has sent me two WR50, so I decided to test their sound quality by means of single track. I put two WR50s both on the WELLPAK to replace the RCA250, meaning, one track sending the sound of 250 and the other of WR50. During the listening test I chose the post-degree 120C purchased from WERSTRN Electronics since it has independent potentiometer in both right and left tracks, thus only a twist of the two potentiometers to conduct AB contrast and get result very quickly when listening to the source of single tracks. At the beginning I used different FM broadcast to open the sound, and when I listened to the familiar voice spoken by the host, I found the sound from both two tracks almost at the same and was hard to find their difference. I should say the midrange performance of WR50 is almost equal to that of RCA250 with listening to only humans’ voice. In view of this, I sense I must listen to music of high level so that could make clear of the difference of these two tubes.   

This time I used Open Reel videodisc, LP gramophone record, CD respectively to conduct the formal sound contrast test. As I expected, in sending the sound of top record, these two triodes had some slight difference, although the sound base had 95 percent of similarity with the tone, emotion, motion, and power, RCA 250 is more appealing featuring the tenderness and gentleness, and WR50 was the winner of perfect Hi Fi effect with sound more clear in high and low frequency, especially of extraordinary extension in high frequency, transcendent and pure in female voice and high frequency musical instrument, and of good analyzing ability in low frequency, more clear in male voice and more obvious power grasp of cello. The points I want to add is, these differences are slight. Because of the Reference audio--TAD 2404 I listened to was of extremely high analyzing ability, enabling me to hear very clearly. The case would not be the same if use another kind of loudspeaker.

    After successive days of listening test, I have found some bigger difference in these two tubes, that is, the adapterization effect, stronger and more sensitive in RCA 250, for instance, when you touched the enclosure of the audio body unexpectedly, it would immediately send back the echoes, which was invisible in WR50 with its quiet sound background and with no any echoes. From this, I believe it is due to the improvement of the shield of 250 adopted by PSVANE and completely erased the adapterization problem, and gained a higher fidelity at the same time.

     At last, I’d like to mention the output power of 250-- the triode with capillary force, with 10 watt in push-pull output, which is stronger and powerful enough in driving the actually mastered TAD 2404. And the push-pull output power of PSVANE WR50 has reached the peak of perfection equal in competing with both the tone and power of the famous 300B, that is, as a triode amplifying tube, WR50 has a complete sound performance and an astonishingly impassioned infection.

      HI FI vacuum tubes of our country has currently ranked top in the world, and WR50 is another great symbol. The high-qualified tubes like it are sure to come out successively. And fanciers wait and see the good news.