Shuguang KT-120 Vacuum Tube

Since owning the three models of the Ayon Audio Triton integrated amplifier (MKI, II, and III) since 2009 I’ve been on a quest to find the best KT-88/120 tube to power my integrated amplifier. I have had many KT-88 tubes makes and variants over the last six years in my system in my search of the best KT-88/KT-120 tube. These have included the Genelex Gold Loin Reissue KT-88, Shuguang Black Treasure KT-88 original (first release), Canada Fuller KT-88, Ayon Audio KT-88SX, and Tung-Sol KT-120. Over the last three years I’ve been checking the internet regularly and with Grant Fidelity, the North American distributor for Shuguang waiting for an internally polymer coated (Black Treasure) Shuguang KT-120 to be released.

For those that are unfamiliar, Shuguang was originally established back in 1965 as a factory supplying vacuum tubes to the Chinese military. Shuguang, translates in English to means “dawn”. Shuguang, located just north of Guangdong province (very southern tip of mainland China), is was one of the very few electronics manufacturer in China that been in existence over the last 50 years surviving the many ups and down in electronics. Shuguang is a conglomerate company that includes 5 plants, 14 subsidiaries, 3 joint-ventures, and 5 property holding companies with over 6,000 employees and currently is still state owned. To its credit, Shuguang has developed over 120 types of vacuums tubes and has manufactured over 70 million tubes over the last 50 years with their 300B tube production accounting for nearly 80 percent of the worldwide output. The Shuguang Black Treasure tube is noted for its internal glass being coated with a “black” carbon polymer compound which is said to focus the electrons in the anode. Another critical design feature touted by Shuguang is the implementation of “Super Alloy” for the internal cathode which helps maintain the tube’s electrical parameters for prolonged period of time. According to Shuguang, these design parameters along with over 60 others distinguish their vacuum tube from other vacuum tube manufacturers’ tubes.

My first experience with tube rolling KT-88 tubes was when I owned the MKI version of the Ayon Audio Triton back in 2010. The stock tubes supplied with that amplifier was the Genelex Gold Loin Reissues which I found to be lacking in weight, musicality and reliability. I was taken by how much better the first release of the Shuguang Black Treasure KT-88s as sourced by Grant Fidelity was in comparison. The gain in signal output for a given volume setting alone was a significant upgrade. I later learned that Ayon Audio was developing their own KT-88 and became interested in rolling that tube into my Triton MKI. Prior to evaluating the Ayon Audio KT-88SX, I obtained two quads of the Canada Fuller KT-88 (another Shuguang produced tube to specific specifications but not carbon compound coated) for my MKII Triton. I found the Canada Fuller to be an excellent sounding tube. Compared to a fully broken in Shuguang Black Treasure KT88-Z which was stock on the Triton MKII, the soundstage was not as forward, the high frequencies were clearer and more extended, the distortion was less as the volume was increased, and they were more natural sounding but lighter in the lower and mid bass frequencies. One to biggest drawbacks of the Canada Fuller KT-88 tube was their overall signal output which was much lower than the Shuguang Black Treasure KT88-Z tubes. I also had the Tung-Sol KT-120s in my system for a short time. I found the Tung-Sol KT-120s to be more dynamic with deeper bass but dry in the midrange and uninvolving in comparison to all other KT-88 tubes.

The Shuguang Treasure KT-120 tube, the subject of this review, has some distinguishing features that include the internal carbon polymer compound coating, gold plated pins, Super Alloy, and Teflon insulator connector housing. One should note the Shuguang Treasure KT-120 tube is definitely taller than any KT-88 tube may not fit within the confines of one’s tube gage. The KT-120 tube is also rated at a higher plate dissipation of 60 watts (42 watts is typical for a KT-88) which may not be compatible with your existing amplifier. This review will compare the performance of the Shuguang Treasure KT-120 against the Ayon Audio KT-88SX (as fabricated by Shuguang to Ayon Audio’s specifications). Also, please note that a matched octet of KT-120 tubes was evaluated in this review.

In case of tube amplifiers it is not possible to make immediate A/B comparisons of vacuum tubes. Tubes have to warm up to reach their optimum operating conditions and after each change waiting about half an hour for that is required. Evaluating tubes requires many trails over extended periods of time. Since owning the MKIII version of the AA Trition integrated for over one year, I’ve only used AA KT-88SX tubes; so I’m quite familiar with the character of their sound which has made it easy to evaluate the Shuguang Treasure KT-120 tubes. To speed the review process, I chose the two 24 bit /96k Hz hirez downloads, Fourplay (Warner Brothers Records) and Neighborhoods by Olu Dara (Atlantic Records) as referenced in a prior review which both possess their own unique styles of jazz and are noted as reference recordings.

I could tell immediately the Shuguang Treasure KT-120 tubes required extensive break-in time since the bass frequencies were light upon the initial installation and warm-up. One hundred hours of break-in on the Shuguang Treasure KT-120 tubes was required before I started doing some serious listening. You can tell rather quickly that the two tubes were cut from the same cloth based on their tonality which shared many similarities but the Shuguang Treasure KT-120 tubes bested the AA KT-88SX in many areas. With the Shuguang Treasure KT-120 tubes in my system, I heard greater sense of space, there was more air if it was present in the recording, and the soundstage was larger in all directions. The break-in time was shown to be necessary in the development of the extended bass frequencies which was better balanced to the mid and high frequencies following break-in as compared to the AA tube. Based on memory, the midrange magic that was absent on the Tung-Sol KT-120 tubes was in now there in spades on the Shuguang Treasure KT-120 tubes. Olu Dara’s and Cassandra Wilson’s vocals on the ninth cut vocals really sounded fleshed out through the Shuguang Treasure KT-120 tubes … I could live with this tube for a long time. On various cuts the Shuguang Treasure KT-120 tubes sounded more interconnected across the entire frequency spectrum. The Ayon Audio tubes seemed less controlled and transparent by comparison almost lacking in headroom and while the Shuguang Treasure KT-120 tubes were more illuminated in the midrange and high frequencies displaying a more live sound. I clearly preferred Shuguangs it to the Ayons.

Over the course of this review, some cable and system grounding changes were evaluated and based on the transparency of the Shuguang Treasure KT-120 tube, it was always easy to hear even the subtle differences each system change displayed. You know what I really like about this tube in this application? It’s the reliability. I’ve power cycled my Ayon Audio Triton MKIII many times over the course of this review and have never once had a tube failure but I have almost a dozen tube failures with the stock tube.

Conclusion

After hearing the Shuguang Treasure KT-120 tube I can declare my search for the best KT-88/120 tube is over. I have no desire to reinstall the Ayon Audio KT-88SX tubes if that tells you something. I wouldn’t hesitate to recommend these tubes and at the price of $349 a quad they’re a steal.

Mike Girardi