MRT 300B New

MRT 300B-GC – Rare Graphite Plate 300B Vacuum Tubes

This is a very rare matched pair of MRT 300B-GC direct-heated triode vacuum tubes featuring a special graphite plate construction with internal brass/copper-alloy electrode structure, designed to produce a rich, full-bodied and highly musical presentation.

I have been listening to 300B amplifiers and experimenting with 300B tubes for decades. Over the years, I have personally listened to more than twenty different types and generations of 300B tubes, including several vintages of the legendary Western Electric 300B, as well as most of the better-known modern Europe’s ,Japanese and Chinese-made 300B tubes.

In my personal system and listening experience, the MRT 300B-GC is one of the fullest, richest and most musical 300B tubes I have ever heard.

Its most impressive quality is the density and body of the sound. Vocals have exceptional weight, warmth and natural presence, with a beautifully saturated midrange that makes singers sound unusually lifelike and emotionally engaging. Compared with many other 300B tubes, the MRT does not sound lean or lightweight.

This characteristic is especially noticeable with classical music and brass instruments. Trumpets, trombones and French horns have real body, scale and harmonic richness instead of sounding thin, sharp or overly bright. The lower midrange is substantial, while the overall presentation remains smooth and very musical.

Even compared with Western Electric 300B tubes, which I respect highly, I personally find the MRT to have a thicker tonal balance, greater vocal body and a more romantic musical character. Some Western Electric versions can sound slightly lighter or leaner in comparison, particularly on large-scale classical recordings and brass passages.

The pair comes with the original factory test charts, showing that each tube was individually tested by MRT.

In addition, I have personally tested both tubes again on my TV-7 tube tester, and they both show strong, high readings.

For the experienced 300B enthusiast who values rich tone, strong musicality, beautiful vocals and a full-bodied presentation, this unusual MRT 300B-GC is a very special pair and increasingly difficult to find.