One thought on “Sylvania JHS 5814 Black Plates Triple Mica”

1. Finding a set of Sylvania JHS 5814 Black Plates with Top Third Mica felt like uncovering hidden treasure. After testing the more common gray plate versions, I spent quite a while hunting for these on the market, but they are extra rare and seldom appear for a reasonable price. Physically, these are triple mica tubes with a unique construction; the getter sits atop a third mica elevated about 5-6mm above the second, whereas the gray plate version has them sandwiched much closer together.

   In terms of sonic performance, the experience is impressive but specific. The bass is beautifully extended and remains under tight control, while the sound-stage is absolutely awesome, providing a massive sense of space. However, the midrange is exceptionally warm—perhaps bordering on “too much” for some listeners. The high frequencies lack a bit of fine detail and extension. When I paired them with RCA 12AU7 clear tops, the balance shifted perfectly, adding the necessary transparency to the existing warmth.

   Final Verdict: These are fantastic, rare tubes that offer a lush, expansive sound, but they are best suited for systems that aren’t already overly warm, as the softened high-end might lack the bite needed for a perfectly neutral presentation.

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