(18 votes, average: 3.67 out of 5)
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Sylvania JHS 12au7 Black Plates
(18 votes, average: 3.67 out of 5)Loading... (18 votes, average: 3.67 out of 5)Loading...2 thoughts on “Sylvania JHS 12au7 Black Plates”
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I recently received a batch of tubes, and one stood out as a fascinating anomaly: the Sylvania JHS 12au7 with a square-getter from the 1950s. It is quite a curiosity, as the JHS military designation is rarely seen alongside a standard 12au7 label. Given my affinity for the “liquid” sound of the JHS and Gold Brand lines, I had high expectations, but I was completely unprepared for the sheer performance of this tube.
The sonic profile is nothing short of fantastic. It masterfully blends the fluid liquidity of a Sylvania JHS 5814 with the authoritative darkness and raw power of Westinghouse 12au7 Carbon Black Plates. To truly test its mettle, I performed a side-by-side tube roll against legendary Mullard Long Plates and Box Plates. To my surprise, I found myself preferring the Sylvania.
In terms of articulation, this tube behaves very similarly to the Sylvania JHS 5751 Black Plates (3-mica version). It is exceptionally lush, highly detailed, and remarkably articulate. When compared directly to other high-end variants like the Sylvania JHS 5814 and JHS 6189, the JHS 12au7 consistently came out on top, offering a deeper and more immersive soundstage.
Perhaps the most shocking aspect is the value; at roughly $7 per tube, it is an absolute steal in the world of vintage glass. I was so impressed that I immediately purchased every remaining unit I could find on eBay. This is an incredible find—a true “hidden gem” for anyone seeking a sophisticated, detailed, and lush audio experience.
Final Verdict: A top-tier vintage performer that outshines legendary competitors with its lush, liquid, and articulate signature—all at an unbeatable price point.
Interesting tube. I was coming fresh off the EH stock tubes. Honestly at first I didn’t like these. I missed the grip and definition when listening to my Lounge and Electronic music.
Then a couple of things happened. I was sitting about 20 feet away at my dining room table listening to a song I’d heard 100 times before and the female singer’s voice projected right onto a wall about 7 feet in front of the speakers – i thought WOW!
I still didn’t love the tubes because they were missing that definition and edge that I became accustomed to. Then I puton a John Lee Hooker blues mix and went to get take out food. When I came back home there was a “performance” playing in my living room – that was my second “wow”. The drums, the dark eerie vocals…the whole scene was in my living room. I started to really appreciate these tubes. They’re so easy to listen to, very pleasing on the ears, and give a good dose or “aura” and “tube magic”. And they are lush and liquid – characteristics that I’m REALLY starting to appreciate. Then I received some Tunsgrams and Teslas from Nick….
Sylvania JHS 12AU7 Black Plates – 4 Stars