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.
“… they are amazingly lush and deep, but still with good detail and imaging….” Read
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