“A bit fuller, richer and a bit more vibrant than the RFTs, not clinical, but still good detail. A more traditional NOS sound.” Read
“if you have to use a 12AU7, then the cleartops are quite good. “ Read
Tube Maze
Guides and reviews of vacuum tubes and audio equipment
The RCA 12AU7 Clear Top is a highly regarded tube that delivers fantastic sonic performance, often rivaling the industry leaders in its group. In a Dared VP-300B amplifier, it holds its own against the 5751, a notable reference tube, and performs excellently when swapped for a 12AX7 in both phase inverter and preamp stages. While it offers tremendous value, it does carry a signature brightness that requires careful system matching, specifically, it can become excessive in setups featuring titanium or aluminum tweeters. For those building a collection, it is a top-tier candidate to “stack up” while it remains relatively accessible.
* Tonality: Exceptionally clear and detailed, though notably bright, it pairs best with warmer components to avoid high-frequency fatigue.
* Performance: Capable of competing with legendary brands like Telefunken, providing a vibrant and open sound.
* Versatility: Functions effectively in various roles, including preamp and phase inverter stages across different amplifier architectures.
* Value: Represents a significant “bang for the buck” in the current NOS market compared to more expensive European alternatives.
Final Verdict: The RCA 12AU7 Clear Top is a highly recommended value leader that brings high-end transparency and detail to a system, provided your speakers aren’t already leaning toward the bright side.
Tried in in Bottlehead Crack. This tube sounds quite nice compared to many other 12au7 tubes, but can’t compare to Tung-sol Black bottle. Issue here is high frequency. In my amp, it was just way over exaggerated, which leads to tiring after a bit. Even with Sennheiser 650 which has very sweet highs, it’s still very pronounced. It might sound good in the older gear, which sounds too warm to begin with.
I had these tubes in my preamp and wasn’t impressed. I mean they are clear and such, but sound stage was OK. Highs were sharp.
I received a matched quad of the RCA clear top (organ issue) and was very impressed at first. It’s a really solid sound with meaty and rich bass, and nice soaring highs. Right when I plugged them in the music jumped out of the speakers. It’s ironic because it has a classic american attitude – in your face.
A little fatiguing after a while and maybe a little bi-polar (mid-range seems to get left behind a bit). I know it’s a very “beloved” tube, but from my experience I’m not sure it quite competes with the big players in areas like refinement, beauty and magic…
RCA Clear Tops (Organ Issue, Side-Getter) – 4 Stars
Tweakers will never find a tube that they can live with. Boutique tubes may sound different but not better. I
have.many sitting in a drawer that have developed problems.. The clear tops stand the test of time. Best ever.