“These are old and fine 1950s vintage blackplates, quality on par with the blackplate RCA 12AX7 tubes, and are excellent, sweet sounding subs for the hard-to-find 12AX7. 3 mica spacers with extra side support rods, and the distinctive square getter all add up to vintage quality that will never be made again.” Read
“These are probably the best for Pink Floyd. I hate them for heavy metal though, it sounds muffled. The vocals and highs aren’t really as dynamic as with the Raytheon. Altogether, this is a nice tube for the money. It certainly beats up a lot of others I have experienced.” Read
“The RCA has a nice big and wet bass. It has a rich and creamy midrange which controls sibilants well. On the downside, brass lacks bite and dynamically, this tube sounds a little bit slow.” Read
The RCA 5751 Black Plates Triple Mica is one of the best tubes I’ve ever used, delivering fantastic results in both my McIntosh and Dared VP-300B setups. It offers a wonderful balance of clarity and warmth, performing so well that it sits just a hair’s breadth away from my top preference, the Telefunken 12AX7 long smooth plates, specifically in the V1 position of the McIntosh, where the difference in sound is only about 2-3%. I’ve tested two different physical versions of this tube, one with a supporting rod and one without, and found that from a sound quality perspective, they are exactly the same.
* Clarity: Exceptional transparency that reveals fine details in the recording.
* Warmth: Provides a rich, musical tonality that complements high-end vintage gear.
* Consistency: Sonic performance remains identical across different internal construction variations, such as the presence of supporting rods.
* Comparison: Competes directly with the legendary Telefunken smooth plates, offering nearly the same level of performance for a potentially better value.
Final Verdict: The RCA 5751 Black Plates Triple Mica is a highly recommended, top-tier vacuum tube that provides an elite listening experience with a perfect blend of detail and soul.