Big-bottle Glass That’s Built to Last
From classic British-style heads to iconic bass amps and beyond, Telefunken’s Black Diamond 6550-TK power tubes will make the most of your amp’s tone with their superb sonics and long-lasting lifespan. These top-quality tubes are built in partnership with JJ Electronic of Slovakia — one of the very few brands still building new tubes today, and certainly among the most revered. Moreover, all Telefunken Black Diamond tubes are subject to rigorous testing to ensure their quality, including cryogenic treatment and an extensive burn-in process. It all adds up to a premium bit of big-bottle glass that offers the utmost in power, durability, and performance.
Built to exacting Black Diamond standards
Produced in partnership with JJ Electronic of Slovakia, Telefunken’s Black Diamond vacuum tubes are engineered to deliver a rich, harmonic-dense sound and superior performance. From big-bottle power tubes to preamp tubes, every model within the series undergoes rigorous testing before it makes its way to Sweetwater, including cutting-edge cryogenic treatment and a thorough burn-in process. Top-quality tubes are crucial to make the most of your amplifier’s tone. Lock in a set of Telefunken’s Black Diamond tubes, and you can rest assured that your valve-powered head or combo will perform at its peak.

Telefunken 6550-TK Features:
- Premium 6550 power tubes, crafted in conjunction with JJ Electronic of Slovakia
- Rigorously tested to ensure peak performance, including cryogenic treatment and a lengthy burn-in process
- Ideal for upgrading a wide variety of amplifier types, from iconic British heads to Leslie speaker systems to iconic bass amplifiers