I’m excited to announce that Ray Tubes is partnering with the Croatian company Limestone to bring our vacuum tubes to their inaugural tube amplifier.
Limestone was founded by Krešimir Meštrić, a successful entrepreneur whose previous company was acquired by a German conglomerate. That acquisition freed him up to do what he was always meant to do—stamp his mark on the hi-fi industry with exquisitely crafted tube amps. Not content with his own engineering background, he’s surrounded himself with a team brimming with tube audio experience, and the result is Limestone’s flagship product: the PP1 tube amp.
Krešimir chose the name of his company to honor his father, a master craftsman who worked with traditional methods for shaping limestone. When it comes to age-old craftsmanship, there’s no cutting corners. The same philosophy drove the development of the PP1. It was built through a tireless process of analytical and technical rigor. Many tube amps can produce great sound quality—few can do it with the consistency that Limestone demands of its product.
I’m tremendously proud that Limestone chose to partner with Ray Tubes. We take quality control and testing very seriously. It’s what makes our 1-year warranty possible. In that sense, Krešimir is a kindred spirit. He put our tubes through a series of rigorous tests before choosing them as the baseline tubes for the PP1. It’s been an honor helping bring the PP1 to life.
The PP1 will be available with our SELECT 6SN7 and SELECT KT88 tubes as standard. In the meantime, our RESERVE 6SN7 and RESERVE KT88 will be available as upgrade options. This is the first partnership we’re announcing in 2025. There’s many more to come. Stay tuned.
If you have any questions or comments, feel free to reach out at nelson@raytubes.com. I’m always happy to hear your thoughts.
Till next time,
Nelson Wu
CEO, Ray Tubes
