Heart has built a name when it comes to tube stages for CD players. We have succesfully modified the Marantz CD4000, CD5000 and CD6000. Since Marantz doesn't make these fine players anymore, we have been forced to stop modifying them as well. However, for those who already own a CD4000, CD5000 or CD6000, these outstanding tube stage add-ons are still available! Take a look at our CD tube mod section for all the details. And be sure to check out the News & Press section for some raving reviews about the tube boards. Heart Audio is a small Dutch manufacturer of audio gear and related products. Our product range comprises hi-end tube amplifiers, MultiChannel tube amps, CD-players, turntables, tube phono stages, DIY amp kits and accessories like cables, record cleaners and mains filters. With our products and services, we invariably try to reach those audio enthousiasts who agree that quality is a good thing. The Heart company puts several brands out into the world. Take a moment to familiarize yourself with the above listing of brands, activities and services, and you'll find yourself browse these pages with ease, discovering an exciting micro-universe of great audio gear.