Bienvenido!, el consejo de Pacyfier es una buena sugerencia, cds a tubos hay varios, aquí te dejo algunos links
[url="http://www.tnt-audio.com/sorgenti/jolida-jd100_e.html"]http://www.tnt-audio.com/sorgenti/jolida-jd100_e.html[/url]
[url="http://www.pacificvalve.us/VacuumTubeDacs.html"]http://www.pacificvalve.us/VacuumTubeDacs.html[/url]
[url="http://www.upscaleaudio.com/products/Ah%21-Njoe-Tjoeb-4000-with-SuperTubeClock%E2%84%A2.html"]http://www.upscaleaudio.com/products/Ah%21-Njoe-Tjoeb-4000-with-SuperTubeClock%E2%84%A2.html[/url]