I have had in my posesion no less than 7 lampi,s. From the small level 4 to 3 B 7 and the new headac. No unit had any issues . But as I loaned my unit to a couple of freinds. One had hum in his home . Hum is a case by case basis I was able to eliminate it. With a power strip and a new water ground clamp in his home. Being a electrical engineer had its merits in audio . I did have A friend who had serious tube noises. But changing the tubes fixed it. Let's face it there is no perfection in any device but customer support and forums with many who own the product rules. Ps audio has great support and great forums too. They also have had there Share of issues and its completely PC boards . Same was with my audio Gd dac. They to had good support. What was not cool was my 40 K msb dac that just plugging in my usb while it was on and the computor was on too . Locked up my usb Input. Tech support advised it to be sent back to msb. I Was lucky to have an idea . I reloaded the usb update firmware and it worked . Not even msb new of this fix. And go find a forum for msb. I only know of two people with one. Not counting the analog ones . There is no doubt that our audio devices have issues playing well with some devices . But having people to post with and getting answers from those who have boldly gone before you matters the most to me.
Al
Al