Review on Enhance Your Vinyl Experience with the iFi Audio Zen Phono Preamp by Jason Chaplain

Ground connection checked, it's sealed. Loose metal inside the unit causes rattling. As much as it sounds, I'm bringing it back. I don't want a short game that can blow my $3,000 speakers and my ears. I think that's what you should expect for a sub-$1,000 device these days. {EDIT} The replacement has arrived and it has the exact same metallic rumble coming from inside the case! So maybe everyone has it, and I don't think it's a defect in any particular device. I keep it because I like the sound and the boomy filter. But it's very hard to recommend an electronic product that rattles inside the case! Free parts? Free wiring? Who knows. {EDIT #3} I recently heard directly from the designer of this device! Fortunately, the knock has no electrical connection! Something with control buttons and no function problem. The buttons work perfectly, there is no manufacturing defect and the sound quality is excellent - better than my three old phono stages - and I like the presence of a rumble filter. Now I can recommend this device as very good value for money. I believe you need to spend 5-10 times more to get better sound quality.