Howdy everybody—Omar here, your Audio Amigo. In this Showcase Ep.13 I’m taking a look at one of the most “audio should be fun” Bluetooth DAC/amps I’ve had on my desk: the Muse HiFi M6 Double. It’s a chunky $400 portable unit with dual vacuum tubes for amplification and a pair of vintage Nixie tubes up top for the volume display, plus an ESS9039 DAC and a Qualcomm QCC5125 Bluetooth chip with the codecs you actually want (including LDAC and aptX). I walk through the unboxing, accessories, build, and the menu system (gain, DAC filters, tube vs transistor mode, sleep timer, and the option to shut off the Nixies to save battery). The big takeaway is sound—and specifically the output impedance. I measured about 13.8 ohms on 3.5mm and 6.7 ohms on 4.4mm, and that can genuinely change how certain IEMs and headphones behave: some sets get more V-shaped, some get bass boosts, and some all-BA IEMs can get brighter/airier. Not everything changes (single-driver IEMs and planars were basically identical to my other sources), but if you’re the kind of person who likes impedance adapters or wants a source that can “season” your gear, the M6 Double is a blast. I also compare it briefly to the Cayin RU9—different niche, way lower output impedance—and wrap with who I think should (and shouldn’t) buy this thing.