Once you’re all plugged in, you can enjoy up to 25 hours of playtime when used as an amplifier only, or 12 hours as a DAC/amp. Should you need to modify the presentation, use the two-step gain adjustment to throw more low end into the mix. Instead of overpowering the midrange or wonking out the bass to oblivion, the adjustment adds depth and quality without a lick of distortion, giving you the holy grail of bass boosters. As compatibility differs between manufacturers and models, check this list before buying.