John Seaber started JDS Labs in 2007 with the cMoyBB headphone amp, which is based on an open-source design. Seaber revamped the cMoy's power supply and volume control, added a DC power jack, and a special bass boost switch. The tiny amp sold well and got the company off the ground. The cMoyBB is still being made, in an Altoids tin box, and currently sells for $60. Seaber is 26 and has an electrical engineering degree from Missouri S&T University.
The JDS Labs Objective2 (02) sells for $144, and it's equally adept with full-size and in-ear headphones. The sound is rich and warm, but still detailed, with no loss of resolution. Better yet, it's battery powered and highly portable, but still gutsy enough to sound great with hard-to-drive headphones like my Hifiman HE 400s and Sennheiser HD 580s. If the 02 retailed for $300 or $400, it would still be a terrific value. The 02 is just 4.25 inches by 1.2 inches by 3.8 inches and the all-metal amp weighs 11 ounces.
The 02 is an open-source design, developed by NwAvGuy (his real name is undisclosed), and it uses two rechargeable 9-volt NiMH batteries, good for 500-1,000 charges (the replacement set sells for $13).
I played some of my best headphones with the 02, including the Sennheiser HD 700, Audio Technica ATH M50, and Grado RS1 full Size headphones, and Ultimate Ears Personal Reference Monitors and UE 900 in-ear headphones, and the 02's sound and power really surprised me. The M50 can sound a little mellow and laid back plugged into my iPod Classic, and adding the 02 energized the M50's sound to a remarkable degree. Bass firmed up and resolution improved; the M50 sounded like a much better headphone. So it's not just that the 02 can play headphones louder than my iPod Classic, the 02 sounds better than the iPod at low and moderate volume.
I compared the 02 with my FiiO E17 headphone amp, and felt both amps are really good, but the 02 wins on clarity, dynamic punch, and bass precision. Voices also have more "body" and sound more natural over the 02. In that sense the 02 sounds almost like a vacuum tube amplifier, but without sacrificing bass articulation. The 02 brought a new appreciation of the P5's sound; it's a great little headphone.
The cMoyBB can't touch the 02's oomph and refinement, but it's a lot of fun. Switching over from the 02, I noted the cMoyBB's leaner tonal balance, but after a few minutes I came to admire the BB's verve. It rocked with the Black Keys like a champ, returning to the iPod's headphone jack throttles back the excitement while listening on my Monster Turbine Copper in-ear headphones. Switching on the cMoyBB's bass boost changed that perception in a hurry. It really pumps up the bass, without losing definition. Bass boosted the cMoyBB may be less "accurate," but I like it!
Of course, you could also hook up either JDS Labs amp to a computer's analog output, or add a USB digital to analog converter (DAC) between the computer and headphone amp for even better sound. These amps can make your headphones sound better than you've ever heard before, but it doesn't make sense to buy a JDS Labs amp if you don't already own a decent headphone. No amp can transform a so-so headphone into a great one.
Seaber ships more than 1,000 items each month. The amps are also available in kit form. JDS Labs sells assembled amps with a money-back guarantee, with a 15 percent restocking fee.