M³ Headphone Amplifier


This is a relatively high-end DIY headphone amp developed by AMB Laboratories for enthusiasts and hobbyists. The blank PCB is ordered from AMB, along with a few of the hard-to-find parts that are necessary, and you're on your own for everything else (resistors, caps, transistors, enclosure, etc). As a result, the cost of the amp is as low as it can possibly be, it just takes some time to get it all soldered together, tested, and running.

I'll be running this amp with the complimentary σ11 regulated power supply, and building them in parallel in matching Hammond enclosures.

I'll be updating this page as this build progresses.


M³ Information
σ11 Information


I've completed the BOM and placed my orders. The power supply I'm building is completely standard, nothing special here. The amp is pretty standard as well, except that I've swapped out the default AD8610AR op-amps in favor of the TI OPA627AP Burr-Brown op-amps that worked so well in my Xin amp.


Well USPS decided to lose the package from AMB that had the circuit boards and other parts. I then had to wait three weeks before filing a claim, another week for them to realize it was lost, and another few days for AMB to package up the parts and send them out again. So finally, 40 days after placing the initial order, the replacement package from AMB has arrived and I can begin construction!


Last night I was able to finish the σ11 in a few hours (minus the front mount LED) and get started on the M³ as well. With any luck I'll get the M³ to the point of testing tonight, and can beautify the enclosures in the coming days.


The σ11 and M³ are completely up and running and the enclosures are finished. It sounds great! It's very smooth and balanced, detailed, with loads of power and no noise to speak of.. I'll get some pictures up here in the next couple of days. It was a fun build, it came together quickly and everything worked on the first try. Drilling/mounting the connectors, knobs, LEDs, etc took the vast majority of the time, the actual circuit board assembly went very quickly.


Below are some pictures of the end result.