AMB Mini3 Portable Amp Detailed Review

[NwAvGuy]

I gave the AMB Mini3 (a DIY portable amp that's also available assembled) the full bench test treatment and it did respectably well in a few areas, but failed to meet many of its published specs--some by a wide margin. It's not very suitable for low impedance loads where it has relatively high distortion at most any output level.

A lot of its problems can be traced to using a virtual ground ("3 channel active ground" in AMB lingo). Such grounds work around having only a single battery in a portable amp, but in this case, it comes with significant side effects. I ended up writing a second article just about virtual grounds and 3 channel designs.

AMB Mini3 Review & Measurements

3 Channel Headphone Amps & Virtual Grounds

Questions and comments, as always, are welcome!