The M³ Stereo Headphone Amplifier

M³ Update (March 2005)

The project has been completed and boards are now available. Please visit the official M³ web site for further information.

Introduction

M³ is a high-end stereo headphone amplifier being developed as a community service project for DIY enthusiasts around the world. See this Head-fi forum thread for the announcement and further information about this amplifier.

Prototype Measurements Aug 25, 2004 by AMB

These measurements were taken on a two-channel prototype, done on a breadboard. These specifications are preliminary. We expect the performance to improve when the circuit is finalized in its three-channel configuration, with the proper power supply, printed circuit board and casing.

Measurement Notes

Measured Specifications Summary

Frequency Response +0dB, -3dB, ref. 1Vrms output at 1KHz:
0Hz - 1.3MHz
Slew Rate 10KHz square wave, at full output:
55V/µS
Total Harmonic Distortion 0.0011%, 1KHz (RMAA)
Note that loopback residual THD of the M-Audio Transit is 0.001% (RMAA)
Intermodulation Distortion 0.013%, 60Hz/7KHz 4:1 (RMAA)
Note that loopback residual IMD of the M-Audio Transit is 0.008% (RMAA)
S/N Ratio 87dBA (RMAA)

Total Harmonic Distortion Spectrum (RMAA)



Intermodulation Distortion Spectrum (RMAA)



Noise Spectrum (RMAA)



M³ Prototype Under Test




Team M³ is Morsel and AMB.