*** NEW - V1.2!! ***
This is it! The V1.2 Millett MAX Printed Circuit Board. TooleAudio has provided the ultimate refinement of the famous Millett Hybrid MAX headphone amplifier. Updated details and a Bill Of Materials may be found on the MOSFET-MAX website
The Millett MAX V1.2 board is a complete package all on one board: onboard power supply with 44uV ripple performance (same as the excellent MiniMAX PS), and space for an onboard BantamDAC or GrubDAC with relay input switching between the DAC and normal RCA inputs!!
Of course, the Millett MAX still includes a vacuum tube stage with an improved Constant Current Supply, a full-blown Diamond Buffer output stage (MOSFETs recommended) with on-board room for extruded heat sinks, and finally, a delay relay to protect your expensive headphones. The delay-relay has been updated on the V1.2 board with a 24V regulator, replacing the old Zener diode, a resistor and capcitor. This makes a much more reliable and simplified circuit. Testing has shown a significantly reduced voltage spike on turn-off, while turn-on is protected with an approx. 45 second delay from a cold start.
Only a 24VAC, 1000ma (1A) wall transformer is needed to operate a populated board.
Since the excellent MiniMAX is as good as it gets with BJT's, we recommend that you build this one with MOSFETs. We have successfully tested extended usage with 125ma bias - it's possible it will go more than that (note 1-1/2" heat sinks required for MOSFETs).
Board Dimensions: 6.3" wide x 6.2" (160mm wide x 157mm)
Board Construction: 2oz copper on an 0.062" (1.6mm) FR4 dielectric