Power Amplifier project by Nelson Brock
ACA MinMax
ACA MinMax
ACA MinMax
Description
The ACA MinMax combines Nelson Pass’ ACA Mini with the diyAudio Store's Amp Camp Amp chassis to get the most out of this design. Strategic part upgrades enable a 36V power supply and 850mA bias current per channel. This kit is for those who want a bit more power out of the Amp Camp series while keeping the original design philosophy of an easy to build, safe, and great sounding class A amplifier.
Can be operated in stereo, balanced mono, or parallel mono configurations.
Features:
- Larger heatsinks of the Amp Camp Amp chassis allow for higher bias current
- Left and right “mirrored” PCBs for simplified chassis wiring
- Power supply voltage increased to 36V
- Capacitors upgraded to 50V
- 2SK170 / 2SJ74 input JFETs and IRFP140 / 9140 MOSFETs sourced directly from Nelson Pass
- Larger TO-247 output transistors and alumina thermal pads help keep parts cool
- Multi-turn potentiometers for finer control when setting bias and offset voltage
- Optional gate resistors (100 ohm provided)
- PCBs support TO-247 and TO-220 footprints for diy-ers who want to experiment with MOSFET variations
Power Output:
Impedance | RMS Power, Stereo | RMS Power, Parallel Mono |
4 Ω | 25 Watts | 30 Watts |
8 Ω | 15 Watts | 16 Watts |
16 Ω | 8.4 Watts | 8.4 Watts |
Please be aware, the ACA chassis has markings on the back panel which do not correlate to this design. The panel can be installed normally and markings can be ignored or blacked out with a marker. Alternatively the panel can be flipped putting the markings on the inside, however two 1/8” (3.2mm) holes must be drilled to mount the XLR connector.