Pi-Amp Rev. 6

Amplifier Power Supply


Pi-Amp Rev. 6 Amplifier Power Supply

Pi-Amp Rev 6. Amplifier Power Supply Schematic

Pi-Amp Rev. 6 Amplifier Power Supply Schematic

Download Pi-Amp Rev 6. Amplifier Power Supply Schematic.

Pi-Amp Rev 6. Amplifier Power Supply Bill of Material

Schematic Reference Description Quantity Manufacturer Stock Number USD ea. Total
T1 TRNS, 625VA, 40V, Center Tap 1 Avel Avel Y236853 67.00 67.00
BR1 RECTIFIER BRIDGE 200V 25A D-34A 1 Vishay DK 26MB20A-ND 6.35 6.35
CP1 CAP 12000UF 100V ELECT TUP SERIES 2 Panasonic DK P10041-ND 15.05 30.10
CP2 CAP FILM 0.1UF 400VDC AXIAL 2 Cornell Dubilier DK 338-3278-ND 1.85 3.70
AC1 AC Receptacle IEC 320-C14 1 Qualtek DK Q210-ND 0.78 0.78
PC1 Power Cable, NEMA 5-15P to IEC 320-C13 1 Qualtek DK Q125-ND 5.16 5.16
FH1 HOLDER FUSE 3AG .500"L 1POS 1 Keystone DK 3536K-ND 1.51 1.51
FH2 HOLDER FUSE 3AG 2.375"L 4POS 1 Keystone DK 3539K-ND 5.13 5.13
F1 FUSE 8A 250V T-LAG GLS MD 1 Cooper Bussmann DK 283-2755-ND 1.00 1.00
F2-F5 FUSE 5A 250V FAST AGC GLASS 4 Cooper Bussmann DK 283-2635-ND 0.70 2.80
R1 RES 3.9K OHM 2W 5% METAL OXIDE 2 Yageo DK 3.9KW-2-ND 0.25 0.50
S1 SWITCH TOGGLE SPST 15A 1 NKK DK 360-1896-ND 4.70 4.70
Total NA NA NA NA NA 128.73

Download Pi-Amp Rev 6. Amplifier Power Supply Bill of Material.


  1. The Reservoir Capacitors (CP1) are attached to a piece of bare PCB board. The Panasonic TUP style capacitor has four sturdy prongs that are bent over to secure the capacitor to the PCB. The Bleeder Resistors (R1) are soldered to the capacitor leads on the underside of the PCB board. The PCB board is attached to the chassis, directly below the HDD mounting bracket, with four 1/4" brasss standoffs. The large gap between the two capacitors will provide space for the hefty USB type B connector required to tie the face plate USB jack to the PC mainboard.

    Pi-Amp Rev. 6 Amplifier Power Supply 3

    Download Pi-Amp Rev 6. Reservoir Capacitor PCB Template.

  2. Power supply components are fitted to the rear panel, listed from top to bottom: Mains Fuse (F1), Bridge Rectifier (BR1) with Snubbing Capacitor (CP2), Amplifier Power Switch (S1), and AC Receptacle (AC1).

    Pi-Amp Rev. 6 Amplifier Power Supply 4
  3. The Four Position Fuse Buss (F2) is attached to the chassis base with #6 machine screws. The chassis ground lug is located to the left of F2. With the toroid transformer placed next to the chassis, the wiring is completed in accordance with the schematic above.

    Pi-Amp Rev. 6 Amplifier Power Supply 5
  4. The amplifier power switch is a high quality, heavy duty toggle switch. It is positioned at the lower left rear of the chassis to eliminate high voltage wiring to the face plate. My experience has been that the amplifier remains powered on most of time so it is not necessary to have the power switch located up front. The AC receptacle is mounted from the inside of chassis to facilitate removal without de-soldering. Inside mounting also provides better mechanical stability.

    Since I had the rear panel off I went ahead and installed the two RCA jacks and the four speaker wire binding posts.

    Pi-Amp Rev. 6 Amplifier Power Supply 6
  5. The transformer is attached to the mounting bracket using the supplied hardware. The piece of blue closed cell foam, between the transformer and chassis, protects the windings. The toroid transformer is typically mounted flat, but in this application space is a premium.

    Pi-Amp Rev. 6 Amplifier Power Supply 7
    Pi-Amp Rev. 6 Amplifier Power Supply 8
  6. One small adjustment was made with respect to the transformer mounting bolt. The hex head on the bolt supplied with the transformer protruded far enough to interfere with the PC sound card. The solution was to replace it with a low profile bolt (see images in apmlifier section of this log).

    Pi-Amp Rev. 6 Amplifier Power Supply 9
  7. A small bracket is used to provide additional stiffness to the rear panel. The mounting screw for this bracket will also hold the audio card riser support bracket (see PC section of this log).

    Pi-Amp Rev. 6 Amplifier Power Supply 10

Amplifier Power Supply Complete.