Power Supply Assembly Instruction.
Getting Started.
Assembly
Standalone Testing
Appendix 1 Connection to Truepath.
Appendix 2 Schematic.
Getting Started
This instruction assumes you are proficient at basic electronics practice including soldering, and troubleshooting.
You need basic electronics tools including a voltmeter.
If you get stuck, email audiophool@maedos.com .
Assembly
| Description | Designator | Footprint | LibRef | Quantity |
| Capacitor | C38, C39, C43, C49 | CAPRAD BULK 40MM/10MM | CAP2 | 4 |
| Capacitor | C41, C42 | RAD-0.2 | CAP1 | 2 |
| LED | D20, D21 | LED3mm | LED2 | 2 |
| Rectifier | D22, D23 | Bridge Rectifier D15XB60 | BRIDGE D15XB60 | 2 |
| Fuse | F1, F2 | Fuse20mm | Fuse 2 | 2 |
| Fuse holder | - | - | - | 2 |
| Header, 4-Pin | J12 | PhoenixV4 | Header 4 | 1 |
| Header, 3-Pin | J13 | PhoenixV3 | Header 3 | 1 |
| Resistor | R55, R56 | AXIAL-0.4 | Res2 | 2 |
Simply solder all parts to the PCB. Suggestions:
- solder the big capacitors last otherwise they may obstruct access to other parts.
- Fit each fuse to the two halves of the fuse holder before fitting to the PCB. This makes it easier to hold in place while soldering.
- Take care to fit the capacitors and LEDs in the right polarity.
- Consider the cabling from the power supply to the amplifier. You may prefer to reverse the output connector J13 with respect to the PCB overlay marking.
Standalone Testing
Take care when applying power to the power supply. If you short bulk capacitors when they are charged then they can burst.
- Connect a transformer (max 40VRMS with the 63V Rubycon capacitors).
- If there is no soft start on the input of the transformer then it is advisable to add either a 20 to 100 ohm resistor or a light bulb in each secondary winding that is connected to the power supply PCB. This will limit the inrush current to the capacitors and also limit current in case of a short on the PCB (eg from reversed capacitors).
- Switch on the power. Both LEDs shold come on.
- Check the voltages on the output of the power supply. They should be approximately +- Vin*1.41-1VDC where Vin is the Transformer secondary RMS voltage. Eg. a transformer with 35V secondaries should have output voltages of approximately 35*1.41-1 = 48. Note that some transformers have higher than rated secondary voltage when there is no load so it may be worthwhile to measure the actual secondary voltage.
- Optionally measure the current. Connect a known load such as 200 ohms (at least 2 watts) between VPP and GND outputs. The current that should flow is V/R. Eg (from previous example). 48V/200 Ohms = 240mA. Repeat for VNN to GND.
- When you switch off the power, the capacitors will gradually discharge through the LEDs.
Appenxix 1 Connection to Truepath.
Connect the Power Supply to the Truepath as shown Figure 3.
| Signal | Power Supply J13 Pin | Truepath J5 Pin |
|---|---|---|
| VPP | 1 | 4 |
| GND | 2 | 3 |
| VNN | 3 | 2 |
Figure 1 Truepath Wiring diagram
Carry on with Trueapth testing per the Truepath testing guideline. Here.
Appendix 2 Schematic
Figure 2 Power Supply Schematic
