XERXES - DIY Audio Projects
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I originally bought the WNA MkII as a completed amp in a case with an external plug-top power supply. Above is a picture of the PCB as supplied. with stock components.
The modified WNA board housed in a larger case with internal power supply. The three original LM1671 op-amps were replaced with OPA627s, the input and outpt capacitors were removed and some of the resistors were changed to bias the amp further into class A. Some heatsinks were added to the transistors to deal with the extra heat output from the biasing further into class A.
The power supply uses a small encapsulated toroid and a Welborne Labs PSREG power supply. I threw in a Shaffner 3 amp dual stage mains filter for good measure.
Another shot of the re-housed WNA.
The rear of the case showing the mains and input connectors and some ventilation holes to keep the PSU, which runs quite hot, cool.
The completed amp in a case.
The bottom of the case showing some ventilation holes. |
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