New Ripple Eater PSU ‘REP’

This is the new hifisonix Ripple Eater PSU aka ‘REP’. It’s designed for use with stereo class A amplifiers up to 30W RMS per channel, or stereo class AB amplifiers up to 100W per channel.

Click here to download the build doc

Click here to download the BOM

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This is how the REP must be used to achieve the peak -110dBr noise floor. Note carefully the following: –

1. There is only one point on the chassis where the incoming safety ground from the IEC mains receptacle and PSU secondary side 0V connect – there are no other connections to the chassis.
2. The speaker output return cable goes back to the amplifier module 0V and NOT directly back to the PSU 0V. Why? This ensures the smallest loop area for noise generation and pickup and results in dramatically lower noise floor.
3. The cables to from the REP to each amplifier modules are tightly bundled and cable tied every 2.5cm (1″)
4. The cables from the toroid to the REP are twisted tightly and cable tied
5. The mains connection from the IEC connector and any power switch are twisted tightly and cable tied
6. Use screened cable to make the connection from the input receptacles to the amplifier module as this guarantees the smallest loop area and therefore minimises noise pick-up.
7. If you are getting your transformer custom wound, include an interwinding screen and a GOSS band. A GOSS band can lower radiated noise from the transformer by 6-10dB inside an amplifier chassis.
8. By rotating the transformer through +-60 degrees, a null point can be found that will reduce noise by a further 6-10 dB.
9. Always mount the input connectors side by side and make sure they are insulated from the chassis metalwork. Bond the two signal grounds together and then tie the bonded signal grounds to the chassis with a 10-50 nF NP0/COG ceramic cap right next to the connectors. This makes the input [metal] source, the interconnecting cable screen and the amplifier metal chassis a single enclose as far as RF is concerned, reducing RFI interference.