RMI-FC100, a single stage audio power amplifier

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Finished the conversion with excellent results. Probably cheaper all up than using transformers. I wasn't game to try with the 8x10,000uF back end PS caps in place so I removed them - less startup stress on the SMPS. I used a 500W LLC PS from Aliexpress. It was nominal +/-36V as ordered, reduced to +/-34V by adding a 910K in parallel with R66 (back of main PCB). A CL60 mounted on a porcelain block was used to connect 0V to the chassis. If you order make sure you get one with a black heatsink which has two tapped M3 holes which allow fitting of an additional heatsink (well worth doing as it then runs just hot to touch with lid on). This SMPS also puts out +/-15v unregulated which powers the front panel pilot LED and a basic 7812/7912 regulator PCB for power to the Sparkfun THAT1206 balanced to single ended converters.

For the FE shunt PS applicable diodes were replaced by links to allow DC input. The 2200uF filter caps were removed as the caused hiccupping with the Meanwell PSs. 47uF caps were used in place. The meanwells are nominal 48V SMPS but are adjustable about +/- 10% such that the input voltage to the FE shunts can be optimally trimmed to minimise dissipation.

Parts used : LLC SMPS https://www.aliexpress.com/item/32846308063.html?spm=a2g0o.order_list.0.0.21ef18029i4zZq

THAT1206 : https://www.sparkfun.com/products/14002

Meanwell SMPS for FE shunt : https://www.x-on.com.au/mpn/meanwell/rs1548

Additional heatsink : https://www.jaycar.com.au/high-effi...574b7034beb32ae19b942e3d030431&sort=relevance

+/-12V regulator PCB : https://www.jaycar.com.au/universal-power-supply-regulator/p/KC5501

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