The above schematic is based on the Hybrid Graetz Bridge concept after a Fulvio Chiappetta paper, 
published by the Italian Magazine 'Costruire HiFi' a reference for the DIYers.
He tested and comparated this topology versus a pure tube vacuum state power supply design with 
a 300B output tube amplifier and there was no difference both while listening and measuring the 
output noise spectrum.

Per Lundahl, email: web_master/AT/lundahl/DOT/se

Lundahl Transformers AB
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Email: office/AT/lundahl/DOT/se