Some people claim that discrete diodes are superior over integrated bridge rectifiers, but I haven't investigated this yet. Diodes can be either mounted to a small heat sink or to the metal chassis.Īnother option would be integrated full bridge rectifiers, but I find those parts a bit inconvenient to design in. Suitable components start at 1€ each up to 2€ each. This is explained later on.įor low to medium power amplifiers I would use diodes in TO-220 chassis and for higher power TO-247 chassis seems more adequate. Different diodes have different turn-off characteristic, but the resonance between diode capacitance and transformer secondary winding is in inherent problem and the best way to deal with it is to add snubbers. Diode turn off causes substantial noise emission. The FFPF30UP20STU diodes have exceptionally low forward voltage drop even at high currents and this helps to lower power loss. Foremost important is forward voltage drop across the diodes. My preference for the rectifiers are soft recovery diodes. The downside of this arrangement is higher component count and power loss.īasically any diode should work well as a simple rectifier. Bifilar winding of the secondaries would also mostly eliminate the problem. Core saturation is an issue with toroidal transformers only. The idea behind is that there is no 100% matching between the two secondary windings and in case only a single bridge rectifier is used, any DC imbalance may saturate the core and this may cause noise emission from the transformer. Since both Nelson Pass and Bob Cordell agree that the dual bridge rectifier arrangement has advantages over the single bridge, this is what I prefer. However, for highly powerful applications, this arrangement has slight advantages, discussed controversially. The rectifier arrangement shown in the example schematic is a bit unusual as one of the bridge rectifiers appears to be superfluous. The output offers many terminals in order to connect either multiple modules or to accept segregated ground and supply connections from the amplifier modules. Transformer secondary windings can be connected in parallel or serial. The transformer terminals accept a lot of different configurations, providing clean point to point wiring, avoiding any messy loose wires around. They can be swapped for some other kind of connectors instead, like 6.3x0.8mm Faston connectors (although I don't like them).Īdding some more terminals adds versatility to both the input and the output. The cage clamp terminals I prefer are from Wago 236 series and come in 5 mm pitch. They are easy to operate, provide good contact, accept any kind of wire end, are DIY friendly and reliable as long as the spring does not fatigue or break. Also, a screw may become loose or even lost and rioting inside the enclosure. I don't like screw terminals because I've observed that torque applied to the screw may damage the solder joints quite often.
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