Advantages of using 50/60 Hz toroidal transformersSuperior audio performance and highest operational safety
Increasingly, power amplifiers for global deployment get equipped again with 50Hz/60Hz mains transformers instead of switched mode power supplies.
The biggest advantage for power amplifiers comprising switch mode power supplies is less weight. But in many applications – very often in fixed installations – weight does not matter so much. In contrast however lies the advantage of 50/60 Hz toroidal transformers: additionally to their well-known audio performance and high quality by design, toroidal transformers of high quality offer maximum protection against disturbances within the power supply grid; switch mode power supplies need to compensate for this lack by adding expensive and very complex protection circuitry.
Toroidal transformers from Dynacord are optimized to protect subsequent amp electronics from transient overload. These transient voltage peaks, which typically last 1-5 ms, not only occur in countries with commonly known poor power supply grid, but also increasingly in countries with a stable power supply grid. A very critical special case is the operation of power electronics on island power grids (e.g. power generator usage), in particular where inductive loads are driven. The design of the transformer itself efficiently dampens short-term transient overload at the primary side of the toroid transformer – and prevents them from making it to the secondary side of the transformer.
In addition, a toroidal transformer offers effective protection in longer overload situations: the transformer switches to saturation mode and usually blows the mains fuse without harming the electronics. After elimination of the overload and reactivation of main’s fuse, the amplifier can be put into operation again.
This protection against interferences from public grid is achieved with little effort. A switch mode power supply unit with similar safety requirements has to be equipped with significantly more complex protection circuitry, which are only justified in the high performance/price segment.
Fig. Close-up view of a toroidal transformer in an L Series power amplifier.