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Yet another transformer type

— By Paul McGowan —
Before we switch subjects from transformers to something else, and I don't yet know what, let's spend two more days looking at other uses for the things. We discussed how transformers work. Two coils of wires, one for the input, the other for the output, couple energy through magnetic fields. The ratio of the turns between the two coils determines their outcome. Typically higher input voltages from the AC wall socket are reduced by the fewer turns of the second coil. This type of arrangement is known as a step-down transformer. But transformers can also work in reverse, where the input coil has fewer turns than the output coil. This is called a step-up transformer. Step-up transformers are found less frequently, but can play an important role in high end audio. One of the most popular uses for a step-up transformer is to boost the low output another type of electromagnetic device, the moving coil cartridge. MC cartridges have a miniscule coil of wire attached to the end of their stylus. When wiggled in response to the grooves of a record, a tiny voltage is produced, one that must be amplifier about 30 times to match that of a moving magnet cartridge. A step-up transformer can be an excellent choice for the task. Here's a picture of one. st-80-se-front The best of the breed are made by the company Jensen, after its late founder, Dean Jensen. Though still bandwidth restricted, Jensen's have extremely low noise and can cover 10Hz to 100kHz, more than sufficient for vinyl records, themselves bandwidth limited.

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