Low level audio transformers are normally wound on mu-metal cores, although some specalised types are wound on ferrite. High level audio transformers are all wound on grain orientated silicon stell. This is usually in the form of the scrapless E-I lamination, but can also be in wide-window E-I and'C' core.
Lamination sizes are, where possible, industry standard and mostly imperial to enable multiple sourcing, although special sizes and formats are available to order, particularly in metric sizes.
Bobbins are in a variety of forms, most usually in the standard slotted cheek form but also in various printed circuit board mounting forms, depending on the size. Mounting brackets vary depending on the size of the stack, the smaller types using the two hole mount wrapover bracket and the larger types using the four hole mount dual universal window bracket.
Individual data sheets are available for each transformer type listed in this guide. These sheets have a photo and mechanical drawing, response, THD and phase plot, specification panels and an oscilloscope photo of the response to a 2kHz square wave at a level just below maxium rated output or input.
While the transformers listed here will satisfy most requirements we will be pleased to discuss the design and manufacture of a transformer to meet your special requirements.