Toronto AES Bulletin Meeting Preview Sept 1999

Toroidal Transformers

Presented by	Menno van der Veen
Date	Tuesday 14 Sept 1999
Time	7:30 pm
Place	Harris Institute for the Arts
Address	118 Sherbourne Street, Toronto, Ontario South of Queen and Sherbourne

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Menno van der Veen will be our guest speaker for the September 14th meeting. For many years Menno has been a reviewer for Dutch high end audio magazines. He is the owner of Ir. buro Vanderveen (audio consultation) and the chairman of the Dutch section of the AES. He will be happy to inform us in a very short introductionary about the activities of the Dutch AES section.

In close cooperation with the Toronto based Plitron Manufacturing Inc., Menno has developed a special line of toroidal output transformers for tube amplifiers. He discovered that toroidal transformers have some distinct advantages compared to standard EI-types, resulting for instance in a wider frequency range and less low frequency distortion. He has published two AES preprints (3887 and 4643) dealing with the theoretical side of his present designs. In the first part of his lecture, Menno will discuss some of his points of view on audio transformer design.

In the second part of his lecture, he proposes to discuss interwoven items. Based on theory development, calculations and measurements, Menno has tried to find answers on questions like: "how do cables (interlink and loudspeaker cable) influence the sound quality" and "consider the amplifier as a device interacting with cables, loudspeakers and sources: how do the specs of the amp influence the sound quality". Both questions are answered from the concept that the transfer function of each of the sound chain devices can be calculated as well as their mutual interaction. What we finally hear in a sound system is the multiplication of all those transfer functions resulting in the final frequency and time response, as noticed by our ears. By means of exemple calculations, Menno will show that "exciting" changes in the transfer function of a sound chain device might not be noticeble at all in the end, when listening.