shivers@cmu-cs-h.ARPA (Olin Shivers) (01/22/85)
I noticed that some high-end amplifiers use toroidal transformers in their power supplies, instead of the usual rectangular kind. Anybody out there know why? -Olin
newton2@ucbtopaz.CC.Berkeley.ARPA (01/26/85)
Torroidal transformers, wound on gapless laminated cores, have the property that they confine their magnetic flux substantially within the core. This, plus their inherently sexy form-factor, makes it possible pack an amp into a small volume and/or to choose a package shape which better exploits the volume-to-front-panel-shape ideal. Until relatively recently torroids were quite expensive and hard to find in high-power versions (except for some reason in England); now they seem more common. Machines to wind torroids obviously must exploit mechanical principles brought to earth by a superior ET civilization-- like the sewing machine. I suppose I've been mispelling toroid in the above.. Doug Maisel
riner@dsd.UUCP (john riner) (01/31/85)
> I noticed that some high-end amplifiers use toroidal transformers in their > power supplies, instead of the usual rectangular kind. Anybody out there > know why? > -Olin Toroidal transformers for Olin' benefit and ant others interested are used for two primary reasons: 1. They are more efficient since the field in the core doesn't go around corners. 2. They emit less stray field for somewhat the same reason. Why havent they been used for ages you ask. Because they are more expensive to make. The windings must be wound on the core directly (ie. the spool of wire has to go through the middle of the core) which limits the size to fairly large cores and it takes special winding equipment, wheras for the rectangular type, the coils are wound on Bobbins en masse and the core is assembled into the bobbins. Also the availability of certain core materials and processes has only recently (last 5-10 years) become reasonable from a cost standpoint. -- John Riner UUCP: !fortune!dsd!riner AMPEX Corp Redwood City, CA.
wunder@wdl1.UUCP (02/02/85)
The toroidal transformers allow wonderfully small packages. My high school (back in 1974) bought a Crown D-60, a two-channel, 60 watt per channel rack-mounted amp that was 1 3/4 inches tall! Think about it. The size was pretty magical. The amp was real reliable, too. The toroid proabably shows up in high-end stuff becuase the hum stays inside the transformer. walter underwood formerly of North Central HS Stagecrew Indianapolis, IN