[Boatanchors] Constant-voltage audio transformers

[rbethman]

On 11/24/2012 3:54 PM, Dave Maples wrote:
> All: After reading the request for a transformer to couple a BC-221 meter to
> low-Z headphones, I thought it might be helpful to some folks to read some
> information about 70.7-volt audio transformers.  These devices are actually
> very handy for solving some of these kinds of problems.  They are also
> cheap, which is always attractive.
>
> Why are they called "70.7-volt transformers"?
The original intent of these transformers was to use a P.A. Audio 
System, such as the Military used to use.

The different taps were designed to match the impedance of "different 
speakers or horns.

Not everyone has actually had the experience of dealing with one of 
these old antiques.

Bob - N0DGN