[Amps] The Pin One Problem - Common Impedance Coupling

[Roger Parsons]

I think that a technically correct generic name for the 'Pin 1 Problem' would be unwanted 'Common Impedance Coupling', and a bit of a search shows that this term has been quite frequently used.

Of course, there are any number of ways in which equipment can be designed wrongly, and there are several other ways in which unwanted signals can be introduced. This is just one of them. 


It is clear that Muncie was the first, in 1995, to describe the problem as related to audio equipment using XLR connectors. However, knowledge of correct design goes back many decades before that in several related disciplines. 


I am sure there were numerous other companies, but to my knowledge, Leak manufactured properly engineered professional audio equipment in the 1940s.


73 Roger
VE3ZI