Thanks for the technical info. Never really understood that. It was of course created by none other than Les Paul as this was originally the Gibson Les Paul Signature bass from the seventies and was a low impedance pickup. Jack Casady rediscovered them and the Epiphone made by Peerless was the result.
I’ve owned both Czech & Korean made and I’d say there was little to choose between them. The Korean ones are made in a factory set up by Stuart and as far as I know still only make Spectors (unless the recent sale of the company has brought about changes).
I’ve still got my 5 string Gibson but it is gathering dust. My return to 4 strings is linked to acquiring my NS NXT electric upright which is a 4 string model. Add to that the gift of a Spector Coda 4 and I am wondering why I ever need 5.