Hello! I just got this beatiful razor-mirror. Can´t find ifo on what R/E switch inside is doing. Do I need the build in amp to work the 6+?. Is it wise to install the KB4OEL mike-matcher to match HI-LO imp? I´m sure that a lot of You work modern T.T. gear with this classic microphone. Thank´s for adwise! Tommy /SM0PCA