Reply To: Universal PreAmp grounding of signal circuits

[Dinx]

Trying to send you image of frequency plot I just took with Audio Spectrum Analyser app on my iPad. Cannot attach, but biggest spike is 301Hz, then 60 then 120. (From what I can tell. The 301 is constant both channels 6 inches away. This might help.
I just sent the attachment to your dad. This was with no music, volume down to minimum. Thanks again. Gilbert Lessard