Wim, I don’t know if your Marantz accepts external USB power. If it does you could buy a high capacity powerbank (say, 20000mAh or more), connecting it with a USB cable, and that would probably solve both problems: autonomy and noise.
all the best, Magnus Robb > On 20 Sep 2018, at 00:13:39, Wim van Dam <wim.van....@gmail.com> wrote: > > [I'm not sure if this newsgroup is still alive, but here goes.] > > This week I finally installed my OldBird 21c microphone and I'm having some > noise issues. In my setting I use a Marantz solid state recorder for my > recordings. When I power this recorder with its standard AA batteries, things > are fine but it does not allow me to record for more than a few hours. When I > use AC power for the recorder instead, a lot of noise shows up at 1500Hz, > 1620Hz, 1740Hz, 1860Hz, etc. Likely this has to do with the fact that the > recorder and the OB21c microphone use the same AC outlet. > > What is the best solution to this problem? > > Thanks > Wim van Dam > Solvang, CA, USA > -- > NFC-L List Info: > Welcome and Basics <http://www.northeastbirding.com/NFC_WELCOME> > Rules and Information <http://www.northeastbirding.com/NFC_RULES> > Subscribe, Configuration and Leave > <http://www.northeastbirding.com/NFC-L_SubscribeConfigurationLeave.htm> > Archives: > The Mail Archive <http://firstname.lastname@example.org/maillist.html> > Surfbirds <http://www.surfbirds.com/birdingmail/Group/NFC-L> > Birding.ABA.Org <http://birding.aba.org/maillist/NFC> > Please submit your observations to eBird <http://ebird.org/content/ebird/>! > -- -- NFC-L List Info: Welcome and Basics � http://www.northeastbirding.com/NFC_WELCOME Rules and Information � http://www.northeastbirding.com/NFC_RULES Subscribe, Configuration and Leave � http://www.northeastbirding.com/NFC-L_SubscribeConfigurationLeave.htm Archives: The Mail Archive � http://email@example.com/maillist.html Surfbirds � http://www.surfbirds.com/birdingmail/Group/NFC-L Birding.ABA.Org � http://birding.aba.org/maillist/NFC Please submit your observations to eBird! ��http://ebird.org/content/ebird/ --