Zoom H2 noise problem

[Colin McDonald]

Just in case this may be of interest or is of some use to anybody else:

I've had an original H2 since December 2008 and up to now it has done the job (mainly speech recording) without any problems, living up to my (fairly low) expectations of it and sometimes giving surprisingly good results.

Recently however, it was used to record a church sermon in my absence, and when I split the stereo recording into 2 mono tracks as usual, (it goes online as an edited mono MP3 to save space), I noticed that the front left mic channel had acquired a previously absent buzz. I would describe the noise as being similar to a ground loop noise (not actually so as the H2 was battery powered and stand alone). Fortunately I still had the right channel track which was usable if slightly "off mic" in quality, presumably because of the angle the H2 had been placed. A short extract of the original stereo file (16/44.1) is attached.

I then ran a longer test recording with the H2 in a quiet room. As well as the buzz which was by now considerably louder, periodic popping noises could be heard on the left mic channel but much less or not at all on the right. An extract of this test is also attached, edited to put two of the "pops" closer together (they were originally several minutes apart).

I thought it might be a loose connection to the left front microphone, so I took undid the 4 screws on the back, removed the sticky orientation pad at the top and separated the 2 halves of the H2 cover and had a look inside. Shoogling the F/L mic connector on the PCB seemed to affect the buzz, so I took the mic "plug" out and pushed it in and out a few times with needle nosed pliers, being careful not to come into contact with anything else. So far that seems to have worked, as a subsequent test indicates.

Anyway, rather than faff about trying to reduce the noise in post in future I thought it would be better to try and get rid of it at source. I can put up with the relatively lo-fi recordings of speech from the H2, but hums, sizzles and pops bring me out in spots. When I want random noises, I use a radiomic :-)

[Rick Reineke]

Without listening to the audio clips, I would surmise some oxidation on the (normaled) Ext. mic or line input. I would recommend spraying some contact cleaner on the connectors. Like most pro audio folks, I use CAIG's DeOxit..
OTOH, a solder joint could be acting up.

[Colin McDonald]

Thanks Rick - since these weren't being used at the time, I hadn't actually considered them, but I will "exercise" and spray these connectors anyway.