https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/ Guitar Noise Discussion Board en-US Wed, 03 Jun 2026 22:14:42 +0000 wpForo 60 https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55217 Sun, 25 Jan 2004 22:26:02 +0000
If its an apparent 60 Hz. hum, look for poor grounding of the power supply components, You don't want any ground loops nohow. If it buzzes (60 Hz but lots of harmonics) then its probably some RF interference coming through the antenna or nearby fluorescent lights, etc. Poor power supply filtering. Capacitor installation wiring errors are classic, like when one negative leg of a paired filter cap does not go to ground.

Your AC/DC transformer, can produce electrical waveforms that are multiples of the normal 60 Hertz sine wave associated with the 120-volt AC. These multiple waves, called harmonics, are actually superimposed over the original sine wave. The original, fundamental sine wave combined with any of the overlaying harmonics will result in a non-sinusoidal wave form of an entirely different shape.

This new waveform then, has the ability to create a mechanical resonance within the transformer section. Overheating of the transformer, additionally, can lead to increased levels of harmonic distortion which usually manifests itself as an audible hum via the mechanical resonance.

Unfortunately, there's not much you can do to eliminate this without really testing it or maybe adding special notch filters to block out or eliminate the offending frequencies.

Joe]]> In The Studio forrok_star https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55217 https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55216 Sun, 25 Jan 2004 17:32:55 +0000     I could reverse the polarity of the dc into the recorder, but not without risking blowing it out.
    I found I can get rid of the noise completely by going dc battery powered.  Which is fine for a couple hours, but I'll have to invest in a lot more batteries to get through a Saturday recording session.]]> In The Studio Anonymous https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55216 https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55215 Sun, 25 Jan 2004 16:33:13 +0000
Joe]]> In The Studio forrok_star https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55215 https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55214 Sat, 24 Jan 2004 23:21:27 +0000 In The Studio greybeard https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-55214 https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-1355 Sat, 24 Jan 2004 21:49:41 +0000     But... sometimes the noise is a bit louder and more shrill and is obviously related to a grounding problem.  When I just touch the metal plate or the strings it drops dramatically in volume.
    I haven't been able to track it down to an individual outlet, but it seems to be common when recording direct, with only the guitar and  the recorder.  The recorder is plugged through an ac/dc transformer (so all I can play is "back in black", ha ha) and is the only thing in that outlet, though probably not the only thing on that circuit, I'd need to spend some time in the cellar to figure that out.
    Do I need to go through a DI box with a ground lift and then a mixer?  or do I have a bad ac/dc converter (it is a cheap one, with no third grounding prong)? or do I have a loose wire in the guitar?  Just to be clear, I have had this noise before with my practice amp, but the grounding in my house is a bit sketchy.  Maybe I need an electrician?  Or a long wire attached to the guitar and a big metal spike to drive into the ground outside?]]> In The Studio Anonymous https://guitarnoise.forum/in-the-studio-in-the-studio/ground-hum/#post-1355