Causes
At certain pressures the fast moving air is at the resonance frequency of the gauge which causes the gauge to buzz. The location of the PVC supply line is also a major cause (see below).

Solution
All that is typically needed to eliminate the noise is a restrictor to dampen the air movement in the hose to the gauge.

Our mechanical boost gauge includes a restrictor on the tee that helps prevent this. Other companies call it an "anti-buzz" or "no-buzz" fitting.

Please see other suggested solutions below:

• put a wad of cotton from a q-tip or cotton ball where the hose goes into the gauge
• install a small fuel filter (i.e. for a lawn mower) inline

Some additional install tips:

• use the included tee fitting with restrictor and/or additional vacuum restrictors in the tubing to the gauge
  
• make sure your tubing is fastened at various points (so it is not loose)
• it is better to locate the PVC tubing pressure source further from the turbo (i.e. in the manifold just before the engine).

Google boost gauge buzzing for more information on this subject.