Boost-a-pump noise

[pumm3l]

I just finished installing a 40amp BAP and I noticed when I turn the dial all the way up that the unit will make a weird high pitch noise. Is this normal for the unit to do this when turned all the way up or do I have a defective BAP?

Video reference:
http://www.stempsite.com/videos/index.php?video=bap_noise.flv

you'll hear the noise at first then you'll see me turn the BAP all the way down and the noise will go away, once I turn the dial back up it comes back, just listen closely in the beginning and when I turn it up again.

A friend told me that he couldn't hear it with his speakers, I can hear it perfectly with my headphones, or if I'm a foot or more near the unit.

 

[trinity_gt]

I just finished installing a 40amp BAP and I noticed when I turn the dial all the way up that the unit will make a weird high pitch noise. Is this normal for the unit to do this when turned all the way up or do I have a defective BAP?

Video reference:
http://www.stempsite.com/videos/index.php?video=bap_noise.flv

you'll hear the noise at first then you'll see me turn the BAP all the way down and the noise will go away, once I turn the dial back up it comes back, just listen closely in the beginning and when I turn it up again.

A friend told me that he couldn't hear it with his speakers, I can hear it perfectly with my headphones, or if I'm a foot or more near the unit.

Although I haven't seen the innards of a BAP, as an electronics geek I'll say that the BAP probably uses what in electronics design is termed a "boost converter" which is a circuit that allows one to generate a voltage higher than the input voltage (that is, it generates 17V output for a 12V input.)

Boost converters have magnetics (inductors) and high frequency switches (MOSFETs) in them as part of their circuit. The noise you're hearing is these components vibrating as a result of this switching action and current flowing. Although it's technically normal, it's a sign that the circuit components may not be deeply potted or are mechanically "loose", such as an inductor whose coils are not tightly wound to the core or a FET that's not tightly fastened to a heatsink.

You can hear a similar effect when you walk by a large power transformer and hear it humming. In that case, the core of the transformer is moving in response to the magnetic field created by the current flowing in the windings, switching polarity at 60Hz and causing the whole structure to vibrate.

The high pitched noise can result when the switcher enters various modes of operation as the duty cycle of the FET is changed in response to voltage output and current demands.

I hear a similar high-pitched whine from my BAP too.

 

[pumm3l]

I'm fine with it making the noise, I just thought I may have wired it wrong it or maybe the BAP might be defective. I honestly didn't even know it was making a noise until I got within a foot of it, the supercharger whine is louder in the cabin than this high pitch noise. I'll go data log and make sure it's actually doing it's job now, maybe I won't need to turn it up all the way and will be able to reduce some of the high pitch noise it's making.

Thanks for the response!