Need help with amp...could earn someone lunch money

I used to know that stuff in year 1 engineering, but in this case, since I plan to use pre-build amps, my issues are more about how to build (or have someone else build for me) a system that meets my requirements. Ie. How to isolate from interference as the amp is near the boat's power distribution panel, now to get clean 12V power from the batteries, etc.
 
The power comes from a 12V distribution bar that is powered by 12V deep cycle batteries. The distribution bar also powers the "house" i.e. lights, cooler, pumps, instruments. So it might have a significant about of variability.

1)Ensure a low impedance ground path(power).
2)Add a RC low pass filter at the input of your audio amp using 1kohm + 680-1000pf ceramic cap. This acts like a high frequency jammer. Good luck!
 

PRR

Member
Joined 2003
Paid Member
This is 100% "car sound", with extra water.

There are marine speakers and electronics that are nominally water resistant. If that is not enough to start your party, there is a vast selection of car-sound gear which can be mounted in water-sealed tubs. Since this stuff is MASS-produced it is not likely you can DIY cheaper or better than you can buy, at Walmart or at a boat supply shop.
 

PRR

Member
Joined 2003
Paid Member
My local shop:
Housing for any car radio:
UNIVERSAL GIMBAL HOUSING

Basic radio, splash resistant:
MARINE MECHLESS BT COMBO WITH SPLASHGUARD, REMOTE, & SPEAKERS

Fancier:
RADIO AM/FM/BLUETOOTH MP4/MP3 USB

Fancy rig, manual, specs, 104W, IPX6-rated water-resistant front panel:
GARMIN FUSION RA210 MARINE STEREO ENTERTAINMENT SYSTEM
https://static.garmin.com/pumac/RA210_OM_EN-US.pdf

And this is really a lobsterman's shop. (Good deals on trap-winches, floating rope, etc.) Go where there is more recreational boating you may find much more choice.
 
Last edited:
LM386 ?

Makes less than 1 watt of power.

I would assume most the noise is Radio Frequency interference.

the internal gain is preset on the LM386 to 30
or some kits use the bypass method which turns it up higher to 200
so they are rather noisy.

otherwise yes use a shielded cable for the input.
and you could add a simple radio interference filter on the input with a small
capacitor.

otherwise no offense, it is a really horrible chip all together.
it was designed for very low power battery operation.
for very low quality audio, for kids toys or other similar applications.
dating back to the 1970s.