U

Unregistered

Guest
I have a JL 600 watt 6 channel amp that is in my boat. I have 4 Polk MOMO component speakers all running off of their own channel and a 10" sub running off the other 2 channels bridged. I was out on the water this weekend and started to notice that there is a clipping sound coming from this amp. You cannot hear it if you drown the sound out by increasing the volume. However if you turn the volume down or to 0 you can hear the clipping with no problem. What would be the cause of this and how can I fix it? Thanks in advance...
 
M

markw

Audioholic Overlord
Whatever you're hearing, it ain't clipping.

Clipping occurs when you push an amp to deliver more than it's capable of. Clipping is exaggerated by turning it up. If you can "drown it out" by cranking it, it ain't clipping.

If you have it "down to zero", then you should hear nothing coming through the speakers. Whatever you hear isn't clipping.

Dunno what to tell ya, guy. Maybe a better description of what you're hearing instead of a commonly used label might help.
 
dsa220

dsa220

Junior Audioholic
This may be due to the electrical system on the boat. It sounds like the same thing that happens to car audio systems when electrical interferance from the coil and spark plugs gets into the rest of electrical. You can try the various spark arrestors sold in car audio stores to see if this helps.
 
U

Unregistered

Guest
The sound I'm hearing is something like that of a helicoptor in the distance. It's a constant tap....sort of like if someone was tapping the top of a microphone.

I didn't have this problem for 3 months. It just all the sudden started happening after last weekend. I was playing the stereo pretty loud all weekend....maybe this has something to do with it? Thanks for the help....!!!
 
O

O'Shag

Junior Audioholic
Because the systems on a boat, regular checks must be neccessary because of the possibility of corrosion on cables etc.

It could be your amp, but another component may well be at fault. Have you gone through a process of elimination to determine that the problem is definitely with the amp? If I was examining this problem with my own system, I would perform a series of checks that would include the following:
a) Amp - Is fan causing noise; is there RF noise getting in the signal somehow
b)Cabling/connection and power/wire check to make sure there are no lose connections or corruption to the signal path through the cables. Make sure all connections are tight.
c) Speaker check - unplug speakers one at a time, checking each time to see if one speaker is causing the problem.
d) If you are using any powered speakers e.*. the sub(s), perhaps they are susceptable to RF interference (some powered speakers can act as an antenna)
e) Check pre-amp (do balance test, flip switches to see if there is a loose connection somewhere)
f) Check source(s) Is your CD player skipping

Hope you get things worked out.

Best,

O'Shag

Austin Powers of Audio
 
O

O'Shag

Junior Audioholic
Continuing route canalysis -

You should check the software compatability of the discs your playing

Some CD players do have problems reading certain material (especially older models), and the result can be a distorted signal. For example there are CDs that've been recorded in the DSD (Direct Stream Digital) format. Sony did a limited release of these CDs, although their maintstream DSD format is SACD. Point is, some CD players have real problems reading these and other non-mainstream formats such as HDCD encoded discs with the result of sonic anomolies such as the 'phut phut phut' helicopter sound you hear.

Have you checked if this problem occurs with all discs, or just one or two?Look on the label of your CD(s) that seem to be having the problem, and see if any are non-mainstream formats, such as DSD or HDCD.

If you get no luck on this, perhaps you could check polarity of wiring, and make sure all interconnects are connected in the correct Left Right inputs/outputs.

Cheers BigEars :D

O'Shag

Austin Powers of Audio
 

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