Soundstream PN4.520D FM EMI reduction
Tourer
Joined: Mar 2013
Posts: 297
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From: Pacific Northwest
Intermediate
Joined: May 2013
Posts: 25
Likes: 3
From: Portugal
Got the ferrites yesterday. Thanks Rob for shipping them out so fast. Plan on doing the amp and speaker installation this weekend (speakers should arrive tomorrow and already have the amp) . I'll let you know how it works out. Thanks again to everyone for the information overload on this audio system... I was getting worried about my head exploding but I think I'll be OK.
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Joined: Dec 2011
Posts: 86
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From: McKinney, Texas
I installed two of the bigger ferrites on my power and ground wires today, 2 wraps in one and one wrap in the second, and a smaller one on the rem wire, 2 wraps. Small improvement in FM reception, but not much really. Apparently my Soundstream 350 amp is NFG, at least for radio. Sounds good on CD, AUX, etc.. This is truly maddening....
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Intermediate
Joined: Aug 2012
Posts: 36
Likes: 0
From: Austin, Texas
I installed two of the bigger ferrites on my power and ground wires today, 2 wraps in one and one wrap in the second, and a smaller one on the rem wire, 2 wraps. Small improvement in FM reception, but not much really. Apparently my Soundstream 350 amp is NFG, at least for radio. Sounds good on CD, AUX, etc.. This is truly maddening....
Extreme HDF Member
Joined: Nov 2007
Posts: 14,670
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From: East of the Sun, West of the Moon
what antenna?
I installed two of the bigger ferrites on my power and ground wires today, 2 wraps in one and one wrap in the second, and a smaller one on the rem wire, 2 wraps. Small improvement in FM reception, but not much really. Apparently my Soundstream 350 amp is NFG, at least for radio. Sounds good on CD, AUX, etc.. This is truly maddening....
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Joined: Dec 2011
Posts: 86
Likes: 0
From: McKinney, Texas
Stock whip antenna on tour pac... and just to make sure, the ground and hot wire should be looped through the ferrites together as a pair, correct?
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Intermediate
Joined: Aug 2012
Posts: 36
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From: Austin, Texas
Correct on the wires through the ferrites as a pair. If they aren't looped together their current will saturate the ferrites and reduce their effectiveness. When they are together the core doesn't see the current.
The additional steps I'd take to further reduce the interference, in order of likely effectiveness, would be:
1. Add a type 31 ferrite to the rear speaker wires (2 wraps) and RCA audio cables (can use the same ferrite if they will fit).
2. Add a "chassis ground" to the amp: run a 10G wire from one of the mounting bolts to the bike ground. You may need to scrape a bit of paint off the amp tangs to assure a good connection.
3. Add a similar chassis ground to the receiver.
4. Add small capacitors within the amplifier between the amplifier power line and chassis. Do the same for the ground. (this would take some testing and experimenting)
These class D amps are just a crap shoot as far as FM band interference goes. The design is inherently noisy. Due to production variation in some cases the noise happens to fall right in the FM band. If you're particularly unlucky one of those noise spikes will sit right on top of your favorite FM station. If that happens it's not likely an amount of filtering outside of the amp is going to help much.
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Joined: Dec 2011
Posts: 86
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From: McKinney, Texas
Looks like this weekend before I get to all of this. One thing to note is that i am not using the RCA connections, I am using the other white wire harness that plugs into the amp. This harness also has a "ground" wire which I have hooked up to the aux ground on the headlight harness. Could this set up be an issue? I'm only running one pair of 651's with this amp...
Would RCA cords help?
Would removing the little harness ground help? Or be a bad idea?
Would RCA cords help?
Would removing the little harness ground help? Or be a bad idea?