I'm back from a week of camping, and a thought had occurred to me in the woods.. (actually it occurred to me before that)

I've tried ferrites on all my power and speaker wires coming out of the SS amp, and FM is still bad. I have one big ferrite left.

Could putting the ferrite on the inbound power lead from the battery to the amp help?

 

Yes. Absolutely. That's the main one that is recommended to be put through a ferrite, together with the ground -- ideally with 2 wraps around the core.

I'm not sure which wire you mean when you say you put a core on the power wire "out of the amp." The amp has 4 types of wires:

1. Audio in (the RCA cables) or high power audio in (as when connecting to a stock HK head unit via the head unit's speaker wires). This might benefit somewhat from a ferrite.
2. Power (+12 and Ground). This is the primary source of noise and is the most likely to yield reduced noise if passed through a ferrite together.
3. Rem (which controls when the amp is on). Perhaps this is the one you already have a ferrite on? I put mine through a ferrite mostly because I had one laying around.
4. Speaker wires out. I didn't put a ferrite on these, but they may also benefit somewhat from it.

 

I went back and looked at the picture of your very nice install. You do appear to have ferrites on the +12 and ground wires, so I must have misread your new idea. If you are asking about putting ferrites on the other end of the power line, near the battery, I would not expect that to help.

 

I did not say what I meant... sorry. I was thinking about putting a ferrite on the power wire back closer to the battery, as you surmised.. maybe somewhere on the frame or before it enters the fairing or right near the battery... Doesn't sound like it would help, though, but I though I'd ask...

Thx!

 

i don't see where that's going to help because the interference is being radiated from the amp and it's only within a couple of feet of the head unit.

 

This is what I was told by our local sound system guru. The problem is that the class D amp submits the same frequencies as the FM on your stereo and your antenna locks on to the strongest signal in the vicinity. In other words if there is a 107.2 nearby and a 107.2 80 miles away your antenna will lock on to the local station because the signal is stronger. He told me that my amp has the strongest signal therefore my antenna is locking on to the amp instead of the head unit (local stations). I ask if there was a solution for this. His answer was a simple one.... NO!!! He did mention a hard to find "nutter steel" could possibly help but, not likely. I searched it and found nothing. He said some of the poor designed amps will steal the antenna up to eight feet away form the head unit . Just passing along the info I was told. Not sure if it is accurate.

 

Is there anything you could sort of wrap around say half the amp to cut down its ability to steal from the antenna? Would there be a heat issue?

 

good info and your local sound system guru is spot on with his synopsis as well as his remedy. I don't however agree with the idiotic statement of "poorly designed amps"! Yes this guy probably has his favorite amp just like everyone else does and I can bet it's not a class D amp but this issue is not based on a manufacturer's name or anything else for that matter OTHER THAN THE TECHNOLOGY ITSELF. ICE, Ascend, JL, Onkyo, Kenwood, Sony, HK, SS, Alpine, etc. the list goes on are all having these same issues and I would hardly call those "poorly designed amps". Just love those people that read a little bit on the internet and preach it to everyone and his brother not having a clue WTF they're talking about. These amps were NEVER designed to be installed within a couple of feet of a head unit/FM receiver nor did anyone ever fathom they would be installed sitting atop a head unit on a motorcycle.

Class D amp technology has been around for a while but only until recently has it really become a "mainstream" technology. Their size, weight, power output, no-heat design (low current draw), and price points make them great products. However that, just as anything else does, comes with a price and that's EMI radiation. Guys the problem is simple, we all know that; the solution however is not so simple for varying reasons and the main reason is FCC guidelines not being adhered to or enforced.

The bottom line is simple for those of you who just don't get it; Don't buy a Class D amp knowing it's inherent flaw of EMI and expect anything less from it. They're great products, they perform well, they're priced right for most, and they're pretty much bullet proof. If you like and want to retain FM reception, then look elsewhere for your amp requirements because Class D is not for you. I personally never paid attention to the FM part of it until long after I installed my first Class D amp. Why is that you ask? because I don't listen to FM, ever. Class D EMI does not have an effect on CB transmission, bluetooth transmission, Satellite transmission (GPS and audio), etc. It's only FM.

 

I might have spoke out of place with the "poorly designed amp" statement. I think he said poorly shielded.. and UN is right about "CB transmission, bluetooth transmission, Satellite transmission (GPS and audio), etc. It's only FM". I am now listening to Pandora when not using the Ipod and the sound is great.

 

Another dumb question but are there other not class D amps that will work without the FM interference? I actually use and enjoy FM.