Anyone blow the OEM head unit by wiring up aftermarket amp

I read a post on here warning of this possibility. I cannot find it again. Not sure if this is real or someone pushing a product. I guess you good blow it with a bad wiring job. Crossing wires etc.. Not too worried about that. I am careful with wiring.

 

I found the post that I was referring to. I read it and went to the linked website, sonicelectronics. Prices looked ok. I might compare them to Crutchfield and Amazon before I buy. Never found the protection parts the post referred to. I have the feeling that someone was just using scare tactics to post a link to their website.

 

I could be wrong but it sounds like you might be referring to my post on page 2 of this thread. If not, just ignore. If so, no, not trying to sell anything......just offering a suggestion for protecting the HU against a condition of improper loading of it's output circuits. Since I had not seen mention of any kind of proper impedance matching between the HU and amp high level inputs being installed in any of the posted upgrades, I thought I would mention it. ********* don't mention it either but their amps by design may take care of this. Maybe tacorob can comment on this. The HU is looking for 4 ohm loads (approx.) which the speakers provide but the average high level amp inputs are in the 15k to 20k ohm range. I don't know what class output our Entune HU's are since I don't have a schematic of one. If it is a class D and does not see the load it expects, it can do a number of weird things from no output to full power out. Full power out could damage an external amps high level inputs if you are connecting directly to them. I used the Audio Control AC-LGD's in my audio upgrade to insure a stable load to the HU. Some LOC's have a 10 ohm resistor across their input to load a HU which is fine but the resistor generates appreciable heat. The LC7 that I installed does not have these input resistors so I used the AC-LGD to provide that stable load. SonicElectronix does have these......just search AC-LGD.

Not trying to be technical about this.....just trying to 'splain it best I could. And yes, be careful about the hookups so as not to fry anything!!

 

Thanks for the explanation. Do you need to order 1 or 2. The link has a picture of 2 which is what you would need. Description reads that the AC-LGD plugs in to LOC then speakers. What if you have an amp. Does it plug in to LOC and AMP? All the amps I am looking at are Class D so not sure if these are necessary.

 

You only need 1 set or 1 pack as they are sold in pairs. Use one for the front leads and one for the rear leads. They are made by Audio Control and the connectors only fit their LOC's. My LOC is the LC7. HU speaker wires connect to AC-LGD inputs. AC-LGD outputs connect to a LOC or can connect directly to an amps high level inputs. I use the LC7 LOC because you can correct for the HU's bass drop off at high volume levels and have low level signal outputs for the amp. If you don't use a LOC at all you can ditch the connectors and wire AC-LGD directly to HU and amp high level inputs. Connection instructions come with the AC-LGD. Most add on amps are class D these days. The AC-LGD is used to provide a proper load to the HU which also provides protection for the amp high level inputs. An open or high impedance output on a class D amp (or HU) may not destroy the amps output circuitry but may cause the weird stuff mentioned in my post on page 2 of this thread. A shorted output or 0 ohms certainly will on any class amp. Another benefit of the AC-LGD is that if an amp fries itself, as they are known to do sometimes, any power surge would be better insulated from the HU. Impedance is a value that is not 100% constant. A speakers ohm rating is a nominal value. Through the speaker, a bass tone, for instance, will produce a different impedance than a high tone to the HU or amp. The AC-LGD is a load generator and a signal conditioner. It works to maintain as close as possible a constant impedance to the HU using reactive internal components.

 

I did some price comparisons. Sonic is lower than Crutchfield on speakers buy Crutchfield includes wire harness and adapters. Not sure if Sonic prices those separate. Sonic is lower than Amazon by $10 on resistors and offers free wire kits with some amps. They are higher on the Rockford that I want but with discount on wire kit and $10 on resistors package price may come out lower.

 

Stumpjumper ..........After re-reading my 2 posts above, I noticed that I had made some contradictions ......my apologies Sir! Read again the edited versions. I am a 2 finger typer so my brain is way ahead of my fingers a lot of the time. My laptop finger pad is very sensitive also and sometimes I delete some text without knowing.