JAMIROBri

Hello all. I'm getting ready to install a Pioneer TS-SW841D shallow mount sub in the stock box. Also, I have an old school Rockford Fosgate 150a2 amp I bought years ago but never used. I noticed the amp has a "high level input." It looks like four speaker wire inputs. Can I tap into the rear speakers and use this input? Or do I need to tap into those speaker wires and convert them to RCA's?

Another question. Where do I mount the amp? Is there room by the battery or sub enclosure? I haven't taken anything apart yet back there to check for myself. Thanks!

Brian

nicktime

DON'T convert the speaker outputs of the amp to RCAs. Depending on what you are looking to do, you can tap into the low-level inputs to the stock amp to drive the new amp.

There are three connectors on the stock amp, C1, 2 & 3. C1 is an 8 pin connector, while C2 and C3 are 16 pin connectors. C1 contains the output to the stock sub. C2 is the speaker outputs, and C3 is the low-level inputs to the amp.

C1 also contains the power and ground feeds for the amp. The outputs for the sub are actually on 4 wires due to the fact that the stock sub is a dual voice-coil unit.

If you need the pin-outs of the connectors, let me know.

At the top of this section, there is a "how-to" for this. https://www.chevyhhr.net/forums/audio-video-17/how-hook-up-amp-sub-woofer-setup-without-affecting-existing-premium-sys-10944/

07azhhr

I use the SUPPOSED low level inputs as RCA's and fried an amps input stage. I measured 6v like others have stated and thought YAY hi voltage low level, awesome right? NOPE the amp played but had a bad whine and then I started to smell it. Looked back to see the amp smoking from the INPUT side of the amp.

Talking to people over on DIYmobileaudio they suggest that these are actuall hi level inputs and that you would not see the 6v unil fullish volumn if it could even produce that much voltage on low level inputs. They have also stated and proved that most hi voltage low level inputs never reach the claimed voltage. So seeing this 4,5 or 6 volts with the volumn at 0 is not what you want to see for low level inputs. But I will say I could have been measuring wrong and they might be thinking I was doing it right.

There are many amps that will switch between hi-level and low-level inputs on their own so I wounder if these are the type of amps that have been used with success in this mannor. I have read other threads on here stating the same ruining of amps by doing this. So be careful.


I actually have tapped into these same amp inputs as well as the factory amps speaker outs and run them thru a standard Scoshe lineout converter from Walmart and get the same volumn out of my amp either way. If these were/are low level I would think I should not get the same results. I actually want to try connecting a speaker to these input wires and see if it will play normally. If they are low level inputs the speaker should not play very much at all if even at all.

nicktime

That's interesting. I wonder if what is being termed as "low-level" by GM only means in comparison to the amplified output? Or is it possible that the amp is really only a crossover and amp for the sub? In other words, does the radio itself provide the power for the normal speakers, but the lows are channeled to the amp for the sub?

When you measured 6V, was that AC or DC? Referenced to ground or between the +/-?

JAMIROBri

Are you guys saying I can't use the high level inputs on my RF amp? I want to do this easily, but also safely. I'd rather not run RCA's from back from the HU (Pioneer AVIC-X930BT) if I do not have to.

Brian

nicktime

Brian,

As you didn't mention you already had an aftermarket HU, the assumption was that you had a stock Pioneer system that you wanted to tap into. This is where there appears to be some confusion over what should/could be done.

As you already have the HU in, it would depend on how you installed it as to how best to get your input for the amp/sub. Did you install an adapter/harness when installing your HU? Such as a Metra or Axxess unit? What type? Did you start with a Pioneer system with sub? Or are you adding the stock sub box?

You should be able to use the speaker level inputs if needed. It's always better, if possible, to send the low level signal to an amp is all.

If you used an adapter that plugged into the RCA outputs of your HU, and have the stock Pioneer amp in the back by the sub, then you already have those low level inputs right there. If you didn't start with the Pioneer amplified system, then yes, you can tap into the rear speaker inputs. Either way, your amp needs to have a way to only send the lower frequencies to your sub, otherwise it will be bad

JAMIROBri

I had the HU installed at Best Buy and they did use an expensive wiring harness. I'm guessing the harness doesn't use the sub outputs on the HU? I wonder if I should just bite the bullet and run some new RCA wires back to the new amp so I can have total control over the sub and amp. I was hoping to cut a corner by not pulling the HU and just tapping into the wires somewhere in the back.

BTW, yes, I have the stock Pioneer "premium" sound system. I have swapped out the front and rear speakers already. Next up are the tweeters and obviously, the sub. I ordered a shallow mount Pioneer sub because I want to keep the stock location and not lose any room inside the car.

Thanks for your help so far!

Brian

SmootHHR

Rockford 150a2 is a good little amp. Wish I still had mine

JAMIROBri

I bought it new years ago and never used it. I recently went through all of my old equipment and sold it on Ebay. I held onto this guy because I wasn't getting enough money for it. Now I have a use for it!

I sold my Power 800a4 and 800a2 amps. I used to have a Power 1100a2 in my Camaro. That thing sure made those three 10W3 subs I had rock!

nicktime

They probably used an adapter that uses the RCA outs for the front and rear channels. You can confirm that once you take a look at your stereo. Pulling the HU back out shouldn't be too bad. Once you start looking, you'll realize that running a patch cable to the back isn't too bad of a job. If you want, at the same time, you could run an amp turn-on wire and two more patch cables "just in case" you decide to upgrade the amp in the future. Cables are cheap compared to the time involved to do it right.

Also, don't forget to run a cable if desired for future amp volume control. If you need any diagrams for your interior and trim, let me know.

Rich