Hello to all!
I have a interesting question..
I recently installed a aftermarket subwoofer and amp which i intergrated into factory HK system in my 2010 clubman...
What i did is run all necessary wiring and tapped the rca and remote into factory amp harness using a RCA converter.
I did various research on the forum to get factory wiring info that i needed and all seemed to be good (at first)
the remote turn on for the amp i used was the red and white wire off the factory amp which does give the amp power but when you unlock the car it comes on right away and when you lock it there is a bit of a delay on turn off which is about 30 seconds ( i can deal with that)..
the issue i am actually getting is when you try to turn up the stereo the amp seems to cut off sound to the subwoofer (almost like that factory safety measure to prevent speakers from getting overpowered) until you turn the volume back down...
I am not understanding this, this is actually my first system install of this type of system..(i have done many installs to various vehicles)
I've looked all through the forum and have found no info on this..
the way i have the rca hooked up is through the front speaker wires off amp ( i believe it was black and red and yellow and purple) using a adjustable level converter which is set a full capacity..
I am definetaly at a loss here and if anyone can help me out i would appreciate it.....
I am sure its a wiring issue but i just dont know what or where to start...

thanks....

 

The first thing to check would be the allowable input range for the RCA converter. The Harman/Kardon amplifier puts out a good deal of power, and it may just be too much for the RCA converter to get it down to "normal" RCA pre-amp levels (about 0.5 volts RMS).

Assuming you don't have an oscilloscope, the next best thing would be to set your multimeter on "AC" and measure the RMS voltage you're getting out of the RCA converter. If you're seeing anything much over half a volt, you're overdriving your amplifier and sending it into protection mode. Also, if you have an input gain adjustment on the amplifier, try turning that down as well to see if you can keep the amplifier from shutting down.

 

About the remote turn on/off, I have not done my subwoofer install yet (a project for early next year, hopefully), but I would think that since the door chime, warning bells, etc come through the car speakers then the amp would indeed turn itself on when the car is unlocked.

And a ton of people report a delay with the amp turning off after turning off the car, so I think that is normal as well.

 

The problem doesnt put amp in to protection mode..it still has power and is functioning properly..What is seems to be doing is just cutting sound to subwoofer itself...if i turn volume up over lets say half way sub will not play, but as soon as i turn volume down it will start playing again..
When it stops playing i went and check all wiring and functionality of the amp and everything was good...
unless there is not enough signal in the rca converter to support the increase in volume????

 

You are correct...but the delay is not that bad and if everything is wired good i dont think it should matter to most people..In my research it seemed to be the easiest way to wire..

 

I don't know - if turning the volume up past a certain point causes the amp's output to shut down, that certainly sounds like protection circuitry to me. The problem shouldn't be *too little* voltage, because if you turn up the volume at the head unit, the output from the RCA converter should go up (or at worst, stay the same). It shouldn't decrease. The subwoofer output may well have its own protection circuitry, so I wouldn't be surprised if the other channels on the amp continued to work normally even when the subwoofer output has cut out.

What kind of adjustments does the amplifier have? (bass boost, input gain, crossover frequency, etcetera?)

Have you checked the output voltage from the RCA converter yet? Also, what's the impedance of your subwoofer(s), and what kind of amplifier is it?

I'm still betting that you're either overdriving the amp's inputs, or you have too little impedance at the amp's output and the amp is shutting off the output to prevent excessive current draw.

EDIT - Re-reading your first post, you said that you have the RCA converter set at "full capacity". What exactly did you mean by that? Some adjustable converters can output several volts, which might be much more than the amp is capable of handling on its line-level input. Remember that the "standard" RCA line-level voltage is only about half a volt. If you have a gain adjustment on the amp's input, I would try turning it down. If the gain adjustment isn't marked, try turning it anti-clockwise. If it is marked with numbers like "0.5V, 2V, 5V, etcetera, try turning it toward the larger numbers.

 

amp im using is a rockford 5002d amp and i have it going to a powerbass s-12td sub..amp has gain , freq, and 1 other one but i forgot off the top of my head..the capacity i was talking about was basically left and right output balance which they are both on the high settings equally..
the reason i was not thinking protection mode is it usually has a red light that would come on but it is possible the light has a failure or something like that...You got me thinking and i think i will hook up another amp i have and see if anything changes...but i think i will check output when i get to work tomorrow first....i will give an update tomorrow...thanks so far!

 

Let us know what you find out, voltage-wise. Also, since your RCA converter has "left" and "right" outputs, are you running the amplifier in stereo mode or bridged mode?

Lastly, how do you have the amplifier connected to the subwoofer? If you have the amp in bridged mode and you have the sub's voice coils wired in parallel, that could be a problem as well.

If you could give a brand/model for the RCA line-level converter, that would help as well.

 

ok heres what i found out - checked rca output and it varied so i couldnt get a accurate reading for some reason ( went from .012 to peaking at 2.54 at times)...the avaerage seemed to be .040 to .054....besides that i changed out the amp to another one i had and system seems to be fine now. I guess it was an amp issue after all..
I had it wired bridge by the way...and as far as brand on converter i reallt dont remeber but i got it at a local stero shop but i know it wasnt top of the line...(probably the same quality as what you get at a pepboys or advanced auto), and the sub is not wired parallel...
The new amp has more sound settings and im also running it through a audiocontrol 2XL and epicenter to better the sound..
eventually i will be putting in a 8" l5 for space with a jl 500.1 amp because its smaller and will tuck away nicely or a zapco DC350.2 because of the same reason...I will also be designing and building my own box for personal preferance..when done i will post pics...

Just a special thanks to ScottRiqui for all the help...
Any more questions on what i did just let me know!!!

 

So how do you have the dual 4Ω voice coils on the sub wired? You said you didn't have them in parallel, so either you've wired them in series for an 8Ω load, or you're only using one of the voice coils?

Regardless, I'm glad to hear it's working now. Also, the Epicenter is a great piece - I've been using it for close to 20 years now. Just don't forget to install it upstream of the crossover so it sees a full-range signal.