Amp help!!!!
October-23rd-2004, 12:19 AM
#1
Registered User
Thread Starter
Join Date: Oct 2004
Posts: 112
Amp help!!!!
I took the setup out of my mazda b3000(JBL P1200.1 amp and two Audiomobile MASS 12s) and put it in my mazda 3 a couple weeks back. I used the high level inputs on the amp using the rear channel as a source as i didnt want to want to mess with the RCA converter(or whatever its called)...now my bass is QUIET, even with the gain turned all the way up, it sounds OK, but its nothing what i was expecting at all...i have friends with far less of a stereo with much more output. Whats the problem? Ive been told that the high level inputs dont put out as much of a signal to your speakers vs RCAs...would getting the converter and running it off the RCA inputs help out my situation? I refuse to replace the stock headunit as i dont want to loose the 6 disc changer, or my stearing wheel controls. Any ideas?? 
November-1st-2004, 05:40 PM
#2
Registered User
Join Date: Nov 2004
Posts: 6
maybe your install is "out-of-phase"
before you transferred the amp and speaker system..do you like the way it performed?..does it "sound" the same or have you noticed a big dip or down trend change on its performance?..
if the performance just about the the same..gues there is nothing you can do about it..specially if it is installed professionaly during the first install..
but if there is a big difference on how if performed before and after you transferred your system?..
my best bet are..
1.you might be using "smaller" size power supply cable..both for the (+) and (-) wires going to the battery and ground system..
2.maybe you have an "out-of-phase" wiring..check for reversed wires..your car speaker (+) should be connected to your amps "HI" positive input and your amps output (+) should be conected to your speakers (+) ..check for both channels (left and right)..simply put..positive to positive, negative to negative..
other enthusiast intentionally do an "out-of-phase" set-up to improve "voice" response..
if the performance just about the the same..gues there is nothing you can do about it..specially if it is installed professionaly during the first install..
but if there is a big difference on how if performed before and after you transferred your system?..
my best bet are..
1.you might be using "smaller" size power supply cable..both for the (+) and (-) wires going to the battery and ground system..
2.maybe you have an "out-of-phase" wiring..check for reversed wires..your car speaker (+) should be connected to your amps "HI" positive input and your amps output (+) should be conected to your speakers (+) ..check for both channels (left and right)..simply put..positive to positive, negative to negative..
other enthusiast intentionally do an "out-of-phase" set-up to improve "voice" response..
November-2nd-2004, 01:31 PM
#3
Registered User
Thread Starter
Join Date: Oct 2004
Posts: 112
The install before was simply incredable...bass that would litteraly make your pantlegs move. Now, its noticable, but FAR from the output i was expecting. Box is very similar in size and shape. Power wires are the same size and within a foot or so of being the same length. Phases are correct. Only thing i changed whas using the high inputs vs the RCAs. 
November-2nd-2004, 03:01 PM
#5
Registered User
Join Date: Nov 2004
Posts: 6
your info is great..
we have eliminated some of the facts that could have affected your "new" set-up..
the only difference i know between "HI" and RCA inputs..
RCA has a lower "noise" factor..since you are injecting a very "low" level signal to your amp to amplify..on the other hand.."HI" inputs tend to inject "noise" or "distortion"..beacuse of the "HI" level of signal...but the later is good if you want good bass runs..
normally RCA inputs/outputs are used when you have signal processor installed inbetween your HU and amp.... hmmmmm...
you can actually test your RCA inputs..remove your "HI" connector and connect a mini-disc (or any other source with an RCA output) player to your amp..and see how it perform..
lets say..this is how you have it wired..
your "rear" speaker's (+) and (-) wires are directly connected to your amp's "HI" input..basically, your car speakers are in parallel with your amp..so the "sound level" will be controlled by your HU volume control..you have to pump-up-the-volume...
i have the same config with my last car..so i have to "fade" the music atleast 50% to the rear to have a good bass on my sub..so that when i pump up the volume..the front speakers will not distort..and the rear speakers will drive my amp set-up 50% higher..
we have eliminated some of the facts that could have affected your "new" set-up..
the only difference i know between "HI" and RCA inputs..
RCA has a lower "noise" factor..since you are injecting a very "low" level signal to your amp to amplify..on the other hand.."HI" inputs tend to inject "noise" or "distortion"..beacuse of the "HI" level of signal...but the later is good if you want good bass runs..
normally RCA inputs/outputs are used when you have signal processor installed inbetween your HU and amp.... hmmmmm...
you can actually test your RCA inputs..remove your "HI" connector and connect a mini-disc (or any other source with an RCA output) player to your amp..and see how it perform..
lets say..this is how you have it wired..
your "rear" speaker's (+) and (-) wires are directly connected to your amp's "HI" input..basically, your car speakers are in parallel with your amp..so the "sound level" will be controlled by your HU volume control..you have to pump-up-the-volume...
i have the same config with my last car..so i have to "fade" the music atleast 50% to the rear to have a good bass on my sub..so that when i pump up the volume..the front speakers will not distort..and the rear speakers will drive my amp set-up 50% higher..
