Some Observations setting the gain on my amp


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My amp is a Audiobahn A8002T running with 2 12" Kicker CVRs 4ohm DVCs at 400wx1@4ohm. My HU is a Kenwood that is a few years old. According to the formula, I am supposed to set the gain to 40 volts. However this can only be achieved by turning the head unit up to 30/35. At my normal highest listening volume, the head unit is at 28 but the output cannot even reach 40v even all the way up with a max of about 36v. I am testing the output with a test cd with 50hz. Whats up with this?

Now for the Remote Bass Boost Controller. Once I have the output set to 40v with the HU at 30/35 I try and plug in this remote controller. The first thing is that it does not light up like it should as in the blue circle around the knob. Secondly, without the bass boost turned on, the max output i can get is 30v with the remote turned all the way up. Thirdly, if I turn the remote all the way down, the protection light + the power lights are lit up. Any reason for these.

Just so u know about the system completely, the subsonic filter on the amp is all the way up at 50hz, with the LPF turned to around 100hz in addition to an external crossover at 100hz with the gain turned to MAX on it. The whole system is securely grounded and wires are perfect so no need to worry about that.

Basically, I would like to know the following:

1) Why can I only get the output of the amp to be 40v when the HU is at 30/35? 75% of max volume as recomended is 27-28 which is the max i practically listen to it at.

2) Why wont my remote bass controller light up?

3) Does Bass Boost have to be turned on in order for the remote to work correctly?

4) Why does my amp go to protection when the remote is turned all the way down?

5) Why can I only get a max of 30v with the remote plugged in with a max of 40v with it unplugged?

Thanks alot guys for taking the time to read this long post. Any help/experience you guys have with this is greatly appreciated.

Gold Member
Username: Carguy

Post Number: 1615
Registered: Nov-04
NateJ, the part that doesn't make sense is the 40v part. Are you sure it's 40v? It looks very high for a HU. Normally, it should be 4v max on older models, and 8v on some new ones.
The A8002T amp will only accept 8v max. So if your HU is 4v rca preout, then set the level half way.
The remote bass control didn't light up on the amp I tested either. It doesn't mean it's not working.
The bass boost should be turned on, if not then you won't hear much differenc with the remote control.
Do use that carefully, boosting the bass to max will overload/alter the gain/level setting on the amp. For example, let's say you set it to 4v and have bass boost to max. It will have the affect of increasing the level setting to 3v or even 2v. This is why as you increase the volume, the protection light will come on.
You DO NOT need subsonic filer past 20hz. 50hz is too high. You'd be losing out some low bass.
One more thing, that amp wasn't meant for subs. A800T is. A8002T works better with component speakers.

Silver Member
Username: Solacedagony

New Jersey US

Post Number: 277
Registered: Oct-04
It sounds to me like he's trying to setup his amp as per the JL audio amp gain setting instructions. You can't set a normal amp's gain as you would a JL Audio amp's gain. You'd use an oscilloscope (sp?) for a normal amp.
The gain is for matching the pre out voltage to the variable input sensitivity control (gain) on the amp. You want to match those voltages so that the amp isn't over amplifying the signal.
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