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  #11  
Old 04-29-2012, 06:36 PM
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Quote:
Originally Posted by Kyle View Post
I'm guessing JL will tell you that they are over powered.

The watts on a channel are what they are. They are either off or on. You have a 150w channel when on no matter what. Gain does not turn up watts or down watts. It turns the volume up and down. If the volume is set properly with the head unit and gain set up from amp then distortion will stay away. Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current.

Ok I'm stumbling over my toungue and can't put down what I am trying to.

Read this.

http://answers.yahoo.com/question/in...0135838AAx5e4d
The input controls on an amp ARE NOT GAIN CONTROLS. They're input sensitivity controls, which are there because any amp will only develop a specified power level when the input voltage is at the designed level. Amplifiers are more accurately called "differential amplifiers" because the input voltage causes it to develop a specific output voltage at a specific ratio. The amplifier's output devices can't usually be controlled WRT this voltage differential- that part of the amplifier's gain is fixed but ahead of the outputs, the input stage often has op-amps (Operational Amplifiers) and their output level is controlled by the input sensitivity pot. This kind of op-amp is often called a VCA (Voltage Controlled Amplifier) although most input sensitivity controls are just attenuating the level going in.

The output section's gain is fixed- if you meant that when you posted "The watts on a channel are what they are", I agree but I would have worded it differently. However, "They are either off or on" are you referring to a Digital Amp? This amp has no digital section, with the possible exception of part of the power supply and I didn't see anything to that effect in the manual.

You can't alter the volume without changing the voltage, somewhere. You can't have the same voltage at the amp's output terminals at 150W and 25W- it's not possible if the speakers haven't changed. The voltage and impedance are directly linked to the calculation for the output power.

"Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current."

Care to explain this? Music signal is AC, not DC. If the amp clips, the top of the waveform can look like pulses of DC but unless the frequency is extremely high and the distortion is really high, it's still alternating current, even if it's a pure square wave.
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  #12  
Old 04-29-2012, 08:03 PM
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Kyle Kyle is offline
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Quote:
Originally Posted by JimN View Post
The input controls on an amp ARE NOT GAIN CONTROLS. They're input sensitivity controls, which are there because any amp will only develop a specified power level when the input voltage is at the designed level. Amplifiers are more accurately called "differential amplifiers" because the input voltage causes it to develop a specific output voltage at a specific ratio. The amplifier's output devices can't usually be controlled WRT this voltage differential- that part of the amplifier's gain is fixed but ahead of the outputs, the input stage often has op-amps (Operational Amplifiers) and their output level is controlled by the input sensitivity pot. This kind of op-amp is often called a VCA (Voltage Controlled Amplifier) although most input sensitivity controls are just attenuating the level going in.

The output section's gain is fixed- if you meant that when you posted "The watts on a channel are what they are", I agree but I would have worded it differently. However, "They are either off or on" are you referring to a Digital Amp? This amp has no digital section, with the possible exception of part of the power supply and I didn't see anything to that effect in the manual.

You can't alter the volume without changing the voltage, somewhere. You can't have the same voltage at the amp's output terminals at 150W and 25W- it's not possible if the speakers haven't changed. The voltage and impedance are directly linked to the calculation for the output power.

"Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current."

Care to explain this? Music signal is AC, not DC. If the amp clips, the top of the waveform can look like pulses of DC but unless the frequency is extremely high and the distortion is really high, it's still alternating current, even if it's a pure square wave.
We are on the same page I just didn't know how to word it. English was never one of my greatest subjects. Wording often comes out wrong.
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  #13  
Old 04-30-2012, 11:08 AM
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If you have the system set up correctly (gains, crossover, etc) and you use the system correctly then you DEFINITELY should not be damaging those particular speaker components with that particular amplifier. If you keep the amplifier out of compression then you will not have an issue. But are you being disciplined by sticking to the volume control limit that was established during tuning when underway and under conditions where you can no longer audibly detect clipping? Also, the amplifier has a high and low input voltage setting. Since the EQ has over 2 volts output, you want this setting in the less sensitive position before you set the rotary input gains.
The distortion at low volumes only is strange. If you hear something at low volumes it would probably be the signal shutting on/off fast enough that is appears to be distortion. It would still be there at higher volumes but you will have more trouble recognizing it in the same way. Remove a speaker in question and connect a multimeter to the terminals so that you can read the DCR. Manually but carefully (in order to keep the cone centered) slowly press in or out on the midbass cone for maximum travel and see if the reading changes from roughly a 4-ohm DCR to 'open'. In that case, you have a speaker problem. If not then you probably need to look elsewhere for a different cause relating to what you hear.
It is always a good idea to have four speakers within the cockpit. The two in the bow and on the opposite side of the windshield provide the cockpit occupants with zero benefit when underway.

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