Symptoms of a bad amp???

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Old 07-25-2009, 12:58 AM
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Symptoms of a bad amp???

I'm having issues with the SQ of my subs. First, amp is a very old Infinity Beta 300 Digital.

SQ with the bandpass box is exceptional. One of it's strong points is the punchiness and tightness of the bass. Many people think I have a 10" in there when listening to rock. Lately, the day before Acurafest it lost some of it's punch and the low end seems over emphasized. I found that I had at some point accidentally hit the bass boost but it's still muddy.

I've noticed bass is inconsistant. Sometimes it's too loud and sometimes it's not loud enough on the same track at the same volume. I've checked power, ground, and signal. I've checked all connections and controls and the HU. I've checked for air leaks in the box.

Anyone know if an amp going bad can cause the bass to lose it's punchiness and not the low "rap" bass, or should I start looking somewhere else?
Old 07-25-2009, 11:54 AM
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what amp are you running for the sub/s?
Old 07-25-2009, 12:05 PM
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A very old Infinity Beta 300 Digital.
Old 07-25-2009, 03:27 PM
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Originally Posted by I hate cars
A very old Infinity Beta 300 Digital.
hook up a multimeter to it and check the wattage it's putting out with a constant bass tone. My guess is that it may be the battery that is causing the fluctuation. Be sure the A/C is ON and the car is setup like you would normally have it.
Old 07-25-2009, 04:04 PM
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What about the "tightness" and punchiness of the bass being lost? It looks like full output and the really low notes are still there.

One thing it started doing is cutting off at very high volumes. Before I had the bandpass I had the gains twice as high and it never cut out. Now with the efficient box and the gains cut way back, it will go into protection with it very loud.

My battery is suspect, it starts the car fine during the summer but it's getting replaced before winter. For instance when the AC fan kicks on, the interior lights dim a lot. It has very little run time with the engine off. The bodyshop let it go completely dead and it's never recovered. I'm disconnecting it today and charging overnight.
Old 07-26-2009, 10:50 AM
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Originally Posted by I hate cars
What about the "tightness" and punchiness of the bass being lost? It looks like full output and the really low notes are still there.

One thing it started doing is cutting off at very high volumes. Before I had the bandpass I had the gains twice as high and it never cut out. Now with the efficient box and the gains cut way back, it will go into protection with it very loud.

My battery is suspect, it starts the car fine during the summer but it's getting replaced before winter. For instance when the AC fan kicks on, the interior lights dim a lot. It has very little run time with the engine off. The bodyshop let it go completely dead and it's never recovered. I'm disconnecting it today and charging overnight.
Have you considered doing the big 3? The infinity amp for the subs is 1000 watts, right? Add in the other amp and your are probably being pretty unfriendly to the TL's electrical system. Also try checking the battery connections again, they may have become loose or may have poor contact due to buildup.
Old 07-26-2009, 12:12 PM
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Originally Posted by csmeance
Have you considered doing the big 3? The infinity amp for the subs is 1000 watts, right? Add in the other amp and your are probably being pretty unfriendly to the TL's electrical system. Also try checking the battery connections again, they may have become loose or may have poor contact due to buildup.
I've been over every connection about 10 times. I'm at the point of pulling my hair out.

When I installed the bandpass box I cut the gain on the amp by 1/2 and the gain on the crossover by 1/2. I doubt I'm pulling more than 150 watts at full volume.
Old 07-27-2009, 12:55 PM
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current issue...r u running a circuit breaker or a fuse...also...check voltage at battery...after fuse/breaker...before distro block if applicable...after distro block...if applicable...and finally at the amp itself...this checks for voltage drop throughout the circuit...rember...through this test...you're only using the ground straight off fo the battery itself..

-Jason
Old 07-27-2009, 11:28 PM
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Originally Posted by CSWBiggs
current issue...r u running a circuit breaker or a fuse...also...check voltage at battery...after fuse/breaker...before distro block if applicable...after distro block...if applicable...and finally at the amp itself...this checks for voltage drop throughout the circuit...rember...through this test...you're only using the ground straight off fo the battery itself..

-Jason
Thanks. Have not checked voltage drop or even voltage itself, just connections. I have something to keep me busy this weekend.
Old 07-28-2009, 12:18 AM
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I forgot, will low voltage cause the bass to sound muddy?
Old 07-28-2009, 02:50 PM
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Originally Posted by I hate cars
I forgot, will low voltage cause the bass to sound muddy?
it may be causing issues with volume, maybe muddiness because the amps need to provide the right amount of power to get the subs moving....:

V= I x R

Voltage = I (amps) x R (Ohms)

So if you are having a voltage drop (big one) then it's the I that is changing, not the R since resistance shouldn't be changing because it's a constant with the speakers...
Old 07-29-2009, 04:11 PM
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I feel like an idiot.

I had two stray strands of wire shorting across the output terminals of the amp. Problem solved with the SQ. Haven't had a chance to try out the cutting off issue but I'm 99% sure it's fixed lol. Thanks for the help guys.
Old 07-29-2009, 05:53 PM
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I'm glad it was an easy fix.
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