Possible fried amp - PAC LC-1 the issue...?

[mdk681]

Over the weekend I was working on installing my second amp which will power my 4 in-boat speakers and a sub. I had an existing 2 channel amp that power my tower speakers. Long story short I got done installing everything at the dock so I decided to take the boat for a spin and really crank it up in the middle where I wouldn't bother anyone. The speakers sounded great now being powered by an amp - I gave them a good workout and played with frequency and levels.

This is where my problem arises - currently I have a PAC LC-1 in line with my tower speaker RCA's. I noticed that the knob was not stopping at the typical low and high hard stops last week, so I ordered a new one and had planned to replace it this weekend. I did not replace it soon enough though... My tower speakers were all the way turned down (using the LC-1) and as I turned the dial up slowly I heard a popping noise coming from where my amps were mounted. The tower speakers were working, but I was getting some strange feedback and they were cutting in and out. I looked in the compartment where my amps were and the tower speaker amp appeared to be almost shorting out - it was flickering on and off and then POOF, I let some magic smoke out the top of the amp. I scrambled to cut power to the amps and shut the system off. The speakers had worked fine when I was at the dock, but I did not not adjust the LC-1 at all when powered up.

So was this just a coincidence that my amp decided to die as I was adjusting the RCA level, or did the LC-1 cause some sort of short and fry something in the amp? I am not too familiar with RCA's and what type of voltage/current is being transferred so I need a little insight. I unplugged the RCA's from the amp once I had the boat back on the lift and powered everything up. No smoke and no protect lights. Help...

[chpthril]

Mdk,

The amp may be dead, but I do not think the POT line level caused it. The LC-1 is just a simple variable resistor/potentiometer. With the PC at wide open, the amp will see the same signal voltage as it would without the PC in line. Now, a shorted signal input would not be a good thing and could and should put an amp into protect mode.

Is everything working as it should now? Or is it still not playing music but is powered up.

[mdk681]

Mdk,

The amp may be dead, but I do not think the POT line level caused it. The LC-1 is just a simple variable resistor/potentiometer. With the PC at wide open, the amp will see the same signal voltage as it would without the PC in line. Now, a shorted signal input would not be a good thing and could and should put an amp into protect mode.

Is everything working as it should now? Or is it still not playing music but is powered up.

That was my thought, it was just strange how it happened right when I started turning the dial. What do you mean by a shorted signal input? Are you referring to the audio input to the amp by way of the RCA's? I'm not sure if the amp went into protect mode or not, I guess I didn't really look into it as I just hit my breaker as fast as I could.

I am not sure if everything is working now, I am going to try and look into it tonight after work.

[chpthril]

The PC has a left and right chnl signal passing through it, each is a 2 conductor. If any of these get crossed, it will surly create some bad noise and could put the amp in to protect mode.

[mdk681]

The PC has a left and right chnl signal passing through it, each is a 2 conductor. If any of these get crossed, it will surly create some bad noise and could put the amp in to protect mode.

Hmm, well I defiantly heard some weird noise but it doesn't sound like this type of short would cause the amp to smoke? Are there any ways to test an RCA, like OHM-ing out each of the 2 leads to ensure continuity? I ran 4 pairs of RCA's just in case one went bad, so I will also just try a different pair.

[mdk681]

Well after spending a few hours working on the boat tonight, it appears that one channel
on my amp is dead. Still powers up and sounds great out of one of my tower speakers. The other is dead. Tried swapping to different pairs of RCAs and I see no difference between them.

I guess it was a matter of time before this old timer crapped out. Bought it new about 9 years ago for my truck and took it out when the truck was sold. Worked great last season for the towers but is done for now. Looks like the last weak/old link of my new system is done for and will be replaced and updated!