Amp died, will this one work?

[jhiestand]

Our "new to us" 08 came with very little in the way of a stereo system. Basically just four boat speakers, a Memphis amp(MM4.50?) and four Titan 2 tower speakers. The Memphis kicked the bucket, so I'd like to throw something else in short term just to get us some tunes. I believe the Memphis amp was a four channel and it was driving the tower speakers using just two of those channels, and the head unit powering the boat speakers. I'm still working on eventual stereo upgrades but in the meantime, I'd just like to get the tower speakers going again. I have an unused Kicker KX700.5 amp just laying around, so thought that might work short term. There are just two pairs of wires coming from the tower speakers so I assume they are wired in parallel, and they were connected to a single channel on the Memphis amp. I could connect them the same way (one channel) to the Kicker amp, but it seems like I could get a little more juice to them if I bridged the two kicker channels and wired them that way. I believe the speakers are Polks that can handle 125w each. Does this sound like a bad idea?

I thought I read somewhere the 6x9 Polks might present an odd impedance when wired in parallel, but I can't seem to find that information again.

[azeus17]

Depends on what speakers you have. Is it the MM691? Those do have a weird rating of 2.7 ohms. No amp would be rated to push 4 MM651's on one channel in parallel. What would be a 0.675 ohm load on the amp. If you have the db 651 speakers, those are 4 ohm load, so 4 in parallel would be 1 ohm load to the amp, which it still would not handle per the pic you attached. Are you saying that all four speakers are wired to the same channel? If so, that's why the Memphis amp died in the first place.

[Tallredrider]

A cheap voltmeter will help. I would not assume that they are wired in parallel. I got one for free at Harbor Freight. It is all the time in the freebie section you can pick up in the front of the store. Measure the impedance of those two wires and see what it says. It wouldn't surprise me if the amp blew because of improper wiring.

I had a Kicker 700.5 in my Malibu and it was a very good performer for me. I wouldn't hesitate to get another.

[swatguy]

Your speakers that year are in parallel and they are 4ohm speakers. Unless they've been replaced those are MMC 690's They are jumped at the tower to create the parallel config. So at the end you're connecting you are seeing a 2 ohm load. Those speakers are roughly 100rms a piece so to match you would want power ratings of 200watts at 2ohms.



You can not use that 700.5 in bridge mode because it would t be stable. It will fry.
You could run each pair off a single channel but that amp is only rated at 85 watts per channel at 2ohms. That means you're splitting that 85 watts to 42.5 watts per speaker. Is it better than 0 sound sure . Is it going to get you anywhere near the performance they can get you. No. There are plenty of budget 2 channels that could get the job done perfectly for decent price. You don't need to spend ton of money to get good solid power to those 4 6x9' s and make them audible to the end of the line.

[MLA]

Lets presume that all the speakers, regardless their nominal impedance, are wired correctly for an amp thats stable down to 2 hm. Yes, the Kicker 700.5 will do just fine as a replacement for a blown amp. However, its quite large, so make sure you have room. As long as you are leaving the sub chnl unused, I would gather the power cabling for the current amp will be sufficient. The 4 hi-pass chnls of the 700.4 is roughly a zx350.4. Not a huge power monster, but they were a solid workhorse in their day.

For a longterm solution, leave the 700.5 in place for the in-boats, add a woofer and then get something like the Kicker KXM400.2 for the towers. At this point, you would want to redo the cabling as well.

[jhiestand]

Yeah, I know it's only stable to 4 ohms but just wasn't sure what load those speakers would present. I haven't had a chance yet, but hooking a multimeter up and checking it would tell the tale.

My other thought was I'd just use the sub channel to run a CVR10 which I also happen to have lying around. Sounds like a budget-friendly 2-channel for the tower speakers may be the best bet to get the tower speakers going again.