With the power output listed at 180w total no matter stereo or bridged operation it tells me the amp has a tightly regulated power supply that’s designed to output that 180w no matter the load or channel configuration. JL Slash & HD amps are the same design… rated power at 1.5-4ohms.

If that’s the case the Kenwood should put out 45wpc into 2 OR 4 ohms and, as with almost all 4ch amps, it’s not able to run at lower impedances when bridged so you just get the 90wpc into 4ohms. Lower impedances will likely put it into protect or fry it, if it doesn’t have a protection circuit.

 

Thanks, Todd. I'm an old EE from the tube & class-A era, AB for car audio. This is my first foray into class-D and I'm seeing some things I'm not used to. I'm comparing the Kenwood ($109) to an Alpine S-A32F ($144). I need very little power, so either will work fine. The Alpine spec is:

• 55 watts RMS x 4 at 4 ohms
• 80 watts RMS x 4 at 2 ohms
• 160 watts RMS x 2 bridged output at 4 ohms (4-ohm stable when bridged)
• 40A fuse

The more I spend on an amp, the less I have for an underseat subwoofer, but I'm thinking the Alpine's extra overhead might be worth the $45 delta.

 

I've been running the M1814 for about three years now in my Jeep, bridged to a passive front component set. So far it's worked great and hasn't given me any issues. I don't remember the exact numbers, but we did test it after the initial install and it was right at (or maybe a hair above) the published 90w x 2 spec using a 1kHz tone. I do remember it had a clean out put on the oscilloscope up until it clipped. It definitely gets a bit hot on the outside, like most smaller amps do.

I picked-up a second one a few months ago from BestBuy (open-box excellent for $45), which will eventually run some Unity 7.5s, with the current one moving to the mid-bass speakers...that is if I can ever find the time (and energy) to do it. Might want to check their website out and see if a store nearby has one, or if there's one they'll ship (only available on some of the 'excellent' ones).

 

these latest D class amps are more or less %80 efficient so yeah a 15 amp fuse should do it technically,
the amp also does seem to do rated on the youtube videos:

by the way if room is an issue and you wish for an AB class amp with not only 4 channels but 6 and that has a built in DSP I couldnt praise enough for the Match PP62DSP it doesnt have bridgeable outputs but with any efficient 6inch driver it surely will please with a good tune and is very capable due to the dsp and very compact.

 

It could also mean that it just can't do anymore than 45W per channel at 2 ohm and stay under 1% THD.

 

Thanks for all the information! I want to convince myself that I should step up to the Alpine (or Polk, I love all things Polk) but reality is that the Kenwood is smaller, cheaper, and sounds like it's probably perfect for my needs.

 

Update: I bought the Kenwood KAC-M1418 and did a temporary/test setup using a fuse tap. I connected one channel each for front L&R (Polk MM6502 components+switchable Eclipse tweeters). The other two amp channels are not connected. At unity gain on the amp there is more clean, crisp power than I will ever need.

The rear speakers are just backfill, plenty of volume from just the HU. Two options for the remaining amplifier channels: bridge the fronts to get double the power, or power the rear speakers.

I've also toyed with using the spare channels to bi-amp the front components. I'm installing a powered subwoofer, so I could have, effectively, a tri-amped front and leave the rear on HU power for fill. It would require some work, and I don't know if my system is good enough to provide audible improvement from that.

[More details about my experience with the Infinity Basslink: https://www.diymobileaudio.com/posts/6329168/ ]