Kenwood DDX393 - Installation Help for noob

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canman

canman

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Picked up a Kenwood DDX393 this week from a local audio shop. They also supplied my with an adapter harness kit (Metra 70-8112) to use with the factory amp. As I have never installed a stereo before, this is new to me, and I'm not sure what needs to connect to what. Right off the bat, I'm not sure where the RCA connects go from the Metra Kit. I think they go to the rear pre amp RCA connectors on the back of the head unit, but the Metra pinouts label everything as positive. If that is correct, then can assume that there is no need to connect the 8 speaker wires that comes on the Kenwood harness? Any help would be much appreciated.
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I can't provide much help, but I will note that it is not uncommon to bypass the amp. Many have reported that it sounds better to have your headunit power your speakers directly. I was able to find quite a bit of information on the subject through searching MUD
 
I'll try it first with the factory amp. I know most bypass it, but I really like the small "sub-woofer" speaker in the center console, so I not sure how I can get it to work if I bypass the amp.
After a bit more review, I think I have figured it out, but would like to know for sure. It seems that there are only five wires that I need to physically connect between the Kenwood harness and the Metra adapter harness. They are:

1. Ground - black
2. Ignition (ACC) - red
3. +12VDC (constant) - yellow
4. Amp power - blue/white
5. Antenna power - blue

They are all coloured the same, so that makes it even easier. There is no illumination pin on the Metra adapter even though there are pins in the factory and Kenwood harness for it.
 
Good idea. There seems to be quite a few high quality mini amps that may fit into the stk amp location. Will look into this further.
 
Made some progress today. Got the front camera installed and most of the wiring for the head unit. I want to have a switch to manually select the rear camera, so I added some diodes and extra wire. Factory brackets fit no problem.
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Got it all hooked up, things worked fine until I went to bolt the HU to dash. As I was moving the HU into position, there was a lot of craclking through all speakers when the four mounting tabs would come into contact with the metal inserts in the dash. Engine is off, and no change when engine is on at idle. Bolted it in, and got an annoying hum through the speakers. Touching a wire between the HU chassis and ground produces the crackling noise as well. Any advice?
 
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Sounds like you pinched a wire. I would tear back out and start there. Learned many moons ago as well to disconnect the battery as will fiddling with any electronics in a car/truck. BTDT
 
Seems from what I read, it is most likely a grounding issue. I grounded the HU by tying into the gnd wire in Metra adapter harness, but advice on the Internet for theses types of problems suggests actually grounding the HU to the vehicle using a separate gnd wire no longer than 18". I also ran a gnd wire and +12V (acc) wire along the video cable from my front camera back to the HU. Seems running power next to RCA cables is a no-no. Will try grounding the HU first to see if that works.
 
Grounded the HU using one of the mtg screws, but still get a bit of a hum/whine but much better. Suspect noise is still coming from the long ground wire coming front the front mount camera. Will ground that at the front bumper tomorrow. Pic from the front camera. Tool box is about 2' from bumper.
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Played around some more trying to get rid of the hum, but no luck. Grounded the gnd wire to my starter battery for the front camera, but no change. Disconnected the CD player connector under the center console, still no change. Found two bare wires at the one of the OEM amp connectors including one that may have been a shield of some type as the bare section was over 1" long. Taped it up, and no change. Suspect that the OEM amp might be the culprit, as there is nothing "ON" that I can think of that might be introducing the hum. Will likely take it back to shop where I purchased the HU from to see what they think.
Also managed to play with some of the audio settings. Not sure how legit all this gimmickry is, but overall, I must say sound quality is good, but volume at highest setting seems to be less than the factory unit, which seems strange. Also, at higher volumes, the front speakers seem to get "clipped" if that is the correct word. Really like being able to stream songs from my iPad using BT, but there is a bit of lag in responsiveness. Overall, for the price, the unit is packed with lots of features, and I would recommend it to those looking for a double DIN replacement that don't need NAV (I use my iPad plus old Garmin 60CSX).
 
I had same issue....get a ground loop isolater from amazon,ebay,crutchfield or supplier of your choice. it plugs in between the rca's between head unit and amp. cheap and this will fix your problem. Some have also used plastic screws to mount head unit to dash. It will fit right on top of head unit,space behind it gets tight.
 
Thanks. I'm going to order the ground-loop isolator today. I still had the hum when the unit wasn't installed, so doubt plastic screws will help.
 
Did you end up running the factory amp with the Kenwood head unit? I have the rear sub, but I bypassed the factory amp and ran a small 40W Alpine amp to a replacement 6" subwoofer. No hums, clipping or crackling and everything works great. I also bypassed the headliner speakers.
 
Ran another gnd wire for the amp, and think it helped a bit with noise caused by the engine. I'm bringing it back to the shop this Wednesday to see if they can solve the problem. He told me today the factory amp was very hot.
 
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indeed bypassing the factory amp is the way to go - unplug it completely -
there is some odd wiring - it that even if you only use one other harness - there is some sort of power lines still going to the amp -

make sure the gnd wire mount is free of paint = bare bare metal and tightly crimped - also check the output levels on your amp -
keep the gains at 3/4 at most...

fwiw - I haven't been a big fan of RCA outs from a harness - I prefer just using the RCA outs from the H/U -

instead - I used this harness

https://www.amazon.com/70-1761-Wiring-Harness-Toyota-Speaker/dp/B0002BEQJ8/?tag=ihco-20

as to the clipping - am trying to figure if you are now running an extrernal amp to power your door speakers ??
if not - again check the levels & eq & xrossover points on your new h/u....

feel free to hit me up more - am always glad to help out with speaker wiring -

bf
 
Went thru that couple days ago, easiest way... paid the audio store where I bought the radio for installation. 30 minutes later, radio was installed. BTW, nice radio! That's was my second choice...
Nakmichi 3020.webp
 
Shop wanted to install a ground loop isolator, but had none in stk. Wait and see..:meh:
 
Spent a good part of the day checking some grounds. Found the one to the intake manifold was cracked and very corroded, so I spliced in a new section and got rid of the connector. Also found that the nut and washer on the positive stud of my alternator were corroded or damaged by excessive heat, probably caused by poor contact with the oversized wire lug I used when I upgraded my alternator. Also found that one of ground wires on the PS inner fender had busted and corroded wires, so I replaced that ring terminal. Also found that the nut on the positive stud of my aux battery terminal was loose. What a mess, but at the end of the day after all the fixes, I still have the hum/whine. I even pulled out all of the fuses, and no change, except of course when I pulled the radio fuse. I even ran a ground wire from where the amp is grounded to the extra gnd wire I tapped into that goes to the HU. Still have the hum/whine, do l'm guessing it is due to the amp for some reason. Will try the ground loop isolator as a last resort, and if that doesn't work, I will have to bypass the amp. What a cluster and waste of time...:bang::bang::bang:
 
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