cheap Double-DIN head units w/ Android and Apple integration

[Paul Carmody]

I learned something... I learned a lot, actually...

When I first killed the head unit, I was sad, but not necessarily in despair. Part of me knew that this would be a learning opportunity, even if I didn't know what exactly I'd learn.

How to power a car stereo with stuff lying around the house.
I wanted to take more time to really study the head unit on a bench, not sitting in the cabin of the car. But how to drive it without the car battery? I quick bit of reading instructables and I realized I had plenty of 12V DC power supplies sitting under my nose--Computer Power Supplies! I'm sure this is old hat to lots of folks out there, but it never occurred to me you could just use the 12V rails on a PC power supply, and all you needed to do was short 2 pins to "fake" the PSU into thinking the power switch was on.

Trace Fuses
So now that I had a solid 12V to drive the head unit, I could still tell it wasn't happy. I scoured the internet for any info I could find on these head units. I noticed a 10+ year-old thread on a Miata message board about an earlier version of the head unit, where the OP was concerned he'd permanently blown his HU because of an improperly-seated aux harness--sounded pretty similar to my situation. He must have been a more talented EE than me, because he was able to hunt around the circuit board and find some very thin traces on the board labeled "trace fuse," one of which just so happened to have broken. He reported that he repaired the trace on the circuit board and the head unit came back to life!

I thought to myself that must be what happened to mine. So I searched all over the circuit board for anything labeled "trace fuse." Nothing. So I put the device aside to deal with later.

A few days later, I decided to get out a magnifying glass and a stronger light. Sure enough, I DID find a blown trace on the circuit board. It was labeled "F12" or something like that. I assume "F" meant fuse. I repaired the trace with 1/4" length of "bus bar" and plugged the head unit into my homemade 12V PSU. BAM! It's perfectly happy and back to normal.

I'm not an EE (obviously). I'm just DIYer who likes to dabble in electronics and audio. But this is the first I've ever heard of such a phenomenon as a "trace fuse." I get why they do it: it's cheap. Making a super-thin trace on a circuit board is way cheaper than sourcing some sort of SMD fuse. But at the same time, it's weird. Like, now that I've repaired the trace with a much thicker "bus bar," well, there is no more fuse in that circuit. Is this the electronic equivalent to playing Mario with 2 lives?

EEs, feel free to chime in here.

[Ray Tremblay]

Hey Paul. Congrats on the Miata. Similar situation, a good friend of mine has also wanted one for about 20 years and just got the same generation. He purchased at a Copart auction in Dallas (4 hours away) so I drove up there with a truck and trailer to pick it up and bring it back to San Antonio. His other two sports cars are a GTS Viper and an old white James Bond Lotus Esprit (right hand drive) with a GM LS V8 and 7875 turbo. Point being, it's a great sports car as he has some serious fire power but prefers to drive the stock Miata.

Does your cell phone have a head phone jack? If it does and you're not opposed to going a little further on the install, maybe investigate the JBL DSP4086 amplifier and DSP combo. I just got one in the mail today that so far appears to be the ultimate one box simple solution for a car stereo with incredible capability. 8 channel class D amplification at 40 watts RMS per channel at 4 ohm, 60 watts RMS per channel at 2 ohm. The DSP is nearly limitless and has a 31 band parametric eq per channel.

I also worried about theft so what I really like about this unit is that I can leave my stock head unit in and hide this little JBL amp/processor under or behind the dash. It can be wired directly to the factory speakers but I'll be installing some tiny OT19NC00 ring radiator tweeters, B&C 6MD38 mids and RSS315HO-44 subs that I've had sitting in the closet forever. If anyone ever broke into the car, the only thing that would be visible will be the Dayton subs in the hatch.

I'll keep you updated and let you know how this thing performs. So far, the software seems to work flawlessly. I just need to get it in the car and make sure it doesn't have issues with alternator whine or a high noise floor and that it is able to drive the speakers loud enough with a cell phone being plugged directly into the RCA inputs. I've had luck plugging cell phones directly into RCA's in the past but I can't find input impedance specs on this unit so I'll just have to try it out.

[Paul Carmody]

Ray,
Wow, that thing sounds fking amazing! Like, seriously, what else do you really need? I honestly had never heard of it, but I love the idea. You get to keep the "stock look," you hide an amp somewhere, and then you basically have an active speaker setup that you can tweak to your heart's content. If my search for a head unit brings me even close to half the price of that JBL thing, I think I'd just go ahead and make the leap and get the JBL. Seriously amazing find. Thank you for the heads up.

[Ray Tremblay]

Seriously amazing find. Thank you for the heads up.

No problem.

Bad news with the install update.....I think I got a dud. Pulled an all nighter and installed the whole stereo. No sound.

I know it's getting input signal because I'm using the "Audio Sensing Turn On" setting which turns the unit on as soon as I start playing music from my phone and it powers off shortly after I stop playing music or if I turn the volume on my phone all the way down.

Green power light comes on and the red protect light has never come on.

The software is straight forward and has basically all the same functionality of my MiniDSP. The only thing that acts funny is the input mixer. I can set it, close out of that screen, then when I go back to it, the settings are completely different. I've uninstalled and reinstalled the software a few times with no luck.

I'm going to sleep on it and call JBL tomorrow. Hopefully it's just a software issue.

[Ray Tremblay]

If my search for a head unit brings me even close to half the price of that JBL thing, I think I'd just go ahead and make the leap and get the JBL.

A week after I purchase on ebay (and get a bad one) the price drops way down on amazon. Wonderful.

Anyhow, you're in luck. $239.95

https://www.amazon.com/JBL-8-Channel...ws_feature_div

[davidB]

Once you're using a phone, why not use BT or Wifi? Why use a cable?

[Ray Tremblay]

Once you're using a phone, why not use BT or Wifi? Why use a cable?

This unit doesn't have any wireless ability and a physical connection is always better in terms of sound quality so I prefer the cable. If it wasn't obvious from my signature, sound quality is kind of a big deal to me. I'll take sound quality over convenience every time.

[Serenitynow]

PM sent to Mr. Carmody

[Paul Carmody]

Looking around at the cheap double-din head units, I saw that our own Toid did a review of a unit called ATOTO SA102, and loved it. His pitch was basically, "This is amazing for less than $200!" Unfortunately, Amazon no longer sells it. But a search of ebay found that ATOTO themselves is selling them on clearance for $100. So like, come on, how could I not?

https://www.youtube.com/watch?v=Z-oeRSaHRcc

Hardware-wise, it seems fine. No knob, unfortunately. Just 6 clicky buttons along the bottom. It's got inputs and outputs galore on the back. With the addition of a kinda crappy retrofit adapter from Metro, and some harness building on my part, I got the radio installed with little fuss.

How does it work? It really does work well! I was expecting the UI to be slow and clunky, but it's not. It's pretty much just as quick and responsive as the fancy system that came with my 2016 Acura. Android Auto seems very stable; the biggest downside is that I have to plug in my phone each time, and "allow data transfer." But once that's done, it's up and ready to go in 2 seconds. Old technology-wise, local radio stations were easy to find, and sound good.

Sound quality seems fine. I use the line-out from the ATOTO to feed the built-in amps in the car. Noise floor is about the same as the factory Head Unit--which probably means any noise floor I'm hearing is probably the OEM amps. The ATOTO has a 12-band EQ, which helps a lot to tailor the sound for the car itself. Although the frequencies they chose for the EQ are really random. I would have preferred something more logarithmic so I could shape the sound more logically. Still, for $100, like how could I possibly get angry about this?

The only drawback here is that the screen is mega-glossy. If it's sunny out, I basically only see the reflection of the passenger seat and nothing else. I ordered a glare filter; we'll see how that goes. Also, the font on Google Maps is so tiny it's basically unreadable. I don't see a way to change this--I'm more than open to use another mapping app, but I haven't really looked to see what other mapping apps support Android Auto. I've gotten used to always having an overhead map whenever I drive with my other car; it makes for a more interesting drive, and willing to find alternate routes to places.

So that's pretty much where I think I'm going to leave these adventures. This is really my first time dipping my toes in car audio, and it's been a lot fun. But honestly I don't want to go too far with this, because I know whatever changes I do, I'll have to un-do when I go to sell the car. However, if I ever were to go one step further with the car: I think the system could really benefit from a sub, to take the load off the midwoofers in the doors. I'd probably design a sub if there was a way to do it without cutting any holes in panels or trim, or running new wiring long distances. See, my goal since getting this car was to revert it back to stock, which I've done (not mentioned in this thread are the other mods the previous owner did that I've removed and/or replaced with OEM). Now that it's at that point, I intend to have mostly-legal fun driving it, and then someday hopefully sell it for at least as much as I paid. And sadly for many, modding cars only decreases their resale value.