iPad head unit

[drtbreau]

I’m trying to figure what to do with my radio. The original one was pulled out and the wires were pulled. I’m basically interested in using an iPad as a head unit. I’m just trying to figure out how.

My basic understanding is: iPad with a splitter going to 3.5mm audio jack to amp and to power pad, amp to speakers, power into amp.

I would be running new wires to 6 x 9 speakers (probably 4), haven’t decided on a sub or not.

Questions: powering the amp from my 200ah batteries/2000w inverter? Will that work? Or do I need to do a remote with my starter batteries?

[Mountain Gnome]

Originally Posted by drtbreau

I’m trying to figure what to do with my radio. The original one was pulled out and the wires were pulled. I’m basically interested in using an iPad as a head unit. I’m just trying to figure out how.

My basic understanding is: iPad with a splitter going to 3.5mm audio jack to amp and to power pad, amp to speakers, power into amp.

I would be running new wires to 6 x 9 speakers (probably 4), haven’t decided on a sub or not.

Questions: powering the amp from my 200ah batteries/2000w inverter? Will that work? Or do I need to do a remote with my starter batteries?

I'm not even sure what you are asking...


What is the "power pad"? Is the splitter feeding this an audio signal also, and why? (or is the second question self-evident when answering the first)



You "should" be able to run an adapter cord with a 3.5mm stereo headphone jack to a pair of RCA jacks, and connect the iPad to the amp directly. You will likely get much better quality sound if you buy a head-unit (I recommend Pioneer and Alpine) that connects to your iPad/iPhone through BlueTooth. The pre-amp in your iPad/iPhone is weak and usually not very "clean", and will send a poor, weak signal to your amp. If you want 4 speakers, a good automotive head unit will have front and rear RCA outputs, that you can adjust individually. If you use the iPad/iPhone directly connected to the amp(s), you will need a "Y" cable as well as the adapter cable, and won't be able to adjust the volume individually, except at the amp's "gain" control. Or you could connect the speakers to the same amp outputs (without the "Y" cable needed), in series or parallel, but make sure you understand the ohm rating of the speakers, and the usable resistance for your amp, or you can blow the amp if not installed correctly.


I would suggest you buy (a) 12V car-audio amp(s). No inverter needed, and therefore can run at any time. Inverters only waste power (even if only a little) anyway. Not sure what you mean by "remote with my starter batteries". You can run it off your house batteries (if they are 12V) or your starter batts. I'm running mine off my house.



If you like audiophile sound, get a class "A/B" amplifier. If you are satisfied with good clear, "OK" sound, you can get by with a class "D" amplifier. The class A/B will, however, pull more power from your batteries, while the class D amplifiers are about as close to efficient as possible (very little power loss to heat). The class D amps are also smaller.



I have a Class D Alpine that I put in my king-cab truck. I really liked it there. I had Alpine 6×9s that were set in 3/4" flooring plywood that filled the space in the walls where I pulled out the rear jumper seats. So they were not in a sealed "box", but the walls vented open to the outside, so this is called an "infinite baffle". It offers the least resistance to the woofer cone going in/out, so little power is needed for big bass sound. I parked at the beach one night, and walked 1000 feet away, and could still feel the bass, and hear the music. However, a "sealed" box offers more accurate "tighter" bass - you can hear the slap on the skins of the drums, not just the "pounding".



I gave that truck away (needed a head gasket, and the roof around the skylight was rusting and starting to leak, and there was another hole behind the dash under the cowl that couldn't be gotten to to fix that flooded the floor, but it still ran) and pulled the stereo and amp and speakers.


I put that same class D amp in my bus with new top-quality Focal speakers along with the same old Alpines that I had in the truck, plus some 8" woofers I pulled out of a set of Acoustic Research bookshelf speakers. But this time the speakers were in air-tight sealed "marine" pods (they look nice, and solved my setup problems). I was so disappointed. Sounded like a $39 boom-box. I also have a home audiophile system from the 1980s (when audiophile was king, before "home theater" ruined the sound quality in the audio market in favor of other expensive circuitry) that is set up at my mom's house, where I'm doing my conversion. Perhaps comparing the class D amp to that system made the difference in my mind, as I didn't have the truck nearby when that was set up.



But with the class D, there was no bass, and the cymbals sounded flat and weak, and not at all bright - like a tin can not brass disks. The sealed pods could effect the bass, but not the tweeters. I saw the woofers were not noticeably moving at all! I swapped the Focals over to a 30-year-old class A/B amp I had bought for my 1977 Dodge conversion van, and the cymbals came to life, and the bass started rolling. The Alpines are known to have very strong tweeters (great for vehicles riding down the road with windows open and rushing air-noise), but the tweeters in the Focals on the class A/B beat the tweeters in the Alpines on the class D with no real competition. Note that both amps are rated for the same RMS wattage.



Then I bought a couple of Alpine class A/B amps. These are audiophile amplifiers. The sound is so much cleaner, clearer, and more powerful. You can have all the power in the world, but if the signal sent to the speaker cone is not "clean", the resulting sound-wave will "fall apart" with very little third-party-sound interference - just the ambient sound around you. The bass-wave will not travel far. With clean sound, you can hear it / feel it far away, even at lower power levels.


With the class D amp, I had to set the "loudness" setting in the JVC head unit - which increases the low-bass and high-treble at lower volume levels so you can hear them - to the highest boost level. With the class A/B amps, the sound is more perfectly balanced at all volume levels. Below "7" was impossible with the class D, or some (a lot of!) sound was lost, even with the "loudness" on. I get it down to "2" or "3" with the "loudness" setting off, using the class A/B amp when it's late at night and I'm heading to sleep....and it sounds wonderful.



I'm making my own subwoofer boxes, soon to be done, but I'll have those added in soon also, on their own Alpine class A/B amp...stay tuned on another thread



In the pics, you can see the Alpine class D amp behind the JVC head unit, and how it is 1/2 the size of the class A/B amps. Nothing is connected to it now. I may add more, cheap midrange speakers above the dash for when driving only, and use this amp to power them.


p.s. I got my JVC head unit from Crutchfield. They talk up their "staff" that "reviews" all products. They lied about this being a 6-channel head unit - it is a 5-channel with 6-RCA outputs, 2 stereo front, 2 stereo rear, and 2 MONO subwoofers. And it said 4V RCA output. And if your amp can't handle 4V input, there is a setting that limits the volume to "25" instead of "35" and the therefore the output is limited to 2V (like most head units offer: 2V). But above "27" on the volume, the sound is so distorted, it is not listenable. Like I said, Pioneer or Alpine. But this JVC one plays my 96kHz FLAC files....waiting for Pioneer or Alpine to catch up.

[rossvtaylor]

My hat's off to Mountain_Gnome...a man after my own heart. I once drove from Arizona to Arkansas to meet Paul Klipsch...I guess I'm a geek, too.

As to the OP's question, we run an iPad audio output (with a 3.5mm>RCA cable, as M_G described) straight into an amplifier at our restaurant. It has adjustable inputs and master volume, like a mixer would, so we don't need a separate pre-amp. We run a Spotify business subscription on it and it really sounds pretty darn good.

[Mountain Gnome]

Originally Posted by rossvtaylor

My hat's off to Mountain_Gnome...a man after my own heart. I once drove from Arizona to Arkansas to meet Paul Klipsch...I guess I'm a geek, too.

I was guessing you to be a man, Ross; is that a trial-case? Ross v. Taylor?

The accident occurred when Mrs. Ross was driving her car on Hicks Road in Taylor County on a clear afternoon.   She was unfamiliar with Hicks Road, and when her car rounded a curve at the end of the paved portion of the road, it skidded into a ditch and flipped over.   The record shows that Hicks Road was built by the county pursuant to a public road contract with the State Department of Transportation.   The original plans for the road were altered by the county before construction began when a railroad objected because the road encroached on its right-of-way.   Pursuant to this change in the plans, a portion of the road was left unpaved.

I'm seeking the heart of a good woman. Yea, she loves music. And hiking in the mountains. Among other things.


And Klipsch. You went to meet Paul because you were a groupie? WOW.


I've got a pair of KG4.2s at my mom's place. They've got horn tweeters and 10" woofers and 10" passive radiators, and the deepest, most powerful bass I've heard besides 12" Klipsch with 12" passive radiators (I used to have a pair of Klipsch Tangent 3-way with horn mids and tweeters). I used to run them off Marantz's flagship 4400 quadraphonic amp (in stereo) at 125 watts RMS. That rocked. My mom blew it flipping a circuit breaker. Now they have a Marantz 4140 quad amp. Both these are 1970s amps, and the 4140 is dying also. Quality stuff. The amps I bought new in the 1980s all died years and years ago.


But the Klipsch KG4.2s are accent speakers. The sound is a bit off balance, very bass heavy. So I have a pair of old-school Harmon-Kardon Twenty speakers, from just before HK, a privately owned company started by two audiophiles, sold out to Infinity, which was quickly bought by Tweeter Corp. in this massive consolidation thing that happened; then Tweeter Corp. went bankrupt. Now the HK brand does not make home speakers. Infinity bought them because of the tweeter tech, and these Twentys do have the sweetest tweeters I've heard. Bells sound like a real bell in the room, not a recording. And the ported bass, yea! Almost as powerful as the Klipsch, but unlike the Kilipsch, the HKs would make David Gilmour's guitar growl loud! Vocals, like the bells, sound real, like someone in the room, not a recording.


I had those HKs running off a Marantz 2230 (also a 1970s amp). Rated at 30 watts RMS, it would kick the living sh*t out of my Kenwood 70-watt RMS 200-watt peak amp. Like I was saying about bass that travels....the Kenwood was loud, yes. But the floors barely shook at max power. And you couldn't hear it at the other end of this large ranch-style house. With the Marantz at 1/2 power, the floor shook at the other end of the house. Turn it up, and it would clearly overpower the Kenwood. I had 2 of those (both bought used), but both sadly died.


To balance and complement the HKs which I ran as front-primary speakers, I have Infinity Reference E-L bookshelf speakers for the rear. I was turned on to these and Marantz when I worked at a restaurant. Someone bought the Marantz used, and the Infinitys were there. Suddenly, the salt-shakers on the tables all danced when the music was turned up. The owner eventually got a brand-new Yamaha amp, and the salt-shakers stopped dancing. I got the Marantz from him, and went out and got similar new Infinitys.


I ran the Infinitys on an old Sony ES series stereo amp, at 75 watts RMS, 200 peak. That was a good clean powerful amp, about like the 30 watt Marantz. I dropped a sliver of speaker wire in it, and a green flash came out when I turned it on. It was never the same, and eventually died. That was replaced by a newer Harmon-Kardon 7.1 channel home-theater amp, at 55 watts RMS per channel. Wish I could use it for 2 or 3 stereo pairs, but all it can do for me is 1 pair of stereo speakers. I typically have it turned way up just for normal listening levels, but it is clean sound. I'm almost certain it is a class D amp.


When all is good, the resulting full surround-sound you get from a stereo recording on my home system is really amazing! Pure joy to listen to old live Pink Floyd! That is in a 25'×30' vaulted ceiling room.


The system I've set up in the BlueBird is getting there. It's hard when your sound-stage is a narrow, long, low-ceiling metal box with sound-reflecting surfaces everywhere; and I don't have the subs in there yet, so the Miles Davis acid jazz is still lacking in that deep deep deep bass grind and roll, and the rock-and-roll kick-drums don't yet kick the sh*t outta ya; but it is still beginning to impress me. Gotta ditch that JVC and get a Pioneer, with the Burr-Brown DACs. I didn't care for digital recordings until I heard a Burr-Brown 24-bit DAC 20 years ago.

[rossvtaylor]

Haha! Mountain_Gnome...I am a man and I identify as a man. I just meant that I share the same love for good quality audio. My sisters don't share that... sorry if I got your hopes up!

Instead of "man after my own heart" I should have said "a man of like mind"...but music goes deeper than the mind for me and I got carried away.

And my screen name is pretty boring...just my first name, middle initial, and last name. No legal background here!

[Mountain Gnome]

I forgot about another of the OP's original questions:


I use a Black & Decker battery charger to keep my house batt alive when not driving. It shows the amperage when charging.


I can also use it as a power supply, with the battery as a capacitor. So when the battery is fully charged, and I turn on the stereo system and then turn on the battery charger, it will show me the amps being used at the moment.


When the volume is low, the stereo is using between about 3-6 amps, occasionally up to a peak of 7 amps. The amps used varies from moment to moment, as the song gets louder/softer. This is with the two 12V class A/B amps and the 12V head unit. I just got the latest Dave's Picks album, very dynamic and powerful music, and had it blasting at the highest volume level. That used 10-14 amps, again varying from moment to moment.


So lets say an average of 12 amps × 12 volts = 144 watts at max volume.