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Discussion Starter #1
I have a windows tablet that I was talking to a local shop about installing in my ride. They told me that there is a 40% chance of engine noise with this type of install, and once you get it you can't get rid of it.

I'm not a pro by any means, but this doesn't sound right to me. Are they right?

In addition, does anyone know of any good shops in NC?
 

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.That's BS, sounds like they just didn't want to do it or they don't know how to do it correctly, either way stay away.

Sent from my DROIDX using Tapatalk
 

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No, they're not nuts. The audio ground in the tablet and the power supply ground are probably the same. When you plug the tablet's power supply into the cigarette lighter and plug the audio cable into the audio system there will be a ground loop. You have 2 choices:

1. Use an isolated power supply (requires a DC/DC convertor).
2. Use a ground loop isolator (transformer type) between the tablet and whatever you plug it into.
 

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Discussion Starter #4
Does it make a difference that the tablet comes with a power cable for the cigarette lighter?
 

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No, they're not nuts. The audio ground in the tablet and the power supply ground are probably the same. When you plug the tablet's power supply into the cigarette lighter and plug the audio cable into the audio system there will be a ground loop. You have 2 choices:

1. Use an isolated power supply (requires a DC/DC convertor).
2. Use a ground loop isolator (transformer type) between the tablet and whatever you plug it into.
Or assuming a "windows tablet" is compatible....

Just get one of these and fo giet about rrit! (ie don't worry about fishing for an appropriate PS)

http://centrance.com/products/dacmini/cx/i/dacmini_case_study.pdf

"1. Audio signal path with full galvanic isolation Proper grounding is extremely important. With DACmini we approached grounding isolation seriously because we wanted to develop a product that could be used in regular households, where RF interference from other consumer electronic devices and imperfect grounding conditions are encountered frequently.

In many DACs currently available on the market, a significant shortcut is taken by
the manufacturer in order to reduce design cost and manage product complexity. In
a rush to bring a product to market, manufacturers tend to neglect a very important
issue in grounding. An issue that is prominent in real-world houses and apartments,
where electrical wiring is not done per contractor’s code. Unfortunately, this covers a lot of today’s households, many of which were built to older standards, resulting in
poor grounding through the power outlet and leading to the formation of ground
loops and a real possibility for hum and buzz in the audio circuits.

The correct solution avoids ground loops by breaking the unwanted connection
between grounds. DACmini does this very effectively because it completely suspends the DAC chip and the associated audio circuitry (including RCA jacks) in “mid air” through sophisticated components and PCB layout techniques. To minimize interference, the main DACmini PCB is actually divided in two – the right side carries analog signals and the left side carries digital signals.

What’s truly amazing is that there is actually no physical connection between the
digital circuitry and analog circuitry inside DACmini – the signals across the analog/digital divide on the PCB travel over a sophisticated magnetic barrier and
never actually make the electrical connection. The RCA connectors are isolated from the chassis by plastic washers, to avoid ground contact.

This technology has a very important real-world benefit. Your computer generates a
lot of digital noise, which contaminates the power strip or the wall outlet’s ground
pin. To prevent the digital buzz from getting into the audio equipment it is best to
plug your audio system into a different outlet, where the ground pin is “clean”.
Unfortunately, this is not possible with the majority of DACs, which don’t offer
ground isolation. When the computer’s USB ground and the analog audio ground are
connected inside the DAC, it actually shorts the clean ground and the dirty ground
together producing hum, buzz and other noises. DACmini is different. Full galvanic
isolation is a rare and a very important benefit. Countless users report DACmini
noise floor as “pitch black” and noise-free.

DACmini makes your listening enjoyable in many ways. Internal signal switching is
performed silently, so that you never hear loud pops or clicks when you turn on the
unit or select inputs. CEntrance uses expensive, audio-grade relays for internal switching. We only use gold-plated, four-layer PCBs, to minimize corrosion and
increase the longevity of your sound investment. There are no capacitors in the
audio path either, only gold-plated internal wiring, for the purest signal path."


"Another significant innovation introduced with DACmini is the custom-made, switchmode, transformer-isolated power supply generating five independent output voltages for the internal circuitry. The power supply creates independent +/-15V supplies for the analog circuitry, +5V and +3.3V for the digital circuitry and a separate, clean +5V analog supply for the D/A converter. A full 30V of power available for analog circuitry lowers the noise and reduces distortion.

The key to designing quiet switch-mode power supplies is isolation. The DACmini power supply is located on its own individual 4-layer PCB, which is properly grounded and shielded inside the unit, and carefully positioned to avoid interfering with the sensitive audio circuitry.

DACmini’s power supply features extremely fast action, allowing it to quickly react to the ever-changing electrical environment, be it a brown-out in the power outlet or a loud “tutti” in the music. A precision checkpoint voltage measurement is made 2 million times per second, followed by a swift correction to the output voltages, as necessary. A complete self-correction cycle happens at a rate that’s 100 times faster than the highest humanly audible frequency. This is more than sufficient to ensure that the critical audio voltage “rails” remain solid and undisturbed over a variety of conditions. The DACmini power supply is “over designed” to preserve audio quality and deliver reliability – it provides clean, smooth power supply rails to the internal functional blocks. Below is the picture of the power supply PCB, which utilizes advanced components and PCB layout techniques."
 
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I am under the impression he wants to just plug up the Tablet PC to the amp by using the headphone outputs of the PC to the amps.
And change the volume by using the PC. Kinda a really bad idea for many reason
BUT its possible
Not sure about all brands but I know some dont have balanced inputs.
Even expensive amps dont.
But I do know JL does.
SoundStream

Overall this idea is a bad one. Its really a bad idea cause you will end up in a wreck tryng to drive while playing with the Tablet PC.
 

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I am under the impression he wants to just plug up the Tablet PC to the amp by using the headphone outputs of the PC to the amps.
And change the volume by using the PC. Kinda a really bad idea for many reason
BUT its possible
Not sure about all brands but I know some dont have balanced inputs.
Even expensive amps dont.
But I do know JL does.
SoundStream

Overall this idea is a bad one. Its really a bad idea cause you will end up in a wreck tring to drive while paying with the Tablet PC.
mp3car.com

"Frontends"
 
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