Why does Alpine insist on having such a high impedence on their pre outs?

[grampi 10+ year member]

I just called Alpine technical support and asked them what the impedence was on the pre outs for the CDA-9887. He said 10K ohms, which is exactly the same as it was on my old HU, the CDA-7892. This was the only complaint I had with this HU as the high impedence basically means instead the of having a true 4 volt pre out, the end effect is about the same as having a 1 volt pre out. Why does Alpine insist on having such a high impedence? Most other company's HU's have an impedence of only 100 ohms or less. When using the the Alpine's with the high impedence pre outs in my system, this means I have to have my amp's gain for the sub, and the HU's sub out level adjustment turned all the way up just to get a moderate level of output. So now if I decide I want to go with a 9887, I'm going to also have to purchase a line driver if I want to get the full output capabilities from my system. Why can't Alpine make their HU's with a normal amount of impedence like everyone else? //content.invisioncic.com/y282845/emoticons/mad.gif.c18f003ab0ef8a0d9c27ca78d77a6392.gif

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[frzninvt 10+ year member]

Probably for better noise rejection/suppression, I have never ever had trouble getting a system headed up by an Alpine deck loud. I have been using Alpine deck's since the introduction of their first component cassette deck the 7307 back in 1979. The 7909 was and still is one of the finest head units ever produced period, it continues to draw big dollars.

Seems you may be in the less than 0.1% that has ever had issues with the impedance. You don't get the full 4V until you reach the upper end of the volume control and it is source program material level dependent this is true for just about every deck out there.

You need to revisit your amplification, CD's or recording quality!

 

[skydeaner 10+ year member]

How bout you list your entire system's worth of components so we can see where the problem really lies. there is no way you should have to have your gains cranked all the way up. Could be grounding problems too as weird as that sounds. Make sure your deck is grounded well, not through the factory harness if possible.

 

[grampi 10+ year member]

My system is composed of the following components:

CDA-7892

JL XR-650csi Comps

Elemental Design e12K sub in a sealed enclosure (dual 4 ohm voice coils connected in series)

Kicker KX 600.4 amp running in 3 channel mode (75 wrms x 2 for the comps, and 300 wrms x 1 bridged for the sub).

The HU is not grounded through the factory wiring harness.

In order to get a balanced sound (I like a little extra bass than you'd have if the system was truely balanced using a spectrum analyzer, but I'm no bass-head by any stretch of the imagination) I have to have the gain on the amp for the sub turned all the way up, the sub level output control on the HU turned all the way up, and the comps faded to about a minus 6 or 7. I made sure the sub enclosure was completely sealed and is of correct volume. The result is a sound level that can barely even be heard at volume control settings of 10 or lower, and to get a decent amount of sound I have to turn it up to 20-25 on the highway. Even at this volume setting the output is not loud. I can turn the volume control all the way up (it only goes to 35) and the system never does get extremely loud, and it won't get loud enough to distort. With the amount of power I'm running (and I know I'm not pushing an extreme amount of power, but it definitely should be a sufficient amount for my system), this system should be able to get a lot louder, and I definitely shouldn't have to have my settings so jacked up just to get a decent amount of output from the sub.

 

[tsenfw 10+ year member]

how do you ground the HU without using the factory harness? I have the same symptoms with a kenwood deck, it's probably my grounds.

 

[frzninvt 10+ year member]

Is the 7892 a 2V or 4v output HU?

Do you play CD-R's, MP3's or store bought CD's?

Are you feeding the 4 channel amp with a single set of RCA's from the deck and having the amp parallel them internally? Or are you feeding the front channels with one set and the other bridged channels with the subwoofer output jacks?

 

[its_bacon12 10+ year member]

more powerful amps

 

[jblayz1 10+ year member]

more powerful amps

x2

 

[jblayz1 10+ year member]

..The 7909 was and still is one of the finest head units ever produced period, it continues to draw big dollars.

my buddy had one years ago. that thing was seXXXy!!!

 

[grampi 10+ year member]

how do you ground the HU without using the factory harness? I have the same symptoms with a kenwood deck, it's probably my grounds.

Are you talking about the car's harness, or the HU's?

 

[grampi 10+ year member]

Is the 7892 a 2V or 4v output HU?
Do you play CD-R's, MP3's or store bought CD's?

Are you feeding the 4 channel amp with a single set of RCA's from the deck and having the amp parallel them internally? Or are you feeding the front channels with one set and the other bridged channels with the subwoofer output jacks?

4V

CD-R's and pre-recorded CD's only.

One set of RCA's for the stereo channels, and another set for the sub.

 

[grampi 10+ year member]

"more powerful amps"

The e12k is rated for a max power input of 300 watts. It should bump plenty hard enough with that amount of power.

 

[BassBallin]

i had a alpine hu and it didnt really start gettin loud till i cracked it up preaty good, i dont really like alpines anyway

 

[grampi 10+ year member]

i had a alpine hu and it didnt really start gettin loud till i cracked it up preaty good, i dont really like alpines anyway

I'm not by any means brand loyal, it just seems the Alpines have had the features I'm looking for when I've been in the market for a new HU without having to pay an outragous price for it. Of the few other HU's that have the features I need, one doesn't fit in my vehicle, and the other two are too expensive.

 

[Demi 10+ year member]

Ive got an easy solution. Being an Alpine HU fan myself, and never running into this problem, trouble shoot thusly... Swap HUs with a friend right fast, and see what you get. I would wager dollars to doughnuts that you will find you have the same problem, and if you dont you know you have a faulty HU.