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Impedance of Alpine Hu's

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Old 05-02-2004, 09:22 AM
  #11  
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Originally posted by Lethal:
100 ohm 4volt preouts on the CDA9833. Tom (alpine Rep) said that number (4volts) was closer to 5.5

I notice an audible output difference from my 4volt 100ohm Panasonic DPX95 to my new HU.
Did you ever get you system working right?
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Old 05-02-2004, 09:44 AM
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If I remember correctly anything less than 100 ohms is considered good. 10kohms is quite high.

My old Alpine 7894 was rated at 4V outputs, but I found the output very weak. Apparently some people tested them to be less than 1.7 volts RMS.
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Old 05-02-2004, 09:52 AM
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Originally posted by Lethal:
100 ohm 4volt preouts on the CDA9833. Tom (alpine Rep) said that number (4volts) was closer to 5.5

I notice an audible output difference from my 4volt 100ohm Panasonic DPX95 to my new HU.
I just checked the Alpine tech centre, the manual for the 9833 states that they are 4 volt at 10,000 ohms. http://www.stylestandard.net/oswego/Rooms/RoomComponents/AssetView/MoreInfo?Document=com.webridge.entity.Entity%5BOID %5BA808CD8D94D07B4489ECC326CF43DBF5%5D%5D&Containe r=com.webridg e.entity.Entity%5BOID%5B260A178E17D1D411B08E00508B B8123D%5D%5D&component=
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Old 05-02-2004, 10:09 AM
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Remember V=IR, so at a constant voltage (4 volts), the higher the resistance, the less current. This higher impedence makes the preouts more impervious to voltage fluctuation due to temperature. inductance, co-axial capacitance, etc.
The current will be much weaker though, but this will not make a differencein most practical applications.
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Old 05-02-2004, 10:15 AM
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Originally posted by Lethal:
100 ohm 4volt preouts on the CDA9833. Tom (alpine Rep) said that number (4volts) was closer to 5.5

I notice an audible output difference from my 4volt 100ohm Panasonic DPX95 to my new HU.
I am not doubting you, but, imo, if an alpine "4 volt" deck is doing closer to 5.5 volts at 100 ohms, that certainly isn't the kind of spec you should have to get from the rep. Those specs would be VERY good, and I would think Alpine would list them clearly in the manuals, lit, website, etc.
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Old 05-02-2004, 10:43 AM
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Originally posted by PerryB:
</font><blockquote>quote:</font><hr />Originally posted by Lethal:
100 ohm 4volt preouts on the CDA9833. Tom (alpine Rep) said that number (4volts) was closer to 5.5

I notice an audible output difference from my 4volt 100ohm Panasonic DPX95 to my new HU.
I am not doubting you, but, imo, if an alpine "4 volt" deck is doing closer to 5.5 volts at 100 ohms, that certainly isn't the kind of spec you should have to get from the rep. Those specs would be VERY good, and I would think Alpine would list them clearly in the manuals, lit, website, etc. </font>[/QUOTE]Very true. My 7894 has fairly weak preouts, I was told that they get their ratings with the sub level pinned, and at nearly full volume.
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Old 05-02-2004, 11:18 AM
  #17  
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Originally posted by JeepBeats:
</font><blockquote>quote:</font><hr />Originally posted by PerryB:
</font><blockquote>quote:</font><hr />Originally posted by Lethal:
100 ohm 4volt preouts on the CDA9833. Tom (alpine Rep) said that number (4volts) was closer to 5.5

I notice an audible output difference from my 4volt 100ohm Panasonic DPX95 to my new HU.
I am not doubting you, but, imo, if an alpine "4 volt" deck is doing closer to 5.5 volts at 100 ohms, that certainly isn't the kind of spec you should have to get from the rep. Those specs would be VERY good, and I would think Alpine would list them clearly in the manuals, lit, website, etc. </font>[/QUOTE]Very true. My 7894 has fairly weak preouts, I was told that they get their ratings with the sub level pinned, and at nearly full volume. </font>[/QUOTE]Yes, I would imagine the rating is at full volume(as I suspect it is for every other manufacturer...whether other manufacturers require the sub level to be all the way up or not, who knows).

I have seen many posts from alpine owners complaining of weak sub pre outs over the past couple of years. One guy tested 2 7897s(I believe I referenced his testing on here). The sub out did 3.5 volts which isn't too far off from 4 volts. That wasn't his issue. The front/rear pre outs clipped very hard at 32 on the volume(so 31 was now max volume before hard clipping). Well, at 31 on the volume, the sub out was at 1.7 volts(the sub out level was maxed, 100hz and 1000hz test tones and tested with an o-scope). Now, if that holds true for other alpines is anybody's guess.

I understand that alpine, ofcourse, wasn't too far if on "max voltage" on that sub out, but if only 40% of that is useable, I think alpine owners would have a legitimate issue with them. I mean, if you have an amp that does 1000 watts, but that is at 40% distortion, that 1000 watt spec doesn't mean a whole lot.

Maybe alpine has solved the issue(if they felt that it was a big enough issue to deal with).

[ May 02, 2004, 12:24 PM: Message edited by: PerryB ]
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Old 05-02-2004, 11:30 AM
  #18  
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Did you ever get you system working right?
Not yet. But I just bought a CPU fan from Princess Auto @ 45minutes ago. The area near the heatsink on the HU is very near the heater duct and my problem may be heat related. Gonna try it this weekend and hope for good results.

I am not doubting you, but, imo, if an alpine "4 volt" deck is doing closer to 5.5 volts at 100 ohms, that certainly isn't the kind of spec you should have to get from the rep. Those specs would be VERY good, and I would think Alpine would list them clearly in the manuals, lit, website, etc.
It's advertised as 4 volt online and in the manual and I bought it with the understanding that it was 4 volt but when I was having problems with my subwoofer output being less than my Panasonic HU I thought perhaps it may of had 50ohm preouts or a higher rating than the Alpine. When I spoke to the rep about this he assured me that there was something (somewhere) in my install not correct and the voltage of the preouts of the Alpine was closer to 5.5 than 4.

Thats all I was stating. I don't know for a fact and am going by someone elses information albeit a rep.

I really love the features and looks of this HU (CDA9833) but I am starting to pull my hair out as to what my issue is with the speakers shutting down through the IC.

I just checked the Alpine tech centre, the manual for the 9833 states that they are 4 volt at 10,000 ohms.
You are correct. I just glanced at my manual when I gave those #'s and my manual has a bit of a blur on the print for the specification page and the

4V/10K ohms looked morelike 4V/108 ohms at a quick glance. Sorry for any confusion.

Perhaps the Pioneer HU are 100 ohm preouts if I remember hearing correctly.
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Old 05-02-2004, 06:34 PM
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Originally posted by Lethal:
</font><blockquote>quote:</font><hr />Did you ever get you system working right?
Not yet. But I just bought a CPU fan from Princess Auto @ 45minutes ago. The area near the heatsink on the HU is very near the heater duct and my problem may be heat related. Gonna try it this weekend and hope for good results.

I am not doubting you, but, imo, if an alpine "4 volt" deck is doing closer to 5.5 volts at 100 ohms, that certainly isn't the kind of spec you should have to get from the rep. Those specs would be VERY good, and I would think Alpine would list them clearly in the manuals, lit, website, etc.
It's advertised as 4 volt online and in the manual and I bought it with the understanding that it was 4 volt but when I was having problems with my subwoofer output being less than my Panasonic HU I thought perhaps it may of had 50ohm preouts or a higher rating than the Alpine. When I spoke to the rep about this he assured me that there was something (somewhere) in my install not correct and the voltage of the preouts of the Alpine was closer to 5.5 than 4.

Thats all I was stating. I don't know for a fact and am going by someone elses information albeit a rep.

I really love the features and looks of this HU (CDA9833) but I am starting to pull my hair out as to what my issue is with the speakers shutting down through the IC.

I just checked the Alpine tech centre, the manual for the 9833 states that they are 4 volt at 10,000 ohms.
You are correct. I just glanced at my manual when I gave those #'s and my manual has a bit of a blur on the print for the specification page and the

4V/10K ohms looked morelike 4V/108 ohms at a quick glance. Sorry for any confusion.

Perhaps the Pioneer HU are 100 ohm preouts if I remember hearing correctly.
</font>[/QUOTE]It says they are on their website.. (pioneer = 100 ohms)
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