system advice... how should i power it all?

[98greyxlt]

need some advice from you audiophiles out there:

here's what i have:

4 pioneer 6X8 TS6865
1 jl audio stealthbox with 10W1-4 sub (125W)
1 4x25 precision power apa-425 sedona series amp

here's what i'm planning to get:

head unit:
1) alpine cda-7878 (45x4 peak / 21 x 4 rms) mosfet
or
2) cda-7876 (60x4 peak / 27x4 rms)
changer: alpine cha-s624

predicament: how should i power everything?

i'm leaning towards running the pioneers off the head unit, since either unit will basically put out the same amt as the ppi will. the ppi i bought way back in 92 for my very first system, and it definitely has sentimental value to me. if i bridge it, i think it'll put out 2x50, which i'm not sure is enough for the jl 10W1 (125W).

should i buy a new amp for the sub? someone i know is offering an old alpine ts-300, i think 2x30, bridgeable to 1x100. also, an option is the alpine mrv-100m, (150x1 rms). 150w isn't too much for a 125w sub, is it?

if i get a new amp for the sub, should i use the ppi for the pioneers or just put it back in the box for another 4 years and run the speakers off the head unit?

as you can see, i'm pretty much an alpine guy, always have been. thanks in advance for your help.

 

[leenjen]

for now keep it simple..... run the pioneers off the headunit. if you want to add more speakers in the future (some 5 1/4's or 6 1/2's for kickpanels) then the amp can power them. just get a decent sub amp like that alpine someone is selling, and you're set.

 

[Jason94sport]

Is you current amp 4 channel or 2 channel. If it is a 4 ch amp, will it bridge into 1ch. That sub needs only 1 channel. If what I read is right, you said it is 50X2 bridged. That would mean you could only power the sub with 1 of those channels with 50W. That isn't alot of power to push that sub, & might damage it tring to. Now if the amp is 2ch, then it should be able to be bridged into 1ch. It would be best to power the sub with at least 100w. But the more power the better. It's better to overpower a sub, then underpower it. I also have a stealthbox, & running 130W to it. also specs at 125W. So my suggestion would be to run the speakers off the amp you have, then get another 2 channel amp, bridge it to 1ch then run the sub with it. I got a good RockFord Fosgate amp off of ebay for $90. An external amp will always make speakers sound better even if it's a low powered one, because most headunits do not put out alot of clean undistorted power.

 

[98greyxlt]

thanks for the replies, guys.

jason - the amp i have now is 4 channel, 25 watts per channel. can't be bridged to 100w. based on what you and leenjen said, i'm going to get a dedicated sub amp, either that alpine that my friend is selling (bridged 1x100) or the new alpine (1x150), if i can find it at a good price.

as far as my old ppi 4x25, haven't decided what to do with it. leenjen had a good suggestion, to keep it until i'm ready to add some kick panel components. i'm leaning that way for now, simply because i don't feel like running speaker wire from the amp to the 4 doors. would rather just go with the factory wiring harnesses for now. if it sounds like crap off the head unit, then i can put the ppi in later and hope for cleaner sound.

 

[leenjen]

Originally posted by 98greyxlt
if it sounds like crap off the head unit...

alpine makes very good headunits. as long as you remember to bypass the factory amp, you will get a nice clean sound.

 

[Rydogg]

Stupid question, but how do you bypass the factory amp??? When they installed my headunit (some promotional garbage at Best Buy) would they have bypassed it or did they wire it up to it? A little confused about it, so maybe someone can help. Thanks...

 

[JTang]

Are you sure that the apa 425 will only put out 50 watts RMS when bridged? That's pretty rare nowadays, and I don't think PPI usually limits the power like that. If connected to a 4 ohm speaker, the usual case is that it should put out about 100 watts RMS between two bridged channels. I could be wrong since it was about that time when it was still sort of difficult to reliably get a bridgable amp back then, but I'm guessing on PPI's good name.

If you can bridge two channels, I'd bridge two and connect it to the sub, use the other two for the front speakers, and have the rear speakers connected the the head unit, until you can afford another amp.

 

[98greyxlt]

jtang -

i was talking to some people and we just assumed that the 4x25 bridged could only put out 2 x 50. how can i find out for sure? i know that the amp DOES NOT have a bridge mono switch.

leenjen -

i thought only 97s and earlier had the separate factory amp in the rear quarter panel. 98s & up had the amp built into the head unit, right? (i have the dual media radio, 98) i believe i read that was the case somewhere on this board. if the amp is built into the stock HU, i don't have to worry about a wire bypass since i'm taking the HU out, right?

 

[Brian's98XLT]

The Sedona series was a entry level amp line by PPI a few years ago. It should do about a 100x2 bridged into 2 channels into a 4 ohm load. Believe me niether head unit will put out the same power as the PPI. Take a look at the size of the PPI compared to the radio. Radio manufacture like to play the over rated power game. It takes a power supply inside a amp to step up the voltage to get the power, headunit do not have these type of power supplies in them.
I work for a Alpine dealer and I think the 60x4 headunit is a joke. The only nice thing about it is that it does sound better at a mid level volume but like all radios the power runs out at louder volumes.
I would use the 4 channel to run your speaker and get a nice class D mono amp to run the sub.
As far a the amp by pass I doubt they by passed it. I have a couple of former Best Buy installers working for me and they say the never bypassed the amps. The had alot to learn when I hired them on.

 

[98greyxlt]

Brian's98XLT: I work for a Alpine dealer and I think the 60x4 headunit is a joke.

Hey, since you work for Alpine, what do you think of the following head units? I realize you're not big on their power output, but what about their other features?

CDA-7878
CDA-7977
CDA-7876

Pretty certain that I'm going with the mono amp to run the sub, I've been looking at the Alpine MRV-100M.

As far as power output from the head unit, I haven't made up my mind if I want to run the doors off the head unit or off my PPI. I would rather have them running off the PPI, but I'm just not sure if I feel like doing all that work, wiring up a second amp and running all the wiring for it.

 

[Brian's98XLT]

If you are into MP3 them the 7878 is the only player Alpine has that is MP 3. All 3 have 3 4 volt pre-outs. The only differences between the 7977 & 7876 is that the 7876 is rate at 60x4 and the 7977 is 45x4. The 7977 has the silver face with blue button and the 7876 is black withthe green button. I personnally like the CDA7977. I did not mean I hate Alpine, I own the CVA-1005.

 

[98greyxlt]

brian,

thanks for the info. i didn't get the impression that you hated alpine, i knew you were just talking about running speakers off an amp instead of a head unit.

i wasn't sure that the 7977 runs 45x4, the alpine site isn't too clear about that. i'm not really sure why the 7977 is $100 more expensive than the 7876. because of the nicer looking face?? Both the 7878 and 7977 have three 4 volt preouts, the 7876 only has a sub 4V pre out, the front and rear are 2 volt.

 

[Brian's98XLT]

All of the tech info I recieved at Alpine training this spring list the 7876 as having 4 volt out on all 3 pre-outs.
The 7977 does have a DC-DC conveter(helps keep the noisr floor low, that anoying hiss during quit sections on a cd) for the pre out section which is why I think the 7977 is a better choice if you are going to use the PPI or another amp.
My mistake but the 7977 is not powered I meant the 7878 was 45x4 my typo mistake. Sometime when trying to remember all the model number, specs kind of run together.

 

[98greyxlt]

brian -

thanks for the clarification... just have to make up my mind now... i'll either go 7878 (for mp3 capability) or 7977. hard to justify paying such a steep price for the 7878, even though it is a fully loaded receiver.

do you have any experience with dash kits? i want something that doesn't look cheap, and that fits nice and flush. i know scosche and metra have kits, in addition to the generic ones carried by wallmart and best buy and such...

 

[jimbo74]

walmart sells scosche kits and best buy sells metra... both are decent looking kits..... and dont make the wallet too thin either

 

[Brian's98XLT]

I deal with Best Kits from AAMP of America at work. They are just repackaged Scosche kits. Buy one with a pocket on it because the ones with the EQ blank out look like crap

 

[Brian's98XLT]

I deal with Best Kits from AAMP of America at work. They are just repackaged Scosche kits. Buy one with a pocket on it because the ones with the EQ blank out look like crap

 

[JTang]

Some amps nowadays do not have a bridge MONO switch. If the above info is correct, and the amp can be bridged, then I'd say run the sub off the two rear channels of the PPI, and the two fronts off the PPI. Then you can run the rears off the head unit. Your choice is whether to run the rears off the front HU channels or the rear. Most people prefer to run the rear speakers off the FRONT head unit outs, so that they're more in tune with the front speakers, rather than with the sub.