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will I lose stock amplification if I replace my stereo?

4K views 20 replies 9 participants last post by  Thunderbird 
#1 ·
I'll be replacing my stereo in the next few days but I was wondering if I would lose stock amplification. I heard the factory amp is under the passenger seat, but does anyone know the wattage? And how can I retain the function of the amp? I bought a wire harness adapter but I don't think it comes with any adapter for the black amp plug.
 
#2 ·
Well I bypassed the stock amp only because all aftermarket units have built in amplifiers, some stronger than others. It may not even have an effect but I wanted to play it safe. My speakers still sound great though. I don't know what wattage the stock amplifier for our cars is but I am sure some aftermarket head units can match the value if not beat it.

It should not hurt anything because it's no different than running an aftermarket amp if your speakers require higher wattage than the internal amp of the head unit can supply.

If you don't get the answers you are looking for, just try the aftermarket unit with the stock amp bypassed. It may not be as bad as you think. I noticed no difference.
 
#3 ·
Well I bypassed the stock amp only because all aftermarket units have built in amplifiers, some stronger than others. It may not even have an effect but I wanted to play it safe. My speakers still sound great though. I don't know what wattage the stock amplifier for our cars is but I am sure some aftermarket head units can match the value if not beat it.

It should not hurt anything because it's no different than running an aftermarket amp if your speakers require higher wattage than the internal amp to the head unit can supply.

If you don't get the answers you are looking for, just try the aftermarket unit with the stock amp bypassed. It may not be as bad as you think. I noticed no difference.
I tunneled right into the amplifier from my aftermarket HU...there is a wire on eBay to do so.

Honestly, you'll lose the center speaker by doing so but with the way that the speakers come to life after installing an aftermarket HU it's totally worth the brick in the center console......plus it gives me room for a tri-pod setup I'm looking to create ;)
 
#4 ·
You need an amplifier adapter cable, they are all over eBay, like this. The green harness supplies power and ground to your aftermarket stereo and the black one lets said stereo send signal to the OEM amp. You'll be losing the center channel unless you wire it in, I did mine via the speaker-level outputs FL+ and FR- from my JVC.

There's an audio subforum here with lots of details.
 
#7 ·
300 watts
 
#8 ·
I'm guessing that's 60Wx5. Any idea if that is RMS or peak? If it is peak, that is about the same most aftermarket HU can achieve.
 
#9 ·
Thanks guys, I think I got some good ideas. When my HU was in my old car I was just using it's amplification with all aftermarket speakers and it sounded great. I can't remember what the wattage is on it but if stock amplification is only 60x5 I can't imagine I'll hear that much of a difference in terms of power. I can't wait to see how this is gonna come out.
 
#10 ·
If the stock amplification that JRL gave is RMS, then 60W is alot more than most aftermarket. Aftermarkets are usually 22W per channel RMS. The 50W they advertise is peak.
 
#15 ·
This is the R forum, all Rs (with the 850) have the 300 watt amp
 
#12 ·
I looked up my head unit and it's 50x4 peak so if I have the 300w stock amp, I guess it would be worth buying the adapter. I can't imagine that 300w figure is RMS for stock amplification, that just sounds like a lot, especially for an 8 year old car.
 
#13 ·
But if you have the 200W factory amp, you are doing no different that with your headunit can do. I can't link to the adapter at work. How much is it?
 
#14 ·
14$ I think. I don't think I'll buy it because I don't think it will make that big of a difference. Only if I hear a difference in power. Any idea how to check the power of my stock amp?
 
#16 ·
I bought the adapter cable off eBay so I could hookup my new Pioneer headunit to the R amp under the passenger seat. Yeah, I lost the center channel but I don't miss it. The sound is well worth it, much better than anything a headunit could deliver. I figure it this way; the amp & the speakers are probably tuned for the Volvo, so it'll be hard to create a system that sounds better in the cabin for the price. The volume counter on my radio goes from 0 to 35, and I rarely push it up to 15. It's still smooth without distortion - and I mean NONE. The only plans I have is to (1) add a 12-inch sub with a dedicated amp and (2) throw down some Dynomat to stop the plastic from rattling apart.

Buy the adapter cable, use the factory amp and you'll be quite happy.

One note; I did suffer some horrible buzz when I first plugged everything together and it turned out that whoever made with RCA wire adapter screwed-up, so I had to reconnect the negative RCA wires within the harness. Other than that, it was pretty simple.
 
#18 ·
Glad to be of help :) If you have any other issues check out my install thread. It was a bit more confusing than I thought but if you need any help post your questions on that thread and I'll do my best to answer :thumbup:
 
#19 ·
The HU 803 has a 25 watt amplifier to drive the center speaker, but no other amplification. The stock amp for the 803 or 850 is the PA200. It's 50x4. The premium amp is the PA300, which is 75x4. They look exactly the same and both mount under the passenger seat. There are wiring kits available to use an aftermarket head with the stock amp as well as the other way around. I'm using the stock HU with an an aftermarket amp. It's a great setup. Volvo's wiring and drivers are pretty good.
 
#20 ·
If I'm not mistaken, all R's have the premium 300W amp
 
#21 ·
From what I can tell, the PA300 (premium audio) is the PA200 with a software update. My 2004 R came with premium audio, I'm not sure all of them did. It's 75w peak at, not kidding, 10% THD. I replaced mine with an Arc XDi 804, which is somewhere in the 100w RMS range with the (tested) 3 ohm load from the wired-up 3 ways in the front.

Ditch the factory amp... it's garbage and the HK drivers deserve better. So do your ears.
 
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