MVS Contributor Goupil shares his work to put a powerful C70 stereo amp into a V70. For whatever reason, Volvo kept these amps to the C70 model only. But the work to swap this into any other P80 is not impossible. Here are Goupil’s instructions to do this swap:
Goupil » Hello,
I spent the last 2 days working on swapping a P80 C70 amp into my 1998 V70, and I’ve seen a some informations on the net that didnt match what I had so I’ll share my experience. This will be purely electrical, as the rest is well documented. As usual, remember to unplug the battery as you’ll have to lift a seat with an airbag.
This only applies to cars that already have an amp and the SC900/901 unit. I recommend reading Fiodor’s thread — How to install C70 amp into S/V70 or 850 — for cars without an amp anyway, it has a lot of pictures that will give an idea of what you’ll have to do.
The C70 amp I have is the 4x100W, it also exists in 4×60 and 4x75W variants. Here it is next to the factory V/S70 4x50W unit.
You might want to look at this video first, this is what got me started into this idea
My install is different in 2 points:
1. Power supply
One thing I noticed on the C70 amp is that the power supply cable are THICK. Meanwhile the stock amp power wires are barely bigger than speaker wire.
Looking at the diagrams, the factory amp (16/2) shares a 15A fuse (N°7) with the head unit.
Meanwhile in the C70, the amp runs off TWO PARALLEL 30A fuses (9 and 12, each on different main fuses)!
Although you probably wont be listening to music at max volume all the time, I definitely wouldn’t recommend using the factory wiring to power this big thing. The C70 amp is a rebranded Alpine V12 and people have pulled impressive currents with them.
So I ran a pair of thick wires all the way to the battery, with two 30A fuses. A single 40A would probably be fine, I just used what I had and matched Volvo setup. Ran the ground wire to the ground point under the A pillar, under the dash.
See the linked thread at the top on how to run the power wire, I did pretty much the same thing.
2. Speaker wiring
At the end of the HandyDan video is an instruction sheet on which wires to connect, but it didnt match with what I had so I did some digging.
The 1998 wiring diagram has two schematics for the S/V70 with 4x50W amp, called MOD1 and MOD2. What’s the difference ? I don’t know, other than some speaker wires have different colors:
MOD1
If your have a MOD2 car you’re in luck, I’ve already done the work and this is how I’ve swapped the C70 plug onto my V70
If not, you’ll have to take both the C70 and mod1 schematics and match up the channel wires
After some soldering/crimping I now have a C70 amp plug on my V70.
- The twisted green-brown wires in the back are the 12V that used to power the amp. Make sure to insulate them properly ! Black ones are grounds.
- There are two white-red wires! The one on the 2pin green plug goes to the front right, main plug one is front left.
You can then plug everything in (power + speaker + 8 pin from HU) and use the Left/right and Fader settings on your SC900/901 to make sure the channels are where they should be.
Install a C70 Amp in a V70
