P80 Dolby system operation question

Post by **scot850** » 21 Mar 2025, 16:37

My buddy pulled a P80 SC-900 radio unit, amp, cable and Dolby unit from a 98 V70R. Now to my knowledge the 850 did not come with the center dash speaker on the top of the dash.

Now this is my question, even if you do not have the center speaker, does the Dobly surround system still work or is it pointless fitting the Dolby unit without the center dash speaker as that is what makes it ,Dolby surround sound'? The center speaker is fed from the back of the head unit separately, so not having it is that an issue?

His car has the behind dash amplifier but to fit the SC-900 I will have to see if we can fit the under seat amplifier as I don't know if the older amplifier can drive the SC-900 head unit.

Just when you think you have covered all the options for P80 head units, you find something different!

I have never seen the older behind dash amp unit so have no idea how it connects in. As the car has a SC-915/6 currently, I will have to remove it to see how it is connected and see if the head unit could be swapped for the SC-900 and it works with the old style amp, or if it has to be retrofitted with the newer system and amp.

So if anyone can school me on how the Dolby system works on these systems, I'd much appreciate it.

Neil.

Nikolaech · Post by **Nikolaech** » 22 Mar 2025, 12:44

Yes, it will work. The soundstage will shift forward. Of course, the absence of a central speaker strongly affects the sound stage. I prefer the standard solution.
Do you install SC9xx on Volvo 850?

Nikolaech · Post by **Nikolaech** » 22 Mar 2025, 12:52

If everything worked for your friend, it will work for you too. All standard amplifiers Volvo P80 have the same pinout of the linear input/output and minor changes in the power part of the connector.

Post by **scot850** » 24 Mar 2025, 10:34

The plan is to try and fit this into the 850. I just wanted to know if it was worth all the effort of fitting the Dolby unit without the center dash top speaker. I have also no idea if the older style of amplifier will work with the SC-900. When our project level on his other cars drops down, we will look at that and fitting the rear wagon load cover. Thanks to another very kind MVS'r I am now in possession of a genuine set of Volvo templates for drilling the 2 mounts in the rear trunk side panels. Way easier than making paper templates and wining it! We will figure it out as to if it can be done or if there are any downsides or benefits.

I'll update when we get around to it. First I have to get the radio code and clean and test alle the parts on my test system!

Neil.

Nikolaech · Post by **Nikolaech** » 27 Mar 2025, 11:33

Old amp, will work. Connection is not difficult. Connect the line output cable SC9xx to the old amp, that's it.

To find out exactly how good it is, you will have to do this. If the The stock speakers are in good condition think you will like it.

Post by **scot850** » 27 Mar 2025, 15:47

I still have the center speaker dash top pad to fit to my 00 V70R and also the Dolby control unit. The cable is already installed but just get fed up constantly working on that car.

Neil.