APS 30 Retrofit to a 1990 300 SL ?

[Doug Gray]

It is practical to retrofit a becker aps 30 in a 1990 300 sl? (I have read Arnie's posts on adding an aps to a newer SL with an audio 10 oem.)

I get the impression there are two issues that I need to understand better.

One issue is whether the speakers and amplifiers from the Becker 1480 that is OEM (in a 1990 300 sl) can work with the aps 30.

The second issue I could use help with is the location of the speed signal on a 1990 300 SL? It does have speed dependent volume control but I am not sure how it gets to the radio.

Any help would be appreciated. Thanks

 

[television]

I do not think that your car has a speed pick up point so it will be a no go, its also an optical unit made for cars 2000 on.


Malcolm

Re the loudspeakes the APS 30 uses 1 ohm speakers, your are probably higher than that but no harm would be done though you might lose some power

 

[marnix]

Models of this series only have a speed pulse signal if they are equipped with cruise control and/or outdoor temperature display.
Behind the speedometer is a single pin, black connector. Green/yellow.
There are different cable colours at this location green/black, green/yellow or yellow/green.
The addition of a hall generator at the speedometer is possible. (Mercedes Benz order number: 0075422917)

 

[Doug Gray]

Thanks Marnix. I do have cruise control and outdoor tempurature display. I guess that means it is possible to run a wire off the black connector behind the speedometer to the pin on the aps 30? I wonder if anyone knows how the speed dependent volume control works on a Becker 1480?

 

[television]

Thanks to Marnix I can give you some more info, the speed signal wire is the green and white on radio plug A pin 1


Malcolm

 

[psmart]

Pin-outs for the APS 30 can be viewed at: http://www.audiocomp.at/aps-pin.html - its in German, but its understandable. ie. Lautsprecher = Loudspeaker, hi=hinter=rear, vo=vorne=front, li=links=left, re=rechts=right, Raddrehsignal=speed signal, KL30 = direct connection to battery 12V, KL31 = car chassis ground, KL15=ignition switched 12V, KL58d=lights.

The Audio 10 is identical to the Audio 30 APS wiring wise, as I changed mine from Audio 10 to 30 shortly after buying it new. Check connector A, pin 1. If it has a cable attached, then you already have speed signal wired up. You need the speed signal to get speed related volume control and GPS navigation, and judging from your initial post, you already have it.

Connector B is generally standard for speakers, so is connector A for the general power 12v/gnd. If you havent got toys like mobile handsfree, then you should be good to go.

I found the APS30 to be slow in Navigation (but I did have my GPS receiver on the dashboard) but a good overall device.
The Audio 30 APS does have fibre optics, for control of a CD-changer etc, but this is not needed.

 

[marnix]

Here is a diagram of the plugs on the back of the APS30

 

[Doug Gray]

Replacing Becker 1480 with APS 30 (1990 300 SL) Speakers and Amps

Thanks for the diagrams and advice. I think I have found some folks to help with the installation that also do speedometer work so I think the navigation issue will work out.

The remaining issue is what to do regarding the speakers and amps that are oem with the BE 1480. The plug for the spekers look like there are enough pins for four speakers but I have six. (I found a thread from psmart that describes a similar issue below)

Three similar questions to psmart's below: Can I 1) use the existing amps without adding a new amplifier? or 2) do I need a new one and bypass the old amps completely? and 3) should I go ahead and replace the speakers..they are from 1990?

Thanks for the help.

I was very interested to learn from members posts, that the Bose Speaker package I have in my ML actually has an amplifier!!

Does anyone know the location of the amplifier, and wether it is possible to feed in a low level (RCA) signal into it (via plug or soldering)?

I always assumed that it was a passive system, and when I installed an Audio 30 APS 4.5 years ago, I added a Sony XPlod amplifier. It looks like the Sony has been doing sweet-nothings!!

My config: Audio 30 APS speaker outputs feed a lo-level converter, feeding a Rio Empeg Aux-In input. The 4 pre-outs from the Empeg feed the Sony Xplod, which in turn connects to the original speaker harness which I believed fed the Bose speakers!! What a waste!

I could ditch the Sony and feed a lo-level directly into the Bose Amplifier, or by-pass the Bose Amplifier with the Sony?

Any insights would be most welcome (even calling me an idiot for such a blunder ).

 

[television]

The bose amp is under the passenger seat, biggest problem may be that your APS is Optical and the old system is not, if you wanted to leave the Bose amp in, and there are no outputs on the APS, it would be very easy to add them
I have said that the wire for the speed is the green/white on plug A pin 1, so you do not have to touch the speedo.

malcolm

 

[psmart]

Anz chance of pics...

.. A becker 1480 only has 4 channels, so either you have an active amplifier, or you have a passive crossover network. The crossover network takes a signal in, and splits it according to frequency and directs it at the woofer, mid-range or tweeter. If its the crossover network, you have nothing to worry about, just connect up and fire away. If its an active amplifier, you still should have no problem, just plug and go, as the existing amp/wiring has the necessary level converters and you have impedance matching to your speakers.

Amps and speakers havent greatly improved IMO in the last decade or so, so as long as they can take the power RMS, you should have no problem. Given that the Audio 30 APS is only 1 ohm impedance, as opposed to 4 ohms from years gone by, the Audio 30 wont be generating its peak power, so you shouldnt have problems with the speakers in the passive crossover situation. You wouldnt have any problem in the Active configuration, as the lo/level converter will work just as well.

Simple solution, get the Audio 30APS and plug it in. If the becker is using a slighlty different A,B,C connector setup, you can get universal wiring looms to make the necessary change.

Ive tried looking for the Becker 1480 pinouts, but all I get is that its a 4 channel Radio Cassette, so cant help any further. If you have pics though, could help a bit more.

 

[television]

Don't forget that the active three channel amp is already there matched to the 1ohm speakers,,,,, Sinse the bose is also used on the APS there should be phono's on the rear of the head unit, if not a 775mv signal could be taken from the wiper of the V/C. Try and leave the amp and speakers, they are an odd size on the SL's.

Malcolm

 

[psmart]

Don't forget that the active three channel amp is already there matched to the 1ohm speakers,,,,, Sinse the bose is also used on the APS there should be phono's on the rear of the head unit, if not a 775mv signal could be taken from the wiper of the V/C. Try and leave the amp and speakers, they are an odd size on the SL's.

Malcolm

On the Audio 30APS, there isnt any low level output (RCA), you only have the connectors below.

On my car, it has analogue Bose, and it converts the Speaker output, by means of a resistive network, into a low level signal (ie. like the old booster amps for cars). On the later cars, they switched to Digital Bose, which uses the fibre optics to transmit the digitally encoded sound and used a D-A converter within the Bose Amplifier.

I believe Doug either has an active amplifier which converts the speaker outputs of his Becker into a low level signal prior to amplification, or he has a passive crossover network on one of the channel pairs to provide the 6 speaker system. I dont have access to this kind of material (SL audio installations), so its only a suggestion based on prior knowledge.

Regarding the thread I posted some months ago, I decided to switch over to a COMMAND 2.0 system, so I no longer have the Audio 30 APS installed (its sitting in my garage awaiting installation into a Smart car). The COMMAND had to be Star Diagnostic programmed because the output at the speaker terminals, which feeds into the Bose was too powerful, and thus distortion occurred!

But, back to Doug. If you extract the Becker, pull off the connector for the speakers, then feed in another amplified source, such as the speaker output of your hifi (on a low power setting), with the car ignition off, this should verify if you have an active amplifier (no sound will be output) or a passive speaker system (sound will be heard).

 

[Doug Gray]

Thanks for all of the input. I will take a look and see if I confirm whether the system is passive or has amps, but it sounds like I can continue to use the existing set up either way. It also sounds like it is a personal preference call on my part on new speakers.

On the speed signal. I still do not know what wire takes the speed signal to the back of the BE 1480 (the rca plugs from 1990 are different that new wiring and so far I have not been able to find a guide to the wiring besides the power portion of the plug.) The pin location (green/white) A-1 is the correct location if my car was a later model with the newer oem plug setup that goes with the audio 10 and aps 30. I did however find a wiring harness on ebay from GB that appears to help convert most of the oem to the new set up with the exception of adding the speed signal.

Thanks again for the help. I let you know how it turns out.