e31 amplifier

There are a couple of fuses worth trying first. The one that is easy to miss is the 10amp between the connector blocks at the back of the Amp.

Daz, I am no expert with this but the symptoms sound very similar to those that I had a few years back. There is a thread about this when NickF had the same problem.

I suspect if you have tried all the obvious faults it could well be the amplifier. They are no longer available and I really don't know if an alternative will work. Many of the guys have simply upgraded with new sets. I sent mine to a firm who shipped it to Blaupunkt and they repaired it successfully.

The down side is that if it is not repairable you still have to pay.

Zitat von Daz850;83101

Does anyone know if the E36 amplifier is the same as the E31 item? The part number on the E36 one I have is 65.12-8 371 024

Four different amplifiers were used during the E31 production. Each of these parts was only used in the E31:

• Up to September 1991: 65 12 1 392 738
• From September 1991 up to September 1993: 65 12 8 354 444
• From September 1993 up to June 1994: 65 12 8 361 126
• From June 1994: 65 12 8 362 438

The first two amplifiers have two 12-pin connectors, the later two have a 12-pin and 26-pin connector. I'm not sure what the differences are between the first two amplifiers but according to the ETK they are not interchangeable despite having the same connectors (this may be an error in the ETK though). Obviously the amplifiers with two 12-pin connectors are not interchangeable with the 12- and 26-pin amplifiers. Since the first two amplifiers are no longer in production this means if yours is faulty you'll have to get a used replacement unit (respect the part numbers) or get yours repaired. The third amplifier is also no longer available but it can be exchanged with the last one which is still available from BMW. A popular plug-and-play upgrade for the later E31 amplifiers is the E36 Harman Kardon amplifier (65 13 8 366 472) which has supposedly better quality than the E31 version. I cannot confirm whether or not the E36 Harman Kardon amplifier is truly better. I've never seen official specifications of either amplifier.

Anyway, before replacing anything first try to confirm whether or not the amplifier is faulty. The fact that you hear a popping sound when turning on the head unit may indicate a working amplifier. You don't happen to have a spare head unit to try? Or a loose speaker to test the head unit's output?

Sure, no problem. But you'll need an adapter for the wiring harness as the Sony is most likely equipped with ISO connectors whereas BMW units have proprietary BMW connectors.

BMW (old style 16 round pins)


ISO


Just for reference, here's what the adapter should look like. The wires marked with an asterisk (*) are optional. They do not need to be connected for a working setup, but may be useful/required for certain functionality (explanation below). Please note that several readily available adapters lack the "remote power" wire which is absolutely essential in the E31. Inquire with the seller when in doubt.

ISO ---  Name            ---  BMW
 
A1  ---  GAL             ---  10 (*1)
A2  ---  Mute            ---   4 (*2)
A3  ---  Reverse         --- n/a (*3)
A4  ---  Permanent +12V  ---   9
A5  ---  Remote power    ---  16
A6  ---  Illumination    ---  13 (*4)
A7  ---  Ignition +12V   ---   5
A8  ---  Ground          ---  15
B1  ---  RR speaker +    ---   6
B2  ---  RR speaker -    ---  14
B3  ---  RF speaker +    ---   2
B4  ---  RF speaker -    ---  11
B5  ---  LF speaker +    ---   1
B6  ---  LF speaker -    ---   8
B7  ---  LR speaker +    ---   3
B8  ---  LR speaker -    ---  12

Remarks:
*1: Optional. The speed signal is used for speed dependent volume control (GAL) and some navigation units.
*2: Optional. The mute signal for the in-car telephone system (if installed)
*3: Optional. The reverse / back-up signal. Only required for certain navigation units. The E31 radio harness does not provide this signal. If you want it, you must run a wire from a location where the reverse signal is available (see ETM diagrams of your car).
*4: Optional. Some head units have a day and night mode or have the ability to dim with the instrument lights dimmer.
Pin 7 and 17 of the BMW plug are not used.

Very interesting if this Harman kardon can be used in my CSI

Just browsing the parts list for CSI and seems like they whent from
65 12 8 354 444
to
65 12 8 362 438
Directly

Will have a look at mine when I get home to see if it can be swapped out with a "better one"

This is what parts list shows for a late prodused 93 CSI
Hi-Fi amplifier telephon-anti-interferer65 12 8 362 438 '93, September — ...

Zitat von huldra66;83211

Very interesting if this Harman kardon can be used in my CSI

If your current amplifier is 65 12 8 361 126 or 65 12 8 362 438, then the Harman Kardon is a plug-and-play upgrade.

Zitat

Just browsing the parts list for CSI and seems like they whent from 65 12 8 354 444 to 65 12 8 362 438 Directly

What the ETK shows for a specific production date is not necessary the part that was installed back then, but the part it can be replaced with. The full BMW ETK (not the trimmed-down online ETKs bmwfans.info or realoem.com) allows you to view the part interpretations (history of retrospectively changeable parts). According to these interpretations, amplifier 65 12 8 361 126 was used up to June 1994. Of course it's possible the ETK is wrong in this case, but it shouldn't matter as 65 12 8 361 126 is interchangeable with 65 12 8 362 438 anyways.

A few words about the (later) E31 amplifiers vs the E36 Harman Kardon amplifier:

E31 amplifiers 65 12 8 361 126 and 65 12 8 362 438 are 10 channel amplifiers good for a total power output of 200 watt (10 x 20 watt). The Harman Kardon amplifier from the E36 Top Hifi sound system (65 13 8 366 472) is supposedly able to output 320 watt. But the Harman Kardon audio system uses 2 ohm speakers whereas the E31 uses 4 ohm speakers. Assuming you would put the E36 Harman Kardon amplifier in the E31, its power output would halve - 160 watt. That's less than the stock E31 setup? Yes, but the 20 watt per channel power rating of the E31 amplifier is measured at 10 % total harmonic distortion (THD) which is ridiculous. I guess the Harman Kardon amplifier has its power rating at a slightly lower THD to emphasize its audio quality or maybe the accompanying Harman kardon speakers are not really 2 ohm but more like 3 ohm. In other words, I think the e31 stock amplifier and E36 Harman Kardon amplifier have exactly the same power rating (and distortions), but the latter one is also capable of driving loads with lower impedances. Perhaps the Harman Kardon amplifier uses somewhat higher quality components which may drive the distortion further down, but the capability of driving 2 ohm loads is probably the only real difference between both. The fact that the Harman Kardon system does sound better (in the E36) is probably because it comes with better and larger speakers.

Don't expect any power gains when you put the E36 Harman Kardon amplifier in the E31. The only way to retain the extra power from the Harman Kardon amplifier is by changing the speakers to 2 ohm speakers - as in the E36 with Harman Kardon audio system. While the amplifier may be a plug and play swap, there is sadly no plug and play swap for the E31 speakers... But if you change the speakers you can just as well use another aftermarket amplifier with higher power rating and lower distortion.

Basically it comes down to this: If you want a considerable improvement in audio quality and power you'll have to replace the amplifier (I mean an aftermarket amplifier - not the E36 Harman Kardon amplifier). For the early cars this also invloves changing the speaker wiring. The later cars (September 1993 and up) can keep the existing wiring but it's recommended to replace it anyway - it's a very thin gauge. The stock Nokia speakers in the E31 aren't that bad, but they are underpowered and (in case of the woofers) way too small if you like loud music with a solid bass. So you'll have the change the speakers too. If you have the BMW Professional radio/cassette or BMW Business CD you don't have to change the head unit - they offer good audio quality but, sadly, lack low-level signal outputs. If you still have an older Business radio/cassette, best swap that too as these can't match the audio quality of the other units or modern head units. To make a long story short: improving the E31 audio system is replacing almost everything...

Zitat von Daz850;84595

My only gripe now is the sound quality. Volume levels are quite poor even though all speakers are working. Can I change the amp to a modern unit without changing the speakers?

Since loudness is subjective it's hard to tell whether your sound system isn't loud enough for your, or that it's underperforming in comparison to other (stock) E31. I'm not sure what you expect, but the E31 sound system is not very loud.

See the last chapter in my previous post where I explained the aftermarket options. In addition to that - If you opt to go with an aftermarket amplifier, I recommend to run line-level signal cables from your head unit to the (aftermarket) trunk amplifier. Not all aftermarket amplifiers support high/speaker-level inputs as the E31 amplifier and it should help further minimizing distortion. Keep in mind that if you replace the amplifier with a much more powerful aftermarket amplifier without upgrading the speakers as well, you'll just burn them if you turn up the volume. If you really want to keep the original speakers and have a September 1993 or later car you will also have to install filters as these were built-in into the later 10-channel E31 amplifier and therefore cannot be reused.

So let me repeat myself: improving the E31 audio system is replacing almost everything...

That doesn't sound right. I have no issues with the sound volume at 100 km/h even with the windows down. What are the specifications of that aftermarket head unit you installed (ie power rating of the output)?

I looked up that Sony head unit but the specs nowhere mention the 4 x 35 watt is the sine wave power (RMS) or marketing music power. Since manufacturers tend to use the most optimistic values, I assume it's music power. My own BMW/Becker head unit delivers only 4 x 30 watt music power (4 x 18 watt RMS @ 4 ohm), so yours shouldn't have problems feeding the E31 amplifier. Perhaps the amplifier is shot as well?

Do you at any chance know another 8 Series owner, just to compare the sound systems?

So it seems that I have the same problem.

Everything work but as soon as I reach for the volume the sound start to break up. Tried with another head unit and it was the same, my conclusion the amp.

The amp in the car is a Blaupunkt with BMW part no: 65 12 1 392 009

I have got a hold of two other with part no: 65 12 1 379 387 and
65 12 8 350 407. I can´t get info if they will work correct in my car, does anyone here know that? I don´t want to buy them just to try...

(Yes a stereo upgrade is coming but it is more important to get everything in working condition first)