billschroeder5842

I've replaced what feels like the entire stereo system in my 91. It is a Bose Gold with the CD and cassette. I've replaced the ECM with a rebuilt version and all 4 of the amps along with rear speakers. The front speakers are the originals.

The system works fine however, my front driver side is "softer" than the other 3 speakers. There are no crackles or hissing, it sounds perfect but just not as loud. It is as if the LR balance **** was twisted?

Now, my "DUH" moment.... if there IS a balance ****, I can't seem to find it. I have the fade working as expected.

So, if there is a balance ****, please let me know and I'll plead idiocy. But, if there is not, why and (more importantly) how to I fix it so the fronts are equalized.

BTW... I have one of those "cassette converters" that plug into my Iphone. Sounds great!

Thanks!

PEKlNGDUCKK

There is no balence ****. The speakers are "balanced from the factory" as the manual says. Your problem is most likely one of the speaker amps are incorrectly placed. The front and rear speakers are 100% physically interchangeable, but the rear amps are designed to output a soft(and quieter) sound. You may have switched one of the front amps with the rear and vice versa.

I too had this issue when I bought a rear amp and installed it on the front. The speaker works, but it was much quieter. The issue was fixed when I bought the appropriate amp. Good luck!

TorchTarga94

Amps are only same side to side, not front to rear. Check there first.

billschroeder5842

Thanks- I believe that The system was installed correctly.

I bought the rear system as a "set" that included mounting grill, amp and speakers. 100% new and specifically mounted to the LR side.

The front amps are "Front only" and I bought them as a pair- new- and they share the same Part number.

Anything else to try?

JimLentz

Is this the amplifier you have in front? Have you tried switching amps from right to left?

billschroeder5842

Yes, I believe that is the one. I bought the whole kit from CC.

I don't think it is an amp issue. Before I replaced all four amps, the front passenger was the only one left working. When I installed the two new ones the drivers was quieter from the git-go and the passenger was the same loudness with both the old and new amp.

Could this be a off grounding issue, a ECM issue or speaker problem?

JimLentz

Do you have access to a signal generator and/or oscilloscope? You could use a signal generator to the input of each speaker amp to verify the issue is truly on the driver's side. If so, you would hear less signal on the driver's side even when feeding each the same level signal. That would tell me it is still a bad amp or the speaker is weak. A bad ground is a possibility and you can test that with an ohmmeter.

pcolt94

First of all it's not a ECM, it's a CDM.

There is a major difference between the rear speaker amps and the front with equalization.

Each amp board has a number. You need to remove both front speaker boxes and remove the boards and compare the numbers to see if they are the same. If they are, then temporary swap the speaker boxes left to right and see if the problem moves. If it does then the amp has a problem.

If it does not move, the CDM might be the problem.

If they are not the same numbers then that is your problem.

RIC96

Do you have the same problem with regular FM vs the cassette adapter?

billschroeder5842

Thanks all! I took the speaker apart and swapped amps with the "old" amp that worked. I plugged it in and bingo- all balanced and much happier!

I'll see if I can return the new amp that does not work. Funny how many times a new part fails.

mike100

That's why I stocked up on $5 Nissan Bose amps from the wrecking yard. None of them have failed to function so far. Been there done that with the proper C4 amps... more trouble than it is worth time-wise and for money spent considering the quality of the sound. I do prefer stock interiors so the radio had to stay on my car as well.

but to answer the original question:
For diagnostic purposes, I discovered that the sound system does indeed have balance, just there is no **** for it. If you have a Tech1 scanner with the body module cartridge, you can go into the radio diagnostics and fiddle with balance.

scrappy76

I actually started a thread about the same problem, should have did some searching would have run across this post. Anyways, my 94 I just got is doing the same thing. Only the right side is working. I will swap an amp from right to left to confirm. I know one thing though, I am not spending $130 a amp to fix the problem. What nissan do i look for to snag some of these $5 amps ?

mike100

In your defense, this post is only about an hour old... but yeah, there's a few BOSE amp threads out there and I don't claim to be the first, I just helped compile information from bits and pieces of advice I found from other people over the years.

There are actually more cars that may have compatible amps, but for sure 96-99 Nissan Maxima's and Infinity clones have a drop-in replacement for C4's 91-up. I think you can make them work in 90's if you resolder the wiring harness from your old amplifier. Just be sure to keep the front/rear straight...which is easy because they say front/rear on the part.

scrappy76

Thanks.

billschroeder5842

Please Please! I'll by a few for the future too!

mike100

The price of a stereo component varies quite a bit at a wrecking yard, but since it isn't really a stereo amplifier in the sense that it is for the entire car, you will be over charged for it most likely. since they aren't very large, they will charge you a cheaper price if you call it a speaker switch. Switches are cheap in the junkyard pricing list. $5-$10 from the kind of places were you pull the parts yourself. Negotiate this as much as your conscience will allow . The first time i bought these I was paying something like $18-$20, but still, a lot cheaper than the C4 parts with the older generation of defective capacitors.

https://www.corvetteforum.com/forums...uidance-4.html

Cliff's "Solutions"-
https://www.corvetteforum.com/forums...post1585219757

https://www.corvetteforum.com/forums...post1581564115

corvette95

Later C4s had a 50 watt vs 25, they probably sent you one later amp.

scrappy76

Maybe a stupid question, but if I was to bypass the amp and go straight to the speaker would it work? Or how bout if I pulled the bose speaker all together and installed a regular car speaker what would happen, would it work?

billschroeder5842

It would work, but not real well. The amplifier "amplifies" the signal giving it more power. Without it, you a re relying on the EDM to power the system, which is it not designed to do.

Sorry, I'm not aware of a work around on this one. You either run the Bose system as intended or you scrap it and get an entirely new one.

BTW... I put my Bose back to specs and it is really very good.

mike100

the bose speakers are only 1 ohm of impedance and standard car radios want to see a speaker with 4 ohms, so no, you can't just cut out the amps and resuse the speakers.

One of the larger corvette vendors used to sell a replacement kit that included a new head unit and speakers that fit into the oem enclosures which allowed for a proper bosectomy.