I have a 2002 RSX Type S with the Acura/Bose "Premium" Sound System. Last week the FM tuner in the head unit gave up the ghost and a certain amount of magic smoke (failed electrolytic) was released. This seems all to common with Matsushita oem head units as this happened on my previous two accords as well.. 
And I don't play music loud either - always just the tuner, cd changer and tape still worked.
Anyway on to some background and my question for the experts here.
I bought an Alpine cd receiver 9985 from Crutchfield, and last night wired up the pac oem2 adaptor that comes with the kit. Works great, and sounds considerably better than the oem piece of **** that came with it.
The installation was surprisingly easy despite some glaring omissions in the installation instructions and the head unit works great.
The head unit is currently driving the pac oem 2 which just basically converts the speaker level outputs to low level ground referenced outputs to drive the bose amplifier. The head unit also has line level outputs (4Vrms) and given the relatively high sensitivity of the Blose (oops) 😉 amplifier I was thinking even better results might be attained driving it with the pre-amp outs instead. The Alpine can turn off the internal power amplifiers in this scenario as well, functioning solely as a line level head amplifier.
Now I don't know what the input impedance of the Bose amp is, but I already know the sensitivity is high enough to drive the amplifier using the pre-outs on the head unit. Has anyone done this?
I used to work at that certain nameless entity, but rarely talk to anyone up there any longer, so I would feel uncomfortable contacting anyone there to ask this question, so I ask here.
I could of course modify the amplifier - that would actually be pretty simple to do. The changes to do this are pretty trivial actually, and the quality gain might be significant.. I worked on a lot of oem projects back in the day..
I am contemplating other possible changes down the road like new rear speakers which would require me to delete the EQ sections in the those amplifier channels. And maybe a real subwoofer with its own amplifier
And I don't play music loud either - always just the tuner, cd changer and tape still worked.Anyway on to some background and my question for the experts here.
I bought an Alpine cd receiver 9985 from Crutchfield, and last night wired up the pac oem2 adaptor that comes with the kit. Works great, and sounds considerably better than the oem piece of **** that came with it.
The installation was surprisingly easy despite some glaring omissions in the installation instructions and the head unit works great.
The head unit is currently driving the pac oem 2 which just basically converts the speaker level outputs to low level ground referenced outputs to drive the bose amplifier. The head unit also has line level outputs (4Vrms) and given the relatively high sensitivity of the Blose (oops) 😉 amplifier I was thinking even better results might be attained driving it with the pre-amp outs instead. The Alpine can turn off the internal power amplifiers in this scenario as well, functioning solely as a line level head amplifier.
Now I don't know what the input impedance of the Bose amp is, but I already know the sensitivity is high enough to drive the amplifier using the pre-outs on the head unit. Has anyone done this?
I used to work at that certain nameless entity, but rarely talk to anyone up there any longer, so I would feel uncomfortable contacting anyone there to ask this question, so I ask here.
I could of course modify the amplifier - that would actually be pretty simple to do. The changes to do this are pretty trivial actually, and the quality gain might be significant.. I worked on a lot of oem projects back in the day..
I am contemplating other possible changes down the road like new rear speakers which would require me to delete the EQ sections in the those amplifier channels. And maybe a real subwoofer with its own amplifier
Why not just run rca's to a replacement 'normal' amp.
Surely it would give much better sound quality.
Just watch the speaker impedance though.
bose like to run 2ohm rubbish...
Surely it would give much better sound quality.
Just watch the speaker impedance though.
bose like to run 2ohm rubbish...
MadMutt said:
I thought about that, but I think the weak point in the system is the speakers, and without the EQ in the amplifier I imagine they would sound frightful. I haven't actually opened up this amplifier yet, but my suspicion given the vintage is that it is probably six class D 50W amplifier channels based on a similar amp I did work on.
While I am tempted to replace the amplifier, I suspect that would have to go hand in hand with speaker replacement (except maybe those dash dome tweeters) and a massive amount of rewiring.
The acoustimass (tm) bass module is probably the single worst thing about this system. The mids and top end actually aren't bad at all now that I have disposed of the original head unit.
When I worked for Bose ages ago all oem amplifier and eq. automotive development was done without the oem head unit using AMS (a digital acoustical measurement system) to perform multiple position interior acoustical measurements.
Possibly the weakest point in the system was the head unit (made by Matsushita - probably for the lowest possible cost) followed by the "subwoofer" .. or the reverse? In either case...
🙄 and then everything else.Well, seeings how the h/u has a built in amp, run new wires to the doors and rear deck, then replace speakers.
Basically convert the car to a std 'deck and four'.
I don't think changing from a loc, to low level and modified bose amp input's, would be worth the effort.
It all really just depends on how much time and effort you want to spend on it.
Basically convert the car to a std 'deck and four'.
I don't think changing from a loc, to low level and modified bose amp input's, would be worth the effort.
It all really just depends on how much time and effort you want to spend on it.
MadMutt said:
I'll think about that, I figure modifying the amplifier to work with line level inputs is actually a lot easier than ripping this car apart to rewire everything - its got a 7 speaker system in it currently. The Alpine head unit is currently driving the Bose amplifier through an adaptor - was just hoping to eliminate that from the signal path.
I would think the loc is using transformers on each channel to make the ground plane more flexible between the aftermarket head unit and factory amp. I wouldn't try to run directly from the head unit. It may actually sound better with the engine off, but with it running you may have severe noise issues. I too agree bose blose but if it sounds as good as you say, leave the converter until the speakers (or the amps) start having issues then swap it all out for aftermarket. Just my opinion 🙂
Why did you use only the high-to-low level conversion?
If I remember correctly, the PAC-OEM2 will allow you to use the "line level" inputs for going out to your Bose factory amp.
Too much "hee-hawing" around in all these posts. Just try it. That's easy enough to do.
I've installed stereos in some of the most difficult "premium sound" systems in cars including Bose in Infinitis, GM, & more. with great success, bypassing factory amp or not.
What the other guys failed to mention is that if you remove the factory amp, there are no crossovers for the factory sub, tweeters, and so on. Hence there is more complication than meets the eye.
The crossovers are built into the amp on Bose & Infinity systems.
Just give it a shot. The results likely won't be significant, but it all depends on what makes you happy of course.
🙂
If I remember correctly, the PAC-OEM2 will allow you to use the "line level" inputs for going out to your Bose factory amp.
Too much "hee-hawing" around in all these posts. Just try it. That's easy enough to do.
I've installed stereos in some of the most difficult "premium sound" systems in cars including Bose in Infinitis, GM, & more. with great success, bypassing factory amp or not.
What the other guys failed to mention is that if you remove the factory amp, there are no crossovers for the factory sub, tweeters, and so on. Hence there is more complication than meets the eye.
The crossovers are built into the amp on Bose & Infinity systems.
Just give it a shot. The results likely won't be significant, but it all depends on what makes you happy of course.
🙂
"What the other guys failed to mention is that if you remove the factory amp, there are no crossovers for the factory sub, tweeters, and so on. Hence there is more complication than meets the eye."
/\ we didn't have to mention it.. he already stated he is aware of it. 😉
/\ we didn't have to mention it.. he already stated he is aware of it. 😉
Well he said EQ, not crossover. But now I realize that's what he meant.
At any rate, the results can be really good removing the Bose amp. Did the same in a BMW Harmon-Kardon equipped vehicle.
Well must have been interesting working for Bose...!
Kind of dissapointed at the OEM "premium" speakers these days, including Bose, that are lightweight, ONE PIECE plastic-basket units!
Blah! Terrible!
At any rate, the results can be really good removing the Bose amp. Did the same in a BMW Harmon-Kardon equipped vehicle.
Well must have been interesting working for Bose...!
Kind of dissapointed at the OEM "premium" speakers these days, including Bose, that are lightweight, ONE PIECE plastic-basket units!
Blah! Terrible!
Its not really the plastic basket that sucks. That actually helps the speaker sound better by preventing unwanted resonance and keeping the magnetic field more focused on the coil. Its the crappy paper cones they keep using. I mean come on, get with the program bose!! 
ppia600 said:
ppia600 said:Its not really the plastic basket that sucks. That actually helps the speaker sound better by preventing unwanted resonance and keeping the magnetic field more focused on the coil. Its the crappy paper cones they keep using. I mean come on, get with the program bose!!
Paper has some useful acoustical qualities, this isn't my biggest concern frankly as the mids and treble performance up front are surprisingly decent - I just wish for some real bass below 100Hz, that acoustimass woofer is real good at just one thing - one note bass.. 😀 It goes neither loud nor more disturbingly - deep.
Given the age of the car, and the complexity of the job involved I don't think I want to pursue a major driver or amplifier upgrade. I might just get a real subwoofer and amplifier, but that is about the limit. Unfortunately the amplifier is incompatible with better speakers both because it is equalized and because the drivers are all 2 ohm. (I expect this amplifier uses the class D amplifier module designed to deliver 50W per channel into 2 ohms - but I won't actually know until I open it up though.)
I will probably buy a bose amplifier and take it apart to determine what would be involved in modifying it for line level input - although if I am smart I'll just leave the whole thing alone so as not to have headaches when I sell the car in a year or two. (At most)
The receiver has an iPod interface which is a plus and one of the reasons I bought it. I thought about buying the iPod/digital media only receiver IDA-X001 to use with a usb drive and iPod, but thought that might not be as user friendly as a simple cd/receiver, and to the less sophisticated potential buyer the inability to play cds might be an issue.
Working at Bose was quite interesting, I learned a lot about scientific method and good cost effective engineering. I have nothing but admiration for the people I worked with, that however does not mean that I have the same feelings about most of their product line.
See my posts on other threads here to understand the depth of my tube affliction, and fascination for giant, ancient speaker system designs.. 😀
I've decided to live with it as is for now, probably not worth the effort or money to take it any further.. I adjusted the pots on the pac-2 interface for about 12dB of attenuation which isn't really enough, but it will do..
I'm happy to report that this Alpine head unit is fully compatible with the iPod classic I just purchased.
I've closed up the dash finally.. I will say it sounds a lot better than the old head unit did, though not nearly quite as nice as my Onkens driven by my SE 300B amps. (for Cal W.. 😀 )
My wife's comment on the Alpine head unit was that it was excessively complicated to operate (I keep the manual in the car because I can't remember all of the details required to tweak it.
) and she immediately noticed how long the disk seek times are... (Me too actually, and they seem excessive.) Seek times with the iPod aren't particularly fast either which is odd, because the iPod by itself is extremely quick changing track to track. FM performance is orders of magnitude better than the oem unit which is worst I have ever owned.
I'm happy to report that this Alpine head unit is fully compatible with the iPod classic I just purchased.
I've closed up the dash finally.. I will say it sounds a lot better than the old head unit did, though not nearly quite as nice as my Onkens driven by my SE 300B amps. (for Cal W.. 😀 )
My wife's comment on the Alpine head unit was that it was excessively complicated to operate (I keep the manual in the car because I can't remember all of the details required to tweak it.
) and she immediately noticed how long the disk seek times are... (Me too actually, and they seem excessive.) Seek times with the iPod aren't particularly fast either which is odd, because the iPod by itself is extremely quick changing track to track. FM performance is orders of magnitude better than the oem unit which is worst I have ever owned.I bought a pioneer 610bt and put that in with the pac oem 2 and the 1998+ honda wiring harness. I'm getting a significant amount of noise coming through. I've been searching the forums and the only possible solution I've come upon is to bypass the amp. I would rather not do this if there is another solution. Anybody have any ideas?
PAC oem 2 could be a source of noise if it has transformers. I try to stay away from any oem adapter that has transformers.
I have done a similar upgrade to my 2001 Nissan Pathfinder Bose system. I replaced the head unit with an Alpine DVA-9860. I used the preamp outputs to drive the Bose amps and found that it sounded thin and distorted. Max volume was not very loud either. I found that Nissan Bose system amps require a drive signal that is floating ground and at least 4 volts RMS or I get severe alternator noise. Speaker level output signals meet this requirement. I went a step further and installed a 1/2 DIN height preamp EQ made by Precision Power. It has a high voltage output that is very clean and 5 bands of equalization plus an auxiliary input and master volume control. This combination is noise free and it sounds many times better than the OEM Bose head unit did. The EQ is model number PAR-225 and it has been out of production for many years. I picked it up used for $75.00. It was considered high end equipment in its day and retailed for over $400.00. Well worth the effort if you can find one. Audio Control sells a similar unit new for about $225.00.
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