Looking for pin out for this bose amp

chinoy

Member
2022-02-17 6:13 am
Just finished fixing my akai amp and a bit disappointed with its output.
So I have these bose car amps lying arround. Which i want to use in my workshop.
My question pertains to the pin out.
And if the input to these is from line out of the car deck or the speaker out of the deck. Also if the input to these are difrential or not .
I hooked it up to a kenwood deck line out but got very faint audio.
I have joined both the vcc and ground pins. And powering off a car bat.
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chinoy

Member
2022-02-17 6:13 am
Any idea what the trimpot does.
Bottom left. I suspect it allows you to tune the cross over.
I'm only getting output on one speaker out. Its not a left and right chanell issue because no matter what signal i inject on the input side left or right i get the output from the working output.
I'm wondering if the reason they used two speaker outpins was to help carry the 100 watts. So while we have in1+, in1- / in2+, in2-. The speaker outputs are simply labeled spkr+ and spkr- for both pairs.
I guess the best way to test the theory would be to scope both output Channel.
If I hook up the pairs to two woofers I only get sound from one.
A schematic for this would be nice but so far no luck.
 

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chinoy

Member
2022-02-17 6:13 am
I cant seem to edit posts else would have put everything in one post.
The problem was a flakey wire on the output. Now both Left and Right Outputs are working. As the PCB trace is common I have a feeling this amp was designed to work as a single woofer driver. Which suits my needs perfectly. Right now. I have some nice speakers. The only thing missing was bass. This should give me all the bass I need. I think it joins the left and right into a mono woofer out.
The only issue is that if you drive it with the line out of the deck the volume is too low. If you drive it with the speaker out. The volume is to high. So Will need to figure out a way to get it to work With some kind of Volume control. And if possible Id like to pickup a bose woofer driver from e-bay. As it would be well matched to this amp. And put it into a vented box.
 

chinoy

Member
2022-02-17 6:13 am
If you're driving it from the rear out from the head unit and have no rear speakers, you could use the front/rear balance control to reduce the drive to the sub amp.

Some LOCs have adjustable output levels. I don't know if the impedance of the amp would allow the use of an LOC.
Thanks I was looking into the LOCs but I like your idea better. My Kenwood Double din deck has the ability to dial down the rears that was a simple solution and Im kicking myself for not realizing it. The setup sounds sweet. I have my bose book shelves on the front right and left and for the woofer I have this amp being driven off the rear outputs. You only need to set the bias once. Its a set and forget after that all 3 stay in sync. Im driving a 250 watt 8" sub with it.