Alpine 3501 Mini Car Amplifier

From my previous post about digging out my storage room, I found an interesting piece of junk. This is an Alpine car power amplifier model 3501. As I remember, I get this amplifier from 1990 Toyota Crown OEM audio. It is a premium car and the audio system that they are using is Alpine double din head unit, which considerably rare. Then from the head unit connect to pair of Alpine 3501 external amplifier. This amplifier is already broken when I taken out from the car and I have planned to restore it long time ago.

Once in a while, then I repair this amplifier with success. The problem at that time is one transistor for remote input is fail. It operate again and I using it in my home audio system. It is sound great. Then my curiosity to test this little amplifier to drive a sub-woofer. The best part of this amplifier is the capability to driving dual voice coil 10 inch sub-woofer with ease. The bass is shaking and solid. No one believe it is only rated 2 x 15 watt.

The draw back after pushing this amplifier so hard is it fail to operate again. This time not on same problem as before, but I guess on the power IC and some pre-amp section.

I have tried to fix it but not yet finished due to lack of service manual. The discontinued NEC UPC1230 power amplifier IC is also become a problem for fixing it. Later on I also found that many cold joint solder and wear PCB lines. I was dismantled some of the parts and I don't have any clue to restore them back.

I compare this Alpine 3501 to Nakamichi PA-100. They are both small amplifier at the same ages.

This time I do quick test to the amplifier section only by doing some jumper. This test showing that one channel works fine.

I bypass the input and connect direct to the IC amplifier. The sound is not good. I really sure that the pre-amp section give a lot of improvement on the amplifier.

At this moment, I tidy up the amplifier again and I think I will put this little amplifier on my collection only.

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