Month: December 2012

I have an old Pioneer SA1480 that does 130W per channel. Only does 2 channels.  Built 1987-88 era. Very little info on it out there. Has a built in 7 band equalizer.

I’m thinking of bridging the channels to drive a 15″ subwoofer  for my home system. 280W may do it. But I’d rather get 1000W, if possible.

If you need the schematics there are here.

So the Lexoxx boombox isn’t a very good boom box. This one was built in 1999. But it could be useful as portable speaker amp with mods. The history on this boombox is simple – it was left behind in one of my rental units. So it is now mine.  I think I kept it just because I might need the transformer inside. I fix stuff and keep xfmrs around.

The boombox doesn’t have any auxiliary inputs, so you either get the CD (dead), the tape deck (dead with a broken pulley), or the radio (works).  My idea was to tap into where the CD output feeds into the amp, run a wire to the outside of the boombox,  and rig an external jack into it.  So then I could input either a MP3 player or my receiver of my wireless mic system.

The wireless mic is the PRO 88W/T from Audio Technica.  FM based, but good to 40 meters.  So my idea was to use the Boombox as a portable speaker amp for convention talks that I give while wearing the mic. Sometimes people in the back can’t hear me. All I’d have to do is hook on my mic and put the boombox and mic receiver plugged into a hacked input jack.

The boombox had some drawbacks:

• Scratchy pot on the volume
• Weird battery wiring for 8 “C” cell batteries that I couldn’t replace with a small 12V motorcycle battery
• Low quality speakers with some distortion. Possibly blown
• Missing battery backplate

So not a great stereo or boombox. But if it burns into a puddle of plastic ooze, not much of a loss.

Once I had the box open, I tried to find the cassette out going into the amp but gave up on that. The CD looked easier.     There was a silver sheathed cable running from the CD player to the power amp on the left in the picture.  It had a cable connector on the CD side.

I unplugged it, snipped off the cable end and found a red, white and uninsulated steel wire. The steel wire is ground, the white is left speaker.

So i put the cut CD input wire up thru the case, found a spare stereo plug and soldered it on. PRESTO! MP3 input, or a mic input.

Update 22DEC12 – Couldn’t stand the speaker distortion, replaced both speakers with some spare 3ohm car speakers. Also hit the CD/radio/off switch with a tad of WD40 to help the contactors. WD40 will often worsen the contacts over time, but it improved it for now. I don’t have contactor cleaner, so I had little choice.