OK IRA, HERE IS THE SOLUTION FOR YOUR AIMOR TO CONVERT IT TO A DOOMER KILLER:
I had this up on ebay. I got an offer which I initially was inclined to accept. HOWEVER, I always offer a 100% money back guarantee and haven't tested this in 20 years. So... I was feeling a little uncomfortable since the buyer's comments suggested that he wasn't able to fabricate a few spade terminals to hook up the power cable. At great expense of time, I found the original cable and decided to test it before accepting the offer. Couldn't find a pre-amp in time before offer expired but it was just as well...... because when I finally tested it, I have decided not to sell it anymore!
Here is how something like this can work for you:
Here is the amp. It is a kenwood KAC-820. Rated at 140wpc into 4 ohms. Well, today, you can find car amps rated at 500 watts, 1000 watts, 1200 watts -- you name it, they offer it. However, don't you believe for 1 second that these amp can actually produce anywhere near that power. This amp -- it's over 20 years old so while the ratings were pretty liberal, it's nowhere near what they advertise today.
So, I finally bring out my Carver C-1 Preamp and hook up a puny sony CFS-550 boombox to use as a tuner -- easy solution. All hooked up to my 8ohm 10" home speakers. They handle 100wpc. At 8 ohm impedance, the power output of the amp should be 70wpc. Is it a fair and true output? See below...
All I can say is that in operation, I believe it easily pumps out 70 watts rms per channel into these speakers. I have lots of home audio gear and if you listen to this amp, it is crystal clear and I hear ZERO distortion, think home audio gear, here. At 1/3 volume, it is as loud as I would feel comfortable with in a boombox and this is definitely a kaboom killer many times over. I have never heard a doomer so I can't comment but with some nice speakers, integrating this amp in a sufficiently sized cabinet will result in a boombox killer, if not doomer killer. In fact, it will give many smaller home audio gear a run for it's money.
Is it a feasable installation? Ok, here are the facts:
At a very comfortable blasting level, (detuned to save the boombox from vibration destruction and conserve power but as loud as, if not louder than a kaboom), it is pulling between 1.5 to 2.1 amps. Voltage was set at 13.7 volts, which is what I expect a normal auto amp to run at, although a 10 cell boombox will create 15 volts, so more power will be noticed. With amp on, at idle (no input), it is pulling .61 amps. With amp off, and in standby mode -- it is running 10ma (.01 amps).
What this translates to is that the amp will possibly run about 5 hours at blasting, about 15 hours at idle, someplace in between at lower operating volume levels, and standby mode should not be used if batteries are going to be stored in the machine for extended periods of time. This presumptions are based on standard alkaline D cells of 10,000mah. Actual battery life will likely be slightly lower since there will be additional current consumed by boombox pre-amp. Furthermore, it is likely that while alkalines are rated normally at 10mah, it's usable life will be less since you can't really run the batteries down to zero. At some point, it's voltage will drop below the threshold necessary to maintain operation.
So, the point here is that this IS a doable upgrade. I probably wouldn't use this kenwood because I believe it may be way overkill. A smaller car amp, however, can certainly be used to great effect.
Ira, are you listening?
Keep us posted 
