Re: MagnaDyne Speakers?
ONLY consider using the existing CD unit with an external amp if the head has preamp outputs, although my guess is that it doesn't. Otherwise, all you'd be doing is using the external amp to boost the crappy signal coming out of the CD units internal amp. <br /><br />Walmart.com shows a Pioneer DEH-16 which I believe is rated for 22W RMS/channel across all 4 channels. This would be a good starting point for you for several reasons including a reasonably decent and fairly powerful amplifier. <br /><br />If after installing the new unit you find that it isn't really loud enough for your needs you can buy a 4-channel amplifier that supports speaker-level inputs (virtually all do) and install it by connecting the speakers to the amplifier output, and connecting the speaker-out connections from the CD unit to the speaker-in inputs to the amplifier. This is only worthwhile if you got an amplifier rated at 40-60 watts/channel RMS at 4 ohms, and a decent 4-channel amplifier at this power rating will run you around $100-$150. <br /><br />Avoid the temptation to pick up one of the $19.99 10-billion-watt amplifiers. <br /><br />I wouldn't worry about the 50W rating of your current speakers. As others have alluded, speakers are much more tolerant of a clean signal than a distorted one - even when the clean signal is much more powerful. Assuming you're using decent electronics, at the power levels I'm talking about there isn't much risk of zapping your current speakers unless you're planning on playing something like rap music at close to maximum volume. <br /><br />If you are happy with the peformance of your current speakers you should at least try to reuse them before considering replacing them. There's a good chance you'll find they sound even better than with the current CD head, because they'll be fed a better signal.<br /><br />As for the recommendation for using replacement speakers whose cones are made from poly, it's a valid one because of durability issues.