Well I received the Aiwa Backtrack. First impressions: It is totally gorgeous. The black with gold accents just does it for me. Big and heavy, which is what I was expecting. But as for performance, unfortunately, I was really disappointed. It doesn't sound nearly as good as some of the vintage offerings.
Sound quality-wise it seems like the CD sounds the cleanest and best. But the CD level is way lower than other inputs such as tuner and cassette. In fact there's a marked difference in signal level between the inputs. Cassette is the loudest, and Tuner is probably 2nd loudest. CD is lower, and Aux is really low. This always bugs me, since during design, that would be an easy thing to address -- make every source signal send LINE LEVEL TO THE AMP. And this is an important thing with mult-input devices; all amplifiers have a sweet spot for sound quality and its usually in the lower 1/3 or so volume range. When you turn volume way up amps tend to of course get louder but also thin out on the bass and sound like they are struggling. So when you have to turn up the volume because of a source being lower level, you move out of that sweet spot. Aux input should theoretically sound the best because you can plug in a super clean source audio and it goes straight to the amp. But on the Backtrack the Aux level is so freakin low that you have to turn the volume way up, out of the sweet spot. Yes of course if you are playing some source audio that on its own is at a low level (e.g. cheap phone into the Aux, USB with sound files recorded at low level etc), but not the case here. I'm testing it with audio sources that I know are at optimum levels, that sound kickass on a good system. In fact my Aux source is very clean, and a bit higher level than LINE but yet is still the weakest sounding source on the Bactrack. : (
Surprisingly, the cassette player sounds to me the best on this thing. Why? Because its output level is loud and drives the amp hard like it should. To my ears it sounds very much like a vintage boombox cassette player -- pretty darn clear (well as clear as cassettes can sound anyway) and loud. Well, if they'd designed all of the other inputs to be just as loud driving the amp then I think we'd be on to something.
But even on the cassette (and I'm playing homemade recordings on TDK SA-90 high bias that sound great on a good player) I expected more boom out of the Backtrack boombox. For 10W RMS per channel with isolated and ported L/R speakers, I expected more in-your-face, ballsy sound. I expected deeper bass. Given that this uses a decent class A/B amp chip, I expected cleaner sound. It's just not there. To me, it sounds dull and unfocused; not crisp and punchy.
The FM tuner is another disappointment. Yes its digital, which I knew going in, but again just does not sound very good. I do much appreciate the stereo/mono switch though. The dial string is not aligned to the actual channel very well either, but i'd overlook that if the tuner audio sounded good, but it just doesn't.
Bluetooth is a major disappointment. Its signal level again is noticeably lower than Cassette, plus it sounds cheap and brittle. BT is capable of stellar sound quality, but not here. Bummer. USB sounds a bit better, but still not great; not super clean and loud like it could sound.
Overall, the Backtrack is better than many other "retro" boombox offerings, but honestly I'd be embarrassed to take it to a party as is and provide sound. It needs help. The manufacturer could have spent pennies to simply adjust the various input sources to drive the amp harder and all at the same level To me, that would have made a big difference. And that's sad, because the manufacturer did go to the trouble of isolating and porting the L and R speakers so well. That wasn't done back in the day, and it can make a big difference in sound quality.
I'm going to try feeding the speakers directly with quality audio to see what they can do. It's certainly possible to just use the case and replace everything inside (i.e. preamp/amp/Bluetooth/USB maybe even the speakers?) with quality components and see what can be done to make this thing sound as good as it looks.