Loud and proud.

Author's Rating:

Pros: Build quality. Sound quality. Powerful.

Cons: Limited filtering options.

The Bottom Line: 
If you need quality sound and power at a reasonable price, take a long look at this amp. However make sure it's limited filtering will work for you.

Author's Review
I bought the QX300/4 to upgrade my existing car amp after buying a Sony CDX-MP30. Although the Sony sounded good through the KEF components upfront and the JL sub in the hatch, I wasn’t entirely happy with how soon distortion set in and was sure that a better amp would give a higher quality bass. I like my bass deep(ish) but tight, something that the old RadioMobile RA400 couldn’t do. I read what little reviews were available and checked out the Phoenix Gold website before ordering. I finally ordered over the ‘net from a ‘local’ supplier for £259 inc taxes and delivery, this was a saving of around £50. The QX has a nice feel about it, heavy and robust. It has most of the features that I think most people will need. There are 3 pairs of RCA inputs, front, rear and pass through, these are controlled by a selector switch which allows a single pair of inputs to feed all 4 channels. The only downside to the QX as far as I’m concerned is that the crossover is limited in its abilities. At first glance it seems quite flexible in that depending on how this rotary switch is set it alters whether the front or rear channels will be high or low pass or full range. However because of the way the switch works it alters both front and rear channels at the same time and there’s a limitation on the filtering that can be applied to the channels. For example only B channels can be low pass filtered, if this is selected the A channels can only be high pass filtered. I would have liked the flexibility to have independant filtering both A&B channels but it can’t be done. The next problem is the variable crossover point, when the amp is set up for a low pass filter on B channels and high pass on A channels, the single adjustable control controls the cut off point of both filters at the same time. So if I choose a low pass cut off of 80Hz, this is also cut off point of the high pass.
So after all this whining how does it sound? Well in a word terrific! The bass is more controlled but still plentiful. But the real difference is up front. The soundstage has opened up to a much greater level than with the old amp. Vocals and instruments can be easily placed, the top end is really clean and clear without being too sharp or painful. Finally there’s plenty of power on hand, I can turn up the amp to the point where I know it too loud to be safe but there’s no hint of distortion, maybe this could be seen as a downside. When sound is free of such distortion it doesn’t seem as loud, which can tempt you to turn it up further. I would say that for the price you’d struggle to find better, just make sure you can make your system work on the limited filtering.