A CD head unit for those looking for high power and a flexible tonal design.

by Brian Smith

The CDA-7875 is a single CD head unit with AM/FM tuner, CD changer control, and XM Satellite Radio receiver control capabilities. Features include three pairs of preamp outputs, internal crossovers, quasi-parametric tone controls, and internal amps with a max power rating of 60 watts x 4.

Performance
Maximum undistorted output from the CDA-7875’s front and rear preamps measured 2.3 volts @ 1% THD+N, with the sub outputs faring a bit better at 4.6 volts at the same distortion level. Source impedance at 1 kHz measured about 340 ohms on all preamp outs.

The internal amps are, of course, over-rated at 60 watts x 4 but they are the most powerful that we’ve seen in a head unit to date. With 27 watts x 4 on tap at 1% THD+N, these amps are about double what we generally see, although, it comes at a price. The chassis of the CDA-7875 became quite warm during the course of testing the internal amps. Our tests are intentionally short in duration to avoid heat build-up in the unit because amplifiers don’t perform as well once they get hot. While I never saw the hi-temp error that the manual mentions, the unit did become far warmer than typical during its time on our test bench.

The tone controls provide eight bass center frequency selections between about 50 Hz and 175 Hz, with four filter bandwidth options and a bit more than 12 dB of cut or boost. The high frequency section provides four center frequency options ranging from about 10 kHz to 17 kHz with about 10 dB of boost or cut. Minimum boost or cut measured about 2 dB in both the bass and treble sections.

User Evaluation
Boy, the index finger on my right hand sure is tired. The big rotary knob on the CDA-7875 controls volume, balance, and fader operations but everything else features button-based operation. Most of the major controls are grouped on the driver’s side of the unit, but there’s an awful lot going on here. The tone controls, in particular, require a lot of finger-work to operate. However, most of the extra work can be attributed to the fact that the tone controls in this unit provide a much higher degree of flexibility than average.

Here’s a thought on those big internal amps, use them as preamps instead - 27 watts into 4 ohms equates to about 10 volts. If you drive a higher impedance, such as that found at the input of an amp (with balanced inputs) or in a LOC, you’ll get even more. When’s the last time you saw 10-volt+ preamps in a head unit? This approach should prevent the unit from becoming overly hot and provide excellent performance from the noise perspective due to the amp’s voltage capabilities.

Overall, the CDA-7875 appears to be a capable performer. While it’s not exactly my cup of tea in the user interface department, I understand that there are a lot of people out there that dig the flash of a loaded head unit. If you’re among them, then check out the CDA-7875, I doubt that you’ll be disappointed.