Alpine PDX-F6 Review

I sent some amps to Audio Science Review to be tested

Here is one of them

Alpine PDX-F6

I purchased it used a couple years ago for $250 locally via offerup.

https://www.audiosciencereview.com/f...plifier.28870/


Below is copied and pasted from ASR.



This is a review and detailed measurements of the Alpine PDX-F6 four channel car audio amplifier. It is on kind loan from a member. When new, it cost US $849 but is now discontinued.

https://www.audiosciencereview.com/f...er-jpg.171209/


Not a fan of the plastic trim which are showing their age now. But otherwise, it is a nice looking unit. I especially liked the stout wiring terminals:

https://www.audiosciencereview.com/f...er-jpg.171210/


The speaker terminals have deep shrouds to keep the wires from shorting out which is a wise move.

Alpine PDX-F6 Measurements
The unit became stable pretty quickly upon powering on:
https://www.audiosciencereview.com/f...er-png.171211/


Don't mind the variations as I had not taken care of grounding it and it was picking up noise. With that in place, here is our dashboard:

https://www.audiosciencereview.com/f...er-png.171212/


I was disappointed with the poor channel matching which persevered through the full range of the gain control (there is only one for each pair of channels so you can't fix this variation). On the other hand SINAD which summarizes noise and distortion is well above average for home amplifiers (79 dB) let alone car audio:

https://www.audiosciencereview.com/f...ew-png.171213/


Distortion in the FFT window is below 100 dB which is excellent. As is SNR:
https://www.audiosciencereview.com/f...er-png.171214/


Multitone test shows essentially no frequency dependency which again is very nice:

https://www.audiosciencereview.com/f...er-png.171215/


Crosstalk is above average for even home amplifiers:


https://www.audiosciencereview.com/f...er-png.171216/


Class D amplifiers have output filters that usually interact with the load to create varying frequency response in the audible band. Not so here:

https://www.audiosciencereview.com/f...er-png.171217/


There is good bit of power and near spec into 4 ohm:
https://www.audiosciencereview.com/f...er-png.171218/


https://www.audiosciencereview.com/f...mp-png.171219/


One channel is lower due to channel imbalance mentioned before.

Switching to 8 ohm we still have decent amount of power:

https://www.audiosciencereview.com/f...er-png.171220/


Varying the frequency again shows how the amplifier operates regardless of input frequency:


https://www.audiosciencereview.com/f...er-png.171221/


Wideband spectrum analysis shows a switching frequency way above average:


https://www.audiosciencereview.com/f...er-png.171222/


This helps a lot with the filtering performance mentioned before.

Conclusions
Can you smell it? Try again. That is the smell of a well engineered amplifier! In every every measurement there is indication of care in design and optimization. This would be nice to see in a home amplifier but is even more impressive in car stereos where bigger "watt" number seems to be the only thing that sells. Cost is way up there though but at least you are getting increased performance for your money. The only hitch is that channel balance which seems to me to be an out of spec part or something like that.

It is my pleasure to recommend the Alpine PDX-F6. Not sure if they are easy to find on the used market. If so, they will be a very good buy. I am hoping Alpine has released newer models with similar excellent performance.