I did not send this one in, but a review of the Pioneer GM-D1004
https://www.audiosciencereview.com/f...-review.11528/
Below is copied and pasted from ASR
This is a review and detailed measurements of the Pioneer GM-D1004 four (4) channel car amplifier. I purchased it after prompting by a member. It costs just $99 including Prime shipping from Amazon.
I must say, I expected a piece of junk but received anything but. It is small to be sure but feels very solid:
It is quite svelte in the other dimension:
It is like a laptop charger.
On the down side, it comes with multiple dongles for connection. These are convenient to plug and unplug (the main connector feels quite nice) but you are stuck with the wiring that comes with it. Better stock up on some splice connectors to lengthen them to go where you need.
In use, the GM-D1004 barely got warm courtesy of its class-D amplification technology. It easily tolerated an accidental short of one of its channels. Under severe stress though, it blew its fuse. Not sure how you rate an amplifier for 400 watts with a 15 amp fuse. Even at very high voltage of 14 volts, that only gives you 210 watts to work with.
Overall, the compact and sturdy unit makes a very good impression. There is nothing budget here other than the price.
Car Amplifier Audio Measurements
My testing was with a 50 amp variable lab power supply. It was set to 14.7 to 14.8 volts which is on the high side but that is how a lot of such gear is specified. Here is our usual dashboard but now with 4 channels driven (only two shown):
https://www.audiosciencereview.com/f...nts-png.50684/
Hey, this ain't junk! We have home amplifiers which have more distortion and noise than the Pioneer! It actually matches the performance of a Yamaha home amplifier I just reviewed:
https://www.audiosciencereview.com/f...020-png.50514/
Signal to noise ratio is decent for a car stereo at this price range:
https://www.audiosciencereview.com/f...nts-png.50685/
32-tone test resembling music is what we already know:
https://www.audiosciencereview.com/f...nts-png.50686/
Frequency response is vert flat in audible band which is great for a class D amplifier:
https://www.audiosciencereview.com/f...nts-png.50687/
Most important metric here is power versus distortion and noise. Let's plot that in both 4 channel mode (two channels shown) and bridged 2 channel:
https://www.audiosciencereview.com/f...nts-png.50688/
In my first attempt at bridged mode, the fuse blew as I noted in the review. So this time I stopped the sweep as soon as current consumption shot up above 15 amps. So likely it could produce more.
To have any shot of validating the spec of 200 watts X 2 in bridged mode, I ran the burst CEA test:
https://www.audiosciencereview.com/f...sur-png.50689/
So for musical peaks that are not sustained, you get a good punch.
Conclusions
In a sea of junk in budget car audio amps, it is a pleasure to see Pioneer not cutting corners and producing junk. With its small size, you can hide this little amp anywhere and get plenty more power than the stock head unit can produce. It seems solidly built with good protection which tells me it is going to last. Output power is as clean as many home units so not much to complain about there.
I am happy to put the Pioneer GM-D1004 on my recommended list.
