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Pioneer GM-D1004 4-channel Car Amplifier Review

amirm

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#1
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:
Pioneer GM-D1004 four channel class D car amplifier audio review.jpg

It is quite svelte in the other dimension:

Pioneer GM-D1004 four channel class D car amplifier connectors auto review.jpg
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):

Pioneer GM-D1004 four channel class D car amplifier audio measurements.png


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:



Signal to noise ratio is decent for a car stereo at this price range:

Pioneer GM-D1004 four channel class D car amplifier SNR audio measurements.png


32-tone test resembling music is what we already know:

Pioneer GM-D1004 four channel class D car amplifier multitone audio measurements.png


Frequency response is vert flat in audible band which is great for a class D amplifier:

Pioneer GM-D1004 four channel class D car amplifier frequency response audio measurements.png


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:

Pioneer GM-D1004 four channel class D car amplifier power into 4 ohms audio measurements.png


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:

Pioneer GM-D1004 four channel class D car amplifier Peak Power into 4 Ohm Bridged audio measur...png


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.

------------
As always, questions, comments, recommendations, etc. are welcome.

Haven't had good curry for a while so thinking about hitting the local all-you-can-eat Indian restaurant tomorrow. No, I have the money for the food. Don't think I am that cheap. But.... I am short of cash for the tip and gas to go there and back. So be kind and donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

restorer-john

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#2
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.
Fuses will hold indefinitely at 100% of their rating. At 150% of their rating it might be 3 or 4 minutes, and at 200% it might be 30 seconds. So if it were me, I'd throw a 30A fuse in it and push it to the limit with full sine waves. You may be quite surprised.

All in all, it looks like a ball-snapping bargain for car audio on the cheap.

PS You're gonna need a bigger boat (PSU) :)

1582016951140.png
 
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Wombat

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#3
Great find. :)
 

Cahudson42

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#4
So it seems it substantially beats the Lepai 2020..

Could one add for $20:
BMOUO 12V 30A DC Universal Regulated Switching Power Supply 360W for CCTV, Radio, Computer Project, LED Strip Lights, 3D Printer https://www.amazon.com/dp/B01EWG6YT8/

and a miniDSP 2x4HD

and have a 4-channel DSP alternate ready to drive each tweeter and woofer independently in a pair of 'good' passive 2-way bookshelf speakers?

A DIY alternate to all those meh-performing actives recently tested?
 

Attachments

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#7
Never expected to see this here but it's a welcome review. I have one powering my S2000 install and have been impressed with the clarity and build quality.

The only annoyance from my point of view is that the connectors for audio in and out/power are on opposite ends of the unit, making for messy wiring and more difficult placement in my particular installation (on what is otherwise a super compact unit).

I ended up buying a couple of cheap ISO adapter cables intended for other pioneer units (with the same connector) and modified/re-terminated those instead of the provided one in case I needed to return the unit. Note that there is at least one other connector with an almost identical appearance that is physically incompatible due to pin placement.
 

JohnBooty

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#10
Just for fun, but it also a channel that really measures things (power @1% THD and burst) as ASR
Great recommendation. One of the very few people out there measuring amps in any kind of objective way. His measurements are simplistic compared to ASR, but still very valuable data.
 

Matias

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#11

anmpr1

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#13
A car environment has to be rough on any component, so you'd suppose they'd at least be built strong in order to stand the environment (heat, cold, bumps and vibrations). I recall Richard Modafferi (in one of the Audio Critic issues) testing a Blau car tuner that actually had better in-use specs than a lot of high-end component FM receivers.
 
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#15
So it seems it substantially beats the Lepai 2020..

Could one add for $20:
BMOUO 12V 30A DC Universal Regulated Switching Power Supply 360W for CCTV, Radio, Computer Project, LED Strip Lights, 3D Printer https://www.amazon.com/dp/B01EWG6YT8/

and a miniDSP 2x4HD

and have a 4-channel DSP alternate ready to drive each tweeter and woofer independently in a pair of 'good' passive 2-way bookshelf speakers?

A DIY alternate to all those meh-performing actives recently tested?
$30, works out the box Lepai, compared to $100 (buy a bunch more stuff and dyi it) Pioneer - Sure, thats a good comparison
 
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#16
A car environment has to be rough on any component, so you'd suppose they'd at least be built strong in order to stand the environment (heat, cold, bumps and vibrations). I recall Richard Modafferi (in one of the Audio Critic issues) testing a Blau car tuner that actually had better in-use specs than a lot of high-end component FM receivers.
Yep, issue #26 (man I really miss getting those once/year issues in the mail....)
https://www.biline.ca/audio_critic/mags/The_Audio_Critic_26_r.pdf
 
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#17
This is good to see. My son has a Pioneer GM-D8704 (100 x 4 @ 4ohms) powering his Focal mains in his car. This can be had NEW on amazon for $135, unbelieveable value - stable to 1 ohm, variable HP and LP filters. Some really good values in car audio nowadays.
I bought the Pioneer GM-D8704 for use with 4 bass shakers for my sim racing cockpit. 4 channels driven they can shake me to death.

I did try the Pioneer with Elac B6.2's and some Klipsch speakers and the sound quality was not good at all. It was easily outclassed by budget AVR's so I would be really interested in seeing how the Pioneer GM-D8704 measures.
 
OP
amirm

amirm

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Thread Starter #20
I am glad you all like it. I did a few tests last year but thought interest was not there to do much more.

If there are amps you want tested that are on the lower power side, either buy and drop ship it to me or suggest here.
 
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