Inside my April 2021 teardown of Amazon’s third-generation Echo Dot “good speaker”:
I wrote:
The latest fourth-generation mannequin is much more radical in its seems, though given how frequent it’s seemingly develop into to bracket-mount Echo Dots to partitions, vertically mate them to energy retailers, and the like, I think the “friendlier” (for such configurations) third-generation mannequin nonetheless has a notable life forward of it.
Aesthetic issues apart, Amazon centered on enhanced audio high quality when introducing the brand new mannequin in September 2020:
It’s compact, however packs in a robust 1.6-inch, front-firing speaker, producing crisp vocals and balanced bass for full sound you’ll be able to get pleasure from in any room of your private home.
So in fact, I had to purchase one for myself (on sale for $24.99 throughout Amazon’s June 2021 Prime Days promotions, bundled with a free good gentle bulb which I tore down that very same August), particularly for teardown functions. I suspected that the fourth-generation Echo Dot’s better quantity versus its predecessor (the identical diameter, however roughly twice the peak) would translate into a bigger acoustic suspension cavity behind the speaker, the basis reasoning for Amazon’s bass-focused sonic enchancment claims (with which audiophile websites akin to What Hello-Fi? appear to concur).
Let’s discover out if I’m proper. As typical, I’ll start with some unboxing pictures…beginning with the field:
and concluding with a closeup of the bottom-side label:
Time to pop open the highest:
The cardboard insert to the proper homes the barrel-plug energy provide:
With specs as close-up proven:
Beneath our affected person are two slim items of documentation:
Now for some overview footage of the Echo Dot (3.9 x 3.9 x 3.5 inches, and 12 ounces), as-usual accompanied by a United States penny (0.75 inches/19.05 mm in diameter) for size-comparison functions:
Alongside the again are two connectors; the aforementioned barrel-plug energy enter, and a 3.5 mm TRS for audio output functions (in case, for instance, you wish to tether the Echo Dot to a beefier exterior speaker as an alternative of utilizing the built-in transducer).
One different attention-grabbing (to me, a minimum of) design change from the third-to-fourth era Echo Dot, revealed on this explicit perspective, is that the open mesh overlaying not extends all the way in which across the unit, in distinction to the equally spherical Apple HomePod mini:
The resultant sound output isn’t omnidirectional, a truth which Amazon is admittedly upfront about; word the “front-firing speaker” point out within the earlier press launch quote.
Flip the Echo Dot the other way up and unsurprisingly, you’ll discover a round rubber “foot”
Equally unsurprisingly, from my previous teardown expertise, peel it off and also you’ll discover 4 uncovered T6 Torx screw heads beneath:
Right here’s a closeup of the still-intact product label, documenting the FCC certification ID and different data particulars; a producing line test-and-programming PCB-exposed contact level cluster at backside can also be now clearly seen (the aim of the PCB-exposing spherical gap at high, which I’ll talk about once more shortly, is much less apparent to me; reader recommendations are welcomed):
Take away the screws:
and the 2 halves of the enclosure cleanly and simply separate:
Right here’s what the within of the bottom seems like:
Word that whereas with past-generation Echo merchandise the standing LED ring was on the high of the gadget, this time it’s on the backside. The translucent plastic ring “spreads” the LEDs’ illumination extra evenly across the base.
Talking of the LEDs, let’s take a look on the PCB now uncovered on the opposite half…
Word the dozen multicolor LEDs across the circumference. Managing them is a Texas Devices LP5036 36-channel I2C fixed present RGB LED driver, which you’ll discover on the backside of the PCB. To the proper of it’s a cluster of passive parts uncovered to the surface by the beforehand talked about round gap within the base…once more, reader recommendations are welcome. And above them is a Faraday cage, whose contents are all the time a curiosity; maintain that thought.
On the PCB’s higher left is one other Texas Devices IC, this time the corporate’s TAS5805M high-efficiency, dual-channel, closed-loop Class-D audio amplifier, which I’m assured is what drives the (mono) speaker. To the proper of it’s a MediaTek chip labeled MT6398AN, whose operate eludes me, regardless of plentiful Google looking out. This teardown’s analysis outcomes have been equally fruitless, however writer Brian Dorey suspects that this explicit IC is a switching energy provide. And beneath and to the proper of it’s Diodes Integrated’s PAM8908 dual-channel 25MW headphone amplifier, which drives the Echo Dot’s 3.5 mm TRS audio output.
Talking of which…earlier than eradicating the screws I think maintain the PCB in place, let’s have one other take a look at these energy and audio-output connectors:
And now for these T5 Torx screws:
Hey, I used to be proper! And judging from the thermal tape, I’m guessing there’s a processor beneath this Faraday cage:
Let’s disconnect that ribbon cable to totally free the PCB from its tether:
Talking of cables…within the strategy of finalizing this writeup, I got here throughout iFixit’s mini-teardown. Discover that the fourth-gen Echo Dot that they disassembled had two cables between the PCB and the remainder of the top-half assemblage; the identical ribbon one proven right here (which connects to the top-side switches and microphones, together with any related circuitry for them), and one different, which went to a secondary LED panel. That top-side supplemental LED panel has seemingly been eradicated from my gadget’s variation of the design. Whereas I’m on the subject of interconnect, word the 2 electrical contacts on the speaker housing, on the high of the sooner picture. They match up with two contacts on the PCB, on the backside of that very same picture. My guess is that that is how the category D amp on the PCB connects to and drives the speaker.
Again to the PCB:
focusing now on the facet we haven’t but seen unobscured:
At backside is MediaTek’s MT7653BSN, a combo 802.11ac Wi-Fi-plus-Bluetooth 4.0 controller. You can even see the related embedded antennas on both facet of the PCB, in addition to the traces operating between them and the IC. And at high, in fact, are the facility and audio connectors. Earlier than continuing with the elimination of each PCB sides’ Faraday cages, let’s take two extra views of them, from a sideways perspective:
And now off with the cages’ tops! Ordinarily, a skinny flat head screwdriver would suffice, however these ones have been too cussed for that. Ultimately, I first utilized my solder-loosening warmth gun to them, then the screwdriver performing as a lever arm, which did the trick. First (backside) facet first:
The now-exposed IC is a curious one from a cage-enclosed standpoint: a Kioxia (previously Toshiba Semiconductor) TC58CVG2S0HRAIJ 4 Mbit serial NAND flash reminiscence. The Echo Dot in Brian Dorey’s earlier-linked teardown used a functionally equal chip from Micron.
Flipping the PCB over:
We’re solely midway there:
Time to get the warmth gun out once more:
And after making use of some rubbing alcohol to scrub issues up, we are able to see clearly now:
At left is the system’s “brains”, MediaTek’s MT8512BAAV 2 GHz dual-core Arm SoC, which apparently additionally integrates Amazon’s AZ1 Neural Edge processor core. Subsequent to it’s an obscure-marked Micron chip: fortunately, by cross-referencing with the teardown from Brian Dorey, whose Echo Dot employed a SK Hynix H9HCNNN4GUML, I do know it is a 4 Gbit LPDDR4 SDRAM.
Now let’s return our consideration to the rest of the Echo Dot’s high half:
Eradicating 4 extra screws, these Torx T8, permits us to see each the speaker and the mics-and-switches cluster on the very high of the gadget:
Let’s concentrate on the speaker first, for the reason that fourth-generation Echo Dot’s claimed sonic enhancements have been key to Amazon’s gross sales pitch:
Right here’s a closeup of the markings seen within the earlier picture:
Curiously, the speaker itself is identical measurement because the one within the third-generation Echo Dot (1.6”/40 mm), however in the event you take away the screws:
It lifts misplaced and…a-ha!…the comparatively sizeable acoustic suspension cavity behind it comes into clear view:
Word, too, that I used to be proper (in fact ;-)); the cable related to the speaker additionally connects on its different finish to the earlier-mentioned contacts behind the speaker housing.
Final, however not least, let’s take a look at the insides of the higher shell (the ribbon cable had been glued to the facet of the speaker housing, and was simply peeled away):
As beforehand talked about, the secondary LED panel talked about in iFixit’s teardown isn’t current in my Echo Dot. However right here’s a closeup of the secondary PCB that is nonetheless right here:
Take away the screws:
Re-apply the screwdriver-as-lever arm:
Disconnect this finish of the ribbon cable:
And we are able to now see the PCB in all its unobscured glory:
The notable IC on this facet of the board is Texas Devices’ TLV320ADC5140, a quad-channel 768-kHz audio ADC (analog-to-digital converter) which, maybe clearly, is fed by the four-mic array additionally seen on this facet of the PCB. Flip the PCB over and also you’ll first see a gasket:
which simply pops off:
And right here’s what the different facet of the gasket initially pressed up towards: the 4 switches and the external-sound entry portals for the aforementioned 4 microphones:
Thus concludes this teardown. And having accomplished it, I’m admittedly kicking myself that I forgot to take heed to the fourth-generation Echo Dot (each in an absolute sense and compared to the two third-generation Echo Dots presently paired to my Echo Sub) previous to breaking out my implements of destruction. Reader ideas are as-always welcome within the feedback!
—Brian Dipert is Editor-in-Chief of the Embedded Imaginative and prescient Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the corporate’s on-line publication.
Associated articles:
