Disassembling the Echo Studio, Amazon’s Apple HomePod foe
Back in late February, within my teardown of an Apple HomePod mini smart speaker, I wrote:
I recently stumbled across a technique for cost-effectively obtaining teardown candidates, which I definitely plan to continue employing in the future (in fact, I’ve now got two more victims queued up in my office which I acquired the same way, although I’m not going to spoil the surprise by telling you about them yet).
In early June, while dissecting my second victim, a first-generation full-size HomePod, I summarized the aforementioned acquisition technique:
I picked up a couple of “for parts only” devices with frayed power cords on eBay for substantial discounts from the fully functional (whether brand new or used) price. One of them ended up still being fully functional; a bit of electrical tape sheltered the frayed segments from further degradation. The other went “under the knife”. Today, I’ll showcase one of the “two more victims” I previously foreshadowed.
Victim #2 wouldn’t fully boot, the result of either a bad logic board or a firmware update gone awry. And today, we’re going to take a look at victim #3, ironically a direct competitor to the HomePod. It’s a high-end Amazon Echo Studio smart speaker; here’s a stock shot to start us off:
That one, matching the one you’ll learn about in detail today, is “Charcoal” in color. The device also comes in white…err…“Glacier”. Here’s a conceptual image of its multi-transducer insides:
The story of how I came to obtain a device which normally sells for $199.99 (sometimes found on sale for $159.99) for only $49.99 is a bit convoluted but also educational—I’ll revisit the big-picture topic later as it relates to other similar-configured devices, specifically computers. So, I hope you’ll indulge my brief detour before diving into the device’s guts. As with its predecessors, this smart speaker was listed on eBay “for parts only”. And in something of a first after more than a quarter century of my being active on eBay, after I bought it the seller reached out to me to be sure I knew what I was (and wasn’t) getting before he sent it to me.
A funny (at least to me) aside: in sitting down to write this piece just now, I finally took a close look at the seller’s eBay username (“starpawn19”) followed by a visit to his eBay storefront (“Star Pawn of New Port Richey”). He runs a pawn shop, which I’d actually already suspected. He told me that someone sold one of his employees the Echo Studio, but the employee forgot to tell the seller (before leaving) to unregister the smart speaker from his or her Amazon account, and the phone number the seller gave the pawn shop ended up being inactive.
After doing a bit more research, there’s likely more to the tale than I was told (I’m not at all suggesting that “starpawn19” was being deceptive, mind you, only not fully knowledgeable). Amazon keeps a record of each customer account that each of its Echo devices (each with a unique device ID) has ever been registered with (in fact, if you buy a new device direct from Amazon, you often have the option for it to come pre-registered). If all that had happened, as had been related to me, was that the previous registered user forgot to unregister it first, I think (although information found online is contradictory, and the Amazon support reps I spoke with in fruitlessly striving to resurrect my new toy were tight-lipped) that a factory reset (which I tried) would enable its association with a new account. If, on the other hand, a previous user ever reports it lost or stolen (or if, apparently, Amazon thinks you’ve been nasty to its delivery personnel!) it gets unregistered and all subsequent activation attempts will fail, as I discovered:
The only recourse that “Contact Customer Service” offered me was to return the unit to the seller for a refund…which of course wasn’t an option available to me, since I knew about its compromised condition upfront. So, what happened? One of two things, I’m guessing. Either:
Whoever sold the device to “starpawn19” had previously stolen it from someone else or,
Whoever sold the device to “starpawn19” hadn’t been happy with the price they got for it and subsequently decided to get revenge by reporting it lost or stolen to Amazon.
With that backgrounder over, let’s get to tearing down, shall we? I’ll begin with a few overview images (albeit no typical box shots, sorry; it didn’t come in retail packaging), as-usual accompanied by the obligatory 0.75″ (19.1 mm) diameter U.S. penny for dimension comparison purposes but absent (I realized in retrospect) the detachable power cord. The Echo Studio is 8.1” high and 6.9” in diameter (206 mm x 175 mm), weighing 7.7 lbs. (3.5 kg). Here’s a front view:
Because I don’t want it to feel left out:
Now a back view:
A closeup of the backside connections reveals the power port in the center, flanked by a micro-USB connector to the left (with no documented user function) and a multipurpose 3.5 mm audio input jack on the right, capable of accepting both TRS analog plugs and incoming optical S/PDIF digital streams.
Like Apple’s HomePod, the Echo Studio contains a mix of speaker counts and sizes, capable of reproducing various audio frequency ranges, and variously located in the device. But the implementation details are quite different in both cases. Here’s a look at the internals of the first-generation HomePod (recall that the second-generation successor has only five midrange/tweeter combo transducers, versus the seven in this initial-version design):
Compare it against the “x-ray” image of the Echo Studio at the beginning of this article. Several deviations particularly jump out at me:
Apple employed a single speaker configuration to tackle both midrange and high frequencies, whereas Amazon used distinct drivers for each frequency span: three 2” midranges and a 1” high-frequency tweeter.
Apple’s woofer points upward, out the top of the HomePod, whereas Amazon’s 5” driver is downward firing. That said, both designs leverage porting (Amazon calls them “apertures”, one in front and the other in back) to enhance bass response.
The varying speaker counts and locations affect both bill-of-materials costs and sound reproduction capabilities. Recall that bass frequencies are omnidirectional; you can put a subwoofer pretty much anywhere in a room, with optimum location guided by acoustic response characteristics versus proximity to your ears. Conversely, high frequencies are unidirectional; your best results come from pointing each tweeter directly at your head (note, for example, its front-and-center location in the Echo Studio). Midrange frequencies have intermediary transducer location requirements.
The Echo Studio was also designed for surround sound reproduction. That explains, for example, the fact that one of its three midrange drivers points directly upward, to support Dolby Atmos’ “height” channel(s). The other two midrange drivers point to either side. And like its other modern Echo siblings, two Echo Studios can be paired together to more fully reproduce left and right channel “stereo” sound, as well as (paired with an Echo Sub) to further enhance the system’s low bass response.
Here’s our first look at the top of the Echo Studio, with the grille for the upward-firing midrange in the middle and an array of seven microphones spaced around the outer ring. Recall that the HomePod’s six (first-gen) then four (second-gen) mics were around the middle of the device.
Left-to-right along the lower edge of the ring are four switches: mute, volume down and up, and the multifunction “action” button. And, in the space between the speaker grill and outer ring, a string of multi-color LEDs shines through in various operating modes, with varying colors and patterns indicating current device status (bright red, for example, signifies mute activation).
Now for the Echo Studio’s rubberized “foot”:
including that unique DSN (device serial number) that I mentioned earlier:
and which I’m betting is our pathway inside:
Yup!
Before continuing, I want to give credit to the folks at iFixit, who (as far as I know) never did a proper teardown of the Echo Studio but whose various repair manuals were still invaluable disassembly guides (in the spirit of giving back, you’ll find comments from yours truly posted to this one). I’ll also point you to a teardown video I found while doing preparatory research:
I don’t speak Hindi, so the narration was of no use to me, but the visuals were still helpful!
Anyhoo….onward. Amazon really gave my Torx driver set quite a workout; I’m not sure that I’ve ever encountered so many different screw head types and sizes in the same device. First, getting the plastic bottom off required removing 15 of them:
Lift off the bottom plate:
Disconnect the wiring harness and a flex PCB cable:
And the deed is done; we’re in!
Let’s first focus on the PCB-plus-power assembly attached to the inside of the bottom plate:
Remove four screws:
and the PCB comes free:
The IC to the right of the flex PCB connector is the Texas Instruments’ OPA1679 quad audio op amp. Flip the PCB over:
and you’ll find another, smaller IC below the audio input jack, presumably also from TI considering its two-line marking:
TI 12
4521
but whose identity escapes me. Ideas, readers? (I’m also guessing, by the way, that the optical S/DPIF receiver is built into the audio input jack? And where does the DAC for the digital S/PDIF audio input, or alternatively the ADC for the analog audio input, reside? Keep reading…)
Here’s another shot of this same PCB from a different vantage point before we proceed:
And now for that wiring harness:
Now for the PCB inside the device, which we saw earlier and which (many of you have likely already figured out, given the massive transformer, passives, and all the thermal paste) handles DC power generation and distribution:
Remove one more screw and disconnect one more wiring harness:
And the PCB lifts right out, leaving a baseplate behind:
I strove mightily to chip away at and remove all that thermal paste while leaving everything around and underneath it (and embedded within it) intact, but eventually bailed on the idea. Sorry, folks; if anyone knows how to cost-effectively dissolve this stubborn stuff without marring everything else, I’m happy to give it a shot. Speaking of shots, here are some more:
About that baseplate:
The plastic ring around it, held in place by a single screw, needs to come out first:
And now for the baseplate itself, which does double-duty (on its other site) in redirecting the woofer’s output through the smart speaker’s two side “apertures”:
Bless you, iFixit registered user Jeff Roske, for suggesting in an iFixit guide comment (step 6, to be exact) that “Power supply baseplate must be rotated clockwise, ~1cm at outside edge, to release catch tabs before lifting out of unit” and, in the process, saving my sanity (I only wish it hadn’t taken me five minutes’ worth of frustration before I saw Jeff’s wise words):
Woof woof, look what’s underneath!
And I bet you know what my next step will be…
Finally, we get our first glimpse at the system’s “brains”, i.e., its main board:
Here are closeups of the insides’ four quadrants, as oriented above. Left:
Top:
Right:
And bottom:
Specifically, to get the system board out, we’re first going to have to disconnect a bunch of wiring harnesses and flex PCB cables. Here they are, sequentially clockwise around the board starting at the left side, and in both their connected and disconnected states:
Pausing the cadence briefly at this point, I encountered something I don’t think I’ve seen in a teardown before; a zip tie bundling multiple harnesses together to tidy up the insides!
And here’s another organizing entity, a harness restraint along one side:
Onward…
Up top are also two antenna feeds that need to be unsnapped:
Now over to the right:
Next to go were sixteen total screws, eight of them shiny and screwed into metal underneath, the other eight black and anchored to underneath plastic:
Here’s the side of the system board that you’ve previously seen in its installed (pointed downward, to be precise) state, which I’ll call “side 1”:
And here’s when-installed upward-facing system board “side 2”:
Time for some closeups and Faraday cage removals. Side 1 first; keeping to the prior clockwise cadence, I’ll start with the left-quadrant circuitry, which includes (among other things) a Texas Instruments LM73605 step-down voltage converter:
Now the top:
Right:
And finally, the Faraday cage-dominated landscape at bottom:
Again, you already know what comes next, right?
That’s MediaTek’s MT7668 wireless connectivity controller at the center. Quoting from the product page on the manufacturer website: it’s a “Highly integrated single chip combining 2×2 dual-band 802.11ac Wi-Fi with MU-MIMO and latest Bluetooth 5.0 radios together in a single package.” The only wireless protocol NOT documented is Zigbee, support for which keen-eyed readers may have already noticed was mentioned in the smart speaker “foot” markings earlier. And by the way, if you hadn’t already noticed, in addition to the earlier noted external antenna wiring feeds, there are PCB-embedded antennae to either side of the Faraday cage (also visible on the other side of the PCB).
Speaking of which…now for the system board side 2. Already-exposed IC at left (a Texas Instruments TPA3129D2 class D audio amplifier) first:
At top (and top left) left is a clutch of ICs only some of which I’ve been able to ID:
The upper-left Faraday cage hides, I believe, the Zigbee controller. Its markings are:
MG21
A020JI
B01U8O
2119
and through a convoluted process involving Google Image search followed by a bunch of dead-end (and dead-page) searches that ended up bearing (hopefully not-rotten) fruit, I think it’s Silicon Labs’ EFR32MG21:
Now for the remainder of the ICs in this region:
The IC at the very top, with the silver rectangular “patch” atop it (which I at first thought was a sticker but can’t seem to peel off, so…) seemingly covering a same-size gold region underneath, is one of the puzzlers. Above the silver patch are the following faintly (so I may not be spot-on with my discernment) stamped lines:
13TTI
CT7NQ4
Below the silver section are also two marked lines, the first stamped and the second embossed:
3221
56A03
And next to the chip is this odd structure I’ve not encountered before, with a loop atop it:
Any ideas, folks?
To its lower right is another puzzler, marked as follows:
TI 13
531A
Fortunately, the remainder aren’t as obscure. Directly below the “silver patch” IC is Cirrus Logic’s CS42526 2-in, 6-out multi-channel codec with an integrated S/PDIF receiver (hearkening back to my earlier S/PDIF discussion related to the bottom-panel PCB). And next to its lower-right corner are two Texas Instruments THS4532 dual differential amplifiers.
Last but not least, there are the Faraday cage-rich right and lower quadrants:
Let’s tackle the cage-free IC at the right edge first: it’s another Texas Instruments TPA3129D2 class D audio amplifier, the mate of its mirror-image at left. Above and two Cages to its left is nonvolatile storage, a Sandisk SDINBDG4-8G 8 GByte industrial NAND e.MMC flash memory:
To its right, underneath the large rectangular Faraday cage, is (curiously) another MediaTek Wi-Fi-plus-Bluetooth controller IC, the MT7658, which is online documentation-bereft in comparison to its MT7668 cousin on the other side of the PCB, mentioned earlier, but which I’ve seen before.
And what about that large square Faraday cage at the bottom? Glad you asked:
Underneath the lid, in the upper right and left corners, are two Samsung K4A4G165WE-BCRC 4 Gbit DDR4 SDRAMs. And underneath them both, befitting the thermal paste augmentation, is the system “brains”, MediaTek’s MT8516 application processor.
Remember that earlier mentioned LED ring, and those up-top buttons and mics? They suggest we’ve got one PCB to go, plus we haven’t seen any midrange or tweeter transducers yet. Next let’s get out those two shiny metal brackets:
Two screws for each attach to the side:
And one screw for each attach to the assemblage above (or below, in the Echo Studio’s current upside-down orientation, if you prefer):
And with impediments now removed, they lift right out:
Next up for removal is the baseplate underneath (more accurately: above) the now-absent metal braces and system board:
More speakers! Finally!
At this point, I hypothesized that I’d need to get the top of the Echo Studio off in order to proceed any further. Holding it in place, however, were 14 screws accessible only from underneath the top, only a subset of which are shown here:
Why? Those speakers. The midranges in particular had really strong magnets, which tended to intercept and cling to screws en route from their original locations to the outside world:
Those same magnets, I discovered complete with colorful accompanying language, would also yank Torx bits right out of my driver handle. I eventually bailed (temporarily) on my iFixit driver kit and went with a set of long-shaft single-piece Torx screwdrivers instead. Here’s the end result as it relates to the top speaker grill, alongside my various implements of destruction:
And here’s the now-exposed upward-directed midrange speaker:
Four more screws removed, less “momentously” than before, set it free:
Now for that top outer ring. With the screws originally holding it in place no longer present, I was able to pop it free using only my thumbnail:
The translucent ring around the underside for the LEDs to shine through is likely obvious (hold that thought), as are the “springs” for the four buttons. The one on the left, if you look closely, is different than the other three: there’s a cutout in it. Again, hold that thought:
Two easily removed screws are all that still hold the LED PCB in place:
Here’s an initial overview shot of the LED PCB standalone, and of its top with the ring of 24 LEDs around its middle, an immediately obvious feature.
Keen-eyed readers may have also already noticed the seven MEMS microphone ports, one of which is missing its gasket (stuck instead to the underside of the top outer ring, which you’ll now notice if you go back and look at the earlier photo of it). Let’s now do some closeups, beginning with the top:
The “mute” switch, at far right in this photo, is different than the others because it has dedicated LEDs alongside it that illuminate red when the mics are in a muted state (in addition to the entire ring going red, as mentioned earlier). And what’s that next to the “action” switch on the far left? Remember the cutout I mentioned in the accompanying switch? It’s an ambient light sensor that enables dynamic calibration of the LEDs’ brightness to the room’s current illumination level. The IC below it, judging from the logo, is sourced by Toshiba Semiconductor, part of its LCX low-voltage CMOS logic line, but I can’t definitively ID it. Here are the markings:
LCX
74
3109
LS3208
The chips at right:
are a Texas Instruments LP5036 36-channel I2C RGB LED driver and, below it, another TI chip unknown in function and labeled as follows:
SN19070
T 0C8
A17V
That same two-chip combo is also present on the left side of the PCB:
The bottom of the top side of the PCB is comparatively unmemorable:
as is the underside of the PCB, aside from the bulk of the MEMS microphones’ housings:
We’re still not the rest of the way inside, but keep the faith; I still see a few screws up top:
Turns out the Echo Studio is comprised of two separate shells, the outer doing double-duty as front and side speakers’ grills (and, along with the top pieces’ colors, the sole differentiators between “Charcoal” and “Glacier” variants, come to think of it), which now slide apart:
Here’s what the outer-shell grilles for the front tweeter and side midranges look like from the inside:
No speaker, therefore no grill, in back, of course:
They correspond to the inner-shell locations of the left midrange:
Right midrange:
And front tweeter:
Again, the backside is bare:
Speaking of which…the midranges are identical to the top-mounted one you already saw. But let’s take a closer look at that tweeter:
In closing, one final set of images. In peering through the hole left from the tweeter’s removal:
I happened to notice the two antenna wires, one white and the other black, that I’d briefly showed you earlier. I realized I hadn’t yet discerned where they ended up and decided to rectify that omission before wrapping up:
This is the inside of the inner shell, looking toward the top and back of the device from the bottom. The antennas are in the back left (black wire) and right (white wire) of the Echo Studio, next to and “behind” the midrange drivers:
My guesses are as follows:
One of them is for 2.4 GHz Wi-Fi (black?), the other for 5 GHz (white?).
The 2.4 GHz one multitasks between Wi-Fi and Zigbee duties, and
The Bluetooth antennae are the PCB-embedded ones noted earlier.
Agree or disagree? And related: I’m still baffled as to why the design includes two Wi-Fi-plus-Bluetooth controller SoCs, MediaTek’s MT7658 and MT7668, plus a dedicated Zigbee controller. If you have any insights on this, or thoughts on anything else I’ve covered in this massive missive, I as-always welcome them in the comments!
—Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.
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