There are way too many cases at this point for that to be a possible cause.
I think it’s unlikely user error is the issue here, based on others accounts apparently this is not the first topping product that has destroyed headphones the original DX3 apparently had the issue and was redesigned to fix it.
plugging 5VDC into something expecting 16VAC would just result in no power anyway, the other way around could be an issue.
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But the Topping guy said that it was only 4 out of 10k units that exhibited this issue. Now there’s more? How can that be?! /s
yup! i was using the one that came with the l30. The one that comes with the e30 is just a usb cord which i plug into my pc (edit. as an addition, my AC adapter came in bad shape, with the box having holes and dust in it. This is not the box the topping l30 itself came in but the internal box of the ac adapter)
I don’t know if this will help, but I’m posting anyway.
I’ve bought my L30 (model serial 2008***) around October through Aliexpress.
I’ve been using it daily as my main Amp (paired with the E30 DAC). So far, no issues, and this unit went through A LOT of power surges/outtages.
Maybe the ones that are having issues are from a very specific batch?
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FWIW Schiit actually paid to replace headphones when that happened.
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Looking at the picture posted by user “M3NTAL” to SBAF (the same that is in the OP here), I would say that is more than a claim.
I got another 2 pcb photos showing the same chip (probably an Op-Amp) blowing up.
Here is the photo of the back of the PCB by “M3NTAL”. The black spot in the Serial Number spot indicates something got pretty toasty. This is the only photo I have of the back (of a blown up L30).
Concerning the layout of the L30: I looked at it a bit now trying to figure out how these can blow up. As I don’t have one myself (or access to my unis electronics labs), I am flying somewhat blind here, so take a grain of salt with the following:
(Picture from ASR review, with my markings)
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There is no fuse or NTC thermistor to limit fault current in case of a component failure
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There are no protection mechanisms against overvoltage on the input, like a Varistor
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There is a circuit marked “DC_Det” (Marked yellow 1 in the picture). Given its proximity to the headphone jack, I assume that is an Op-Amp to detect DC components on the output. Question is if that controls one of the relays (marked pink 1, 2 & 3) or just reports to what I assume is a micro-controller (marked yellow 2). The Transistors below the uController suggest it being in charge of operating the 4 relays in the device.
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Supply rails are provided by LM317, LM337 and one chip next to the Micro-controller. Except for the unidentified chip between the uController and the top-left LM317, all of these are LDOs. Due to their design, these will current limit to 1.5A continuous (1.5A @ 15V ≈ 22W).
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There is a pair of Texas Instruments TPA6120A2’s under the blue heatsink. I don’t know how these behave when exposed to DC accross their input terminals.
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Op-Amp (marked yellow 3) is what fails catastrophically and probably short circuit exposing the two TPA6120A2’s to DC.
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There are Flyback (= Freewheel) Diodes next to all 4 relays.
Block Diagram
This is drawn from the pictures I have and the datasheets for components I could identify.
Solid lines and solid arrows are what I am reasonably certain about.
Dotted lines, dotted arrows and ?-marks identify components and connections I am unsure about.
The red box marks the group which failed.
Concerning some of the theories I found on various sites:
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This is not caused by ESD!
Op-Amps may be damaged by ESD. ESD will not cause burn marks on the back of the PCB though! As the Op-Amp is sanded down
, it is anyones guess what make and model it is. So “known failure modes” of the Op-Amps can not easily be determined. -
Anything under 22V DC on the input does not cause this. 15V AC rectified comes out to ~21V DC. Running the L30 off USB will not achieve anything as the TPA6120A2’s will not turn on.
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Yeaaaaa I just returned my whole Toppings stack because of this concern…it may be an isolated incident but it is rather worriesome which is a shame because I actually liked it a lot the form factor and use of it is nice but the customer service side of things has me a bit worried.
I have already written in the L30 Thearth.
At the moment, China is on Christmas break, which means the whole of January.
And that as an L30 owner you should not use it until something new has been announced as a precautionary measure.
Furthermore, you can’t believe everything that has been written - a lot of it is exaggerated.
Especially in the Asr forum they condemn the L30 and almost sue John Yang.
Of course it is regrettable that the only statement is that only 4 units were affected and that everything was not so bad.
That is certainly not good and does not serve the interest of the owners.Then it would have been better not to write anything and to clarify the case carefully.
But he will also be on holiday.
At the moment, we can only wait until February for news.
As I read it, the warranty only covers the device but not the headphones if they are damaged.
Of course, that’s also bad and makes things even worse.
Which is understandable when a Focal or Audeze goes up in smoke that cost money.
One could now ask the question why one thinks to buy such headphones and connect them to a Chifi amplifier that is susceptible.
But you should not do that either, because it only leads to unnecessary discussions.
Hey! I’m the guy from the reddit post: not much to add to the story, the only thing I can add is that topping did not get my unit back to analyze since they could not arrange a pick up, and I’d have to arrange shipping to China ( I’m located in the EU).
I could not fully disassemble my unit, the pcb would not slide out. From what I’ve seen the caps were ok, no obvious damage. Since it’s going back to Amazon I did not want to go any further.
Hope it helps, please be safe with your L30, mine popped the coil from the driver, would not be great if against my ear.
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What was the serial number and how long did it last?
Furthermore, you can’t believe everything that has been written - a lot of it is exaggerated.
Especially in the Asr forum they condemn the L30 and almost sue John Yang.
Of course it is regrettable that the only statement is that only 4 units were affected and that everything was not so bad.
That is certainly not good and does not serve the interest of the owners.Then it would have been better not to write anything and to clarify the case carefully.
But he will also be on holiday.At the moment, we can only wait until February for news.
Therein kinda lies the rub though. Most people if they bought it recently like myself have a short window to return it. If it is such a small issue if they offered to compensate people repairs to their headphones (Or replace) then I would feel a lot more comfortable with them but that is not the case. Instead you are left with a gamble. If one can return it then it makes sense to do so and mitigate the risk. If one cannot then you are left with a quandary of should you then replace it? To me that is the bigger issue. These are budget amps so people who are using them presumably do not have the luxury of disposable income to sit there and replace their headphones that died simply because of a faulty amp design. All hardware fails in some capacity its just a matter of life that this happens. It is how the companies respond to it that matter.
Sorry I did not check before shipping it back, stupid mistake. Bought it for 11/11, used it daily without any problem till the 31/12, when it died.
Yes, I absolutely understand.
Anyone who has bought it recently should just return it without hesitation.
The risk is too great.
Apart from that, the question is whether something can happen when it is in use?
And to be honest, if Topping refuses to replace headphones from customers who can prove that they were destroyed by the product, why should I have regrets if I bought one recently?
None !!!
Those who have ordered from Amazon can still return them after the return period or exchange them.
Of course, it would be a bit expensive for Topping to have to replace every second pair of headphones.
If every second customer was affected.
That would probably not be possible for financial reasons.
Nevertheless, the whole thing is annoying.
There were a few problems with the E30 in the beginning and now the L30.
And @Mazeframe has also uncovered some things where you have to ask yourself as a developer that this was not right.
With a simple fuse, this wouldn’t be a big issue. In China, they cost ridiculous amounts in cents.
But let’s take a look at Schiit, Jds Labs, who offer a 99$ amplifier. There is also no fuse installed and it works strangely enough.
As I said, at the moment we can only recommend to wait until Topping has something to say and not to use the L30 for safety reasons.
I am not sure about that.
Depending on placement, it may just protect the device enough to not go up in flames.
It it was placed after the big internal caps and before the LDOs, it should protect connected headphones under fault conditions.
I don’t know about the Atom, but the Schiit Magni amps do have a fuse (F1) near the power switch.
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If someone were using the L30 as a pre-amp and not using the headphone out what would the risk be?
Without stabbing the PCB with a multimeter, impossible for me to tell.
Best guess would be it’s probably OK because the odds are there is a capacitor on the input to the power amp.
What destroys the headphones is likely a DC voltage applied to the voice coil.
EDIT - looks like someone did have a failure in preamp mode, I can’t find the original post to determine if it damaged anything downstream.
Here what John Yang said about Headphone repair:
Sorry guys.
The short version is that there was probably an update in November and the final result is now there.
The update is explained briefly on the previous page from this link or afterwards.
A couple of pages further on, one person reports that he noticed a small electric shock at the volume pot, and another who had his headphones on and was lucky not to have put them on before it went bang.
I know that ASR tends to exaggerate.
When I personally read this, I get the impression that even though the developer isn’t even stupid about the sale.
But they also seem to have taken a bit of a risk with the update.
Currently, the device seems to be safe from nothing.
Apart from the headphones and amplifier blowing up.
You can also lose your hearing or suffer electric shocks, which is very bad if you have a pacemaker in you.
I find this very negligent on the part of Topping and not okay. At least there must be an official confirmation of this somewhere.
Even if my reaction may seem exaggerated.
Obviously, it seems to be a bit immature even after 6 months.From a purely rational point of view, it should be taken off the market until this is clarified.And a clean revision should be worked out that has been extensively tested.And learn from this for the future.
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Any recommendations for a replacement amp that would pair well with the E30 (I like it for the remote control volume for when I’m not next to the amp to adjust). I’ve enjoyed the L30 so far but I’m definitely open to getting more audio equipment.
Thanks for your time, I hope you have a nice day 