EDIT: According to John Yang this is solved in the 2012 batch.
Hey everyone, I’ve been seeing and hearing reports of topping L30 amplifiers blowing up and taking headphones with them.
I would ask that anyone who has experience with this problem contribute to this thread so we can get all the information in one place.
AS ALWAYS I encourage you all to do your own research on this! Resources will be attached for you to look though.
From what I’ve read a few instances seem to be random and a few seem to be from ESD (small static discharge).
Reports in Z’s telegram chat of HD600’s Focal utpoia’s, w5000, LCD-i4, and many other headphones damaged.
I’ve been TOLD but have not personally confirmed that topping is claiming no liability for people’s damaged headphones.
There’s a number of people in these threads who claim to have experienced their amps blowing up and sometimes frying headphones in the process.
EDIT: IF THIS HAS HAPPENED TO YOU OR SOMEONE YOU KNOW: It’s been suggested that people list the last 4-5 of their serial number so the community can identify a range (or batch) that’s at risk of this problem.
one thing to consider is the E30 DAC uses a DC power supply, as is normal, and the L30 Amp uses an AC power supply, which is rare, and then uses a standard DC port for it. a potential reason for these being fried would be either upgrading the power supply without realizing it’s AC and not DC, or accidentally using the E30 power supply for the L30. I would still hold off on using the L30 at all, but it is an avenue for investigation
My l30 went a few weeks ago, 2007 number and went for seemingly no reason. Was just plugged in to the wall, not in use. Ac adapter was what went in mine tho, not sure if the unit itself was damaged and i didn’t wanna test it (heard a pop and smelled the electrical burning smell). Got it replaced thru amazon and got a model number 2010 but still thinking about returning it.
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.
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)
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)
There is no fuse or NTC thermistor to limit fault current in case of a component failure
There are no protection mechanisms against overvoltage on the input, like a Varistor
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.
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).
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.
Op-Amp (marked yellow 3) is what fails catastrophically and probably short circuit exposing the two TPA6120A2’s to DC.
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.
Concerning some of the theories I found on various sites:
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.
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.
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.
, it is anyones guess what make and model it is. So “known failure modes” of the Op-Amps can not easily be determined.