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Topping L30 Headphone Amplifier Review

Cujobob

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Anyone with 2006 serial numbers had this issue? I use this L30 amplifier and like it a great deal, but my young son also uses it and I’m not really much for taking a chance there.

Also, is there any chance this affects other Topping products?
 

Seeing_Red

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So funny enough, my L30 just blew as I was reading this thread.

Setup: Had my MMX 300s by my side but not on my head. I had the amp on with 0% volume. Right now, it's stacked on top of a E30 on top of a STAX amp which isn't on. I was just inspecting it from a seated position and I was touching other metal objects including E30. No audio input signal from the PC at the time.

Incident description: As I was making sure the stack was lined up correctly by pressing across all three devices I heard a loud pop and crackle from my headphones. Immediately turned off the amp. I checked the headphones with my phone and they seem to be okay. Since I have KPH30is which are basically disposable, I plugged them in to check on the amp. Large pop when turning on the amp followed by some crackle at 0% volume. As I turn the volume knob I can hear some static. Noise floor is audible with 0% volume also. Another large pop when turning off the amp. Also weirdly a large pop when switching to pre-amp mode. All with no input signal.

With input signal, audio is heavily distorted, but still plays.

Additional details: Almost sounds like a constant DC voltage is being applied which is bottoming out the driver. The pop that occurs can very well damage headphones depending on fragility of the drivers. My S/N starts with 2007 and I've been using it with no other issues since October. I'll run some more tests after work tomorrow. Although I live in New England, I haven't had issues with ESD in my office and I was touching the metal case of a couple grounded devices. Also, I was just about done inspecting the amp so I would of been discharged already.

Unless there are earlier documented incidents, it could be related to early component failure. To assist in the root cause analysis, all failures should be documented with descriptions of the events and timelines for the different failures. Failures due to ESD would be more random and we would of likely heard of more cases than just recently, but without data it's hard to tell.

I've been lucky enough where it hasn't damaged any headphones and I'm within the return window.
 

Giangi71

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[QUOTE = "PSO, post: 632962, member: 16281"] A meno che non venga segnalato, non credo che altri prodotti siano interessati. Sono un utente come te e ho Topping NX4 DSD (funziona anche a batteria, e uso quella modalità), e funziona perfettamente. Di solito c'è un forum per i rispettivi prodotti. Puoi controllare anche lì, per maggiore certezza.

>> .. anche mio figlio lo usa e io non voglio correre rischi. >>
molto vero, signore. [/ QUOTE]
Unless reported, I don't think other products are affected. I am a user like you, and I have Topping NX4 DSD (works on battery too, and I use that mode), and it works perfectly fine. There is a forum for the respective products, usually. You can check there too, for more certainty.

>> .. my young son also uses it and I’m not really much for taking a chance there. >>
very true, sir.
But the affected series is 2010?
 

threni

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My guess (BUT IT'S ONLY A GUESS) is that at this point is not an ESD problem or something like that. If it was something ESD related, it shouldn't leave such burned marks on the pcb, specifically on an opamp. Maybe the static discharge triggered the problem, but for me it's something that has to be related with the feedback circuit. In particular, something related with such a low output impedance, when 6120A2-based circuits are known to be stable with an output-Z of 10 ohm. Even the DX3pro v1 reported a similar problem and the v2 was corrected with an higher output impedance.
This is only my guess, I'm happy to discuss it.

I think we might be in agreement. I'm not suggesting "someone touched the volume knob and the static zapped the board and burned it". More like, suppose there's an amp component that takes the input and multiplies it by 10, and is normally dealing with 0 -> 0.1v input and 0 -> v output, and it suddenly gets 1000v input from the static. And supposing there's nothing that can/does say "woah, 1000v input? Let's not amplify that.."
 
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solderdude

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ESD discharges commonly are well over 10kV. Just very short of duration.
The input of the OPA is protected for ESD on its input.
The effectivity of this depends on the series resistance with the input pins.
It would appear that the input resistance is the low resistance input pot only.
Fortunately this is also partly to ground.
The problem is it would have to 'jump' from the potmeter shaft to the wiper.
For this you would need a not-grounded metal potmeter shaft + clear metal knob.

The other possible path is via the switches but these have a relay.
 

bithloman

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Mh seems to be a more serious issue than i thought. Will take my sundaras off the L30 till this is more clear.
Just a thought.
@JohnYang1997 you said that the device was never tested for ESD compatibility, and you said that only now you've bought the insulation resistance tester to perform an analysis on this fault, but per IEC 61000-4-2 required to obtain the CE certification and the subsequent marketing of a product on the European territory, the ESD test is mandatory alongside a bunch of other EMC tests... Every company invests money doing that.
Even HiFiman, of which I have an headphone, and a brand that certainly doesn't shine for its QC on build quality has the ESD test on their headphones. And those are "passive" components. An amp should be tested better before putting it on the market.


Funny of you to think this chinese company would show integrity to its customers. look at his responses in other forums being rude, its beyond unacceptable. I will be buying american or european from now on. This measurement war started by chinese cheap products had to end some day. only a matter of time. Made a lot of people a lot of money you can see them panicking in real time. paying for good reviews and cant replace headphones they destroyed yet everyone on here shits on shciit when they have integrity.
 
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bithloman

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It was the other part I bolded, came off to me at least that everyone seems fine with possible hearing damage on this forum, seems like a blanket statement on this forum. Did I misread that? If so, my apologies.
The first quote I have not read anyone here post anything close to, who is telling others to STFU about this?

it is extremely obvious what he meant with the STFU statement. The topping representative being rude and people still defending the company saying people are over reacting. i was about to purchase this amp and will no longer buy chinese products based on the companies responses here and on hifiguides which were even deleted by him.
 
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filo97s

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Whatever decision you take (return or retain) is fair, IMO. You said you are a student, right? Obviously, your purse will be tighter than other groups. But you are also in the second least-affected group (unharmed amp/HPs, and having the option to return your amp), next only to folks who have not bought the amp but still hurt for others. It is just that showing our anger might not resolve the issue faster.

Its a practical fact that electronics fail, and in many brands. Please note that some of us got angry and some of us felt reassured too (and some users are not that bothered, probably because they have been through these cycles earlier). IMO, very few L30 owners will be cool or indifferent to what's happening, but hopeful that no more blow-ups happen, and that we will have a solution soon, if things aggravate.
What he's trying to say, I think, is that of course an amp can fail and the company offers to replace it, nothing wrong with it and everyone who has ever built something knows that there are infinite variables to take into account that are virtually impossible to certify that a piece of electronic is indestructible. What is unacceptable is that alongside with the fail it takes out everything you've connected at it, including your ears. And the company seems to ignore this, as the headphones are not refunded. On Zeos chat, there are guys who have lost a 2.5k LCDi4, or a 4k Focal Utopia, for these guys the 100 USD replacement of the amp is nothing compared to the loss, not mentioning the hearing damage that can occur.
More important, all of this could be avoided if only the company tested the device for ESD as every marketing rule requires, from FCC to CE. Why skimp on tests when every other company do that? Who are they to avoid tests that normally requires money and time to other companies?
I can't understand how can you feel safe by continuing using a device that has a probability to do serious damage. It's like someone tells you that you have 0.01% of probability to die if you cross a minefield, and you answer "well ok but I have 99.99% of probability of staying alive".
 

solderdude

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More important, all of this could be avoided if only the company tested the device for ESD as every marketing rule requires, from FCC to CE.

Assuming:
A: it actually caused by ESD. (looks like it but not confirmed)
B: One only tests a prototype and perhaps 1st production run.

When there is a bad batch of components or grouding in reality is problematic but wasn't on the proto/production one (see Schiit enclosure issues) then you can have all the certificates you want but that won't help.

It's unfortunate that expensive headphones are blown up. Perhaps a more expensive amp would have been wiser to pair with it.
In all honesty, given the DC protection this amp has, I would not expect it to destroy amps.
 

BDWoody

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paying for good reviews

So, if you're going to throw out that kind of accusation against the site and the company, I assume you have evidence? If not, this is simply coming across as anti-Chinese, not to mention being rude and offensive.
 

Giangi71

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Still not understand the wide extension of the issue. I'll wait an official answer by Topping
 

Jose Hidalgo

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what should Topping do now to resolve these customers' issues?
Please suggest something constructive.
For future readers, I've already said this twice, and there's no other way IMHO. Now let's all calm down and wait for Topping's official answer. :)
 

solderdude

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The “can’t recommend strongly enough” rating in the first post of this thread really ought to be amended until the issue is resolved. There should be at least a warning for potential buyers.

Acc. to John the not properly functioning DC protection is already 'fixed'.
So even when the OPA, for yet unclear reasons, should burst in flames the headphones should be protected.
The eventual warning could be that less than 1% of L30 with a certain serial number range could potentially fail and take the headphone with it.
Well over 99% of owners will most likely never experience catastrophic failures.
It looks like those not willing to take a chance can send it back to have it replaced by the newer version.


Yes, perhaps calm down but the very few people that had (expensive) headphones burnt to a crisp may feel differently.
The warning should be on the Topping website. ASR is not responsible for this.
 

bboris77

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Acc. to John the not properly functioning DC protection is already 'fixed'.
So even when the OPA, for yet unclear reasons, should burst in flames the headphones should be protected.
The eventual warning could be that less than 1% of L30 with a certain serial number range could potentially fail and take the headphone with it.
Well over 99% of owners will most likely never experience catastrophic failures.
It looks like those not willing to take a chance can send it back to have it replaced by the newer version.


Yes, perhaps calm down but the very few people that had (expensive) headphones burnt to a crisp may feel differently.
The warning should be on the Topping website. ASR is not responsible for this.

From what I could surmise, Topping has not yet clearly established what actually caused this failure, so it is not certain that current production units are safe to use with expensive headphones. Once they do establish what exactly caused this, I am hoping they will issue an official full recall of all the affected units.

As for ASR's official response to this, I would prefer hearing from @amirm directly since he is ASR. Of course, ASR is not legally responsible for notifying its members about this. However, perceptions are also important and it is not looking good that the official review of this product does not even mention this fairly significant incident and that @amirm has not yet said a word about this since it started happening.
 
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