Topping L30 xploding and taking headphones out

Discussion in 'All Points Bulletin / Be on the Look Out' started by M3NTAL, Dec 17, 2020.

  1. soekris

    soekris MOT - Soekris Engineering

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    Back in the days when I made communication boards, in the beginning I had a few ethernet controllers die, then I added heavy TVS protection on all ethernet ports, and the problem went away completely....
    Nowadays I also try to protect all ports, so the Headphone output on all my DACs have TVS protection.... Other ports are either protected by design or also have TVS protection....
    The topping either died from ESD coming in somewhere, or the opamps are cheap chinese copies. Topping are probably running the power lines of the chips close to their limits....

    From TPA6120 datasheet:
    These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
     
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  2. Baten

    Baten Friend

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  3. dBel84

    dBel84 Friend

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    Just a TPA6120 comment - it is a real finicky chip and is susceptible to instability if not set up with appropriate input buffers

    upload_2021-1-8_8-14-32.png

    I discovered this the hard way when building chip based headphone amps in the early days . The above is taken from the datasheets and you REALLY need those input buffers
     
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  4. Brause

    Brause Facebook Friend

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    My Singaporian friend scanned the Chinese audio forums. No L30 explosions reported there, although northern China is very cold and dry (bordering on Siberia).
     
  5. yotacowboy

    yotacowboy McRibs Kind of Guy

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    This amp should be included with every pair of HD700s. Great synergy!
     
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  6. bboris77

    bboris77 Friend

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    It may be related to the power supply, considering the fact that China is on 220V and most of the reported cases were on 110V. Just guessing here.
     
  7. Psalmanazar

    Psalmanazar Most improved member; A+

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    These are all using random cheap OEM switchers that output universal voltage.
     
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  8. Cspirou

    Cspirou They call me Sparky

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    doubtful. Only difference are wall-warts and you aren't going to accidentally use a 220v one since the plugs are different. If they do somehow manage to use a 220v wall-wart, then it would result in 7VAC. A lower voltage that wouldn't explode chips.

    Plus the amp uses linear regulation and should give consistent voltage.

    I do wonder what's going on with the DC circuit though. If it only works on power up or if it's actually in case of failure

    This one actually uses a 15VAC wall-wart. Rectified internally with 3 regulators.
     
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  9. bboris77

    bboris77 Friend

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    According to the pics on the Interwebs, the included PSU for the L30 in North America only supports 120V. Thankfully, I have no personal experience with this device.

    Edit: It is a Topping-branded PSU which should give further assurance to the purchaser. ;)
    It would be interesting to open up one of these devices to see what is inside.
     
  10. purr1n

    purr1n Finding his inner redneck

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    It could be a batch of bad parts. Haven't most of these incidents occurred within a short interval?

    This is why I said Topping / SMSL should post an advisory and in the meantime investigate. Shit happens. Instead Topping via John Yang essentially says "Fuck you, not a problem. Only happens 4 in 10000." (this is assuming everyone who had an exploded part reported it publicly). We already know 99% of people will never post on the Internet and simply move on with their lives. And we also don't know what Topping / SMSL isn't telling us. This is as @Psalmanazar says, a Chineseum company, so my trust isn't exactly there. And if it's cumulative damage from ESD, it could be a ticking time bomb waiting to happen.
     
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    Last edited: Jan 8, 2021
  11. netforce

    netforce MOT: Headphones.com

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    From reading John's posts in the past, he seemed to come off a little arrogant to me and that put me off a little. But whatever I have been on headphone forums for years and that isn't new.

    The fact that the L30 is his doing, we have had 4 known cases of an L30 blowing and taking 4 headphones with it. His two responses so far had been first to say sbaf is FOS and not even acknowledging the content posted here about the L30 blowing an i4. And then oh it was only 4 unit out of 10k. This really irks me the wrong way. Be arrogant as you want but when you pretty much acting as the English representative of Topping on ASR, show some freaking compassion to your customers.

    He could have so far said absolutely nothing and gone into hiding and said nothing at all which he hasn't done. He could of empathized with people having their headphones blown up but just browsing his posts, he hasn't. He said he was going to investigate here on Wed and honestly should have stopped there. But his further posts after that strikes me as him acting indifferent and dismissive.

    I just saw also in the ASR, another member there mentioning their L30 blew and took another headphone, a post which John obviously saw since he liked the post:
    https://www.audiosciencereview.com/...e-amplifier-review.15226/page-117#post-624071

    A friend on discord mentioned his buddies L30 blew, didn't have any headphones plugged in at least. And always cautious with a secondhand story. But still, sounds like more than the four units mentioned previously. The audio world is really bigger than we know. I have talked to countless people coming in to try and buy headphones that aren't on the big forums or reddit or discords or whatever. They browse, they lurk, they go to shops, events, meets, etc without ever interacting in the standard ways. There are likely many more cases happening of L30 blowing that we don't know about.
     
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  12. Baten

    Baten Friend

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    ctrl+f'ing for "transformer" gives me this:

    [​IMG]
    https://www.audiosciencereview.com/...-headphone-amplifier-review.15226/post-519245

    "Where's the fusing on that transformer??? It needs one (or two) on the high voltage side or it's really unsafe! That would never pass certification in North America and puts your home at risk of burning down if anything goes wrong! It doesn't have any surge protection either." <-- this could have been a harbringer of the bad news lol. not sure if the comment is correct though, but considering the recent failures...
     
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  13. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    The tranny can be internally fused and inrush filters... prolly 20VA which isn't that big. I'd say 100VA is where inrush starts being a problem.
     
  14. Brause

    Brause Facebook Friend

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    Silly question - which I may have to answer myself: I have an L30 on order from a reputable Shenzhen company. I was talked into it as the L30 is neutral sounding and therefore good for earphone tuning and reviewing.

    Probably the best thing to do it refuse delivery...Canada Post will return it. Then ask for a refund.

    My Singaporian friends recommend purchasing a humidifier :)...but Calgary is semi-arid essentially all year round.

    Any better ideas?
     
  15. netforce

    netforce MOT: Headphones.com

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    Tell the vendor with what is happening at the moment with other L30 that you are not comfortable with it anymore and see what they say also. Tell them you are thinking about refusing the package or if there is anything they suggest to remedy the situation. Its not the vendor's fault the product they sold may have an issue that kills headphones.
     
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  16. rlow

    rlow A happy woofer

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    Maybe Shenzhen Audio should offer an add-on humidifier for all the Topping amps in their online store. What a great upsell opportunity!
     
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  17. Elmer Danilovich

    Elmer Danilovich MShenay trying to pretend to be an old man

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    Yikes... I've got an L30 I've not used in a while and it seems it's time I start gravitating away from it... @purr1n I think a -6 dB gain Magni 3+ would be excellent! The -9dB gain on L30 was useful at times and with everything now coming out of the wood works... I can't say Topping is a brand I want to be discussing in any of my content

    Sooo having another product with at least that gain option around a similar price point FROM a well established company like Schiit would be excellent!
     
  18. HHS

    HHS Rando

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    I guess fewer people will be making fun of the plastic knob and chassis on the JDS Atom after ESD blows up their L30 ;)
     
  19. Brause

    Brause Facebook Friend

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    Done already earlier today! Vendor is a good guy and not related to that company quoted by @rlow. And he is on his weekend :)...but nevertheless just told me they are taking it back.

    And now? A Geshelli instead?
     
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    Last edited: Jan 8, 2021
  20. yotacowboy

    yotacowboy McRibs Kind of Guy

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    L30 + HD700 + DeLonghi dehumidifier bundle! I'm waiting for the Drop version.
     
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