Geshelli is good but for low impedance and sensible headsets better L30...
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Topping L30 Headphone Amplifier Review
- Thread starter amirm
- Start date
Ok seems fair. Id like to keep the stack, in the meantime ill be on the lookout for something new just in case.
Geshelli on their site states " All fee's due will be the buyers responsibility. " such as customs etc.
Monoprice on the other hand doesnt have that many options to choose from, based from their site, sure it has thx 887 but i dont really need that.
Geshelli on their site states " All fee's due will be the buyers responsibility. " such as customs etc.
Monoprice on the other hand doesnt have that many options to choose from, based from their site, sure it has thx 887 but i dont really need that.
artburda
Active Member
I‘m trying to inspect the board, but how do you remove the front and pull out the board?
solderdude
Grand Contributor
is yours defective ?
AFAIK it is a matter of pulling off the volknob, removing the 2 rear screws and slide out the PCB.
Edit: behind the volknob there is a nut that has to be removed.
Last edited:
Hi guys. Sorry if this is a redundant question.
So is there no clear reason revealed for this issue?
My understanding so far is as following:
- Some suspect that the issue is caused by static spark
- Some says it's not likely to be the case based on the burnt position of the board
- Static up to 5kV have not reproduced the issue at topping's lab
- Some people felt 'spark' or 'electricity' when they touched the knob or housing before the incident
- The 'spark' could have been a current leakage, not a static, indicative of a short or a failure on the board
- The DC protect circuit is updated after '2012' batch
- Some suspect that the board is lacking protection circuit for overcurrent / surge at power input part
If my understanding written above is correct, could it be the surge from 15VAC input that have caused the short or break inside the amp?
If so, can we add some breaker / fuse between 15VAC input port and 15VAC output cable, to protect the board from the surge?
So is there no clear reason revealed for this issue?
My understanding so far is as following:
- Some suspect that the issue is caused by static spark
- Some says it's not likely to be the case based on the burnt position of the board
- Static up to 5kV have not reproduced the issue at topping's lab
- Some people felt 'spark' or 'electricity' when they touched the knob or housing before the incident
- The 'spark' could have been a current leakage, not a static, indicative of a short or a failure on the board
- The DC protect circuit is updated after '2012' batch
- Some suspect that the board is lacking protection circuit for overcurrent / surge at power input part
If my understanding written above is correct, could it be the surge from 15VAC input that have caused the short or break inside the amp?
If so, can we add some breaker / fuse between 15VAC input port and 15VAC output cable, to protect the board from the surge?
Now you couldn't do anything. We'll wait next official Topping message on this 3d
ninetylol
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Designer of the amp said wait a 1-2 days for more infos.
artburda
Active Member
I think it is. As I wrote yesterday night:
"I finally did the ESD stress test. All I can say is: I had to retire the L30. It sent my Motu M4 into some sort of protection mode and a samsung galaxy 3303 earbud has now a crippled right driver that gets hot when playing music."
When I connect that earbuds now to my iPhone and play some music the right driver makes weird rattling noises. When you shake it, you can hear that a part is loose inside.
OK, thanks. I'll try to pull off the volume pot and slide out the board.
highpurityusbcable
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After that new safe L30 will magically appear on my table.
Don't do anything
solderdude
Grand Contributor
- Some suspect that the issue is caused by static spark... is plausible, not confirmed.
- Some says it's not likely to be the case based on the burnt position of the board.... not necesarilly true
- Static up to 5kV have not reproduced the issue at topping's lab... so it seems, however, the human body can hold around 20kV. Devices may be able to withstand 10kV but can fail at 20kV.
- Some people felt 'spark' or 'electricity' when they touched the knob or housing before the incident... the moment one feels/sees a spark the body discharges through the amp to ground (most likely via the connected DAC)
- The 'spark' could have been a current leakage, not a static, indicative of a short or a failure on the board.... I don't think so. A leakage current would always be felt, have no spark and would indicate that the amp is not grounded.
- The DC protect circuit is updated after '2012' batch .... yes, this will prevent the headphones from being blown up in case something goes wrong inside the amp leading to DC on the output of the amp. (there is a slight delay so a loud pop could still be heard)
- Some suspect that the board is lacking protection circuit for overcurrent / surge at power input part... some are wrong.
If my understanding written above is correct, could it be the surge from 15VAC input that have caused the short or break inside the amp?
No...
If so, can we add some breaker / fuse between 15VAC input port and 15VAC output cable, to protect the board from the surge?
No is not the problem.
There are regulators inside.
- Some says it's not likely to be the case based on the burnt position of the board.... not necesarilly true
- Static up to 5kV have not reproduced the issue at topping's lab... so it seems, however, the human body can hold around 20kV. Devices may be able to withstand 10kV but can fail at 20kV.
- Some people felt 'spark' or 'electricity' when they touched the knob or housing before the incident... the moment one feels/sees a spark the body discharges through the amp to ground (most likely via the connected DAC)
- The 'spark' could have been a current leakage, not a static, indicative of a short or a failure on the board.... I don't think so. A leakage current would always be felt, have no spark and would indicate that the amp is not grounded.
- The DC protect circuit is updated after '2012' batch .... yes, this will prevent the headphones from being blown up in case something goes wrong inside the amp leading to DC on the output of the amp. (there is a slight delay so a loud pop could still be heard)
- Some suspect that the board is lacking protection circuit for overcurrent / surge at power input part... some are wrong.
If my understanding written above is correct, could it be the surge from 15VAC input that have caused the short or break inside the amp?
No...
If so, can we add some breaker / fuse between 15VAC input port and 15VAC output cable, to protect the board from the surge?
No is not the problem.
There are regulators inside.
Yup it's already disconnected from the power. just sitting on the desk. Thanks!
artburda
Active Member
Can't do it. The pot is to close to the front, not enough space to insert a credit card inbetween.
solderdude
Grand Contributor
Sounds like it is toast alright. Curious what you will find. There was a hint on how to remove the volknob.
artburda
Active Member
I was able to remove it with this technique. Now I have to unscrew the nut screw and pull it out from the backside?
Attachments
Yes. one nut screw at the front, and the two screws on the side are everything that keeps the board in place.
these two screws will be easily removed with 2mm hex driver.
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