Topping A90 supposedly lacks ESD protection?

[NTK]

Topping initially had a problem with static discharge with their L30 headphone amplifier. If a product is CE marked, it is supposed to meet certain EMC (electromagnetic compatibility) requirements. Please see this post for the specific test requirements.

Sequential damage

Audio Technica w5000. Ouch! My condolences

www.audiosciencereview.com

 

[kenshone]

purchasing inexpensive, far-eastern audio gear and expecting miracles

Well, every country is different. I think many Chinese companies in general are still proving themselves, and I think at least some of them eventually will. But I wouldn't pause to research reliability if I were purchasing audio gear from Sony, Yamaha, etc. I wouldn't think twice about buying an SSD from Samsung, and the list goes on.

Same idea applies to Europe. I wouldn't worry much about reliability from a German car, but if a car manufacturer from, say, Greece or Spain or Norway, started going international, I think they'd have a lot to prove.

 

[KSTR]

Topping initially had a problem with static discharge with their L30 headphone amplifier. If a product is CE marked, it is supposed to meet certain EMC (electromagnetic compatibility) requirements. Please see this post for the specific test requirements.

Sequential damage

Audio Technica w5000. Ouch! My condolences

www.audiosciencereview.com

I have one Topping product, the D10 balanced, and it is definitely not optimized to handle ESD. For example, the metal case is not connected to anything which is a no-go. Human model ESD discharge then becomes machine model discharge.

In a former life I stress-tested equipment and ESD related issues were #1 reason of failure. My personal pre-certification ESD tests (still during product development) were 3-fold, using a simple piezo lighter:
- direct injection of the pulse.
- E-field pulse incidence with attached dipole antenna, using short spark-gap.
- H-field pulse incidence with closed wire loop running alongside the equipment.
The latter two typically cause latch-up of analog and digital circuits, oftentimes recoverable with a power cycle.
The first typically causes actual damage to unprotected inputs/outputs, be it analog or digital.

 

[usern]

I live in SoCal so the dry air + carpet is a legitimate risk. Good to know.

Warm weather does not automatically mean dry air. It's the opposite. Cold air holds less humidity. When a ventilation system is constantly replacing inside air with outside air during freezing temperatures winter month, then the air will be dry even when outside air relative humidity is 100%.

If you don't get static electricity zaps in your home when touching metal doorknobs, metal water taps or anything where it can discharge then there is low chance of damage due to ESD. A90 has earthed metal enclosure so it has advantage in that aspect over amps that use power bricks or two prong power connectors. The ESD charge can dissipate through earth connection in your home wiring. Earthed enclosure is probably most robust anti ESD measure there is. It's one of the reasons I preferred to get A30pro.

 

[restorer-john]

It's one of the reasons I preferred to get A30pro.

Or just buy something properly designed and built in the first place.

In 2022, nobody should be worrying about static/ESD zapping preamplifiers/HPAs. Topping needs to go back to the drawing board, refund/recall and start again. It's a joke and ASR's cred is being dragged into their hell-hole.

 

[Keened]

The ESD charge can dissipate through earth connection in your home wiring. Earthed enclosure is probably most robust anti ESD measure there is. It's one of the reasons I preferred to get A30pro.

I have a SH-9 and it has a 3 prong built in power-supply and a metal case, I still build up a charge using headphones on a 10ft 6.35mm extension cord.

I think the issue is less about the amp having the ability to ground the case and more about how there is no method to discharge static buildup on the cable itself that doesn't involve using the signal conductors if it isn't a true shield balanced connection. I was ever considering adding a short run of copper on the side of the jacket that can brush the top of the case to fix it.

 

[Jimbob54]

The front connection is not XLR ... it's an amp output and it's a DIN plug.

There is some confusion here. I suspect the headphones.com quote in the OP means the front XLR headphone jack, not the xlr amp inputs at the rear. And yes, the Topping A90 headphone amp most surely does have a front 4 pin xlr

 

[Deleted member 46664]

There is some confusion here. I suspect the headphones.com quote in the OP means the front XLR headphone jack, not the xlr amp inputs at the rear. And yes, the Topping A90 headphone amp most surely does have a front 4 pin xlr

Check this....

4-Pin DIN Plug Connector

Insulated 4-pin DIN plug suitable for a range of uses with matching sockets.Straight typePVC bodyCable mounting

www.switchelectronics.co.uk

 

[Jimbob54]

Check this....

4-Pin DIN Plug Connector

Insulated 4-pin DIN plug suitable for a range of uses with matching sockets.Straight typePVC bodyCable mounting

www.switchelectronics.co.uk

Sadly, every single reference to 4 pin headphone sockets I have ever seen calls them 4 pin XLR- including Topping themselves https://www.tpdz.net/productinfo/472128.html

 

[Deleted member 46664]

Sadly, every single reference to 4 pin headphone sockets I have ever seen calls them 4 pin XLR- including Topping themselves https://www.tpdz.net/productinfo/472128.html

Yes, I've noticed that as well ... it seems to be a very common mistake.

It's of no real consequence, unless you're ordering parts.

 

[Bamboszek]

@Douglas Blake is either drunk or trolling. This is DEFINATELY 4 pin female XLR on front of Topping. De facto standard for differential or balanced headphone output at amplifiers.

XLR connector - Wikipedia

en.wikipedia.org

 

[somebodyelse]

Sadly, every single reference to 4 pin headphone sockets I have ever seen calls them 4 pin XLR- including Topping themselves https://www.tpdz.net/productinfo/472128.html

There's a reason for that...
https://uk.rs-online.com/web/c/conn...ors/?applied-dimensions=4294885308,4294882807
https://uk.rs-online.com/web/c/conn...s=4294882807,4294885308,4294765840,4294430318

 

[Deleted member 46664]

@Douglas Blake is either drunk or trolling. This is DEFINATELY 4 pin female XLR on front of Topping. De facto standard for differential or balanced headphone output at amplifiers.

XLR connector - Wikipedia

en.wikipedia.org

How about that .... ya learns something new every day!
Thanks.

Neither drunk nor trolling ... just something I didn't know until about 5 minutes ago.

 

[Jimbob54]

There's a reason for that...
https://uk.rs-online.com/web/c/conn...ors/?applied-dimensions=4294885308,4294882807
https://uk.rs-online.com/web/c/conn...s=4294882807,4294885308,4294765840,4294430318

Clarity!

 

[edahl]

Or just buy something properly designed and built in the first place.

In 2022, nobody should be worrying about static/ESD zapping preamplifiers/HPAs. Topping needs to go back to the drawing board, refund/recall and start again. It's a joke and ASR's cred is being dragged into their hell-hole.

Are all Topping products like this? I was considering getting one, but not if it's not up to EU safety standards.

 

[kenshone]

I have a SH-9 and it has a 3 prong built in power-supply and a metal case, I still build up a charge using headphones on a 10ft 6.35mm extension cord.

I think the issue is less about the amp having the ability to ground the case and more about how there is no method to discharge static buildup on the cable itself that doesn't involve using the signal conductors if it isn't a true shield balanced connection. I was ever considering adding a short run of copper on the side of the jacket that can brush the top of the case to fix it.

Earlier in this thread, someone suggested that this static buildup could be discharged by touching the amp's case as the headphone is plugged into the amp. Do you think this is insufficient?

Is there a product that already does this, such as an XLR cable or adapter with external ground? Or is this ESD-through-headphone-cable issue too unusual to warrant such a product's existence?

 

[pma]

ESD protection guide

https://www.ti.com/lit/sg/sszb130c/sszb130c.pdf

 

[Keened]

Earlier in this thread, someone suggested that this static buildup could be discharged by touching the amp's case as the headphone is plugged into the amp. Do you think this is insufficient?

If you're just worried about the initial grounding, sure, but if you're moving around with a cable and/or building up a charge it might not be enough.

Is there a product that already does this, such as an XLR cable or adapter with external ground? Or is this ESD-through-headphone-cable issue too unusual to warrant such a product's existence?

I haven't heard of one, but I'd love for someone else to chime in on this. From what I understand, the issue is that 99% of front XLR out on headphone amps aren't true XLRs and may not be properly shield grounded. The other side of the equation is that most headphones don't have a shielded cable anyways so there would be no way to get the charge on the outside into the ground wire without either exposing a live circuit or dumping it to ground at the headphones/speakers themselves.

 

[usern]

Is there a product that already does this, such as an XLR cable or adapter with external ground? Or is this ESD-through-headphone-cable issue too unusual to warrant such a product's existence?

I measured resistance between earth wire from another power outlet and my A30pro and its enclosure is earthed. Also the unbalanced headphone output TRS plug ground connection seems to be earthed, but 4 pin XLR outer ring did not seem to be earthed. I don't have thin enough multimeter probe to check XLR pins, but since it is not balanced amp and this connector is just for convenience I would say A30pro XLR headphone connection is also earthed. A90 is balanced so might not be the case.

 

[RHO]

Can you elaborate on what you find surprising about this?

Maybe because it's a 4 pin XLR?