Failed, Teardown: Cowin E7 Pro Active Noise Cancelling Wireless Headphones

It looks like I haven’t been entirely fortunate with Cowin products. After the HE5A failed, I reverted to using the E7 Pro for my day-to-day commuting needs. Just this week, the E7 Pro failed as well, which doesn’t do much to instill confidence in their products.

The Problem

Hopping onto the bus on the way home on a Thursday night, I take out the E7 Pros and unfold them for a session of video watching when …

… pop – the right earcup comes free of the headband and flops around like a limp fish. Oh no. I try frantically to pop it back in … but it just pops back out! I guess I’ll have to go home listening to the grumpy voices of fellow commuters then.

As a former review item, I wasn’t going to be bothered to try sending it back – after all, that’s not how “review items” usually work. Instead, I was going to sacrifice it in the name of a teardown. The first part was to disassemble the hinge mechanism for a closer look, but already, the prognosis is not good. It’s clear from inspecting the joint that there had been some lubrication applied, but despite this, the plastic appeared to have been “chewed up” and whatever was left of a flange was now worn down to nearly nothing.

Inspecting the innard of the joint suggests that the headband has a round plastic shaft with a groove/flange around it. This shaft pokes through a retainer on the frame holding the ear-cup where a metal piece is inserted to “grip” the flange, forming a joint that is free to rotate in one axis, secured by the metal bracket. Unfortunately, either the metal finish, lubrication or moulding was at fault, and now the plastic flange has worn to the point that the joint disassembles itself automatically.

While disassembling it, I decided also to try and get a look into the battery compartment. Not having a clear route of entry, I pried at the cover plates to find nothing – sacrificing a thin screwdriver along the way. That’s what happens when you don’t take care of your tools … bad Gough!

As it turns out, it is internally glued in place rather than screwed and reveals an M2T prismatic 750mAh cell. This is at odds with the claimed 800mAh on the website, and measured 832mAh in testing. I suspect the testing figure was a bit high due to losses in the charging circuitry – maybe the 800mAh is “typical” with 750mAh “minimum”?

Conclusion

I might have been unlucky that the E7 Pro I had might have had some burring on the metal “clip” that holds onto the flange in the plastic, causing it to chew away and cut at the plastic until the flange failed altogether. Whatever the cause may be, unfortunately, this makes the E7 Pro unserviceable, as the ear-cup likes to plop out, hence the teardown which seems to have discovered a slight battery capacity discrepancy as well. Unfortunately, with the way that Cowin products have served me, I cannot really recommend them as much as before having both failed me within one year of ownership.

For now, I’ve reverted back to my Audiotechnica ATH-ANC9s which still serve me well – historically they usually last three to four years, but it’s a reminder that the durability of a product is not something that can be assessed in a short-term review.

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