OPPO HA-2 Portable Headphone Amplifier/DAC Discussion Thread
Apr 12, 2017 at 8:01 AM Post #4,351 of 4,883
There have been reports of problems with the Mojo and iOS 10.3. Not sure if they involved the old or new CCK.


As I've understood it, we're talking about two separate problems. The HA-2 had the interference problems even before 10.3, and after 10.3 something seems to have happened that has started to cause problems with other DACs as well. Which ought to mean that for iPhone users with 10.3 and the HA-2, we're going to have two problems at the same time - random dropouts because of 10.3, and the interference problem when you reach a low coverage area.
 
IMO, it will be hard to fault search the interference problems again until the problem with totally random dropouts on all DACs is resolved. Copper tape or not, your HA-2 is very likely to have dropouts because of the 10.3 issue.. If you have dropouts even with copper tape, well, you could have solved the interference problem, but still have dropouts because of the 10.3 issue..
 
Apr 12, 2017 at 8:27 AM Post #4,352 of 4,883
As I've understood it, we're talking about two separate problems. The HA-2 had the interference problems even before 10.3, and after 10.3 something seems to have happened that has started to cause problems with other DACs as well. Which ought to mean that for iPhone users with 10.3 and the HA-2, we're going to have two problems at the same time - random dropouts because of 10.3, and the interference problem when you reach a low coverage area.

IMO, it will be hard to fault search the interference problems again until the problem with totally random dropouts on all DACs is resolved. Copper tape or not, your HA-2 is very likely to have dropouts because of the 10.3 issue.. If you have dropouts even with copper tape, well, you could have solved the interference problem, but still have dropouts because of the 10.3 issue..


I think this is a fair assessment of the situation.

Before 10.3 I only experienced dropouts on my iPhone in specific locations on my subway commute - areas between stations where I'd go from having no service to suddenly having a little bit of service. For example, approaching 59th street station after being in the tunnel. My theory is that as the phone starts to pick up a bit of service, it boosts power, and that causes the HA2 to reboot.

However, since 10.3 I also started having dropouts when I'm at my desk at home. I'm not 100% sure this isn't related to the same service thing, because service in my apartment can be spotty.

But at least for the original problem I get to test that today.
 
Apr 12, 2017 at 9:06 AM Post #4,353 of 4,883
 
As I've understood it, we're talking about two separate problems. The HA-2 had the interference problems even before 10.3, and after 10.3 something seems to have happened that has started to cause problems with other DACs as well. Which ought to mean that for iPhone users with 10.3 and the HA-2, we're going to have two problems at the same time - random dropouts because of 10.3, and the interference problem when you reach a low coverage area.
 
IMO, it will be hard to fault search the interference problems again until the problem with totally random dropouts on all DACs is resolved. Copper tape or not, your HA-2 is very likely to have dropouts because of the 10.3 issue.. If you have dropouts even with copper tape, well, you could have solved the interference problem, but still have dropouts because of the 10.3 issue..

Trust me, I understand, but JazzWants2BFree (to whose question ekrauss and I were responding) was specifically asking about other DACs that work with 10.3.1. He had already returned the HA-2 for a refund.  The reports on the Mojo indicate it is one of the other DACs struggling with that "upgrade." 
 
Apr 12, 2017 at 10:28 AM Post #4,354 of 4,883
As I've understood it, we're talking about two separate problems. The HA-2 had the interference problems even before 10.3, and after 10.3 something seems to have happened that has started to cause problems with other DACs as well. Which ought to mean that for iPhone users with 10.3 and the HA-2, we're going to have two problems at the same time - random dropouts because of 10.3, and the interference problem when you reach a low coverage area.

IMO, it will be hard to fault search the interference problems again until the problem with totally random dropouts on all DACs is resolved. Copper tape or not, your HA-2 is very likely to have dropouts because of the 10.3 issue.. If you have dropouts even with copper tape, well, you could have solved the interference problem, but still have dropouts because of the 10.3 issue..


There is no "interference problem when you reach a low coverage area." This has been explained many times. Rather, iOS 10.x broke compatibility and iOS 10.3 has made the matter worse. This is the same issue, and it clearly affects many DACs and amps other than the HA-2.

It doesn't make sense to keep clinging to a faulty interpretation of the issues. We have heard from Oppo that iOS 10.x is the source of the problem. It's not due to a lack of shielding or other Oppo engineering issue. These problems only started after iOS 10.x came out and became worse with the release of iOS 10.3. Other users' prior research into this issue has been noble, but their conclusions were incorrect. When I hear more from Oppo, I will post here.
 
Apr 12, 2017 at 1:22 PM Post #4,355 of 4,883
There is no "interference problem when you reach a low coverage area." This has been explained many times. Rather, iOS 10.x broke compatibility and iOS 10.3 has made the matter worse. This is the same issue, and it clearly affects many DACs and amps other than the HA-2.

It doesn't make sense to keep clinging to a faulty interpretation of the issues. We have heard from Oppo that iOS 10.x is the source of the problem. It's not due to a lack of shielding or other Oppo engineering issue. These problems only started after iOS 10.x came out and became worse with the release of iOS 10.3. Other users' prior research into this issue has been noble, but their conclusions were incorrect. When I hear more from Oppo, I will post here.

..except the fact that Oppo confirmed it. You're funny :)
 
Apr 12, 2017 at 2:25 PM Post #4,356 of 4,883
..except the fact that Oppo confirmed it. You're funny :)


I am still waiting to hear from Oppo on this issue. Oppo last told me they ruled out interference. Until I hear otherwise from Oppo, I am going by what I have been told. No offense intended to you. Remember, I am only trying to help you guys.

Chord is now reporting that iOS 10.3 has broken compatibility with non-Apple Lightning/USB cables and is recommending Mojo users switch to Apple-manufactured cables.
 
Apr 13, 2017 at 7:30 AM Post #4,361 of 4,883
I'm going to give the Dragonfly Red a shot -- with the camera cord.

Audio quest rep claims he's not heard of any iOS problems.

Colin Elder said the following in the Oppo HA-2 dropouts on iOS 10.3  thread:
 
"I have the same issue with both the usb2 and 3 lightning connectors both with a chord mojo and a dragonfly red under ios 10.3 on an iphone 7 plus - both worked fine with 10.2.1. I have now upgraded to 10.3.1 and now the mojo doesn't work at all - i just get the message that the accessory uses too much power. "
 
You might want to compare notes with him.
 
Apr 13, 2017 at 7:32 AM Post #4,362 of 4,883
Well, Day 1 with copper tape on the commute. No dropouts.

I'm almost tempted to just keep going back and forth to keep testing it
smily_headphones1.gif

I haven't needed to ride the subway for the past week.  I'll be on one this evening and retest my naked HA-2.
 
Apr 13, 2017 at 8:06 AM Post #4,364 of 4,883
   
If you've already removed the leather and you're local, I wouldn't mind giving you some of this copper tape to experiment with. I'll be testing it on the N/W this morning.

Sorry for any confusion.  I have not removed the leather.  I just haven't applied the copper tape.  And I'm still on 10.2, so my testing will isolate issues not relating to the 10.3.x.
 
Apr 13, 2017 at 8:56 AM Post #4,365 of 4,883
Taking my little experiment to the next level, I ordered the copper tape that they use for EMI shielding in guitars.

I applied it to one side of the HA-2SE on just one side. Honestly I could have done a better job, but we're going for results, not aesthetics in this round.
On my commute tomorrow I'll try it with either side facing the iPhone and see if it drops in the usual spots, and report my results.
Hopefully if it works, it won't be just a "coincidence" :rolleyes:




Well folks, day 2 of commutes with the single layer of copper tape and no dropouts.

Who knows. Maybe there are other factors in play - all I know is that this seems to be working.

This is what I bought: https://www.amazon.com/dp/B01I1XNY1E

I have not tried any other brands, I am not an engineer. All I did was google for EMI shielding tape, watched a few videos about this tape being used in guitars, and tried it. Before tape, the Oppo dropped out every day in the exact same spots on my commute. With tape, it's not happening.

iPhone 7 plus, latest OS, using the Oppo short lightning cable with the Oppo attached to the back of my phone. My phone case is the same 0.3mm plastic eBay case, which had remained a constant. I don't notice any drop in signal since the Oppo-with-tape does not block the phones antennas any more than it did before.

I hope this helps someone out there.
 

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