[money4me247]

Oppo told me that the extra ground in the headphones and amps was there to tick that marketing box, because they could, because the competition does it. Sound quality doesn't seem to be a real issue with the older method.

basically this. i think they probably made it initially thinking about selling balanced cables, but then decided that it wasn't worth it. the oppo spokesperson here basically said as much.

also, people interested in fancy cables generally prefer to buy from the esoteric cable brands anyway.

 

[Neo Zuko]

However the jacks are ready for it if you want to use a balanced amp for extra power. Which is nice, but the power requirements are ready so low on this headphone.

 

[ClieOS]

HA-2 is definitely not a balanced design, given it only has one TPA6120A2 on the output stage (you need two for balanced audio). I think the TRRS, if it isn't internally shorted for ground, is most likely has two separated sink circuit for left/right ground.This is not actually balanced output, but might improves stereo crosstalk and power output a bit, though unlikely to the level of balanced output.

 

[miceblue]

I think the TRRS, if it isn't internally shorted for ground, is most likely has two separated sink circuit for left/right ground.

I don't think anyone said the HA-2 is balanced/uses differential signaling. : p

So are you suggesting the HA-2's PCB has two ground layers/floating ground connections? I haven't heard of that before but I guess it's possible.

 

[SmilinKev]

Spent the last several hours reading this entire thread. Just wanted to mention a few things:

1. THANK YOU to all who contributed to this discussion! I have learned a lot about the HA-2 and a wealth of related topics and equipment.
2. I've ordered the Ha-2 to pair with my iPhone 6+. Should be here in 4-5 days.
3. I'm going to try a variety of music genres with the HA-2 and, in addition, assess how well it pairs with the kind of mid-fi on-ear headphones I reach for when going "portable": Sennheiser HD 239, Skullcandy Grind, Beats Solo 2, V Moda XS, and Sennheiser Urbanite. I didn't see any of these sorts of pairings mentioned in this thread, so I'll post a brief summary about what I discover. I love my Shure 1540s and my Etymotic ER4s, but they aren't going to get tossed into my backpack or hung around my neck when I'm out and about!
4. Again, THANK YOU for all the info and insights. And, as always, I take full and final responsibility for the damage you . . . uh, um, er . . . the damage I have done to my wallet.

Keep listenin' and keep smilin'!

 

[ClieOS]

I don't think anyone said the HA-2 is balanced/uses differential signaling. : p

So are you suggesting the HA-2's PCB has two ground layers/floating ground connections? I haven't heard of that before but I guess it's possible.

 
That's the only explanation for 'isolated' ground for both channel, IF that's the case. Active ground isn't a new idea of its own, but it usually means a shared active ground. Haven't really come across any dual active ground amp myself, but I guess it kind of takes the idea of shared active ground to the next level.
 
Again, not saying in 100% that's the case for HA-2 - just that it is one of the way to implement dual isolated ground

 

[miceblue]

That's the only explanation for 'isolated' ground for both channel, IF that's the case. Active ground isn't a new idea of its own, but it usually means a shared active ground. Haven't really come across any dual active ground amp myself, but I guess it kind of takes the idea of shared active ground to the next level.

Again, not saying in 100% that's the case for HA-2 - just that it is one of the way to implement dual isolated ground

Ah I see. I was talking to an electrical engineering-oriented friend and he mentioned that it could mean two ground PCB layers (although I really see no reason to do this because multi-layered PCBs get expensive and having two separate ground layers would be cost ineffective), a single ground layer is shared but there are two traces from the TRRS jack instead of one for a TRS jack, or there are two circuits within the HA-2 for a separated configuration (I don't think this is the case either for the same cost limitations as mentioned).

 

[Ivabign]

  Hey guys, 
 
I've been reading through this thread and I'm at a crossroads, so I figured i'd ask my question here and see if I can get direct feedback vs trying to mull everyone else's opinions over. 
 
I'm getting the 1964Ears V6s shortly, and I'm looking for a DAC/AMP to bring them out and have the sound quality and loudness be dependant on the source, which can vary widely. The source is an HTC One [M8]. I was strongly looking into the HA-2, but reading through this thread, it seems like people are saying it's a bad option for sensitive CIEMs....? 
 
Is there a better and/or cheaper option I should be looking at if the primary use for it will be pairing with IEMs?

I know you asked this a while ago - but I get zero hiss with my V6S and my V8 - I mean I can tell when the amp switches on, but that is because I'm smart. But for all intents and purposes (and porpoises in tents) it is silent. Not a problem with my 1964 Ears CIEMs - haven't mucked about with all my IEMs - but I will....

 

[TheChillburger]

I know you asked this a while ago - but I get zero hiss with my V6S and my V8 - I mean I can tell when the amp switches on, but that is because I'm smart. But for all intents and purposes (and porpoises in tents) it is silent. Not a problem with my 1964 Ears CIEMs - haven't mucked about with all my IEMs - but I will....

Wish I could say the same about my IM02 :/

 

[ClieOS]

Ah I see. I was talking to an electrical engineering-oriented friend and he mentioned that it could mean two ground PCB layers (although I really see no reason to do this because multi-layered PCBs get expensive and having two separate ground layers would be cost ineffective), a single ground layer is shared but there are two traces from the TRRS jack instead of one for a TRS jack, or there are two circuits within the HA-2 for a separated configuration (I don't think this is the case either for the same cost limitations as mentioned).

 
Using two ground PCB layer doesn't means two separated ground channels though. It usually is done to isolate one active signal path from another, like two slice of cheese separating three pieces of beer patties, but the ground planes are usually shared. Plus, this is usually done to isolate RF, not audio range though. If you look at PC's video card, 7~9 layers are pretty common. But for audio purpose, you'll use multi-layer PCB mainly to save space, but not as much for isolating interference or even improving SQ. Pretty sure HA-2 has multi-layer PCB just because how tight the internal components are (I have seen the internal picture), but dual isolated ground will be all together a different beast.

 

[money4me247]

correct me if I am wrong, but from my understanding, 'balanced' can either be used to refer to bridged designs (aka there are x2 of the circuitry) or balanced impedance of each line respective to ground that allows for common mode rejection (both at input & output). I don't think the HA-2 will really fall under either of those two categories, but I am not an expert on this particular topic. I recall @Steve Eddy explaining these concepts quite well & he can correct me if I misspoke.

 

[ClieOS]

  correct me if I am wrong, but from my understanding, 'balanced' can either be used to refer to bridged designs (aka there are x2 of the circuitry) or balanced impedance of each line respective to ground that allows for common mode rejection (both at input & output). I don't think the HA-2 will really fall under either of those two categories, but I am not an expert on this particular topic. I recall @Steve Eddy explaining these concepts quite well & he can correct me if I misspoke.

 
I believe @Steve Eddy was explaining the misuse of the word 'balanced' in headphone word vs. the rest of the audio world. That'll be a discussion of semantics and Steve isn't wrong about it, but it is so widely used and accepted at this point that there isn't much of a point to insist on being semantically correct, as long as we all understand what we are talking about... and you are right, HA-2 should neither be bridged nor balanced, as far as we know.

 

[Steve Eddy]

correct me if I am wrong, but from my understanding, 'balanced' can either be used to refer to bridged designs (aka there are x2 of the circuitry) or balanced impedance of each line respective to ground that allows for common mode rejection (both at input & output). I don't think the HA-2 will really fall under either of those two categories, but I am not an expert on this particular topic. I recall @Steve Eddy
 explaining these concepts quite well & he can correct me if I misspoke.

Very good, Grasshopper.

I'm pretty sure that Oppo is using a TRRS plug/jack simply to avoid the common ground contact resistance that's inherent with a TRS plug/jack combo. Nothing more, nothing less. The left and right signal grounds on the jack are combined internally and that connection will have a lower resistance than a mechanical contact and technically reduce crosstalk.

Personally I think the crosstalk issue has been blown out of all proportion and is little more than an unhealthy obsession with a technical specification as has too often been the case in audiophilia.

I doubt the crosstalk due the common ground contact resistance would even be audible under typical listening conditions. And then of course you have capacitive and inductive coupling within the cable itself, though I have seen some extremists use completely separate left and right cables on their headphone to avoid this.

And if crosstalk was the Bogey Man it has been made out to be by some, people would be ditching their PM-1s and PM-2s in favor of the PM-3. Because as far as I'm aware, both the PM-1 and PM-2 are open back headphones. That means crosstalk. The PM-3 is closed back and a lot less crosstalk.

And even though I can enjoy music using headphones, nothing for me beats a good pair of loudspeakers. You want to talk about crosstalk? Just turn the balance control over to one channel and put your finger in the opposite ear. Not a lot of difference, is there? If crosstalk were so bad, loudspeakers would be unlistenable, but I'll take a good pair of loudspeakers over the best pair of headphones any day of the week.

So just use a TRS plug and don't get all neurotic about a largely meaningless technical specification.

se

 

[Neo Zuko]

All I want to know is if I buy a balanced headphone amp later can I use the PM-3 in balanced mode with custom cables.

 

[miceblue]

All I want to know is if I buy a balanced headphone amp later can I use the PM-3 in balanced mode with custom cables.

Yes. You just need a TRRS jack that goes into the PM-3 and it can be terminated with another TRRS end, or XLR.