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Balanced TRRS Connector on Future Hifiman IEMs

Discussion in 'Portable Headphone Amps' started by nankai, Jun 15, 2010.
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  1. Nankai Contributor
    We decide to use 3.5mm balanced TRRS connectors in our future mid to high price level IEMs. For headphone amplifier manufacturers, TRRS jack is much easier to get. Hope amplifier builders will be interested in.
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  2. LevA
    what's the benefit of using balance trrs?
    considering all other manufacturers (AT, JH, Senn, Sure etc.) using normal headphone jacks, I doubt amp manufacturers would change their jacks and limit their potential market base.  
  3. ClieOS Contributor
    I don't know much about balanced audio but if what I understand is correct, you can connect a regular TRS to a balanced TRRS output and all you have to lose is the headroom (and along with it the benifit of having a balanced setup), assuming the R- and L- is going to the ground.
  4. LevA
    I think the RE-zero is using that adaptor. looks similar to double splitter adaptor and is not very small. most were not happy considering there are no daps or amps that use balanced TRRS, so practically making it unnecessary. I guess hifiman will go down this route, so we should probably expect 602 to have TRRS?
  5. qusp Contributor
    please dont, there is a world of quality connectors out there much more suitable for high end portable audio, you dont have to use that.
    why is every single manufacture bringing out their own idea, why didnt people get together and choose the best option that suited the purpose moving forward, instead of everyone releasing a product in isolation and forcing the customer to get new and different cables or adapters for everything? there is even a new series of mini 4 pin XLR from neutrik like those on LCD-2 that would work. this is like VHS vs beta al over again, but much worse, I knew this would happen :frowning2: I can think of 4 different interfaces being used at the moment by different companies
    I'm quite dismayed with the choices by manufacturers in this area. it really doesnt take much thought to take the route less travelled and talk to one another. there are suitable compact locking multipin connectors by lemo, odu, neutrik, amphenol[​IMG], just to name a few
    this is the small 0 size lemo, these are not all that cheap when bought separately, but in numbers would be better, but they are small (smaller than a mini actually), come in up to 8 pin in this size (JH3A anyone??) are rugged, locking with push-pull ring, they are keyed so cannot be inserted incorrectly and there is also a cheaper polymer version the same size that is interchangeable. as you can see they also come in all the variants we need, male and female cable inline and male or female chassis mount with PCB mount being an option there too. The female socket below is fitted with the optional dust cover that is springloaded and covers the opening when there is no cable inserted, it can easily be removed if desired. it also has a reasonable (but not over the top) size cable exit with adjustable strain relief collet. Sexy as well IMO
    as a whole, headphones and portable amps with balanced output are not a budget offering and neither the aftermarket cables to suit. very few aftermarket cables would fit in such a connector as above and there is not an alternative 4 pin mini that they will. that one is even molded, so of no use to upgrade cables or DIYERS
    the customer is supposed to win out of this new era, having a different cable for every headphone and amp does not sound like progress to me.
    sorry for the rant, but I saw this happening a long time ago and made numbers of posts on the matter; its frustrating me to see it becoming reality. we need to get together and sort this out NOW, before its a big mess. I think a committee needs to be formed to move forward. below is just one option and as I said the polymer version will fit the same socket provided the same number of pins are used.
    lemo 4 pin.jpg
  6. jageur272 Contributor
    Actually, shorting the two negative channels in a balanced amp risks damaging the amp...
  7. qusp Contributor
    indeed, depending on how it is set up it could result in the inverting opamp pins being shorted to ground
  8. jelt2359 Contributor
    well it would seem we missed potentially a good opportunity at Canjam.
  9. Very Legal
    I think detachable cables would be a better solution for this. Preferably with a standard plug at the earphone end for all iem`s and full sized cans too. I guess the last part is a little far out but still something to think about.[​IMG]  
  10. forever1
    Why use an L shaped plug on a connector that 99% of the people using it will need to use an adapter to use your IEMs?
    L shape + adapter = snag point. [​IMG]
  11. qusp Contributor


    for manufacturers to talk about this issue before it gets out of hand?? absolutely!! I mean sure I understand companies want to keep a certain amount under wraps, but I think its fairly safe to assume that many of the higher end amp manufacturers will be working on balanced portable systems, so there is no surprise there and that is the only thing that would need to be admitted, other than that all they would be doing is agreeing on a format for the connector, no trade secrets there
  12. El_Doug Contributor
    Qusp, I agreed with you a year ago, and I still agree with you today. 
    It brings my piss to a boil thinking about how the lack of cooperation between relatively few, small companies is screwing all of us (pretty much their entire early-adopter market) over :/ 
  13. justin w. Contributor


    that's how it should be setup if the TRRS connector is used.  fortunately, Fang chose the correct pin-out for this.  the amp can then be designed to only need 1 output connector for TRS (unbalanced) and TRRS (balanced)
    ^ have not tried this.  i do prefer the idea of TRRS because then very thin amps can still be built.  the Lemo connectors are too expensive and labor intensive to be practical.  the mini-XLR are a lot bigger than would be expected for portable amp sizes today.  the 4-pin square connector is not designed for repeated insertions, according to its manufacturer.  they warned against using it for a headphone jack.  but i think there are still far more significant ways than unbalanced->balanced conversion to improve portable audio, and what connector is made "standard" is not really a big issue
  14. Jamey Warren Contributor
    My concern with using a TRRS connector is that a lot of headsets are built with this type of connection for microphone signal.  Plugging in a headset into to a portable balanced amp could cause some problems for the headset owner. 
    I'm not saying this isn't a good idea.  Just voicing what my concern would be.
  15. qusp Contributor

    I realize that justin, I was trying to be kind to one of our other designers.....
    unfortunately every one I have seen so far is tiny cheap molded plastic (no offense Fang), some OEM cables come with gold and are still tiny and cheap with a 2 micron gold plate....  that is totally unusable for any kind of aftermarket cable and people do tend to like the odd aftermarket cable around here I have noticed. there is not enough of a market in our segment to force manufacturers to make something decent. if you have a ground connection as anything but the tip, at least one of the other terminals would be shorted to ground on insert and removal which is something I now enjoy not having to worry about.
    there are cheaper than the lemo as I said and the lemo polymer versions are actually not that pricey even in small numbers. I think if you asked people you would find that they would happily pay a few dollars more to have a better balanced connector than the above when buying a 300-500 dollar amp with 100-400 dollar cable and 200-1500 headphones (remember all you need to change is the output connector, which is the cheapest of the lot and is available in PCB mount, what could be easier for manufacture? I certainly have no problem soldering them) there is literally thousands of multipin connectors in the mouser and elfa catalogs I only mentioned a few
    and justin, if your agenda is slim amps, then fine and if your agenda doesnt cover balanced then why is it of any importance? and BTW, i'm not talking about a balanced conversion stage, just using the balanced output that all modern dac chips are designed and tuned for. pretty much ANY THD+N or DNR spec quoted for a dac nowadays is for balanced operation and without it you either must add another opamp summing stage or lose a significant amount of performance. 
    like it or not, balanced is very popular, it will continue to gain ground and until a quality standard that is usable is reached, there will be a big mess. dacs will continue to be released with differential output as that is how the best performance is gained; both to my ears and on every datasheet I have seen for a dac released in the last decade recommends a differential IV stage there are very real benefits to these ears and there must be something to it, or the component manufacturers would not be pursuing it.
    as a nice biproduct, those using phones as source, which is becoming more popular and with digital out on iphone v4 pretty much guaranteed, it will continue to do so. with balanced they will not have to worry about GSM ping due to CMMR quashing it to inaudible levels
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