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O2 + Grado = ....not that great?

  1. FatherVic
    I'm running around in circles and am now at a loss of what to do. Sorry for the long post, but here goes -

    Intro: I've been into HiFi for some time and have built what I think is a pretty decent system.
    I enjoy music on the go and have used in-ear and more recently IEMs.
    For years I've had Grado SR60 though rarely used due to little need having the HiFi and not being suitable to outside use.

    Decided to treat myself to a pair of RS2e 2nd hand. Plugged in to my Bryston preamp with sadly not so good a result. Reading the manual it does state it recommends 50ohm +. Things just sound.... wrong.

    And this is where the trouble begins...
    To get some use I plugged them in to my little Sony DAP and actually got a better result to what I was expecting.

    Had a look around and without spending too much and wanting more out of them to what they are capable of, took up the recommendation of purchasing an Objective 2 (desktop, 1x/3.3x).

    Initially on first listen I thought great!, but on extended listening with other music it was showing the same problems I encountered plugged in to the Bryston. O2 was being fed directly from fixed level line out of a Sonos Connect.
    Decided to try the line out of the Sony DAP (just a little A10) and again seem to get what I think I should be getting - a more evenhanded (?) sound.

    So what's wrong? Basically on simple music they sound great. I do listen to a lot of rock and metal (which some folk have said Grado are suited to?) and this is where it falls down - the mids seem incredibly congested and screaming at you and although you can hear bass and treble details there's no weight to the bottom and no air up top.

    I did come across an article suggesting that even set at 1x the input from a standard line level source is still too much. I've tried to understand other posts when talking about impedance and sensitivity etc but it's confusing and at times contradictory.

    Before the amp even arrived and expecting great things I already invested in and ordered some new ear pads from Beautiful Audio and really want to make these work....

    What's wrong? What do I need to be looking at to fix this?

    Cheers, TIA
  2. castleofargh Contributor
    I can't find output specs for the sonos connect(you're not talking about the connect:amp?), so I assume it's 2V but I really have no idea. if it's 2V then with the O2 set to 1X should have no trouble. you can always check if lowering the output on the Connect and turning up the volume knob on the O2 changes the sound significantly. a sony DAP, aside from maybe having some DSP or EQ turned ON, is for sure not going to send 2V(or more) to the O2, so reducing the volume on the Sonos seems like something to try.
    other than that I don't really have any idea. maybe something is defective? maybe you're just looking for a different sound and the O2 just doesn't light your fire? maybe a better EQ would do it for you, maybe not. it's hard to know what you mean with your description, something isn't satisfying, but beyond that... I don't have a clue.
  3. FatherVic
    I believe the Sonos to be a standard 2v but I don't want to go down the route of using the variable output, nor should I need to. It's something I did think of but didn't have the time for last night. I don't want to have to keep switching back and forth when wanting to listen to the main HiFi.
    I wish you were here to hear what is going on, I find it hard to describe. It's not that I don't like the tone of what the O2 produces, I really feel there's something in the compatibility and not being technically minded (high end headphones and amplification is new to me) is difficult to diagnose. It has similar characteristics to what the Bryston is doing that isn't designed with the impedance of the Grado in mind.
    On the DAP I do use some EQ but have turned it off for experimenting.
    If the voltage is too high from the input (not to the point of massive distortion as if plugging in a line level to a phono input), how would something like that manifest itself? How does improper impedance matching affect the sound?
    The sound is as if the mid is coming through a plastic cup and far too much in the foreground. As I said, taking a simple acoustic piece can soud fine but anything busy and the mid is massively exaggerated, hard and loses a lot of definition.

    If this is what they're meant to be like then I'm sorely disappointed. It might just be the case of booking some demonstration time and see what else is out there and how things perform in comparison
  4. audiobomber
    Do you still have the SR60's? How do they sound through the O2?

    My SR60's sound really good through a Magni 3 and also through the internal headphone amp on my Korg DAC. They are a bit sibilant and deep bass is missing, but still very enjoyable to listen to. I passed on a pair of RS-2e's because they weren't enough of an improvement over my old Grados. I found the RS2 pads uncomfortable too.
    Last edited: Oct 6, 2018
  5. FatherVic
    They don't fare much better.... A slight improvement if any but only slight. The resolving power drops massively making them hard to go back to lol.... Also tried a set of old Sennheiser PC headphones but they're even more of a step down.
    Whipped on my SE215s and the staging or contour of the sound is more what I'm expecting and don't get that 'cupping' of the mid.

    Some more experimenting to be had I think but at the moment I can only put it down to compatibility, my ears don't like Grado or they don't like my music.
    The latter two I'm not too sure of as I'm pretty impressed how my DAP performs.
    The pads do suck hence the anticipatory purchase of the Beautiful Audios.

    I'm going to see if I can steal my friend's HD 600s at some point...
  6. ProtegeManiac Contributor
    You have two different things going wrong.

    The Bryston preamp has a very high output impedance and screws up the Grados' sound. Don't believe when people say tehy have high sensitivity anyway, the electrical characteristics make for an easy load even with an impedance mismatch, etc - since output impedance interacts with different loads differently. A Little Dot MkII will boost the lows and soften the highs on a Grado, but every integrated amp I tried Grados on make them sound like tin cans.

    On the O2 you're not getting exactly the same sound, but because it has a tendency to sound brighter than, say, a Violectric, it's just going to make the treble on the Grados even worse. Assuming that's what you're hearing, everything else is actually good, but the treble is bad enough you think it's still overall similar to the Bryston preamp.

    Two ways around that. First, the cheap way is to deal with the Grado's response and put a sock on it. Literally. Look for the Sock Mod on the earpads. Second is to replace the O2 with something like a Burson Fun or Meier Rock FF or the Jazz FF.
    FatherVic likes this.
  7. FatherVic
    Thanks for the recommendations! I'll have to take a look later...

    In regards to the O2, I don't find it bright or harsh at all. Having tried my Shure - though basic - I find it to be quite even handed and in regards to the Grado I find they quite happily work with my DAP and playing with the EQ I sometimes do like to push the treble rather than roll it off.

    I just find this cupping for want of a better word, very perplexing.

    I would like an amp to push what these cans I believe can be capable of through my main HiFi. If they happen to sound great with a Walkman then that's an added bonus.
  8. episiarch Contributor
    A respected amp designer once said,

    Most if not all of the standard opamp-only headphone amps have trouble driving Grados with any decent bass, because they want a high current output.

    Although that was a long time ago and both opamps and circuits built around them have improved, the O2 is absolutely an opamp-chip design, so there could be something to this. Though to give NwAvGuy his due, he did specify a high-current chip as the preferred choice. (See http://nwavguy.blogspot.com/2011/08/o2-details.html and find "NJM4556".)
  9. ProtegeManiac Contributor
    At 99dB/1mW power isn't the problem. Nearly all problems with Grados have to do with output impedance, in a few cases noise or outright distortion, but never really power. Even a 15mW smartphone will get loud enough without totally breaking up on them. Dynamics will improve if you put them on, say, a Meier or Burson of course, but it's not like a decent smartphone much less a decent portable amp would still suck on their own.

    Did you try wiggling the cable? Pushing the plug in deeper or pulling it out then pushing back in?

    Or check polarity - they might be out of phase.

    And what earpads are on your RS2e? If you have the closed ones try the second size up that's fully open in the center.
    Last edited: Oct 6, 2018
    serman005 likes this.
  10. megabigeye
    To clarify:
    Grados + Bryston = wonky
    Grados + Sony DAP = fine
    Grados + O2 = wonky
    All other headphones + all amps = fine

    This sounds to me like the plug isn't quite seating fully in the jack. I have some Amphenol plugs that work fine with some of my equipment, but not with others. That one just kind of unplugs itself, but I wouldn't be surprised if some plugs are more subtle in their unwillingness to work.
    Do you have another cable or an adapter you can try it with?
    Last edited: Oct 6, 2018
  11. FatherVic
    Sorry, when I said 'push these cans' I meant in terms of performance, not that I thought they weren't getting enough power. The pads them are the open design.

    The Bryston does have a polarity switch but does not affect the headphone socket.... I'll check out doing something once I've read up on how to on the laptop.

    The plugs and sockets seem pretty solid with nothing happening with a wiggle.

    Think I'm gonna try get some demos or some more 'phones and amps and see what results I get.
  12. megabigeye
    A plug might not necessarily wiggle if it's not seated properly.

    Anyway, this is just a guess on my part.
  13. FatherVic
    I've nothing else to hand... Only the same 2 types that come with the Grado.
  14. ProtegeManiac Contributor
    Well, pushing them is kind of related to power, just that raw power on its own is mostly just getting loud without clipping but it might have noise and distortion; "pushing" in a more general sense is "gets loud without getting distortion and noise." Something I highly doubt the O2 can't do apart from exacerbating the treble.

    If the sound is just outright weird like it's like putting the drivers into an oversized helmet and then putting on that helmet, something's wrong there. Like the polarity or the plugs.

    OK don't try the other pads.

    Even if it still flips the polarity, that's alright since the signal to both drivers will have their polarity flipped. It's when only one flips that it becomes a problem.

    If it sounds normal on the Walkman then that means the copper conductors are fine; if the Bryston works properly with an amp and speakers, then that's fine. But it could be the headphone socket, except the problem happens with the Grado too, making it more likely that the plug isn't getting good contact on at least the O2 while the Bryston still has that impedance problem, or both have a problem fitting the Grado's plug somehow.

    That said, try the O2 with ohter headphones to see if it still gets that "cupping" sound.

    It doesn't have to wiggle. It can be tight enough front to rear but it might not be getting in deep enough for example, and there's no way to push it in deeper.
  15. god-bluff
    I'm sorry if I sound like I am stating the obvious but why not listen to the Grado through the Walkman?!

    The last pair of Grados I had (just SR80e) actually sounded best through my Walkman (A15). Really great combination, in fact, and at 1/2 volume. I would probably still have them now if I could gust stand the feeling of Grado pads against my ears.
    Last edited: Oct 7, 2018
    ProtegeManiac likes this.

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