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ibbilbo
97
Jun 10, 2016
Got mine this morning. Listening with the mahogany X00's. All I can say is wow...just...WOW!!! Coming from an O2/Odac I'm simply stunned. Anyone trying to decide between the two, don't waste another moment reading reviews. Buy the m9xx! (even if it means having to sell your first born child. :)
CarlosUnchained
122
Jun 10, 2016
ibbilboHas the m9xx better quality/price than the O2/Odac? Are you sure it's not the standalone power of the m9xx that makes you say that? I just want to be REALLY sure that spending almost twice the price is worthy.
The power gap between the two is huge for your X00's impedance (around 1030mW vs a bit more than 613mW for de O2), but for higher impedances the O2 (88mW) actually gives more power than the m9xx (57mW). I really can't see why choose the m9xx having high impedance HP.
ibbilbo
97
Jun 10, 2016
CarlosUnchainedActually, the price of the m9xx was a bit outside my comfort zone price wise. I purchased it hoping to affirm my belief that after the O2/Odac any improvement in SQ would be so incremental that I could go back to the O2 as an end game solution. Boy, was I wrong. The m9xx is better by every measure. I'll be selling the O2 and will never look back. I currently own a Bravo Audio Ocean, a Matrix M-Stage HP1, SMSL M3, Micca Origen+, and the O2/Odac. The m9xx puts them all to shame. Is it worth twice the price? Only you can decide that but I would say, unequivocally yes.
CarlosUnchained
122
Jun 10, 2016
ibbilboI like that you have experience with others as well. Could you make a ranking of them?
ibbilbo
97
Jun 10, 2016
CarlosUnchainedThat's a tough request. Kinda like ranking your children. I love each one for their unique qualities. I did a lot of research and purchased each based on great performance at their price point but not one of them did it all. Without getting too long winded>
M-Stage - great amp, meh dac, heavy, odd form factor, gets hot Bravo Audio Ocean-powerful Class A amp, tube warmth, tube rolling opportunities, you can fry eggs on this one O2 - nothing but praise here, great clarity, like a wire with gain, powers everything I throw at it Odac RevB - dead silent background, great clarity and imaging, older design using a PCM chip, (feeds all of the above) SMSL M3 - portable, decent dac, weakish amp, DSD, can power from a power brick, OTG support for Android, inexpensive Micca Origen - great form factor, knob on top, DSD, plenty of power, uses the same Cirrus Logic chip as the SMSL
Here's the thing...the m9xx does all the things that made each of the above special...only better. Oh, and the crossfeed feature alone is worth the price of admission.
CarlosUnchained
122
Jun 10, 2016
ibbilboThanks a lot for taking the time. Awesome review! Btw, are you going to sell the O2? I might be interested.
ibbilbo
97
Jun 11, 2016
CarlosUnchainedI'm probably going to hang onto it for a bit as a backup in case something untoward were to happen to the m9xx. Sorry. However, there is a drop happening right now for the Massdrop O2. If you join, I would suggest springing for the extra $15 for the desktop version. The 1/4" jack and the RCA inputs are worth the extra $.
CarlosUnchained
122
Jun 11, 2016
ibbilboI saw the drop. Yes, the ¼ jack and RCA are a must have for the price. Thanks again!
will_y
9
Jun 12, 2016
ibbilboI'm planning to get this amp but not sure if it has enough power to drive my HD 800S. I've been using O2+Odac the whole time and it drives 300ohm headphones perfectly. Since you also own O2, could you shed some light on this? Would Grace be able to drive my headphones to a normal listening level if O2 can do it?
ibbilbo
97
Jun 12, 2016
will_yI have not yet had the pleasure of hearing the HD800S with the m9xx. I have read that is is a good pairing. I do, however own a pair of HD600's (also 300ohm) and use the high power setting (both usb's) with foorbar2000 with WASAPI. I set the volume level in fb2k at about 75% and the m9xx is set at 90 for a comfortable listening level. So there is quite a bit of additional headroom if you like it LOUD. I did some testing with a SPL meter and found that my preferred listening level in headphones is 70-75db. One completely unexpected result of the HD600 and m9xx pairing is that for the first time the HD600's actually have satisfying bass. Don't know where it came from but was quite a pleasant surprise. The HD600's are supposed to pair better with higher impedance amps but the m9xx really makes them something special. Unless the HD800S is much harder to drive than the HD600's, you should be good to go.
will_y
9
Jun 12, 2016
ibbilboThank you ibbilbo. I think my headphones would be fine. Just out of curiosity, did you find m9xx struggles more to drive headphones than o2? O2 seems to have more output power. Based on some reviews out there, I am under the impression that with high impedance headphones, you probably hear nothing until you turned the volume all the way up. However, I guess you probably don't have that issue given your experience with HD 600 which is also 300ohm.
ibbilbo
97
Jun 13, 2016
will_yJust tested the HD600's and you begin to hear audible sound at about 38-40 on the m9xx. Anything above about 95 is pretty uncomfortable. No doubt the O2 is the more powerful amp and struggles a lot less with high impedance hp's. That being said, the m9xx drives the Senn's beautifully Hmmm...I may try running the m9xx as a dedicated dac through the O2 and see what happens. :)
Update: I ran rca's from the m9xx to the O2 and OMG! You CAN have the best of both worlds! The m9xx will simultaneously power the amp on both units! On the O2 comfortable levels at 3:00 o"clock on low gain and 11:00 o"clock on high gain. More power than you will ever need!
Uzuzu
1431
Jun 15, 2016
ibbilboyou guys are fucking crazy, I wouldn't go above 75 on the m9xx for hd600s and that is loud. Where the fuck is your hearing? At normal listening levels the m9xx isn't good enough to properly drive sennheiser cans. It does the job but it's a bit lacking.
will_y
9
Jun 15, 2016
UzuzuCould you please measure the volume maybe using a phone app. I found the best volume level to be between 70-80 decibels. It's loud enough to make my cans shine but not too much to make me feel uncomfortable. I doubt if the '75' indicated on the amp means 75 decibels.
will_y
9
Jun 15, 2016
ibbilboHi ibbilbo, is it possible for you to give a visual demonstration of how you set up O2 to work with m99x. I would really appreciate some photos.
jimpx10
46
Jun 15, 2016
will_yibbilbo, when you use the M99x as a DAC to another amp via the RCA line out connections, the volume switch is still active (a lot of DACs in this case set the volume to the best signal and disable the volume control). Not sure if this is correct, but I read that the best volume to to set when using the the DAC to feed another amp is 90 (and then use the volume control on the amp to get the level you want). Personally, when I use the M9XX as a DAC I set the volume to 90 and don't use the headphones. Unfortunately when I want to use both, I can't set the volume to 90 as the headphones would be way to loud, so I have to set the volume lower than 90 and a I am therefore not getting the optimal line out signal. I haven't played around with it to see if it degrades much when it isn't set to 90, odds are I couldn't tell much of a difference, but in theory it is not optimal. Another thing is if you attach an amp via RCA and you plug headphones into the right plug it disables the RCA out. Haven't tried it but that is what I read.
ibbilbo
97
Jun 15, 2016
will_yIts really not that hard. Use one of these: https://www.amazon.com/Ugreen-3-5mm-Auxiliary-Stereo-Splitter/dp/B00LM2Y2U4/ref=sr_1_16?ie=UTF8&qid=1465965469&sr=8-16&keywords=rca+to+3.5mm+stereo+adapter connect the RCA's to the RCA output on the m9xx and insert the 3.5mm into the input jack on the front of the O2. Plug your headphones into the O2 and there you go! I don't see any need to do that though. Unless you like bleeding ears. The m9xx does just fine without the O2. It is nice to know it's possible in case I every want to try 600ohm cans in the future though.
ibbilbo
97
Jun 15, 2016
jimpx10I concur with everything you just said. Both volume controls still work and setting the m9xx at 90 is optimum for the full 2v output. And yes, setting the volume level lower than 90 does degrade the SQ a bit. When testing this, I have been unplugging the hp's from the m9xx and plugging into the O2 so the volume thing hasn't been a problem. I haven't needed to plug into both.That said, my ears do still ring a bit from the first time I un-muted the m9xx after replugging into it after testing. (when it was still set to 90) I'm a fast learner. Won't make that mistake again.
fjrabon
456
Jun 15, 2016
will_yThe m9XX + HD800s pairing is incredible. Definitely enough power unless you frequently listen at 100dB
Uzuzu
1431
Jun 17, 2016
will_ywell yeah, 75 isn't 75 decibels because amp and volume vary headphone to headphone......... But I'm pretty sure my listening level is way below 75 decibals. That isn't good for long-term hearing.
FaezFarhan
43
Jun 18, 2016
fjrabonI listen to 85db on my K7XX. Max peak 91db
Uzuzu
1431
Jun 19, 2016
fjrabonWhoa, just saw this post. I have an m9xx but no hd800s to test them on. But aren't the hd800s 300 Ohms impedence? And the m9xx doesn't have much voltage at all when pushing 300 ohm cans. I own hd650s which are 300 ohms, and straight out of the m9xx..... well they sound alright. I mean they are hd650s, they almost always sound good as long as you can drive them to decent volume. But something is missing. Most people recommend 500 or so mW being pushed through those babies to get them sounding to pure gold, and I can say that the 115 mW pushed through the m9xx at that load just doesn't cut it. The sound is there but isn't fully flushed out. Part of why everyone says they scale with better equipment. Also Jude himself says the hd800 sounds interesting (in a good way) out of the m9xx. But in no way could it replace his desktop or home-listening setups for the hd800. It simply doesn't have enough power. At least in my opinion. In the case of my hd650 it is clearly audible to me. m9xx functions very well though for lower-impedence mid-fi cans. In fact, it doesn't get much better for them. And for those hard to drive cans it can serve as a very decent dac feeding into a better amp.
will_y
9
Jun 19, 2016
UzuzuYa I think I'm getting Oppo ha1 instead.
Uzuzu
1431
Jun 19, 2016
will_ytell me how it goes.
fjrabon
456
Jun 19, 2016
UzuzuCommenting like this on things you've never heard is both useless and misleading. I have spent about 6 hours total with that pairing. A lot of HD800S owners have talked about how much they like the pairing.
Also if you go back to Jude's review, his comment was more that he preferred tubes to roll off some of the early production HD800's at times harsh treble. Not that the m9XX lacked power. I never even got above 85 when using the m9XX with the HD800S. Which means that I was using less than half its available power.
The HD800 is more efficient than the HD600 and HD650. In fact Michael Grace literally used a HD800 as his personal reference when he designed the m9XX. I had the HD650 and I'll agree I didn't like it that much with the m9XX. But the HD650 is a notoriously amp picky headphone.
To my ears the HD800 (unmodded) was a good pairing with the m9XX. The HD800S with it was near magical. And most people who have actually heard it will say so, instead of just reading off spec sheets.
MassEDU
182
Jun 20, 2016
fjrabonWell said and I agree. People ought to be careful when stating things to avoid stating it as if it's fact, especially when they haven't even heard the headphones/pairing (not meaning to sound arrogant). I've been fortunate to briefly hear a modded HD800 on the m9XX and also thought it sounded good. The solid bass presentation surprised me most because according to measurements that is where the major impedance swing mostly occurs, which could add to the erroneous assumption that the m9XX is "insufficient" for the HD800.
Uzuzu
1431
Jun 21, 2016
MassEDUOkay but either way why use a mid-fi amp on some end-game gear. I mean I'm all for mid-fi, but dang.
will_y
9
Jun 21, 2016
UzuzuWould you believe if I tell you my o2+odac sounds a lot better than a 2000 dollar violeteric when pairing with 800S , at least to me. So I really don't believe in those expansive amps.
MassEDU
182
Jun 21, 2016
UzuzuI get ya but IMO I think that's more of a conditioned mindset. It's to the benefit of some of these companies over-charging for their products that we believe that "end-game" 'phones can't run properly on "mid'fi" gear. Pay us a crap-ton for this amp or DAC when the math and/or listening experience says you're easily covered by much cheaper. Even the mere existence of those categories (mid-fi, etc) is to the benefit of their pockets. Now I'm not saying that there isn't stuff that can perform better objectively, it's more just the practicality of it all and the misleading (and expensive) way of thought that can take root. Also does "end-game" really even exist, at least in the way most people think of it? ;)
Hopefully I don't sound biased, since I'm fortunate to own an m9XX.
fjrabon
456
Jun 21, 2016
UzuzuWhy worry about labels? Pick based on your own experiences and what sounds good rather than labels like "mid-fi" and "endgame"
A lot of people have remarked how similar the m9XX sounds to the m920 and most everybody considers the m920 to be endgame.
Uzuzu
1431
Jun 21, 2016
fjrabonthe m9xx amp isn't very good, mine is used as a dac only these days........
EDIT: ok the amp is pretty good for easy to drive iems or headphones, bad for hard to drive ones, ok.
fjrabon
456
Jun 21, 2016
CarlosUnchainedBecause the m9XX has a better DAC and has fewer high order harmonics (thus sounding less harsh) than the O2/ODAC.
I like the O2/ODAC for what it is, a lot. It's not in the ballpark of the m9XX at all. And it has nothing to do with power. Their power specs
The O2/ODAC is also getting a bit long in the tooth. These days it's being outperformed by things like the audioquest dragonfly
ibbilbo
97
Jun 21, 2016
fjrabonDon't feed the troll. He'll just keep coming back.
CalebRoberts
56
Jun 23, 2016
ibbilboI suggest that there may be a minor misconception regarding operating m9xx at an "optimal" volume setting. It is true that setting the volume above 90 raises the noise floor because it raises the gain of the output amplifier. However, the noise floor is constant from 90 all the way down to 0. At the volume setting 90, the digital gain control in the AKM DAC IC is set to 0dB / full scale. I think that it is incorrect to suggest that there is a compromise in signal integrity if the gain is set below full-scale. The digital gain control in the AKM DAC IC is at least as accurate as the volume control in FB2k or other player apps. The AKM DAC IC has a 32-bit datapath and the dynamic range is greater than any analog circuitry and loudspeaker combination you can connect to its outputs. Note too that the channel matching of a digital gain control is far better than a stereo potentiometer. Listeners are often distracted by a bias in perception that louder signals seem to sound better.
Uzuzu
1431
Jun 26, 2016
MassEDUI also own an m9xx. It does very good especially with easy load headphones. I really love the m9xx. But it just isn't good for Senns 6xx-800 series. 100 mw at 300 ohms just doesn't cut it for those cans. Even if you think the hd800s sound fine enough on them, meh that's your own opinion, but don't go running 600 ohm puppies on the m9xx. The designer may have tested it with the hd800 and that is great, it's fine even if he helped make the device able to run it decently, but like I said Jude says that it can't replace a desktop setup (but he's referring to the Senns). I think that for cans with little resistance and high enough sensitivity will usually sound pretty good out of the m9xx. My 650s sound bad out of them. My ad2ks and 400is as well as the k712 sound phenomenal.
Amp matching is important, but the m9xx can basically push any good modern designed cans because of how easy most are to drive, and it does it while sounding divine.
For my 650s though I can feel a noticeable improvement running the m9xx to a lyr 2, for instance. So much better.
fjrabon
456
Jun 27, 2016
CalebRobertsthanks Caleb! I've thought the DAC sounds best at 90, because as you say you don't get the >90 increased noise floor, and it's also helping the noise floor on the next level of the chain as well when it's at 90, ie the more powerful the signal you feed your amp, the less the amp's noise floor gets amplified. Because, as you say the m9XX itself sounds just as good at 60 as it does 90, that isn't strictly an issue with the m9XX, but rather the next piece in the chain sounding better when it's receiving a stronger signal. Basically what I've been telling people who are using the RCA outs to feed powered speakers or an additional amp is "go with 90, but also don't be worried about going below 90 if using the m9XX's volume control is more convenient than the volume control on your speakers or amp." In fact I have some powered speakers that sit some distance from my chair in one of my rooms at home, and I definitely use the m9XX to fine tune control their volume, as it's way more convenient and enjoyable than getting up to adjust the volume knob for a minor song to song level adjustment.
CalebRoberts
56
Jun 27, 2016
UzuzuThere seems to be a common misconception that higher impedance loads are more difficult to drive. In reality, lower impedance loads draw greater current for a given voltage. In the case of m9xx driving high impedance phones, the only limit is the maximum voltage that m9xx will produce. This translates into a limit of maximum loudness. m9xx can drive far more current at maximum voltage than a 600 ohm load will draw, and the damping factor is very high. Because the maximum voltage produced by the m9xx is below the clipping point, the signal is at least as accurate into a 600 ohm load as into low impedance. My opinion is that there are two categories of reasons that some prefer amps that can produce higher voltage for high-impedance headphones: 1 - many of these amps are tube and perhaps these are listeners who prefer the sound of elevated harmonic distortion (warmth) or non-flat frequency response that is typical of tube amps; 2 - loudness bias.
fjrabon
456
Jun 27, 2016
Uzuzuagain, when Jude said the m9XX wasn't his favorite (but that he did like the pairing very much, just not his absolute favorite) for his low serial number HD800, he said that it was because he preferred tube warmth on them (like Caleb mentioned), not because m9XX didn't drive them sufficiently. (the lower serial number, early production HD800 was notoriously bright; even before the HD800S debuted, it was noted by many that the later production, higher serial numbers were significantly less bright)
Since the m9XX has such low output impedance, you're never out of current, so the only issue is if they will make your headphones loud enough. With the HD800S, the m9XX will drive them to 117dB in high power mode, and 115dB in "regular power" mode. That's plenty of headroom unless you listen at VERY high volume levels. And again, you aren't lacking for current whatsoever, since the m9XX is 0.08 output impedance.
I agree that I don't love the HD650 with the m9XX, but that has to do with the HD650 being so amp picky, not lack of power. There are plenty of 4 watt amps I don't like with the HD650. I don't think the HD650 sounds very good with the Gustard H10, for example. And, again, everybody who I know that has heard the HD800S with the m9XX reports it as not just "passable" but flat out incredible. And, while this is my/our opinion, again, we have heard the HD800S with the m9XX, and as you mentioned elsewhere, you've never heard this pairing. You saying "meh, that is your opinion" when you have literally never heard the pairing is completely unreasonable, and misleading.
sambrla
Jun 28, 2016
fjrabon@fjrabon Have you by any chance heard the HD600 with the m9XX?
fjrabon
456
Jun 29, 2016
sambrlaonly briefly at a meet. I also don't really have a good feel for what the HD600 generally sounds like to compare. Finally, I've never really liked the HD600 that much (liked the HD650 significantly more) so I'm not the best person to ask. I didn't like the HD600+m9XX, but I also don't know for sure which part of the chain I didn't like, and I also didn't spend a ton of time to really get a feel. It wasn't a headphone I was interested in, so I didn't spend too much time. Sorry I couldn't be more help.
sambrla
Jun 29, 2016
fjrabonThanks for the reply. I've read mixed impressions of the pairing so was interested in whether you had an opinion given you have experience with both the HD650 and HD800(s).
Uzuzu
1431
Jun 29, 2016
fjrabonperhaps, but I have no problems with the balance of sound from my m9xx feeding the hd650s. I also listen at way lower volumes than most the people that post here (not quiet but not loud, I don't think louder sounds better). I'm not unhappy with the way the hd650's sound sig pairs with the m9xx, but the way the bass sounds. Sounds like it has zero presence from m9xx. Also I already know the whole current ordeal with the m9xx. Like I said m9xx sounds fantastic on easy to drive cans. I'll be getting a lyr 2 tube/ss soon. Also sure I haven't heard the hd800S, but it's like what 20 percent better than even the hd650 (law of diminishing returns). Still any gain is worth the money in my book. Saying I have over half a dozen cans in the 300-600 dollar range on my desk, I'm thinking ebay is my next move. I'll be buying the hd800s within a month. I'll let you know just how good or overhyped they are, fjrabon. Let's just say I'm not much of a Sennheiser fan as it is, mostly because of their poor build quality and sound design on about 85 percent of their headphones.
also I don't believe Sennheiser admits to tweaking/changing the tonal balance of the hd800. Some people may have done their own measurements but those could be just within tolerances and completely biased and subjective. I'm sure Jude has heard more than one pair of hd800s, too ;-)
fjrabon
456
Jun 29, 2016
UzuzuI don't know if Sennheiser has "officially" admitted they changed the tonal balance on the HD800, but a Sennheiser rep confirmed it to me.
It sounds like it isn't power you're missing with the Hd650, but rather you like the bass boost the Hd650 gets with higher impedance amps due to the impedance hump the HD650 has in the midbass. But then again, the Lyr2 won't create that effect, so I don't know.
My main point is that it just simply isn't true that the m9XX is underpowered for the HD800 (unless you regularly listen above 100dB). That's an objective fact. At 90 dB the HD800 is only drawing about 15mW from the m9XX.
Uzuzu
1431
Jul 1, 2016
fjrabonCurrent isn't a problem, but current isn't the only and certainly isn't the most important fact alone when it comes to properly driving headphones. ¯\_(ツ)_/¯ is all I have to say. I will make extensive comparisons with the HD800S once I get my pair. I could buy them right now but if I don't sell off the cans that aren't in my rotation I'll probably have some explaining to do and get yelled at ;-). But let's put this conversation aside until that later date, when I can make more than just a guess. Hell maybe I'll return the Lyr 2 if it doesn't offer anything more than my m9xx in terms of amplification, naturally I'll be using the grace as a dac while doing the comparison so it's just an amp v amp battle.
As for your other conversation with that man about the hd600..... I wholeheartedly agree. hd650 is a lot better to listen to, but that is just our opinion. Some people call it a dark hp but the newer models sound fine to me. Not the biggest but far from small and very realistic soundstage. Bass that has perfect impact, but a bit shy of what I'd call perfect extension... midrange is balanced and I think treble sounds fine, not veiled. Just not lifted enough to blast your dang ears. Close to perfect headphone especially for the price range.
Other favorite can in rotation is the ATH AD2K and nobody will ever have my pair ;-)
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