[TheInquisitive1]

Hello head-fiers.
 
Today I acquired some beloved HD600 with the O2 ODAC combo and I love them, they sound fantastic!
 
But, one problem... I plugged my HD600 directly into some cheap PC World Essentials 2.0 speakers (worth £7, they have a headphone jack) expecting bad results.
 
It's not that there is a minor difference- there is none whatsoever. I just paid £165 more for the O2 ODAC and I'm stumped...
 
Also, I have read the HD600 are pretty average without a reasonable amp. There is supposed to be a huge difference.
 
THEN, I plugged them into my android and my volume was just over 3/4 and they were my listening levels, everything else would have been too LOUD.
 
I don't get it. Is my amplifier working? I thought the 600's won't draw enough power from an android to get anywhere near listening levels.
 
The detail and clarity between my android/cheap pc speakers and the odac are IDENTICAL (not a single difference I can hear).
 
 
 
Can someone help? Have I set up correctly (USB into back of O2, other end into PC> HD600 plugged into 3.5mm adaptor, plugged in 'output' on O2>AC into AC>PC, Playback devices> Properties> Advanced>24 BIT 96000hz)

 

[TMRaven]

Welcome to hi-fi, where most everything besides headphones give you subtle improvements that you need trained ears for.

 

[TheInquisitive1]

I can near enough promise somethings up.
 
I previously owned MDR-7506, used em on my android at full volume and it was still sub-listening levels.
 
These are notoriously harder to drive, and I'm 3/4 up

 

[Shazb0t]

  Welcome to hi-fi, where most everything besides headphones give you subtle improvements that you need trained ears for.

 
This, makes you wonder about some of these people now doesn't it?

 

[Sefelt103]

This seems rather unusual. With the HD600's 300ohm impedance they are hard to drive and require a dedicated amplifier to drive them well. What sort of music files are being played ? Also I have noticed that because of the way certain tracks are recorded you won't notice a big difference going to a more compressed version of the track or playing it on a lower quality media player. It also takes some time to get used to and hear the subtle abilities of quality equipment.

 

[Brooko]

Actually - the HD600 (despite what a lot of people say) is pretty easy to get loud enough, even on a portable device. I was listening to my X1 with the HD600 last week, and at 60% volume it sounded pretty darn good.  Even my iPhone4 can sound pretty good (no amp).
 
Working through your post (OP) I see some comments that I'd like to take a look at as they may have some bearing on the situation.

 Today I acquired some beloved HD600 with the O2 ODAC combo

 
I'm guessing so far you haven't had a lot of time with the HD600 with any of your sources - so in reality your ear/brain combo is still adjusting to the nuances of the sound.  I've highlighted this simply because I've found it can take days (sometimes weeks) to fully adjust to the subtle nuances of different combos of headphones and sources.
 

But, one problem... I plugged my HD600 directly into some cheap PC World Essentials 2.0 speakers (worth £7, they have a headphone jack) expecting bad results.
 
It's not that there is a minor difference- there is none whatsoever.

 
There will be a difference - the question is will it be audible, and if it's audible, will it be large or subtle?  Often (on this forum) differences are heavily overstated.  But at the same time, realise you are on an audio enthusiast forum - so some people will go into the smallest detail, and make it sound like a huge thing.  In short - your expectations may have been a little high - but at the same time you probably haven't taken the time to actually absorb any small changes in sound.  Quick A/B (if you're not used to looking for small differences, and not used to the headphones), is probably not going to tell you a lot.
 
On the android being the same as the O2/ODAC combo - on quality of output - I can give you pointers here.  The HD600 is actually a relatively easy load to drive over most of the frequency graph - but it does have a measurable impedance spike peaking at around 100 Hz (http://www.innerfidelity.com/images/SennheiserHD600.pdf).  So to drive the headphones properly and overcome this spike you need to be outputting enough voltage and current to drive them properly.  Failing to do so will cause some issues at this particular hump in the frequency response.
 
It's subtle but noticeable on my iPhone (and even on the X1) that the HD00s whilst being loud enough, also have slightly less bass response with both devices.  On these devices, the HD600s are slightly brighter (less bass), and the bass is not as well defined. Plug the HD600s into my NFB-12 or LD MKIV, and the bass response is where it should be.
 
Spending more time with the HD600s so that you begin to notice the difference more easily is the secret.
 
But in the meantime, celebrate the fact that the HD600 still sound pretty good out of your cellphone.  That's one of the things I love about them - no matter what your source, they still sound remarkably good 

.

 

[TheInquisitive1]

This seems rather unusual. With the HD600's 300ohm impedance they are hard to drive and require a dedicated amplifier to drive them well. What sort of music files are being played ? Also I have noticed that because of the way certain tracks are recorded you won't notice a big difference going to a more compressed version of the track or playing it on a lower quality media player. It also takes some time to get used to and hear the subtle abilities of quality equipment.

FLAC.

Side-by-side (A/B i believe?)

The Eagles - Peaceful Easy Feeling, replaying the backing vocals about 30 times on each, couldn't make out any difference (volume equal)
Claude Debussy - Clair De Lune, the third passage many times over...nothing
Herbie Hancock - Blind Man, all of it 3 times...still can't hear a difference.

Granted, I am NOT an audiophile. But I should hear a difference from the highly regarded O2 ODAC+AMP over my terrible speakers...

Even a 'subtle difference' would make me happy. I can't help but shake that feel that I'm not getting the most out of these.

Will give it a week before verdict as these have only had about 8 hours of 'play-time'.

 

[Head Injury]

Granted, I am NOT an audiophile. But I should hear a difference from the highly regarded O2 ODAC+AMP over my terrible speakers...

Not necessarily. The O2 is highly regarded because of its transparency and the work that went into documenting it. It's not highly regarded because it sounds better than anything else. It just guarantees you inaudible noise, distortion, and other issues. If your speaker's headphone out also has inaudible noise and distortion and enough power, it should sound the same. Just because it has more noise and distortion (it probably does) doesn't mean it'll be audible.
 
You might notice problems with your speaker eventually. You might not. If you don't, awesome! Pawn the O2 and be happy, or keep it just for peace of mind.

 

[WHertz]

Usually well educated audio pros have a saying..: 'An amp is just a wire with gain'. It's not only my opinion that ANY well designed amp doesn't add (or detract) anything to/from the source sound.
 
The o2 is well designed...and it seems the engineers of your other (much cheaper) devices did their homework, too...
 
I'd recommend to head over to the sound science forum inhere and read the relevant threads...
 
Regarding the many 'Only amp Y can drive can x properly' posts..: Forget it. It's just marketing. I'm hooking up all my headphones (many too many) through pro IEM transmission paths (AKG IVM 4 / 4500 or Sennheiser EW 300 IEM  G3) since years because I HATE cables - there is no big difference compared to cabled setups... (the 'flat' reproduction range of these is usually 30 Hz - 15 kHz...which is PERFECTLY fine from a musical POV).
 
Some audiophiles (in my circles that's a REAL cussword

) would say it's impossible to drive any 'real' headphone through such devices.
 
It isn't.

 

[Headzone]

You won't notice a difference with compressed material. Yes the HD600 sounded excellent right out of my cellphone too.
 
Play some high dynamic classical, or theatrical (with some bass) and no, your PC or cellphone can't power the HD600. They will sound anemic.

 

[Sefelt103]

If your HD600s have only had 8 hours of play then that explains why they sound similar when plugged into a cheap speaker amplifier. New headphones often sound terrible before they loosen up. Once they cohere after 100 hours and you get used to their sound you will notice a difference if you plug them into your speaker amplifier.

 

[TheInquisitive1]

If your HD600s have only had 8 hours of play then that explains why they sound similar when plugged into a cheap speaker amplifier. New headphones often sound terrible before they loosen up. Once they cohere after 100 hours and you get used to their sound you will notice a difference if you plug them into your speaker amplifier.

I'm going to run pink noise overnight. I tried these plugged straight into my PC aswell and they sounded exactly like my cheap £15 Ozone Attack headset plugged in...no difference- it's just the HQ audio files that make it sound good.

I don't want to spend £400 on a myth about 'burning in', but I just realised they already had an adaptor on (the bigger one, from a 3.5) and i had a cheap 3.5 adaptor on top of that. Will that make a difference? I figured if cables do, adaptors might...

also, should I keep the gain off, if possible?

 

[Head Injury]

I'm going to run pink noise overnight. I tried these plugged straight into my PC aswell and they sounded exactly like my cheap £15 Ozone Attack headset plugged in...no difference- it's just the HQ audio files that make it sound good.

I don't want to spend £400 on a myth about 'burning in', but I just realised they already had an adaptor on (the bigger one, from a 3.5) and i had a cheap 3.5 adaptor on top of that. Will that make a difference? I figured if cables do, adaptors might...

also, should I keep the gain off, if possible?

Yeah okay, there might not be much difference between amps, but there are still very large, measurable and audible differences between headphones, even two of the same model. Improvements don't always correlate to price, so I can see you liking your Ozone more in certain situations, but they should definitely not sound the same. Give it some time, I think you just need to adjust to the differences and learn to appreciate (or hate) them.
 
Running pink noise overnight won't do anything, driver burn-in is highly exaggerated. "Brain" burn-in is a real thing though; it's more about listening to the new pair and getting used to them yourself. Try the HD600 for a week exclusively if it's within your return period (with or without your O2 amp) then switch back to the headset and see if it still sounds the same.
 
Cables don't make a difference, and neither do adapters, unless they're broken or faulty. Then you'll get pretty obvious issues like audible static or sound from only from ear. If you're not getting those, you're OK.
 
HQ audio files don't make much of a difference either, unless you're comparing against really low bitrate (128 kbps, maybe less) files. Differences are potentially audible at all lossy bitrates, but not night and day. Any "hi-rez" files with more than 16 bit depth or 44.1 kHz sampling rate won't make any difference unless they use an entirely new mastering.
 
In short, it's safe to say most of the differences you do hear are the result of the headphones

 

[TheInquisitive1]

Yeah okay, there might not be much difference between amps, but there are still very large, measurable and audible differences between headphones, even two of the same model. Improvements don't always correlate to price, so I can see you liking your Ozone more in certain situations, but they should definitely not sound the same. Give it some time, I think you just need to adjust to the differences and learn to appreciate (or hate) them.

Running pink noise overnight won't do anything, driver burn-in is highly exaggerated. "Brain" burn-in is a real thing though; it's more about listening to the new pair and getting used to them yourself. Try the HD600 for a week exclusively if it's within your return period (with or without your O2 amp) then switch back to the headset and see if it still sounds the same.

Cables don't make a difference, and neither do adapters, unless they're broken or faulty. Then you'll get pretty obvious issues like audible static or sound from only from ear. If you're not getting those, you're OK.

It's not that I prefer the ozone, I literally cannot tell them apart. It doesn't take an audiophile to hear an improvement over £15 (I only use the price in a circumstance like this) HEADSET. Heck, I even seen a few old guys with tinnitus say they heard a HUGE difference between the HD600 amped and un-amped.

People were saying FiiO products only had a slight improvement, and the O2 vastly improved them noticeably straight away...but I'm critically listening both amped and unamped/soundcard comparing to OZONE and everything about them sound the same.

I have 14 day return policy, I'll see what happens...it's kinda dis-heartening really...I've been researching them for months and months.

 

[WHertz]

(...) Heck, I even seen a few old guys with tinnitus say they heard a HUGE difference between the HD600 amped and un-amped.

If they really heard HUGE differences caused by an amp, their amp was broken....or they smoked too much stuff that's illegal in my country

 
 
Stay in reality - and try EVERY HP unamped (well...externally unamped) first.