[ButtUglyJeff]

  @ButtUglyJeff I would be careful not to dumb down changing an amp for another one to just being a power difference. that would be conveniently forgetting about so many other possible reasons that comes from using 2 different amps.
while I agree that I also kind of felt that with the 650, and it indeed usually happens that the amp with more power feels like it still brings something to damping the sub, I certainly wouldn't draw any conclusion about power alone. first because I never conducted an actual test at matched volume levels. but even more so when the laws ruling electricity aren't the kind to bend just for one headphone. at some point the only way to get more power to pass through the hd650 is to push the volume louder.

@whirlwind   all the grados roll off sub bass so much that your comment makes sense to me. the reason is simply that a good deal of what would change due to the equal loudness contour stuff of our ears when listening at lower level, is already too rolled off on the grado at normal listening to make a noticeable difference compared to the mids.
to me it's more like the grado sounds as bad at normal level as it sounds bad at quiet level, but I'm a sucker for sub bass, so I'm very much partial on this I'm afraid.
for low volume listening, I instead go with V shaped stuff that feel more balanced when used quietly. that way I still have some feeling of bass/sub. but the side effect is that I hate V shaped signature, so I never ever listen to those stuff at normal listening levels

. they have an exclusive "quiet usage" in my case. at least you can still have fun with a grado at normal level.
whatever the method, it can be challenging to really enjoy music at low volume levels. I wish someone would upgrade our ears already.

 
Power isn't a dumb down thing, its actually quite complex.  You have your watts, amps, ohms, volts.  You have tubes vs. solid state.  Ask any HD800 owner....

 

[JacobLee89]

   
Power isn't a dumb down thing, its actually quite complex.  You have your watts, amps, ohms, volts.  You have tubes vs. solid state.  Ask any HD800 owner....

 
Not to mention "speed".. I forgot what the term was, bit it had something to do with how fast the voltage/current (forgot which one as well) jumps back to nominal value after the volume reaches certain peaks/transients in recordings. I came across this when doing the O2 mod.

 

[castleofargh]

  Power isn't a dumb down thing, its actually quite complex.  You have your watts, amps, ohms, volts.  You have tubes vs. solid state.  Ask any HD800 owner....

 
let's say we have a headphone of 300ohm and an amp can provide up to 10V into 300ohm(like a crack maybe? my imagination is limitless ^_^) then the maximum power given in the specs into 300 ohm would most likely be 10²/300=333.3333mW. because P=U²/R
 
  that's how much power you can expect to use if you feed 10volts into the 300ohm headphone(or a 300ohm whatever, really). now what if the headphone is already loud when reaching peaks at 3V? well then you will never ever come close to the maximum power output. from that point, a more powerful amp will be like spitting in the wind as long as it reaches without distortion or clipping, the 3V peaks into 300ohm that you use to listen to your music.
driving power is directly related to how loud we listen. reaching 120db with a hd650 might be somewhere around 4V so about 54mW into 300ohm). you might want to measure your own hd650 and check for several frequencies, keep a little headroom under your foot just to feel reassured, etc.  but at the end of the day your hd650 will use a determined max power when you listen to it at a given loudness. the job of the amp is to provide that much, it cannot and will never provide more at a given loudness.
the idea of scaling up is as much of a subjective idea (so very much subject to biases of all kinds) as it is because most of us have experienced some headphones badly driven before. but once it is well driven, be it a hd650 or a hd800, there is no going above that or scaling up anything. other might be changes that are noticed by people just aren't power related.
 
tube or SS have nothing to do with it except when clipping, but who would like to clip an amp? not me. getting the proper amp is also to avoid that and sometimes taking the DAC output into account might be a good idea. but that's about it.
 
and from what time I have spent reading the hd800 topics before giving up on it, the vast majority of amp talks were ignorance 101. not all  thanksfully, but many of the claims about driving needs were just preposterous. and if I had to guess, I'd say too many people mistake signature with driving power in that topic.
the hatred for EQ associated with the preconception that a hd800 is neutral(lol) has led to a lot of paradoxical nonsense. it's a very dangerous topic IMO.

 

[JacobLee89]

Heavy amounts of current research on children has proven that the best scientific way to raise a child is to give it lots of hugs and attention. No. Seriously.
 
So I believe that the more we go into this topic, the more it's going to boil back down into "if it sounds good, then it's probably good". Just like all the ridiculous amount of formulation Einstein had to go through to give us the magical E=MC^2.
 
I still don't quite understand why the HD650 benefits from Voltage over Current. If somebody can shed some light on this, I would greatly appreciate it.

 

[castleofargh]

  Heavy amounts of current research on children has proven that the best scientific way to raise a child is to give it lots of hugs and attention. No. Seriously.
 
So I believe that the more we go into this topic, the more it's going to boil back down into "if it sounds good, then it's probably good". Just like all the ridiculous amount of formulation Einstein had to go through to give us the magical E=MC^2.
 
I still don't quite understand why the HD650 benefits from Voltage over Current. If somebody can shed some light on this, I would greatly appreciate it.

 because it's 300ohm. if we go with the good old water analogy, the higher the resistance opposing the passage of water/current, the less water/current quantity can pass at any given moment. and the other situation, if the flow meets little resistance, then more current can pass. that would be like that for a low impedance headphone.
 
or another simplified idea(as music is not DC): V=RI and V is equal to how loud you listen, so you will set V yourself to be a given max value. in that system, when R goes up, I can only go down if the formula stands true.
 
and the rule of thumb about that is to say that low impedance headphones tend to need mostly current, while high impedance headphones tend to use/require more voltage. the hd650 being the later. but that's told as voltage relative to current, not in the sense that a hd650 needs 150V to work well ^_^.
just like a 8ohm IEM will need mostly current, but only relatively to voltage. the total power will still be super small.

 

[coastal1]

Speaking of power though a little off-topic, for. people w/ the BH Crack + Speedball/HD 650 combo, how high do you turn the Crack up to fully drive the HD650?

Im turning the volume on the Crack (using stepped attenuator) higher than expected -- maybe 3 o clock, I'll check exactly next time I use it. So there's room to spare and I'm not getting any distortion or negative effects, just curious/surprised.

I'm using Foobar or jriver (PC vol at 100%)-> iFI Micro solely as DAC->Crack. Using TS 5998 and Telefunken 12a7 tubes. Part of my surprise is that the Micro as DAC/amp delivers more volume in Normal mode (haven't even touched Turbo) compared to the Crack

 

[mikoss]

 
Power isn't a dumb down thing, its actually quite complex.  You have your watts, amps, ohms, volts.  You have tubes vs. solid state.  Ask any HD800 owner....
 
Originally Posted by castleofargh /img/forum/go_quote.gif
 
let's say we have a headphone of 300ohm and an amp can provide up to 10V into 300ohm(like a crack maybe? my imagination is limitless ^_^) then the maximum power given in the specs into 300 ohm would most likely be 10²/300=333.3333mW. because P=U²/R

 
I agree with both of you... and I think you're both correct.
 
My WA2 will drive my LCD-3's to ear bleeding levels, volume wise... however, the frequency response sounds like utter crap. There is plenty of volume, and the amp is not distorting, however the output impedance and OTL design make it sound like crap with planar headphones.
 
I also agree with the calculation above, however, dynamic drivers such as the ones in the HD-650's are not equivalent to hooking up a 300ohm resistor to your amp and measuring the power output. We are not feeding a DC voltage into a resistor!! We are feeding an alternating signal into a driver, which has a varying impedance which changes with frequency. The reason why the impedance changes so much is because the driver load is not purely resistive... it's a coil which has capacitance and inductance. In fact, the power factor of the driver changes considerably, depending on the frequency you're pushing through... from a lagging power factor, into a leading power factor even... this is MUCH different than producing power in a purely resistive circuit.
 
The source; your amplifier, will see the voltage and current go out of phase pretty much constantly- the actual power calculation involves the power factor, which by all accounts is changing nearly constantly while we listen to music. The power output rating of the amp is always at a specific ohmic value, which coincides with the overall impedance. I'm certain the design of the amp and the nature of the design of the headphones will dictate how well they play together.
 
I believe that this accounts for why some designs and amps sound better/different than others, not strictly their voltage/power rating... (This is all my opinion, of course. I'm open to further discussions, however I can't deny that the HD-650's sound their absolute best to me with an OTL amp...)
 
One other edited point: IMO, this is why people can simply change how their amplifier sounds by swapping components... for example; different types of capacitors affect the response of the current in the circuit, also adding or subtracting capacitance can change the overall tone (body/transient response, whatever you want to quantify). If you change the capacitance, inductance, or resistance in the output circuit, you will affect the response of the driver and possibly the presentation of the music.

 

[Kodhifi]

Well I didn't end up getting the IE80's due to a delivery problem. Instead I got the Shure SE215k's and I got to say, for single dynamic driver IEM's, these are pretty damned good. Out of the box they have a sound stage comperable to the 650's. They have a similar kind of slight V, relaxed sound presentation that makes for flattering sound. These are the closest I've heard in other headphones to the HD650 sound but with a little more bass emphasis. I think I know why these were rated over the ie80s in the review section. This is especially true for jazz music which has an amazing soundstage I never thought I'd hear in an IEM. I've been doing back and forth all afternoon.
 
 
Back to the 650's, I think I've broken in enough now on my amp and such that I'm ready to maybe experiment rolling some tubes. I don't want to break the bank, I'm simply looking for something with relaxed highs, and a good midrange for Lyr 2 HD650 combo.

 

[castleofargh]

  I agree with both of you... and I think you're both correct.
 
My WA2 will drive my LCD-3's to ear bleeding levels, volume wise... however, the frequency response sounds like utter crap. There is plenty of volume, and the amp is not distorting, however the output impedance and OTL design make it sound like crap with planar headphones.
 
I also agree with the calculation above, however, dynamic drivers such as the ones in the HD-650's are not equivalent to hooking up a 300ohm resistor to your amp and measuring the power output. We are not feeding a DC voltage into a resistor!! We are feeding an alternating signal into a driver, which has a varying impedance which changes with frequency. The reason why the impedance changes so much is because the driver load is not purely resistive... it's a coil which has capacitance and inductance. In fact, the power factor of the driver changes considerably, depending on the frequency you're pushing through... from a lagging power factor, into a leading power factor even... this is MUCH different than producing power in a purely resistive circuit.
 
The source; your amplifier, will see the voltage and current go out of phase pretty much constantly- the actual power calculation involves the power factor, which by all accounts is changing nearly constantly while we listen to music. The power output rating of the amp is always at a specific ohmic value, which coincides with the overall impedance. I'm certain the design of the amp and the nature of the design of the headphones will dictate how well they play together.
 
I believe that this accounts for why some designs and amps sound better/different than others, not strictly their voltage/power rating... (This is all my opinion, of course. I'm open to further discussions, however I can't deny that the HD-650's sound their absolute best to me with an OTL amp...)
 
One other edited point: IMO, this is why people can simply change how their amplifier sounds by swapping components... for example; different types of capacitors affect the response of the current in the circuit, also adding or subtracting capacitance can change the overall tone (body/transient response, whatever you want to quantify). If you change the capacitance, inductance, or resistance in the output circuit, you will affect the response of the driver and possibly the presentation of the music.

sure but everything is done to make it simple for us. the amp specs are given when feeding a load, and the headphone specs give sensitivity saying "if you feed me this, I'll get that loud". super nice of them, and that's specs with AC signal already. as long as the headphone isn't a pile of crap, there will be a nice follow up between voltage and loudness that let us estimate the needed voltage even without bothering with AC formulas(anyway we're looking at peak aplitude of the AC signal so sin and cos will be 0 and 1 and wouldn't affect the results).
 
before I did the math in my head from specs, and landed with about 4V for 120db.
from sennheiser :
Nominal impedance 300
Sound pressure level103 dB at 1 kHz, 1 Vrms
 
well if I do it with the computer and not like an idiot counting my fingers, 4V get me 115.05db instead(not that far off ^_^).
if I keep going with "my" way, to get 90db that's 25.05db lower, that gives me about 0.2235V
now I take Tyll measurements here http://www.innerfidelity.com/images/SennheiserHD650.pdf
first I see that it's not 300ohm @1khz but 320ohm. not the best start, welcome to high precision audio by castleofargh ^_^. still, let's play the game, he measured 0.205V needed to reach 90db.
20log(0.2235/0.205)=0.75db !!!! that's my error at 90db compared to an actual measurement. I'd say that good to use when I wonder if an amp will drive my hd650.
and the other frequencies are above 300ohm, so they'll need less to reach the same loudness, and I don't have to calculate for another frequency when looking for a max. pretty cool in the end.
 
 
 
 
about your wa2 amp with a lcd3, that's a source of 70ohm plugged to what? about 100ohm for the lcd3? I personally wouldn't want that amp for that headphone even before looking at the power needed for the LCD3. because of the damping factor being real poor.
it's not a law, but it's certainly a nice way to avoid taking chances IMO.

 

[whirlwind]

  Well I didn't end up getting the IE80's due to a delivery problem. Instead I got the Shure SE215k's and I got to say, for single dynamic driver IEM's, these are pretty damned good. Out of the box they have a sound stage comperable to the 650's. They have a similar kind of slight V, relaxed sound presentation that makes for flattering sound. These are the closest I've heard in other headphones to the HD650 sound but with a little more bass emphasis. I think I know why these were rated over the ie80s in the review section. This is especially true for jazz music which has an amazing soundstage I never thought I'd hear in an IEM. I've been doing back and forth all afternoon.
 
 
Back to the 650's, I think I've broken in enough now on my amp and such that I'm ready to maybe experiment rolling some tubes. I don't want to break the bank, I'm simply looking for something with relaxed highs, and a good midrange for Lyr 2 HD650 combo.

Nothing more fun than rolling tubes in this hobby, IMHO.
 
Have fun  

 

[Solrighal]

  Well I didn't end up getting the IE80's due to a delivery problem. Instead I got the Shure SE215k's and I got to say, for single dynamic driver IEM's, these are pretty damned good. Out of the box they have a sound stage comperable to the 650's. They have a similar kind of slight V, relaxed sound presentation that makes for flattering sound. These are the closest I've heard in other headphones to the HD650 sound but with a little more bass emphasis. I think I know why these were rated over the ie80s in the review section. This is especially true for jazz music which has an amazing soundstage I never thought I'd hear in an IEM. I've been doing back and forth all afternoon.
 
 
Back to the 650's, I think I've broken in enough now on my amp and such that I'm ready to maybe experiment rolling some tubes. I don't want to break the bank, I'm simply looking for something with relaxed highs, and a good midrange for Lyr 2 HD650 combo.

 
The HD 650 doesn't have any kind of V-shaped presentation. It is relaxed though.

 

[ButtUglyJeff]

Boy, I'm listening to my early iTunes purchases right now.  And, I'm sure glad my HD650s are a bit more forgiving then other headphones I have....

 

[mikoss]

 
about your wa2 amp with a lcd3, that's a source of 70ohm plugged to what? about 100ohm for the lcd3? I personally wouldn't want that amp for that headphone even before looking at the power needed for the LCD3. because of the damping factor being real poor.
it's not a law, but it's certainly a nice way to avoid taking chances IMO.

My point was that even if the amp is spec'd to have enough power/volume, it may not have a quality presentation. This is the 650 thread... the WA2 kind of makes sense I bought the LCD's after and never planned to drive them OTL, but according to the power specs, it should produce 550mW at 120ohms; ~116dB. Oh, it's plenty loud, and sounds terrible with the LCD's... delightful with the 650's.
 
I personally don't worry too much about damping for planars... 

 

 

[upstateguy]

 

Quote:

and I know a guy who knows a guy.......

 

Quiet revisions in headphones are no secret, especially if suppliers change or if there is some manufacturing shift. Some don't admit it and some don't make it public they made a revision, doesn't mean there wasn't one. This happens with all sorts of consumer goods in general, whether electronics, food, etc. The new and old HD 650's have very different dampening material over the driver and even the drivers may be a bit different. And personally hearing both versions with new pads, I know for a fact they do sound different, at least the two pairs I heard did. Whether they officially admit it doesn't matter, there is a physical difference between the two and everyone I know who's heard both says they sound different.

  you listened to at least two pairs of 650s and well, I guess that settles it.
 

I have two hd650's. One with old black drivers and one with new white/silver. Both have new pads.

The new one is just a tiny amount brighter in the top. Not a lot in it though.

wondering how many hours were on the old drivers vs. the new drivers and how tight each headband was and what difference did you expect to hear......
 
just wondering......... nothing more.

 

[DavidA]

I've also asked this on the SennGrado thread since there was so much difference between the three that I built, but was wondering has anyone listened to two or more different HD-650 with the same drivers, ie; new and new or old and old, is there a difference?  Interested if variations within the same production run could account for differences in peoples opinions/impressions.  I've noticed that my two HE-560's sound slightly different, one has a little more kick in the bass, only noticeable on some songs.  The other is the K7XX, one has slightly more extended highs, again not easy to notice and only with a few songs.