[renlute]

Quote:

I don't see the usefulness of posting a photo of a box with a switch on it.  But, when I have time, I will take some photos of it and post them here.

Of course a photo of a metal box is not very useful. But that is not what I was after. I wrote in post 273....
 
"I am curious if you've been asked how to make your A/B comparison device, or if you make copies for others? It sounds like a handy contraption for a person who has a serious headphone habit."
 
The point is, given that this device embodies a very useful concept for evaluating amplifiers for a given headphone, how do we get one or construct one ourselves?
 
 

 

[milosz]

Quote:

Help me make sure I understand you correctly...
 
You're saying that the variance of 4 ohms to 16 ohms is greater than 300 ohm to over 600 ohms?  i.e. 12 is greater than over 300?   Specially considering the typical driving impedances of the amp?  Granted the ratio of change is 4 to 1 vs. 2 to 1, but the actual change in absolute impedance is far greater with the cans.
 
BTW, the phase anomaly is mostly due to multiple drivers and crossover reactance.
 

 
The ratio of impedance variation to the "average" impedance is more important than the absolute magnitude of the impedance variation, especially as far as the driving amp is concerned.
 
And, yes, the current leading or lagging the voltage in the impedance phase characteristic IS coming from multiple drivers and crossovers.  But that's my point exactly- there's a whole lot more going on in a typical speaker in terms of interaction with the driving amp than thee is with headphones.  A headphone typically has one impedance peak and voltage and current phase doesn't vary all over the place; this is a fairly easy load to drive and even with transformer coupled tube amps you'll see just one possible response peak at that single frequency; with speakers (and tube amps especially)  you have the possibility of multiple frequency response bumps -bass, mid, treble- and some speakers have such weird reactances that they are hard to drive well with ANY amplifier. The chances for this sort of complex interaction between transducer and driving amplifier are much greater with speakers than with headphones, the variation in sound between the same speaker on various amplifiers is therefore likely to be much greater than a given headphone on various amps. This is especially true for tube amps with speakers. My point is that audiophiles experience trying a speaker with various (tube) amps gives a sense of a lot of variation between amps.  I think some of this expectation of great variation gets carried over by us when we try a given headphone on different amps.  We experience how different amps sound on a speaker and so we expect a similar magnitude of variation with a headphone.  This expectation gets passed down by reviewers, bloggers, thread contributors.....
 
 

 

[upstateguy]

      
Quote:

"Yet we're constantly assured that the 650 is very hard to drive and sounds like crap without a great amp, whereas in practise I've found they can be driven adequately, even if not optimally, by a slight breeze. It's a contradiction I often puzzle over late into the night  --not.

 
@pp312
 
I agree with you completely.  The 650s can be driven by a breeze and still sound like  650s.  Adequately if not optimally.
 

 
Quote:

In my experience with the HD650 I found them amp dependent. I went through several amps before I found a good match with the Gilmore Lite. It was mostly bass control I had issues with and found the biggest improvement with the GLite over other amps I had and have listened to them with. Including the Matrix M Stage and Headroom Micro Amp that weren't best suited for them. Of course the b22 sounds nice with then. The M^3 also. But many lesser amps weren't optimal. I never did listen to them with tubes though.

@Baka
 
I agree with you as well.  My GS-1 does a very good job with the 650s, as does my M^3 and Woo3 but to a slightly lesser extent.
 
USG

 

[pp312]

 I'd say anyone who can agree with both me and baka1969 on the same issue should get a job as a diplomat.

 

[kwkarth]

Quote:

The ratio of impedance variation to the "average" impedance is more important than the absolute magnitude of the impedance variation, especially as far as the driving amp is concerned.
 
And, yes, the current leading or lagging the voltage in the impedance phase characteristic IS coming from multiple drivers and crossovers.  But that's my point exactly- there's a whole lot more going on in a typical speaker in terms of interaction with the driving amp than thee is with headphones.  A headphone typically has one impedance peak and voltage and current phase doesn't vary all over the place; this is a fairly easy load to drive and even with transformer coupled tube amps you'll see just one possible response peak at that single frequency; with speakers (and tube amps especially)  you have the possibility of multiple frequency response bumps -bass, mid, treble- and some speakers have such weird reactances that they are hard to drive well with ANY amplifier. The chances for this sort of complex interaction between transducer and driving amplifier are much greater with speakers than with headphones, the variation in sound between the same speaker on various amplifiers is therefore likely to be much greater than a given headphone on various amps. This is especially true for tube amps with speakers. My point is that audiophiles experience trying a speaker with various (tube) amps gives a sense of a lot of variation between amps.  I think some of this expectation of great variation gets carried over by us when we try a given headphone on different amps.  We experience how different amps sound on a speaker and so we expect a similar magnitude of variation with a headphone.  This expectation gets passed down by reviewers, bloggers, thread contributors.....

 
Depends upon the amp.  I think you're right about misperceptions abounding.
 
I think lately, the most significant issue people have dealt with is power output capability needed to really make the latest generation of cans shine.  Only recently have we seen amp manufacturers respond with products specifically designed to meet this need more fully.  The Lyr is a good case in point.  My AKG 701s sound better than they ever have in the years that I've had them because they finally have the power they've always needed but never received in the past.  Then of course are the planar magnetic cans.  From the Fostex T50RP to the LCD-2, even though far lesser amps allow them to make music, with a truly powerful amp they can at last make music the way it ought to be made.  Until recently, many amps didn't even readily disclose their power delivery capability.

 

[baka1969]

Quote:Originally Posted by pp312 

" I'd say anyone who can agree with both me and baka1969 on the same issue should get a job as a diplomat."


It's a crazy world. LoL

 

[upstateguy]

Quote:

 
Depends upon the amp.  I think you're right about misperceptions abounding.
 
I think lately, the most significant issue people have dealt with is power output capability needed to really make the latest generation of cans shine.  Only recently have we seen amp manufacturers respond with products specifically designed to meet this need more fully.  The Lyr is a good case in point.  My AKG 701s sound better than they ever have in the years that I've had them because they finally have the power they've always needed but never received in the past.  Then of course are the planar magnetic cans.  From the Fostex T50RP to the LCD-2, even though far lesser amps allow them to make music, with a truly powerful amp they can at last make music the way it ought to be made.  Until recently, many amps didn't even readily disclose their power delivery capability.

I'm not sure I completely understand you KW.  I've always had problems with this concept.
 
I normally listen at no more than 9:00 with my T-1s, 650s, 880s or 701s on my GS-1, M^3 or Woo3.  How loud are you listening?
 
Are you saying that a more powerful amp will sound better at the volume levels I normally use or are you saying that if I want to turn up the volume to rock concert levels, a more powerful amp will be able to handle it better than the ones I already have, (which are capable of playing louder than I ever want to go)?
 
USG
 

 

[kwkarth]

Quote:

I'm not sure I completely understand you KW.  I've always had problems with this concept.
 
I normally listen at no more than 9:00 with my T-1s, 650s, 880s or 701s on my GS-1, M^3 or Woo3.  How loud are you listening?
 
Are you saying that a more powerful amp will sound better at the volume levels I normally use or are you saying that if I want to turn up the volume to rock concert levels, a more powerful amp will be able to handle it better than the ones I already have, (which are capable of playing louder than I ever want to go)?
USG

It has nothing to do with how loud I listen.  Most of the time I listen at pretty low volumes.  ~80-85dB.  It has everything to do with the fullness of sound and the purity of sound with real life uncompressed playback.  My volume control is normally set at around 9 o'clock on both the Lyr and the Asgard.  On rare occasions it approaches 12 o'clock with 24 bit quietly recorded material, but then I usually end up turning it down when it comes to the creshendos.  With the K-1000, I listen usually at 11-12 o'clock, and as loud as 2:30 or 3 o'clock on rare brief occasions.  They are way less sensitive than any of my other cans.
 
 

 

[upstateguy]

Quote:

It has nothing to do with how loud I listen.  Most of the time I listen at pretty low volumes.  ~80-85dB.  It has everything to do with the fullness of sound and the purity of sound with real life uncompressed playback.  My volume control is normally set at around 9 o'clock on both the Lyr and the Asgard.  On rare occasions it approaches 12 o'clock with 24 bit quietly recorded material, but then I usually end up turning it down when it comes to the creshendos.  With the K-1000, I listen usually at 11-12 o'clock, and as loud as 2:30 or 3 o'clock on rare brief occasions.  They are way less sensitive than any of my other cans.
 

 
Hi KW
 
I wish I was an engineer like you are, because I don't understand how a more powerful amp running at a low volume can have a fuller sound than an less powerful amp running at the same  low volume level. 
 
At a 9 o'clock setting for instance, what electrical parameter does a more powerful amp like the Lyr supply to the headphones, (that a less powerful amp like my GS-1 does not,) that enables the Lyr to produce a fuller sound?
 
If the Lyr sends more amps or volts into a headphone than my GS-1 for instance,  won't it just play louder? 
 
USG
 
 
 
 

 

[kwkarth]

Quote:

Hi KW
 
I wish I was an engineer like you are, because I don't understand how a more powerful amp running at a low volume can have a fuller sound than an less powerful amp running at the same  low volume level. 
 
At a 9 o'clock setting for instance, what electrical parameter does a more powerful amp like the Lyr supply to the headphones, (that a less powerful amp like my GS-1 does not,) that enables the Lyr to produce a fuller sound?
 
If the Lyr sends more amps or volts into a headphone than my GS-1 for instance,  won't it just play louder? 
 
USG

Suffice it to say the real music with real dynamic range is not a static sine wave.  The real bottom line is that if something sounds good to you, let it go at that and pay no attention to what anyone else says including me.
 
 

 

[milosz]

I agree that the amount of power a headphone amp can cleanly deliver to the headphones of your choice is quite important.
 
Some headphones are really very efficient and work fine with just about any outboard amp, power-wise. I had a pair of Grado GS1000's and even though they were "low impedance" at 32 ohms,  they seemed to work with any amp I tried them on at the time. (Although I did not have a Bottlehead Crack at the time, I would guess it would be "iffy" on that amp.)
 
Some OTL tube headphone amps can't provide enough power into low-impedance phones, the Bottlehead Crack is one of these- it is not intended to work with low-impedance phones.  So, if you have low impedance phones you have to make sure that the amp you choose will be happy driving low impedance loads.
 
This "low impedance vs. high impedance" thing is not the same thing as the interaction between an amp with the frequency-dependent impedance curve a given set of headphones.  This is simply an issue of power- can the amp put out the current to drive low impedance phones.   Some just can't, like the Bottlehead Crack.  
 
So, there's that.
 
Then there is the issue of their being several well-like headphones out there that require a lot more power to drive than most other 'phones.  The AKG k1000, the HiFiMan HE-5 and especially HE-6, and the Audeze LCD-2.   My HE-6 just doesn't play loud enough on any amplifier not capable of at least one watt output into their 50 ohm impedance.  HiFiMan says the amp should have at least 4 watts output capability, but in my experience an amp with one clean watt - like the Musical Fidelity XCAN V3 for example- can drive these OK.  The portable amps I've tried don't have the power to drive these, and neither do the OTL tube amps I've tried-  Bijou and Little Dot MKIII  were sorta OK on the HE-6, but left me wanting more power.  Even the M³, an otherwise capable solid-state amp, ran out of steam driving the HE-6.  The Audeze LCD-2's are not quite as power hungry as the HE-6's, but they want more power than the Crack can deliver, and the Bijou starts to fold up in the bass when played loud into the LCD-2's.  LCD-2 is also a 50 ohm 'phone, and of lower efficiency than most other headphones.  LCD-2 and HE-6 are planar type headphones, like a Magneplanar speaker, and this design is less efficient therefore requiring more power.
 
Aside from this handful of headphones that requires power fed to them in WATTS, most other headphones are happy with a few hundreds of milliwatts. (A milliwatt is 1/1000 of a watt.)  An iPod can't deliver that much power, but almost any external hi-fi headphone amp can. Phones like Sennheiser HD600/HD650 and HD800 can  play loudly off just about any headphone amp, although typically to have good bass the amp should have enough power capacity so that it is not straining to drive the headphone at your chosen volume level.  So my experience with these headphones (I've owned all three) is that they are OK on just about any headphone amp, but you get extra goodness with amps that have MORE than enough power.
 
So, really, the power thing comes down to:
 
1. Can it drive the headphones to your desired loudness at all? 
-and-
2. Does the amp have enough power not only to drive the headphones, but to drive them without ANY strain?
 
Amps that satisfy #1 let you listen and enjoy, and then there's #2 which gives you that extra "more" that audiophiles are always seeking.
 
So, yeah, power does make an important overall difference.
 
In my experience, headphone amps vary from about 100 mW at 50 ohms to about 8 watts (!) at 50 ohms.  At 300 ohms, you'll see more like 300 mW to 4 or 5 watts as the range of what various amps can deliver.  
 
When I was talking about impedance curves, though, I was talking more about "voicing" type interactions between the driving amp's source impedance and the headphones load impedance, both of which vary somewhat with frequency.
 
 

 

[Skylab]

With OTL amps, it's more than just the current delivery - you can get a mismatch between the high-ish output impedance of the OTL amp and the low impedance of some headphones.  In the case of dynamic-driver headphones, this will create damping factor issues, and that WILL be audible.

 

[Bacci]

Quote:

Of course a photo of a metal box is not very useful. But that is not what I was after. I wrote in post 273....
 
"I am curious if you've been asked how to make your A/B comparison device, or if you make copies for others? It sounds like a handy contraption for a person who has a serious headphone habit."
 
The point is, given that this device embodies a very useful concept for evaluating amplifiers for a given headphone, how do we get one or construct one ourselves?
 

 
If you're not afraid to sling some solder, you could make one based on AMB's ε12 PCB, cf. this thread.
 

 

[Wedge]

 
Quote:

Suffice it to say the real music with real dynamic range is not a static sine wave.  The real bottom line is that if something sounds good to you, let it go at that and pay no attention to what anyone else says including me.
 
 

I'd say this is some very sound advice.  Although its just fun sometimes to pay attention to what everyone is saying including you.
 
Quote:

Then there is the issue of their being several well-like headphones out there that require a lot more power to drive than most other 'phones.  The AKG k1000, the HiFiMan HE-5 and especially HE-6, and the Audeze LCD-2.   My HE-6 just doesn't play loud enough on any amplifier not capable of at least one watt output into their 50 ohm impedance.  HiFiMan says the amp should have at least 4 watts output capability, but in my experience an amp with one clean watt - like the Musical Fidelity XCAN V3 for example- can drive these OK.  The portable amps I've tried don't have the power to drive these, and neither do the OTL tube amps I've tried-  Bijou and Little Dot MKIII  were sorta OK on the HE-6, but left me wanting more power.  Even the M³, an otherwise capable solid-state amp, ran out of steam driving the HE-6.  The Audeze LCD-2's are not quite as power hungry as the HE-6's, but they want more power than the Crack can deliver, and the Bijou starts to fold up in the bass when played loud into the LCD-2's.  LCD-2 is also a 50 ohm 'phone, and of lower efficiency than most other headphones.  LCD-2 and HE-6 are planar type headphones, like a Magneplanar speaker, and this design is less efficient therefore requiring more power.
 

Technically, the difference between 1w and 4w is 6dB and since the human ears are log based it doesn't actually seem 4 times louder.  I think in this case it depends equally on the users preference of volume and the particular amps design.  Just so I am clear though I do believe that different amps will sound different, albeit to some two different amps will sound less different to some than they will to others, but based purely on a power discussion the average volume the user listens to will determine how much dynamic range margin they require before the amp either runs out of power or just starts to sound to distorted.  Some amps are designed with more dynamic range margin, than others and this will play a large roll as every active device has some sort of linear and non-linear operating region and depending on where the designer decides to run the components at, will ultimately give you a less distorted output or more distorted output.
 
I am not sure what drove me to say all this but its late and well I just decided to say it.  

 

[kwkarth]

Quote:

I'd say this is some very sound advice.  Although its just fun sometimes to pay attention to what everyone is saying including you.
 
Technically, the difference between 1w and 4w is 6dB and since the human ears are log based it doesn't actually seem 4 times louder.  I think in this case it depends equally on the users preference of volume and the particular amps design.  Just so I am clear though I do believe that different amps will sound different, albeit to some two different amps will sound less different to some than they will to others, but based purely on a power discussion the average volume the user listens to will determine how much dynamic range margin they require before the amp either runs out of power or just starts to sound to distorted.  Some amps are designed with more dynamic range margin, than others and this will play a large roll as every active device has some sort of linear and non-linear operating region and depending on where the designer decides to run the components at, will ultimately give you a less distorted output or more distorted output.
 
I am not sure what drove me to say all this but its late and well I just decided to say it.  

Too much coffee?  

  Hey, howz that Leben?