[kodreaming]

Buy an second hand amp and try it. If you can't tell the difference, then sell the amp.

Don't believe what you read, trust what you heard...

 

[earwicker7]

Quote:

Originally Posted by tfarney /img/forum/go_quote.gif This has been the often-repeated conventional wisdom on Head-fi, but it happens to be wrong. Most vintage and modern receivers and integrated amps simply step down the output of their speaker amps through a nest of resistors in front of the headphone jack. This can create rather high-impedance output, possibly altering the frequency response of low impedance phones (though people report good results, even with Denons, so listen before you assume). It has no audible effect on reasonably high impedance phones like most Senns, AKGs and Beyers. In other words, the headphone jack is no more of an afterthought than the speaker terminals, as it shares all the same design, parts and assembly. A good amp should have good ouput at the headphone jack. A bad one will, of course, be bad. Tim

According to your signature, you don't own any headphone amps... on what are you basing your belief that they don't matter? Maybe I'm a purist, but a bunch of cheap resistors (I still stand by the belief that the jack is an afterthought) in my signal path doesn't give me much hope.

 

[VeipaCray]

Most headphone amps are in fact pointless. Most of the ones I've seen are rectangular or even rounded. I can't say I've ever seen a pointed amp.

 

[ClieOS]

Quote:

Originally Posted by earwicker7 /img/forum/go_quote.gif According to your signature, you don't own any headphone amps...

Tim lists two amps in his profile.
Headroom Airhead
70's Harman Kardon integrated amp

Quote:

Originally Posted by VeipaCray /img/forum/go_quote.gif Most headphone amps are in fact pointless. Most of the ones I've seen are rectangular or even rounded. I can't say I've ever seen a pointed amp.

I remember the Diablo has very sharp edge. Does that count?

 

[tfarney]

Quote:

Originally Posted by earwicker7 /img/forum/go_quote.gif According to your signature, you don't own any headphone amps... on what are you basing your belief that they don't matter? Maybe I'm a purist, but a bunch of cheap resistors (I still stand by the belief that the jack is an afterthought) in my signal path doesn't give me much hope.

I didn't say that headphone amps don't matter, I said that the conventional wisdom that the headphone sections of most integrateds and receivers are an afterthought is false. I stand by it. Resistors are cheap, that doesn't make them ineffective. High-end stepped attenuators are full of them. There are some potential problems with resistored-down headphone outs. I mentioned them in my other post.

Regarding my experience: I just spent a week with a Glow Audio Amp One. A point to point wired, SET (actually pentodes, EL84s used in triode configuration) tube amp. I own an Airhead. I have heard a couple of Headroom's home products, the headphone section of a McIntosh tube preamp, my own digital class D receiver and a Linn. But really, none of that matters. I don't have to hear any headphone amps to know what good audio sounds like. I have decades of experience listening to and working with high end and professional audio. I know good sound reproduction when I hear it. I understand what balance, detail, transient response, low and high frequency extension, coherence, etc, etc, sounds like. Headphone listening removes the anomalies of a room (and I've heard plenty of studio control rooms with the anomalies tuned out), and removes all chance of a natural sound stage. Other than that, all listening experience applies. Your argument, which is little more than an attempt to dismiss a differing opinion, is not logical. Headphone amps are not the only source of quality audio. They are not even the primary source of quality audio. I do not need to have heard even one of them to be able to recognize quality audio.

Tim

 

[smeggy]

I can't honestly say headphone amps are of any use to me whatsoever as all my phones run off power amps or integrateds. My NAD preamp dishes out plenty of power too.

Electrostats, orthos and K1000s are my staples.

 

[pp312]

Quote:

Originally Posted by earwicker7 /img/forum/go_quote.gif Maybe I'm a purist, but a bunch of cheap resistors (I still stand by the belief that the jack is an afterthought) in my signal path doesn't give me much hope.

I wonder why you still stand by that belief. Tim has pointed out what we now know as a fact, verified by the manufacturers, that most budget and mid-priced integrateds/receivers (not sure about HT receivers) feed their headphone jacks through resistors from the speaker outs. In what way is this an "afterthought"? Your "bunch of cheap resistors" is hyperbole: resistors are resistors and, where there's only two or at most four, the second two most likely in parallel, will not be heard even by the golden Eared unless they're faulty. The fact is, and I suspect you realise this, the signal from the HP jack in such an amp will be a reduced version of the signal to the speakers, and if the amp is well designed, the sound will be great; if not, the sound will be lousy. The complicating factor, as Tim has also pointed out, is the possible effect of increased output impedance on the frequency response of low impedance phones. However, anecdotal evidence on these forums suggests there's little to worry about in practise--not surprising, given that the measured response of even the best phones already resembles a distant mountain range.

Sorry for repeating what's already been said, but you didn't seem to get the message.

 

[coldkeith]

Quote:

Originally Posted by VeipaCray /img/forum/go_quote.gif Most headphone amps are in fact pointless. Most of the ones I've seen are rectangular or even rounded. I can't say I've ever seen a pointed amp.

good point

 

[DefectiveAudioComponent]

What we can learn from this is that when buying an expensive amplifier, it's a good idea to pick one that has a headphone out.

 

[Turgidson]

Quote:

Originally Posted by pp312 /img/forum/go_quote.gif I wonder why you still stand by that belief. Tim has pointed out what we now know as a fact, verified by the manufacturers, that most budget and mid-priced integrateds/receivers (not sure about HT receivers) feed their headphone jacks through resistors from the speaker outs. In what way is this an "afterthought"? Your "bunch of cheap resistors" is hyperbole: resistors are resistors and, where there's only two or at most four, the second two most likely in parallel, will not be heard even by the golden Eared unless they're faulty. The fact is, and I suspect you realise this, the signal from the HP jack in such an amp will be a reduced version of the signal to the speakers, and if the amp is well designed, the sound will be great; if not, the sound will be lousy.

Excepted that speaker-amps are primarily designed to drive a very small impedance (typically 4 or 8 Ohm) with strong current, rather than a high impedance with low amounts of current (headphone out, behind a network of resistances). High impedances are usually easier to drive (and should be less of a high-pass issue with the coupling caps), so the response should be OK; however in terms of strict quality/price ratio this solution cannot be better than a dedicated solution (considering that both would be designed and priced the same - which may not be the case when considering that the headphone amp market is smaller).

Quote:

The complicating factor, as Tim has also pointed out, is the possible effect of increased output impedance on the frequency response of low impedance phones. However, anecdotal evidence on these forums suggests there's little to worry about in practise--not surprising, given that the measured response of even the best phones already resembles a distant mountain range.

The measured response of headphones must NOT be flat, because the head does have a filtering effect on the sound, which means headphones have to reproduce a part of this HRTF (head-related transfer function).

As for the impact on low-impedance phones, it comes from the fact that their impedance/frequency curve isn't always a constant (by design - and as they're meant to be driven by a voltage that is the same whatever the impedance, it's not a flaw). Thus, with an added serial resistance, the attenuation will differ depending on the frequency, and further distort the frequency response (compared to the nominal design).

Adding a serial resistance is quite easy to do, and can be tested. In practice, I've found that it's something that can easily be heard with low impedance phones (much more easily than differences between good amps), so the effect is (IMHO) definitely not zero.

 

[FallenAngel]

So much discussion over such a simple thing.

Fact #1: Power amps are designed to drive SPEAKERS
Fact #2: Headphone amps are designed to drive HEADPHONES

They differ in design to suit their own purpose. Why is this so difficult to get across?

 

[smeggy]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif So much discussion over such a simple thing. Fact #1: Power amps are designed to drive SPEAKERS Fact #2: Headphone amps are designed to drive HEADPHONES They differ in design to suit their own purpose. Why is this so difficult to get across?

The point is that many preamps, receivers or integrateds have a headphone out every bit as good as many overpriced or expensive headphone amps. In a lot of cases they're more powerful too. The simple fact that something is made as a headphone amp by a small shop doesn't automatically make it better than their larger brethren.

I reserve the right to be totally wrong on this next part, but as I see it...

Many amps have very good headphone sockets, and not all are just speaker power run through some resistors. As far as I can tell, a headphone amp is little different than a normal preamp section and I'd guess the output power is broadly similar. Run that to a headphone socket and voila! Headphone amp in all but name.

 

[rds]

What FallenAngel is trying to say is you're totally wrong. It's akin to saying speakers are just like headphones and therefore if you take good speakers turn down the volume and put them beside your head you have good headphones.
I think you know why that is wrong. To know why you're wrong about amps you need to understands electronics a little. Bring your power amp to a meet and compare it to a PPA, M3, CkIII, etc. and you will see for yourself. Hell even compare it to a nice cmoy.

EDIT I shouldn't assume what FallenAngel is trying to say...

 

[sunseeker888]

Nothing is pointless unless you cannot find a use for it.

Headphone amplifiers are a NECESSITY for certain cans. Electrostatic cans, for example.

Of course, dynamic cans can benefit too

That KA-907 is unbelievably nice. I have a KT7500/KA8100 stack which i enjoy the hell out of.

 

[ClieOS]

Quote:

Originally Posted by sunseeker888 /img/forum/go_quote.gif Nothing is pointless unless you cannot find a use for it.

To me, a power amp will be useless as I have no use for them in my house because I am mainly a headphone person, and that's all that matters to me.