[seefeel]

Why are not all headphone amps powerful enough to drive ANY pair of headphones? Why don’t all headphone amps weigh as much as a home receiver and put out ample power for even the toughest to drive cans? It seems like we’re getting gypped by paying hundreds of dollars for headphone amps that are repeatedly underpowered. Why must we have to pay $3,888 for a Blockhead to have enough power to really drive a pair of headphones with a lot of oomph?

 

[MusicLover]

You need low power amps for headphones like the CD3000 and RS-1, and you need high power amps for headphones like the HD600 and DT880. Usually, high ohm headphones don't work well on low power amps and vice versa.

 

[seefeel]

Yeah, that's what I'm thinking. Why aren't there any high-powered headphone amps priced well below $1000? Or are there? High power, when it relates to what a HD600 needs in a headphone amp should be much cheaper to manufacture. If I can buy a very heavy 200WPC amplifier with a lot of internal expensive parts for my speakers for $1000, shouldn't I be able to get the equivalent in an amp for a pair of headphones for much less than that? I hope my logic is coming across right.

 

[MusicLover]

There are ones much below $1000. The MG Head, the Headroom Supreme and Cosmic, and the Gilmore V2 (I think) are all I can think of right now, but there are many more. Search around and look more closely into many of the amps around here.

 

[tom hankins]

There are many amps with more than enough power to drive the HD600's under 1000.00. Even my little Rega Ear has no problem driving the Senns or the DT880's. Most headphone amps are under the $1K price tag and they have no problem as far as power go's. If you want alot of umph out of the senns get one of the Singlepower amps, or the ASL OTL32 with the high voltage setting. The Headroom MOHR has more than enough power to drive the HD600's. You can also get alot of good vintage stuff for next to nothing that have lots of power. The list of good amps for the HD600 is very long even in the under 600.00 price. Do a search and you will find a ton of good amps for the HD600, that cover every price range.

 

[kwkarth]

I could be all wet on this, since I'm not an amp designer, but with headphones, small signal performance is critical. When driving speakers whose sensitivities are typically in the 85-95db/watt @ 8 ohms, small signal performance issues won't be revealed because you're operating out of that area just to make noise audible from the speakers.

Headphones on the other hand need only a milliwatt to produce the same sound levels but the voltage swing typically needs to be large (on the order of 10vp-p) for higher impedance cans.

Different design criteria speaker amp vs headphone amp. The market for headamps is MUCH smaller than that for speakers so margins have to be appropriately scaled to pay for development.

 

[seefeel]

Thanks for spelling it out guys! Nice bunch of info there. I've been hearing a lot about those singlepower amps. In order to get one you have to email the guy that makes them? Are they that much better and more powerful than say, the MG Head OTL MKII or OTL32? As far as being able to powerfully drive the HD600s, are they are up to the task of give some major oomph for them? More so than all the others in that price range of under $1000? I must admit, it seems a little scary buying from a part time person instead of buying from a store. Are the singlepower amps reliable and have good warrantee with quick responses from the guy that makes them?

 

[tom hankins]

The guy that makes the Singlepower amps is Mikhail. They are powerful and he stands behind his products. He takes great pride in the amps he builds. Do some searchs in the amp section of the MPX3 and the Supra and you will read about a few people that had minor dislikes or problems and he corrected them very quick. I can only think of about two people that had any thing wrong with any of the amps. Use the search button and you will find all you need to no about amps for the HD600.

 

[mkmelt]

The K1000 headphones are rated at 1 watt continuous power, so assuming peak power levels can be 10db higher, the K1000 should be able to handle 8-10 watt peaks without being damaged.

Most amplifiers that can deliver 100 watts of power into a 4 or 8 ohm load will have a difficult time providing 10 watts of power into the load presented by a high impedance headphone.

Roughly, every time you double the impedance of a load, the power is cut in half.

4 ohm : 100 watts
8 ohm : 50 watts
16 ohm: 25 watts
32 ohm : 12 watts (Grado phones are rated at 32 ohm, Senn 590 too)
64 ohm : 6 watts (Some Sony headphones are 60 ohm)
128 ohm : 3 watts (K1000s are 120 ohm)
250 ohm : 1.5 watts (other AKG, Beyer Dynamic, and Sennheiser
580 and 600 headphone impedance ratings
are 250 - 300 ohm )
600 ohm : 0.75 watts (Some older AKG headphones are 600 ohm
Sennheiser 580/600 phones have 600
ohm peaks at certain resonance frequencies.

At high impedances, the demand on an amplifier shifts from delivering current (amperage) to delivering wide peak-to-peak voltage swings of 30 or more volts to provide the power needed to drive some headphones to realistic volume levels.

Most dynamic headphones, even the high impedance designs, work with most amplifiers because the power required to achieve very loud peak volume levels is only a fraction of 1 watt.

The AKG K1000 is rated at only 74db sensitivity compared to 90 db or higher for most other designs. As a result, some amplifiers are unable to drive the K1000 to realistic levels because they cannot deliver the needed power into the 120 ohm impedance load of these headphones.

Tube amplifiers generally have an easier time driving high impedance loads than low impedance loads. Tube amplifiers that are able to drive the K1000 headphones to full volume, at 8 ohms these same amplifiers might only be able to deliver 20 - 30 watts of power.

A given tube amplifier may only be able to deliver 3 watts of continuous power at 120 ohms, and while that does not seem like alot of power, it can be several times the power available from many solid state amplifiers at this impedance, and more than enough for listening to K1000s at levels that most people would consider loud for headphone listening.

 

[neggy]

You know another reason there so expensive is because most people in the world dont even know a headphone amp exists. There is not a huge market like home theater, also there are few companies that make them so they can charge as much as they want, within reason.

 

[markl]

Quote:

You need low power amps for headphones like the CD3000 and RS-1, and you need high power amps for headphones like the HD600 and DT880. Usually, high ohm headphones don't work well on low power amps and vice versa.

This is not true, in my experience. Low-impedence cans benefit as much as high-impedence cans from having ample current and voltage to drive them.

To expand on what mkmelt has said, as I understand it, as a layman, but as someone who has read about this here a bit, some headphones need extra voltage, some need extra current. There seem to be design trade-offs, particularly in tube amps, that make it hard to offer high voltage *and* high current. Headphones are appearently relatively complex loads to drive correctly at all frequencies. Someone more knowledgable than I should clarify.

Regular speakers are rated at 4, 6 and 8 ohms, yet for many of these speakers, we require mega-watt amps to make them sound their best. I believe this is because these large speakers require lots of current to drive them. Low impedence headphones also need a lot of current compared to high-impedence phones like the HD600. I think when we say that the "HD600 is a hard load to drive" it's because it needs lots of extra voltage that not all amps are designed to give. Or maybe its vice-versa--- really need a techie here to elaborate. The point is there's a trade-off of some kind due to the wide range of loads presented by different headphones.

Most speakers present a load to an amp between 2-8 ohms, so the operating range of the power amp doesn't need to be so wide, whearas a headamp may be called upon to drive a 32 ohm Grado load all the way to a 600 ohm Beyer load. That's a wide variation, and apparently this is a tricky problem to solve and to make "one size fits all" amps.

BTW, if anyone is looking for an amp with power to burn, look long and hard at the Ray Samuels Emmeline HR-2, its an all-around monster, drive any load.

Mark

 

[kwkarth]

Well, let's get some terms straight.

POWER is what gets the work done. Power is expressed in Watts and is the product of voltage (volts) AND current (amps).

A headphone's sensitivity is usually expressed in a certain amount of POWER required to produce a certain volume level.

To DELIVER the required (appropriate) amount of POWER to a given headphone, a given amplifier needs to be able to produce the product of volts times current.

Consider a 32 ohm phone who's sensitivity is expressed as 90db/mw.

Consider a 320 ohm phone who's sensitivity is expressed as 90db/mw.

Consider a 600 ohm phone who's sensitivity is expressed as 90db/mw.

They all have the same sensitivity.

The 32 ohm can needs an amp capable of delivering 0.2 volts and almost 6 milliamps of current to make that 90db noise.

The 320 ohm can needs an amp capable of delivering 0.6 volts and only 2 milliamps of current to make that same 90db of noise.

A 600 ohm can of the same sensitivity would need almost 0.8 volts and 1.3 milliamps of current for the same volume level.

Does this help anybody conceptualy? If so we can continue this discusson...

BTW, headphones are typically a very easy load to drive compared to speakers. (almost purely resistive and inductive) Little to no capacitive loading to speak of.
Happy Listening!

 

[Geek]

I've heard lots of headphone amps which easily drive high impedence cans to deafening levels. For example, the airhead can push the HD600s well over one hundred decibels. No sweat.

What matters most though is the fidelity of the signal; I think that's a bigger criteria. Mabye I'm just too inexperienced or something; but I haven't ever heard even a cheap dedicated amp that couldn't drive a pair of 300-ohm cans to deafeningly loud levels.

The ability of a headphone amp to bring out the best characteristics of the headphone it is driving is what matters most. Those characteristics we all know as fast transients, tight bass, smooth detailed highs and mids, attack and decay, dynamics, and an overall natural sound. This is what a higher end system promises and why "big" amps cost thousands of dollars. They may not necessarily deliver more power, that's a moot point. They deliver a blacker, cleaner, purer electrical signal to the headphone which results in increased fidelity.

Cheers,
Geek