Headphones and amps...
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Printed Date: July 19 2025 at 11:02
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Topic: Headphones and amps...
Posted By: The T
Subject: Headphones and amps...
Date Posted: May 31 2011 at 00:59
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I hope someone here can answer a few questions since headphone forums are too full of audiophiles who describe things in inexact terms. I love headphones. I do most of my music listening via headphones. I used to have a regular sharp mini component with a pair of on-ear bose cans. They did ok but then I bough some sennheisers hd 380 (actually aimed at the dj crowd; was the only thing I could buy at work) and they showed me the difference between sh*tty fake bose sound and real sound. Then I changed the source for a denon dm38 mini-hifi and things improved even further (though there's an annoying hissing noise in the headphone out playing cds that's almost unbearable). I decided to try even better headphones going open this time (instead of closed headphones) and I settled for the senn's hd 650. I haven't received them yet. Now, everyone says they will achieve full potential using a headphone amp. I don't have money to spend on a headphone amp. Is it that necessary? Does it make such a difference with high impedance headphones? Due to the annoying hiss, and because it has a headphone out with a buffered amplifier, i bought a marantz cd5004 cd player, because I'm sick of the annoying hiss of the denon and because this seems to solve the headphone problem at least partially. It's still no dedicated headphone amp. Is it really that big of a difference with headphones with amps? ------------- 
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Replies:
Posted By: oliverstoned
Date Posted: May 31 2011 at 03:25
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I've owned HD600 and HD 650 and first i must say that i much prefer HD600 which is more balanced and musical, it has a fantastic midrange and highs, very natural whereas the 650 goes further at both extremes but is veiled in the midrange and has an overall less natural sound. This said, the 650 remains a good headphone in the absolute; It indeed requires an AC powered amp (portable amp will not give you the full potential, far from it) and a real good one that will be expensive. To plug directly on the headphone stage of a CD player (weak headphone output on all levels), i'd recommend an HD25, as usual, the one with the cooper cable version to be precise. I can recommend an amp that will give you the full potential of your 650's, but it's out of your budget: Sugden "Le Bijou". To sum up, it's really day and night, with or without amp. A 650 without real amplification will give an anemic sound, i much much prefer an HD 25 in this case. It's the classic mistake, like buying high end speakers and not having a decent system to drive it, you end up with nothing decent. There will be no dynamic and you'll be dispointed thinking that people exagerate when they rave about Senn HD6XX HPs whereas the problem comes from the lack of amplification. For a little more money, i'd buy instead a RSA Mustang P51 portable amp, an HD25 (cooper cable version) and a (cheap) mini/mini Cardas Cable so if you already have an Ipod, you'll end up with an excellent portable setup and a decent indoor setup for music (that will work BETTER than the 650 without amp, whatever the source) and -why not- for movies from your DVD player (you'd have to add a decent mini/RCA cable for this option). Too bad you did not asked before... On the bright side, the Marantz is a nice budget little player. |
Posted By: Triceratopsoil
Date Posted: May 31 2011 at 11:38
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Since Oliver didn't really answer you on that, no, it's not necessary, but yes, it will make a huge difference to use an amp for your headphone. Not all amps will make it sound a way that you appreciate, which is why as with most things the "try before you buy" rule comes into effect. Even something for a few hundred dollars can make a huge difference. A good site to find out which amps people like to use for particular headphone models is head-fi.org |
Posted By: Dean
Date Posted: May 31 2011 at 12:41
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Quick answer: You do need a dedicated headphone amplifier to drive the HD650's from the Marantz CD5004 - the output of the Marantz is 18mW into 32 ohms - the HD650 are 300 ohms - basically you do not have enough voltage to drive the headphones and the maximum power you can feed into them from the Marantz is 1.9mW. [this means that the HD650's will be three times quieter than your HD380's when plugged into the Marantz]
However, you do not need a dedicated headphone amp - any amplifier with a headphone jack will suffice, you can even use your Denon DM38 as a headphone amp in the interim (just plug the CD player into the AUX in phono sockets at the rear).
Personally I would advice against the RSA Mustang P-51 Amp (which at $375 is not exactly what you would call "budget"), because it is a portable amp so needs batteries - and AC powered amp is better suited to your set-up, and will be a lot more versatile in the long-run. ------------- What? |
Posted By: oliverstoned
Date Posted: May 31 2011 at 13:44
| I've never adviced any portable headphone amp to drive the HD650, but to drive the HD25. Pluging the HD650 on the output of the Denon will give a poor result but you have not the choice anymore, since you ordered the 650's. |
Posted By: Catcher10
Date Posted: May 31 2011 at 15:15
T this suggestion will help push your ear "walls" so that the sound is more dynamic, the bass will have a sonic sound better than what you currently have. The mids and highs will be crisp and clean...sonically of course.
Its the best.
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Dean wrote:Posted By: Dean
Date Posted: May 31 2011 at 18:14
The O/P of the Denon DM38 is quoted at 30W into 6 ohms, this equates to a driving voltage of 15.5VRMS. Typically a headphone O/P will have a 270R series resistor on each channel to reduce the voltage levels, which in this case would halve the drive voltage to 7.75VRMS, so when driving the HD650 the max O/P power will be 0.2W, or roughly half what the HD650 are rated at. In theory this should still produce sound presure levels around 100dB, which is more than enough. Of course I don't have the circuit schematic of the DM38 so I don't know how the headphone socket is wired, but in principle it should be able to drive the HD650 to "typical" listening levels without any detremental affect to the "sound", but only listening will tell for sure. ------------- What? |
Posted By: The T
Date Posted: May 31 2011 at 18:50
Thanks guys! I know without the headphone amp my headphones won't push walls (ear walls that is  ) but that's the next step!-------------
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Posted By: oliverstoned
Date Posted: June 01 2011 at 06:33
Because headphone output stages on amps and sources are always bad. You said "you don't need a dedicated headphone amp": you'd avoid doing such categoric statement because you've never heard a 650 drived by a good dedicated HP amp so you don't know what you're talking about. But you said something true after: "but only listening will tell for sure" so as you've never heard it...the conclusion is quite obvious. The T bought a 650 because he's looking for an excellent musical and sonic experience and he's about to get an excellent pair of electrodynamic HPs which has a fantastic (not as musical as the 600 but still)potential if paired with a real good dedicated headphone amp. That's why the T deserves real advices because he's about to be dispointed. I talk because i know very well these two headphones: 600 & 650 which i owned, tried in many configurations and that i compared one against each other many times. The DM38 is a nice micro system but will be unable to reveal the full potential of the 650. IMO the 600 remains currently the best, the 650 and the new 800 are less musical but anyway Senn does the best eletrodynamic HPs in the world. To do better, one has to go to Stax, electrostatic technology which really pushes wall-ears  with the Lambda Signature, including its dedicated (valve) amp, which is simply the best headphone in the world. An ear-blowing experience!
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Posted By: Dean
Date Posted: June 01 2011 at 07:00
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Let's not get into this here - Teo ask for advice, we gave it.
You have your opinion, I have mine. ------------- What? |
Posted By: oliverstoned
Date Posted: June 01 2011 at 07:01
| I have the experience, you don't. Now everyone is free to say what he wants. |
Posted By: Dean
Date Posted: June 01 2011 at 07:43
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------------- What? |
Posted By: Mr ProgFreak
Date Posted: June 01 2011 at 07:58
^^ Except that when people like me say too much, you leave the thread. ------------- https://tagyourmusic.org/users/Mike" rel="nofollow - https://tagyourmusic.org/users/Mike |
Posted By: oliverstoned
Date Posted: June 01 2011 at 08:03
| You try to rescue your friend... |
Posted By: Mr ProgFreak
Date Posted: June 01 2011 at 09:33
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^ He's not in a situation that needs a rescue ... your claim of superiority ("I have the experience, you don't") is totally baseless and ultimately self-defeating. ------------- https://tagyourmusic.org/users/Mike" rel="nofollow - https://tagyourmusic.org/users/Mike |
Posted By: Dean
Date Posted: June 01 2011 at 09:38
waving, not drowning  ------------- What? |
Posted By: The T
Date Posted: June 01 2011 at 12:04
Damn I never knew someone who had Stax headphones! Oliver really pushes walls here...  I realized from the beginning that the HD650 were going to be under-juiced by either my DM38 or my CD5004. I don't have the money for a Beyerdynamic headphone amp or something like that. I will buy a 200$ v-can headphone amp that is getting praise everywhere for being low-cost-good-value. I hope it does the job. If not I'll have to wait a while for an economic recovery good enough to allow me to spend money on a better amp. I also changed the speakers in the DM38 from the stock denon to a couple of Definitive Technology 800 and a sub. So much improvement. Oliver must have heard or even used the Sennheiser Orpheus he90. Did you? That was supposed to be in the same league as those mythical Stax headphones... I also assume once you get to a certain point diminishing return start to appear and the sound difference is minimal... -------------
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Posted By: Triceratopsoil
Date Posted: June 01 2011 at 12:28
lolk |
Posted By: Catcher10
Date Posted: June 01 2011 at 12:47
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^ Not sure I have ever had my ears-blown.......? -------------
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Posted By: The T
Date Posted: June 01 2011 at 12:48
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^But you certainly have your ears pushed... -------------
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Posted By: oliverstoned
Date Posted: June 01 2011 at 13:36
No actually i'm not that rich, i don't own the Stax, but one friend does so i had the chance to listen it quietly and moreover fed by his great system. It's incredibly dynamic and smooth, really push the ears into the brain! It's a fantastic experience but to be honest i'm not very up for indoor headphone listening, i quickly feel claustrophobic or simply tired wearing headphones indoor. I prefer listening to my speaker system indoor and to the high-end portable setup outdoor in the garden or on travel when you have nothing else. That's why i eventually sold back my Senn and the Bijou amp because i quickly got tired of listening headphones indoor. Well, this beautiful class A amp was not as musical as the big valve system. But it's not the same listening experience at all, headphone is much more transparent (on this criteria, a well driven 6XX can compete with big speakers) but is more of a "cerebral" kind of experience and lacks the physical aspect of listening provided by a well working system doing good low and extreme low. The V Can is decent, not excellent but decent and will let you hear more of the 650. No i didn't heard the Orpheus but from reliable source i know that it's a little overpriced and behind the Stax Lambda Signature, very musical but not as dynamic. The potential dynamic from the Stax is unbelievable... The 6XX in itself has a huge potential and the price is ridiculous in this aspect but requires an amp many times its price (at least until today) to express its full potential. And you can keep it a lifetime. 
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Posted By: The T
Date Posted: June 01 2011 at 23:49
Thanks Oliverstoned. I always make jokes using your now-legendary "pushes walls" comments but I really appreciate your passion, though sometimes you're not very clear
. Yep, the V-can is not state-of-the-art but for now will have to suffice. I'll upgrade it later on. Sennheiser makes great headphones so I want to experiment open-back ones, and before going crazy with the Grados and HD800 and Beyerdynamics, the HD650 was the best solution (also available at half price at work). I also want a closed-back one so I'll probably get an Audio Technica or a Denon. I really love headphones. -------------
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Posted By: oliverstoned
Date Posted: June 02 2011 at 03:53
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I'd would be happy to clear any point that was not. Anyway the V can will be a big step up to any "ordinary-integrated output" and i'm looking forward your impressions when you have all you gear and so that you'll be able to compare. I think that you know that your headphones and even your V Can will need some run-in period. So, be patient and let us know how it work then. I don't advice you the HD 800, it's not so great, better go for a killer amp to drive you 650, because like great speakers or valve amp, you can put a lot behind to reach its limits. The Grado is another school, less neutral and dynamic than Senn but very warm and laid back and need a lot of power, in your current/future setup (Marantz CD + Vcan), may be too soft, with the Senn should do a better combo but only listening will tell, as someone said. And i also hope that you'll be abble to compare with a 600 on your future setup.
Concerning Denon, i was very disapointed but Audio Technica is a good brand as well as Beyerdynamic, not that neutral for the latter but very musical. Let us know how it turns in this thread anyway. |
Posted By: Dean
Date Posted: June 02 2011 at 05:06
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@Teo - please try before you buy. Listen to the V-Can driving HD650's before spending any money. Like Oliver, I have not heard this set up, but I can read and understand specifications - the V-Can is rated at 0.25W into 32 ohms, which equates to 0.026W (26mW) into 300 ohms - while this is a significant improvement on the Marantz h/phone output it is still nowhere near what the HD650s require.
It is better to look for an amp that is designed to drive high-impedance headphones, such as the Pro-Ject Head Box II, which can deliver 60mW into 300 ohms for about the same price as the V-Can.
http://www.hifiheadphones.co.uk/images/proj-ect-head-box-II-silver-600x600.jpg" rel="nofollow">  ------------- What? |
Posted By: timothy leary
Date Posted: June 03 2011 at 10:39
| My headphones are sennheiser hd-595 through a dac, they sound good. My computer speakers are Roland cakewalk ma-7a and they sound and look good. |
Posted By: Dean
Date Posted: July 16 2011 at 05:24
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Now that Teo has bought his V-Can and HD650s and is a happy bunny this thread is pretty much over, so I thought I would delve deeper into this Headphone Amplifier lark to show what the game is all about from a technical point of view. I suggest most people should stop reading as soon as it gets too mystifying/boring as I'm going to be very objective about this and not make any subjective comparisons, and I won't be doing anything silly like recommending brands or models of various amps to anyone - if you want that kind of information, ask Oliver.
Headphone Transducers
Headphones are essentially small loudspeakers, being small they are very efficient compared to the big drivers that are fitted into bookshelf or floor-standing speakers but that is generally by-the-by, efficiency is not a prime factor here. Headphone speakers are a small coil of wire in a magnetic field that moves when an electrical current is applied, this movement moves a diaphragm that pushes air in sympathy with the electrical input, thus an electrical signal is converted into a air movement, and our ears detect that air movement as sound. The same mechanism works the other way around - moving air on the diaphragm will move the coil of wire in the magnetic field and induce a current - just like a microphone - in fact I have used microphone inserts as tiny speakers, and I have used small speakers as microphones, and in the good-old-days intercoms did exactly that, using the loudspeaker as both speaker and microphone.
Impedance.
The amount of wire in the coil, the number of turns and the gauge of that wire determines the impedance of the headphone, this impedance determines how much current is drawn for a fixed voltage input -- the amount of current drawn and the number of turns in the coil determines how far the coil will move in the magnetic field and thus how loud the sound will be. More turns of wire means less current is needed for the same movement but more turns mean more impedance which means the current is less for the same voltage in. If this was all nice and linear then it would be a 1 for 1 trade-off, but it isn't: the movement is proportional to the number of turns but the impedance is proportional to the number of turns squared, so if we double the number of turns we get 4 times the impedance so for the same voltage we get a quarter of the current, which results in the half the movement. So to achieve the same movement (air displacement equates to sound pressure level [SPL]) we need to double the voltage every time we double the number of turns in the coil... or to put it another way, double the voltage every time the impedance is quadrupled. As Mr Ohm and Mr Watt will point out, the power in each case is the same.
Ah, you may be thinking, then what is the point of having more turns if we have to increase the voltage? Basically -none, it is all down to application and use - with different "standards" being used historically in different applications.
Headphone speaker impedances come in three broad flavours: low (8, 16, 32 ohms) for domestic use, medium (60, 150, 300 or 600 ohms) for professional (studio) use and high (1.5K ohms or higher) for broadcast use. We can ignore the high impedance h/phones as these are rarely seen and concentrate on the domestic and professional. Simple word-association would imply that the Pro are better than the Domestic, and therefore medium impedance are better than low impedance, but this is not the case - the "Pro" tag may be indicative of better design, construction and perhaps performance (and a higher price ticket), but it is not a direct function of the impedance itself - pro headphones and the h/phone sockets on pro equipment are designed to be compatible, (and so it is with domestic h/phones and domestic equipment). One of the reasons why medium impedance headphones are used in studios is that several sets of headphones can be connected to one amp without affecting the volume of the other headphones.
The low impedance values of the domestic h/phones mean that for a given power lower voltages are needed and this is ideal for portable equipment with 3, 6 or 9 volt batteries and these h/phones are often called "Portable" headphones for that reason, whereas the medium impedance headphones would require more voltage than the batteries can provide and are not suitable for portable use. However, the "portable" tag is a misnomer - the headphone socket on most amplifiers, receivers and CD decks are designed for low impedance h/phones.
This is not to say that domestic amplifiers and CD decks cannot drive medium impedance headphones, they can, but as Teo discovered, they do so at much reduced volume ... because they cannot supply enough volts, or are noisy because of mismatches. For example, the HD650s are 300 ohm, the HD380s are 52 ohms - as the HD650s are 5.7 times the impedance they will need SQRT(5.7) = 2.4 times the voltage to drive them.
Integrated Amps
The headphone sockets on integrated amplifiers come are of two basic designs - the first is the simplest and the commonest - they take the low impedance output that would normally drive the loudspeakers and switch it to the headphones - usually through a very simple one or two resistor attenuator to prevent the 100W of your amp from blowing your head off - this is obviously the cheapest option (for the manufacturer). Since these outputs can normally drive an 8 ohm speaker to 100W then they can in principle produce enough volts to drive medium-impedance headphones, but the simple resistor attenuator may prevent that - it depends on the values and without the schematic it is impossible to know.
The other basic design is to use a dedicated headphone amplifier that is part of the main circuit design. When I scratch-built amps, this is the method I preferred, the designs of these internal dedicated amps are identical to the ones you get in external headphone amps (and just as varied), but more of these later. If your receiver, tape deck or CD player cannot drive loudspeakers directly, then the headphone socket will be of this design - it will be a dedicated amplifier designed to drive headphones. The important consideration here is that in most cases the dedicated amp will be designed for low impedance headphones and still will not be able to supply the voltage that medium impedance headphones need.
Dedicated Amps
Dedicated headphone amplifiers are designed to drive headphones, the type of headphones they can drive is dependant upon the design, some have a gain switch that allows low, medium or high impedance headphones, some can only drive one type and some are set somewhere between low and medium so they can drive both, but those will be louder for low impedance h/phones than for medium impedance ones. As a general rule, portable headphone amps for medium (Pro) headphones will have two or more 9v (PP3) batteries in series to get the needed voltage while others use two amplifiers in Bridge (BTL) configuration to drive both sides of the speaker connection.
Output Stage Configurations
The output stage that feeds the headphone has three basic designs that generally determine how the circuit works, the simplest is called Class A - this is not a measure of quality but a classification of the transistor (or valve/tube) configuration - The next is Class B - which is the commonest in any high power amplifier, and finally Class D, which is becoming more popular, especially in portable equipment and in ICE amps for cars. There is (obviously) a 4th class of amplifier (called Class C) but this cannot be used for Audio as it is an RF amplifier using tuned circuits.
Class "A"
This is considered (by audiophilists) to be the top-dog of audio power stages, but it is horribly inefficient, uses a lot of power to produce a relatively low-power output, runs hot, can be very non-linear if the biasing is wrong and can produce a lot of harmonic distortion, it also requires a large capacitor on the output to produce a usable frequency response - Class A amp can be good, but that's not guaranteed. Simply put, this has one transistor (or FET or valve/tube) driving the speaker and the transistor (or FET or valve/tube) is always conducting so even when there is no signal present it supply current is still being drawn. Basically you don't get a lot of power out of a Class-A amp and it is pretty useless for portable equipment ... a Class A amp running off a 9V battery would not drive the higher impedance (32, 52 ohm) domestic headphones too well and the high quiescent current would drain the battery very quickly. Class A amps can be transistor, FET or valve (tube) and even though the circuitry is simple, with very few components compared to Class B or D, they command disproportionately high prices because audiophilists like them. True Class A amps are pretty rare.
Class "B" (and "AB")
This is also called push-pull since it uses two transistors (or FETs or valves/tubes) to drive the speaker - one transistor drives the positive cycles of the signal and the other drives the negative. The advantage of this is that when there is no signal neither transistor is working so the quiescent current is practically zero, the disadvantage is that the change-over from one transistor to the other may not be perfectly matched and this results in crossover distortion. However, simple circuitry has eliminated that from designs and has done for many decades now so this is not a problem - these amplifiers are called Class "AB", but in reality they are just Class "B" that are biased differently. Most dedicated headphone amplifiers use Class "B" or "AB" amplifiers in their output stage.
Class "D"
Class D is basically digital and is common in a lot of portable equipment and in some portable headphone amplifiers such as the FiiO E1, 2, 3 etc. and it's a fair bet that the amps in Bluetooth headphones will be Class D. This design uses Pulse Code Modulation working much like a lamp dimmer, switch-mode power supply or motor speed controller - in headphone amp designs the inductance of the coil in the speaker acts as the low-pass filter of the high-frequency digital "carrier" signal - the advantage of these is that no power is wasted in the amplifier itself as the drive transistor is either fully on or fully off. Obviously the presence of an HF carrier signal (even when far above the audio range) is psychological barrier for some. The main disadvantage is the circuit is very complex for a home-build unless dedicated Class D amp chips are used. For high and medium impedance headphones (and automotive ICE systems) Class D amps are often driven in bridge configuration to achieve the required votlage swing, this is designated as BTL (Bridge Tied-Load) on some advertisements and sometimes called Class "T".
Conclusion (if any)
With any hifi system, it is a case of ignoring the advertising spiel and the audiophilist hyperbole and trust your ears. Class A amps are not necessarily better than Class B, valve/tube amps are not necessarily better than transistor, descrete transistor amps are not necessarily better than monolithic ic amps and analogue amps are not necessarily better than Class D amps. ------------- What? |
Posted By: Mr ProgFreak
Date Posted: July 16 2011 at 05:54
^ Awesome breakdown of the different amp types. Nothing mystifying about all of that IMO, more like de-mystifying!  ------------- https://tagyourmusic.org/users/Mike" rel="nofollow - https://tagyourmusic.org/users/Mike |
Posted By: TheGazzardian
Date Posted: July 16 2011 at 10:56
| Dean, thank you for the time you spent writing that out, I don't think I understood it all 100% but I still got enough to understand a more now. |