Newbie question: What's the proper way to hook up a headphone amp?
Feb 23, 2007 at 11:12 AM Thread Starter Post #1 of 12

strangelove

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Hello all,

I recently purchased a pair of Senn 650s and am finding that neither of my receivers, a Denon and a Harmon Kardon, adequately powers them; although the Denon is somewhat better than the Harmon. I'm looking into getting my first headphone amp, but as silly as it may sound, I'm not entirely sure how it it supposed to fit into my setup.

Currently I just plug my headphones into the headphone jack on my reciever and listen (duh). With headphone amps, I've noticed some amps have 1/4" or 1/8" plug inputs while others have RCA stereo inputs. Should I hook up the headphone output of my reciever to the input of the headphone amp or am I supposed to hook the output of my CD player directly up to the amp? Right now I've got my CD player connected to my receiver via a digital cable since the DACs in my receiver are better than the ones in the player, so I'd think connecting the receiver's headphone output to the amp would be the way to go.

If that's the case then, do you then adjust the volume with the volume knob on the amp or can I set the amp volume to a fixed level and adjust the music volume via my receiver (which would be more convienent since it has a remote and all). Would there be a difference in sound quality either way?

Lastly, as I mentioned before I have the two recievers. I use the Denon for my home theater setup and the HK in my bedroom for music exclusively. The HK is the one the amp and headphones are going to be used with, but as I mentioned before the 650s sound considerable worse powered by the HK than the Denon. Will a good headphone amp negate the short-cummings of it's source, or will the weakness of the source always shine through?

Also, any suggestions an which non-portable amp in the $100-300 range to pair with some HD650s would be appreciated (I also have a pair of HD595s as well).
 
Feb 23, 2007 at 11:45 AM Post #2 of 12

ricksome

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Take the "line out" from the back of the receiver and hook that up to the "input" of a headphone amp. As for which headphone amp....I'll leave that to someone else. My elevator stops at the under $100.00 price point. I must also tell you this..........."Sorry For Your Wallet"....Welcome to Head-Fi....Rick
 
Feb 23, 2007 at 12:08 PM Post #3 of 12

silverrain

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Compare the 2 amps using line-out to headphone amp -- if one sounds better, that is the one with the better internal DAC, generally. Headphone outputs on sources can vary wildly in sound quality, which is why most headphone amps use that instead of headphone jack.
If your receiver's line-out is volume-controlled (some aren't, of course), then find a good balance of volume on receiver and headphone amp (no over-drive distortion, for instance), and you can then use your remote for volume control.
Hope this helps too.
Oh -- for $299 the HeadRoom Micro amp (with free upgrade desktop module) is great with HD650.
 
Feb 23, 2007 at 1:08 PM Post #4 of 12

werdwerdus

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Line out from the CD player straight into the headamp, or line out from the receiver (sometimes this is labeled as Record or Tape Out for sending to a cassette deck). I can't think that it would ever be better to go from a headphone jack into an amp.
 
Feb 26, 2007 at 2:55 AM Post #5 of 12

strangelove

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Hmm. I might have a problem then. My receiver doesn't have a line-out except for the tape out. Since I'm connecting my CD player to the receiver with a Toslink cable I don't think it will output anything from the tape out (I thought that justed looped out whatever was coming in from the tape in, which is nothing in my case). And since my receiver has much better DACs than the cd player I really don't think I'd be happy hooking up a headphone amp directly to the cd player outputs (plus I have more than one source hooked up to my receiver that I'd like to use headphones with and I don't want to constantly be hooking and unhooking the headphone amp to and from the different sources). Ideally a micro DAC and an amp would probably be the way to go, but that's getting into more money than I want to spend right now.

I was sort of counting on being able to hook up the headphone amp from my receiver's headphone out. For my situation nothing else would really be that convienent/ideal. When someone hooks up a portable device to a headphone amp they're connecting it via the devices headphone out, correct? So while connecting my headphone amp from my receiver's headphone out might not be ideal, I would think it would still give me better sound than the receiver's headphone out is giving me now with no amp. It would be the same signal being sent to the headphones now, just more amplified.

Otherwise I think I'll just end up returning my HD650s because the way my receiver's powering them currently, I think the HD595s sound better.
 
Feb 26, 2007 at 3:16 AM Post #6 of 12

zipdisk

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In my system I use "tape out" as the headphone-amp input. If the tape out had gone to a cassette/cd recorder, then the "tape in" would bring the signal from the recorder back into the pre-amp so that I could also use the recorder as an input (actually in my system it is no different from any other input). At least that's the way my system works So I would think that the "tape out" would supply whatever signal has been selected by your preamp and send it to your headphone-amp. Perhaps someone can confirm this. For your budget you may want to reconsider a portable. You know, they don't have to be carried around, and some are quite good and affordable. See Skylabs review "Review: Portable amp roundup! 16 portable amps reviewed and compared ."
 
Feb 26, 2007 at 3:38 AM Post #7 of 12

zipdisk

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You mentioned wanting to use the amp's volume control to adjust the volume of your headphone amp, rather than use the headphone amp's volume control. I have also considered this, so that I can use my amps remote to adjust my headphone volume. To do this I would use my "preamp out" to drive the headphone amp with my preamp (and therefore avail myself of the preamp's volume control). I see two issues here: (1) when I increase my headphone volume I will also be increasing my speakers volume. Therefore, I may want to have the speakers muted when listening to headphones. And (2) I will be changing my headphone volume by increasing the input signal to the headphone amp. This could possibly damage the headphone amp which is not necessarily designed to handle an amplified input signal. My solution would be to set the headphone-amp's volume higher than my desired listening level (when hooked-up conventionally with "tape out"), so that the input signal (that I'm changing with the preamp volume control) is always relatively low. Of course, the signal quality may be degraded by doing this, because the signal is now being affected by both the preamp and the headphone amp. I hAVE NOT TRIED THIS AND WOULD APPRECIATE ANY COMMENTS ABOUT THE WISDOM OF MY APPROACH. THANKS!
 
May 20, 2013 at 5:59 PM Post #8 of 12

radioguy1

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Hi, can someone please help me with the same headphone amp setup question please?  I see the logic of having the receiver output come from the Tape 2/VCR output jack, into the headphone amp--you get a clean signal.  However, not having had a head. amp before, I'm concerned that the bass and treble won't be where I want them, and the headphone amp I'm looking at buying (Topping TP21 Class T Amp IC Tripath) doesn't seem to have treble/bass adjusts.  And I don't know if adjusting the bass and treble on my Denon receiver while sound is going from the Tape 2/VCR output into the head. amp will have any affect at all on input into the head. amp.

So, if I want to be able to adjust bass and treble while using a headphone amp, I guess that means I need to find a headphone amp that comes equipped with those adjustable controls?  I do see the logic of what the poster "above" me was saying--having your receiver output be through the receiver headphone jack, you can control bass and treble (using the right jack adapter), though a person would probably have to be careful not to feed too much signal from that into the headphone amp.  OR--maybe I need to buy an equalizer separately?  Any comments are welcome...thanks.  PS...I'm planning to buy Sennheiser HD 600.
 
May 21, 2013 at 6:26 AM Post #9 of 12

ProtegeManiac

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Quote:
Hello all,

With headphone amps, I've noticed some amps have 1/4" or 1/8" plug inputs while others have RCA stereo inputs.

 
I can't recall what headphone amps, aside from headphone distribution units for professional recording*, have a 1/4" jack. You're probably looking at one of two things:

1) Both are output jacks, and some have it in both 1/4" and 1/8" so adapters won't be necessary. Another advantage - the larger jack may have a higher gain setting, with the presumption that harder to drive headphones will not be using compact plugs found on portables; and of course the smaller jack has a gain setting for more efficient headphones, most likely in-ear-monitors, since some might want to use them at home if one's housemates are loud enough.
 
2) The amp could have both a 1/4" output and a 1/8" input, the same way other speaker amps - like HT receivers - have a 1/4" output for headphones while it has an auxilliary 1/8" input jack, both in front, to allow anyone not using an Apple (or nowadays, Android) device, since these usually have their own dedicated USB port on receivers nowadays.
 
 
 
*to get the same signal to several people on headphones, instead of the one engineer sitting in the sweet spot between the monitors)
 
Quote:
Should I hook up the headphone output of my reciever to the input of the headphone amp or am I supposed to hook the output of my CD player directly up to the amp? Right now I've got my CD player connected to my receiver via a digital cable since the DACs in my receiver are better than the ones in the player, so I'd think connecting the receiver's headphone output to the amp would be the way to go.

If that's the case then, do you then adjust the volume with the volume knob on the amp or can I set the amp volume to a fixed level and adjust the music volume via my receiver (which would be more convienent since it has a remote and all). Would there be a difference in sound quality either way?

 
First off, there could be a gain or impedance mismatch that will make fixing the gain structure complicated and not as good as directly feeding the headphone amp with the appropriate signal. The input on a typical integrated amp or hp-amp could be around 10k ohms and designed for a 2V signal; your HK's headphone output may be designed with a 120ohm impedance and maybe up to 5v.

I'd say forget using the remote with headphones, given you aren't likely to sleep on your bed with the headphones on anyway, might as well get up occassionally or, well, push your seat closer. Did you check if your HK receiver has a fixed analog output at the back? If it has one then use that, essentially using the receiver as a DAC.
 
Quote:
Lastly, as I mentioned before I have the two recievers. I use the Denon for my home theater setup and the HK in my bedroom for music exclusively. The HK is the one the amp and headphones are going to be used with, but as I mentioned before the 650s sound considerable worse powered by the HK than the Denon. Will a good headphone amp negate the short-comings of it's source, or will the weakness of the source always shine through?

Also, any suggestions an which non-portable amp in the $100-300 range to pair with some HD650s would be appreciated (I also have a pair of HD595s as well).

 
If between your two amps you notice a marked disadvantage on the HK vs the Denon, by all means get a dedicated amp. One problem though - you'd have other issues for using the HK along with a headphone amp. If the HK has a fixed analog output on the back, any headphone amp will just be added to the system; otherwise, check if it has an analog input, at which point you will have to use the DAC on your CDP (or get a separate DAC if you really don't like its DAC) to feed something like the Fiio E09K and connect its line out pass-through into an analog input on the HK.
 
May 22, 2013 at 1:13 AM Post #10 of 12

radioguy1

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Protege, I don't know if you knew the post you replied to was from 2007.  If so, that's cool.
 
Can someone tell me please how to solve this problem: I want to make sure my headphones sound good and am thinking of buying a headphone amp, but I'm concerned that I won't be able to adjust the bass and treble levels to account for differences between different music CDs.  How do you solve this?  My receiver "output" that would go into the headphone amp. is just a straight signal, and adjusting the receiver bass, treble, volume won't affect the line out dynamics. 
 
Is base and treble through a headphone amp a concern?  Is the solution to get a headphone amp that has bass and treble controls?  Or maybe I should scrap my receiver and buy a stronger amplifier for my whole stereo system that might make the headphones sound better?  Or would a preamp going into that amplifier help?  Thanks very much--this website and you guys are great!
 
May 22, 2013 at 4:34 AM Post #11 of 12

ProtegeManiac

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Protege, I don't know if you knew the post you replied to was from 2007.  If so, that's cool.
 

 
I saw it AFTER I hit "Submit," I thought I might as well leave the info there for future reference considering people just revive threads now than create new ones. My bad, the thread was so short I thought it was an ongoing one and missed your question!
frown.gif

 
Quote:
Can someone tell me please how to solve this problem: I want to make sure my headphones sound good and am thinking of buying a headphone amp, but I'm concerned that I won't be able to adjust the bass and treble levels to account for differences between different music CDs.  How do you solve this?  My receiver "output" that would go into the headphone amp. is just a straight signal, and adjusting the receiver bass, treble, volume won't affect the line out dynamics. 

 
You mean it's a tape loop from the input (basically just to add another amp) ? Most headphone gear nowadays were oriented for computers (or even tablets and mobile phones) and hence, EQ is expected to be applied at the digital level; or in the case of 2ch purists, none at all. Some headphone amps do have a bass boost function, so that's at least one part of the problem out of the way.
 
Quote:
Is base and treble through a headphone amp a concern?

 
It really depends on the listener's preferences and expectations. Do you really like bass? That might mean you'll need it. Are all your music recorded well enough? If you have some where the bass is missing - like heavily-compressed formats (64kbps mp3 or wma, etc) - or otherwise weak in the original recording, then your system will have to compensate.

And yet one can manage expectations. One can be one sort of basshead - that is, in terms of speakers, enjoys some of the tactile sensations of bass notes. Most people who do tend to be the ones who blast Lil Jon in their cars attempting to blow their windows off and feeling the bass crawling on their skin, but there are those who just enjoy the feeling of standing front-row at a Deftones or STP concert and feel the kick drum notes on your chest. Either way, if one can get around the more realistic presentation of music (at least in reproducing a live performance) and not in any way "feel" the bass aside from what may resonate on the cheeks, and focus more on what the ears can hear that the headphones can play, it shouldn't be a problem.
 
Although of course that presumes the entire system's response does not make the bass any weaker, but personally this might even be more prevalant with speaker systems given many speakers at 1m to 1.5m away don't reach down far enough. Many standmounts with a single 5" driver only get down to 45hz at best (and those are probably nearfields measured at 1/3 of the usual distance).
 
Quote:
Is the solution to get a headphone amp that has bass and treble controls?

 
Going back to what I posted above, it can really depend on a lot of things, however the cheapest way to have bass and treble controls just in case you need it is to use a computer of some sort as your source, then using a DAC, feed a signal into it but apply the EQ using a music player that has one. This is still easier than before there were USB DACs - I heard of some guy did before who needed an EQ to correct room modes, but didn't want any bulky, old, analog EQ his Dad might have used. What did he do? When he upgraded his car audio receiver, he mounted his old //////Alpine CDA-98xx (can't remember the exact model, it's one of those that have a panel that expands to show all the buttons on it) onto a wooden box and hooked it up to a 12v power supply so he can use its EQ, and have a high-quality 16-bit DAC and 4v output. At the very least it not only gave him an EQ, it saved him money from buying a new CDP for his room - but admittedly we at the car audio group still laughed at the whole thing when we first heard about it. No idea if he went further and scrapped the passive crossover on his speakers in favor of the digital crossovers on the Alpine.
 
Quote:
Or maybe I should scrap my receiver and buy a stronger amplifier for my whole stereo system that might make the headphones sound better?

 
You mean a stronger speaker amp? It might not help with the speakers - some speaker amps don't use the speaker amp circuit to drive the headphones, and instead have some kind of simple amp circuit that works off the same potentiometer (my NAD has this; Marantz amps have had a dedicated headphone driver chip for the longest time until now, same one used on the Fiio E9 I think).  Basically, the power sent to the speakers won't affect the headphone driving capabilities, and depending on what the design is, it could be worse.

Instead of outright power though better to focus on clean power. 100w on speakers, or 1w on headphones, won't be good enough if you have the distortion at, say, 1% already, also the possibility that either one at reasonable sensitivity levels may already be too loud at that point anyway. Current or voltage (depending on design) instead of pure, brutal wattage with distortion are more important, and it depends which one your headphone needs more, but a good headphone (or speaker for that matter) driven well will sound musical. One thing about headphone amps though - since it doesn't need a lot of outright power and hence cooling, it's easier to implement a pure Class A design, and a lot of headphone amps out there have that (or a lot more Class A bias) at a form factor smaller than preamps. A Pass Labs 10wpc Class A power amp needs two people to carry it because of the heatsink on the chassis, for example. (More on this below)
 
 
Quote:
However, not having had a head. amp before, I'm concerned that the bass and treble won't be where I want them, and the headphone amp I'm looking at buying (Topping TP21 Class T Amp IC Tripath) doesn't seem to have treble/bass adjusts.  PS...I'm planning to buy Sennheiser HD 600.

 
The Topping isn't actually a dedicated headphone amp design - it's an integrated speaker amp. Unless you're broke and the speakers are your primary listening devices by a wide margin, and given you already have something to drive the speakers with anyway, get a dedicated headphone amp. I can think of one way to get around this problem, but not for all solutions/sources: get a DAC-HPamp with USB input and analog inputs.Or better, SPDIF inputs if your source (I assume it's a disk player) has another SPDIF output that is not connected to the receiver, or if the receiver has an SPDIF pass-through output. Chances are you still won't be using the receiver's EQ with it, but as the SPDIF allows for a cleaner signal transmission into it, you'll also have the USB for connecting a computer to it where software digital EQ is more accessible.
 
As for the HD600, my persoal take on it is I never needed EQ when the pads are brand new and I'm using the one DAC-HPamp (and others like it) I finally settled down with - the Meier Cantate.2 (went through the LD MkII and Ibasso PB-1 before this, and a Marantz CDP with a good headphone amp whose transport broke down). It's surprisingly close to the HD800's spectrum balance on fresh pads, however, more wear on the pads means the measured "hump" in the response up into the lower midrange is more pronounced, plus some sharp spike somewhere in the treble, so just wearing out the pads might not work right for you. Seriously consider using a computer as an optional source, it really can simplify any adjustments you want to make on the signal.
 
Quote:
Or would a preamp going into that amplifier help?  !

 
I'd avoid this, as well as using the receiver's headphone out to send a signal into the line-in of a headphone amp. Check my previous post on the problems of using a preamplified or headphone output signal as a line-in on what essentially is an integrated amplifier.
 

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