Are Headphone amps worth the expense?

I have a Mac tube amp and grado phones. Would I benefit from a headphone amp? How are they hooked up? Thanks for any thoughts.
If it sounds better than what your currently hearing, than yes. Otherwise no.

Sorry for the smart-aleck answer, but as with all things audio, any component, even expensive ones, can be better or worse than whatever you currently have. My headphone systems sound much better than most speaker systems I've heard, but I've spent many years getting my headphone systems to the level they are at. And to me, a tubed headphone amp is indispensible.
Oh, and you'd do better to look on head-fi for headphone info.
I would get a headphone amp on trial for comparison. Grados are easy to drive and it's possible you will not hear a worth-your-money difference. Your dealer should be able to help you with hook up.
Are you into DIY?

Try building a CMOY headphone amp. Strictly low cost and fun. The good news is you can than 'roll opamps' and test the different ones available.

I use OPA2134s as a good compromise.

Very good amp when properly built. Not as good as the 'best' but no more than 5% of the cost.
Headphone amp? I assume your MAC has a phones jack?
If so.. you would have to spend around $1000. to get a headphone amp you will notice is really better.
The ones that cost less will sound 'different' than your Mac, but not realy 'better'.
I own Beyerdynamic old 990's and Sennheiser new HD800 phones along with:
The jack in my Bryston BP-26
the jack in my Sony 555ES changer
The headphone amp "Lil Dot ($250)
the TADAC DA converter with 'tubyness control' and headphone out (used $500) How could anyone resist a 'tubyness' knob?
the headphone amp Rudistor MkII ($1,800)
The headphone amp SinglePower MPX with major upgrades ((Retail with extra tubes and adaptors $4,000==== I paid $1,000 used for my 'exploding killer deathstar' headphone amp. (LOL inside joke))
The Bryston is good. The SinglePower with 6BL7 tubes is the best ... dangers of sudden death due to use notwithstanding (many strange and crazy posts about SinglePower being dangerous and going blind and being electrocuted or burning up house and home over at HeadFi made it irresistable as a conversation piece, and it IS a good headphone amp.)
Anyway, unless you can try one, Or want to spend a lot.. I would say you are just as well off with your MAc phone out.
Some specialized headphone amplifiers simulate crosstalk between channels making sound appear in front and not inside of the head. It cross-feeds portion of delayed sound to the other ear - the same way that it happens when listening to speakers. I had sound card with this option and it was great. It is also possible in analog domain - I have link to Headphone Amp project with cross-feed somewhere. I remember seeing headphones that have built in crosstalk (tube) from one cup to another - but don't remember the name.

I found the link:
That's what I didn't like about always seemed like the sound was coming from the sides or actually behind you instead of in front of you the way speakers sound. Maybe I need to research amps and find a decent one with crosstalk. Anybody have suggestions? products) Meier-audio headphone amps also use cross talk.
I pondered this very same question a few years ago. I use AKG701's and Ultrasone 8's. I have a McIntosh C2300 (previously a C2200). I used both phones with the built in C2300 with great results.

I bought a Creek headphone amp, and then a Pro-Ject SE. In short and in substance the McIntosh sounded better. More separation of instruments, tighter deeper bass. The add on headphone boxes had a very dry sound in comparison.

Also, I gave up remote control ability. The C2300 has a superb headphone amp built right in and is perhaps under appreciated.

By the way the C2300 has the 1/4" phone plug vs. the 1/8" mini plug on the C2200 requiring downsize adapters (why McIntosh did that was bizarre).
Aren't there special recordings made for headphone listening?

I think they are called binaural and are made with microphones in the ear positions of some kind of artificial head.

Am I mixing this up with something else?
Didn't the Carver Sonic Holocaust try to eliminate the out of phase stuff coming from the other speaker? Didn't Polk make speakers with double mids and tweets which had a wire pair between speakers to remove this out of phase information mechanically, if you will? The double speakers were located about 6" apart, the distance between the ears so the time cues remained.
This is not a new idea.
Good headphone amps are great if you do alot of headphone listening with a good set of phones. Headphone amps (lots of tubed models available, as well as solid state) are hooked up directly to the source component (cd player, dac, fm tuner, phono stage) or can be be placed on a tape loop monitor output on a an intergrated amp or receiver. It is pretty much a preamp and amp, with a headphone jack.

Inless your Mac tubeamp is an intergrated, you cannot connect a headphone amp. They do not get connected to speaker terminals (or headphone input jacks except for ipod like headamps).
There is a headphone jack on my Luxman 509u integrated amp, and my Beyerdynamic T1's sound wonderful when plugged-in. How does it compare to a dedicated headphone amp? I am not sure how much better a high quality dedicated amp would be, but as I am quite satisfied with what I have I am not going to lose any sleep over it.
Can a headphone amp be fed by the "line out" or "tape out" of a conventional preamp?
I do say tape out in my post. If you use the line out, make sure you don't drive the preamplifier volume up to high. The headphone amp would distort too high a signal. It should be an unamplifiedoutput.

A good quality headphone amp with god headphones will blow away most receivers with a headphone Jack. Thi receivers or intergrateds with a phono stage. You really need to look high and low to find one as good as a standalone, but I have heard they are out there.
thanks for all the advice
I think they are. I have read that the headphone outputs on high end equipment often are not up to par with the same quality of output as the device. I built a cheap cmoy headphone amp using a Burr Brown 2227 opamp. I use it with
Grado SR-80 phones and WOW. I didn't believe the sound. I can't believe that high end phone amps do much better. I took my homebrew amp into a high end audio shop and they said it sounded like a 250.00 phone amp. You might consider building a cmoy amp. Many places on the internet with info. Dean
I never owned a separate headphone amp until recently.
I just relied on whatever headphone input a piece of gear had built in.

Then when I no longer had any gear with built in headphone inputs I purchased a Burson headphone amp, and discovered how poor the bulit in units mostly are.

My phones are the entry level Grado SR 60,which sound so much better thru the Burson, that I am considering moving up to the top of the line Grados.

Headphone listening can be quite educational.
You can remove all the influence the room brings to your sound, and really hear what's on a recording.

I used headphones to discerne the differences in power cables.
The differences I heard from entry level Shunyata to Annaconda was quite easy to hear thru the phones.

A good set of phones and a good headphone amp can be quite a smart investment,and provide a real high end musical expereince for way less dollars than a conventional amp, speaker pre amp set up.

And did I mention, there's no room interference?

I agree. According to John Siau (technical director of Benchmark) headphones are the only way to accurately reproduce a piano - an instrument with very complex harmonic structure. Speakers' Xover screws up this complexity thus timbre. On the other hand I don't like headhones on my head (reminding me it is not a live performance), feeling of immobility (cord) and sound inside of my head instead of soundstage projected in front of me. Sennheiser HD-580 (same drivers as 600) was my last attempt. (I used them with good sounding Benchmark DAC1 built-in headphone amp).
Preamps can drive headphones. I had one of mine modified to do so. It is great but I cannot stand headphones. They put me to sleep.
I guess headphones are an acquired taste.
I'm a musician, I've used them for decades,for me they are a tool.
They are the only gateway that I have found to unravelling the intricasies of recorded music.

I enjoy listening to music in the conventional manner,sitting in a dedicated chair in a dedicated room with dedicated lines and dedicated gear and dedicated listening only to the music and in the end of all this dedication, enjoying the music for what it is.

And what it is is not the music that is on the disc, but the music that is in the room.
ROOM in bold letters, because you are hearing the room as much as you are hearing the music/system.

If it's "all about the music" and that this hobby should only be about the music and not the gear, then those folks who preach this should be using top grade headphone/headamp systems.

Because they are hearing the room's influenace on the music.

Understanding full well that no headphone or headamp is perfect and free from colourations, (as no amp, speaker, pre amp, cdplayer, turntable etc is perfect and free from colourations)you do remove one very big obstacle between you and the music.

Some folks find headphones uncomfortable-I have to wonder, how many and at what price points did you try?

I spent about $70.00 for my Grados, they sound ok, and are not uncomfortable to me, so I don't think you need to spend big bucks for comfort.

Also, I can add on extension cable and am not bound by a captive cord.

Falling asleep?
If they are uncomfortable, how can you fall asleep?

I fall asleep more often in my recliner listening without headphones,what does that mean?

Moving to a dedicated headphone amp(Burson)was such an improvement even with entry level Grados,that I am seriously in the mood to upgrade the phones to something more in line with the quality of the Burson.

I would have to state that headphone amps are worth the extra expense, and perhaps even going one step further and upgrade your current phones while you are at it.

I also have to side with the folks who state that listening to a proper headphone set up is the least expensive way to get state of the art sound comparable to amp/speaker systems costing tens of thousand of dollars more.

I think the few reservations concerning mobility and comfort can be easily dismissed in the trade off of high end sound.

And by the way, if you are listening to the music,why the need to roam about?

I don't move around listening with phones or to my speakers, because my attention is focused on listening to the music, and, oh yeah, isn't that what this is supposed to be all about?
Oh G-d yes good headphone amps are worth it. Good headphone sound can be a glorious thing and quality amplification is just as important as it is with speakers (and often, unfortunately, more expensive). 50,000 headfiers can't be wrong. Check out Apex, Eddie Current, Woo, Ray Samuels, Cavelli, HeadAmp. I would lean towards tubes. Great solid state from Rudistor and something called a Beta 22 design done by small suppliers. And of course there is Stax.
(I have tried/heard/owned some of these, not all, but it's enough to be convinced of the value of a dedicated headphone amp.)
Most headphone jacks out of other amps are not too good (at least to my ears) but there are some exceptions that are extremely popular (I have not heard them), like Leben, Accuphase 3800, and the Cary SEI 300.
With a nice headphone amp, you get natural tonality, rounded images, out-of-head staging, air, and lots of joy.
Headphone listening has it's own special pleasures, with an intimate portrayal all its own that carries different pleasures than speakers, and is an art form in itself, with a special insight not found with speakers. But you need great amplification to get there. Try Audeze headphones (my current favorites).