Headphone Amp/Headphone Impedance levels

[snared]

I am thinking about getting a better pair of Headphones. I like the AKG K240Ms or the K141Ms or something similar. They have high impedance levels, though(600 ohms). I don't know much about impedance levels, so I need to know what to look for in a Headphone Amp.

I have looked at some of the Rolls products. However, they all say something like 100 ohms unbalanced or something else that means nothing to me. Does the impedance of the Amp need to be the same as the Headphones?

Some of the descriptions I have read for HP amps use different terminology than others. So, for someone like me, who knows very little about the subject, its hard to compare them, and tell which I need.

[GRRAVEE]

for the money.......the best phones evermade(all around)sony mdr 7506.........ask around you will find many agree.....just a good product.........as for hp amps.......any will do for standard phone listener apps just make sure each phone outlet has a seperate volume control......other wise you defeat the purpose of seperation.now keep in mind the 240s are decent studio phones but for the home user their impedance level is much too high.......if you can get matched phones do it.....if not ,try to make sure they are atleast close.impedance is the same as resistance on electrical level......the path of least resistance will always be sought by free flowing current.....if your basic phones you have at home(probably 32 ohms or less)were plugged into a y connector with a pair of akg 240s you would hear the "cheapy" headphones alot louder and make the false assumption that the 240s suck.......not so, the just need to be driven more.thus taking the lesser phones out of the picture because the volume levels would be unbarable........if you decide on multiple 240s,cool no volume probs there......just alot of innitial investment..........hope this helps............by the way mention your gear,size of band,etc-when you post if you could to give the great wealth of members a better all around picture of your needs and such. have fun.

[snared]

Thanks for the reply, GRRAVEE. I don't have a band as of yet. I have a Hart Giga Pro and a TD-10.

So, are you saying that a Rolls HP amp with 100 ohms can drive the AKG K240s?

[GRRAVEE]

if you are wanting someone else to hear what you are playing yes.......but you can do that with a y adapter and some cheap headphones.....but i'm not clear as to the approach or application you are looking to use.......if multiple listeners are in volved avoid the 240s.....they are better suited to mix down and mastering......

[snared]

I do want more than one person to hear what I am playing at one time. I just wasn't sure about the impedance levels listed for the HPs or the HP amp. I have read the specs for the HPs and the amps and they are all different numbers(no patern that I can see). There doesn't seem to be any standard. I have found some HPs that are the same as the AKG 240s but they have a lower impedance level. I just wasn't sure how the impedance listed on the HP correlated with that in the amp, ie: does it have to be the same or can the level on the HP be lower than the amp?

[hifizen]

If you really want to hear something truly amazing, check out the Sennheiser HD-580 and HD-600 headphones. They blow the AKGs out of the water. I now own a pair, and I have to say that they are by far the most amazing headphones I have ever heard. They put other good phones like the MDR-7506s to shame. You can get them for around $200 from www.musicians-gear.com. No, I don't work for Sennheiser or m-g.com... read the online reviews. The HD-600s are considered the best dynamic headphones in the world, and i think the only thing better than them are elctrostatic designs ($$$). In any case, almost a year after buying them, I am still marvelling at how much you can hear... people breathing and turning pages of music in the middle of an orchestra, like you were standing right next to them! crazy stuff like that! I'm not kidding! If you're really serious about recording, or even just enjoying good music you owe it to yourself to at least test out these phones.

Anyway, I'm an Electrical Engineer, not a salesman, so let me answer to the technical aspects of your questions...

Back in the early days of studio recording, impedance matching was important due to the limitations of the technology of the day. But, we don't make much use of vacuum tubes anymore these days, so unless you're working with microphones, or using antique equipment, you won't need to worry much about impedance matching.

As far as headphones go, what you need to know about impedance is as follows:

The lower the impedance, the more current (I) will be drawn from the headphone output for a given voltage (V). Since power P = IV (yes, it's a simplification, I know...), then for a given voltage applied to the headphones, the lower impedance headphones will draw more power. But, sound level inside the headphones is proportional to the electrical power consumed. So, one would perceive that lower impedance headphones sound louder at a certain volume setting than higher impedance phones (as mentioned in a previous post). Some headphones are also more efficient than others at converting electrical energy into sound (there can be as much a a few hundred percent difference in efficiency!). In any case, the difficulty of driving a load such as headphones is basically how much power that load consumes, and so we can roughly conclude that it is no more "difficult" to drive high impedance headphones (around 300 ohms) than low impadance headphones (around 30 ohms) for the same loudness. It just takes more voltage to get the same power output from higher impedance phones.

BUT... for some rather esoteric reasons that I'm not going to get into, low impedance headphones can be problematic for some equipment (it's related to amplifier stability and open-loop output impedence... topics which are far beyond the scope of this post). As well, when an headphone output is driving higher voltages, there will be a greater amount of resolution maintained in the electrical signal, due to the fact that it has been attenuated less. The amount of resolution lost will depend very much on the quality of the equipment, but you can basically conclude that you will get higher quality sound out of higher impedance headphones.

As always, theres a caveat: you may not be able to get high impedence headphones to go loud enough. This is not because they are difficult to drive, but because some sound sources are limited in the maximum voltage output they can deliver to the headphone jack. This might be the case for something battery powered like a discman, but most wall-powered equipment should have plenty of voltage available to drive your headphones.

My recommendation: stick with high impedance headphones for studio applications and home listening, and go with lower impedence headphones for portable listening.

[hifizen]

Oh yeah, almost forgot... what you want in a headphone amplifier is a low output impedence. 100 is way too high. Under 10 ohms is a good start, but ideally you want it to approach nil. An output impedence of 0.1 ohms isn't too much to ask for from a good separate headphone amp. I build all my own equipment, so I can't recommend any specific models though. Check out www.headphone.com.

[deus62]

Let me add my 2 cents worth here.

hifizen: re the Senneheiser headphones.

I own the Sennheiser HD 545 Reference, the Sennheiser 580-1, the HD 590-1 and the HD 600. Yeah, I know. I'm a hifi freak and have been upgrading frequently.

Whereas the 600s are way up there for hifi equipment along with the 580 and especially the 590, which in some scenarios actually out-perform the HD 600, I much prefer to use the "old" 545 for my TD-10.

With the 545 I get a broad, clear and punchy sound, whereas the 590 and 600 tend to smoothen the whole sound and mix it too much into the middle of the soundscape. I've asked quite a lot of musicians and others to try all the headphones on the TD-10 (headphone out; then through Mackie 1202 VLZ and finally through my HDB Audio headphone amp) and every single person went for the HD 545.

I don't have the foggiest notion why that is (impedance: 590s [120 Ohm], the 545 [150 Ohm] the 580 and 600 [300 Ohm]), but they are way better than the others for the TD-10.

I'm tempted to try the Sony pair everyone has been talking about on this board ... but I've only got one pair of ears which tends to get really warm wearing all these headphones (at once).

[This message has been edited by deus62 (edited June 07, 2002).]

[Boingo]

I have the Sony V6 phones. From what I was told, they are similar to the 7506. While I like the V6 on my TD-10, I always thought they could stand an improvement in the bass response.
About a year ago, I bought the 7509. Larger driver, better bass, bigger price. I was disappointed when using them on the TD-10 and prefer the V6 phones. On a decent stereo, the 7509's are great so I kept them. From time to time I switch out. The 7509's sound separation is definitely better and effects take on a new dimension, but the brightness of the V6 was really missing. My guess is the Roland headphone amps could stand a bit of improvement and that phones with a great reputation don't necessarily mean they'll sound great on the Roland units. You really have to find just the right fit - try before you buy seems to be critical for the TD's.

Your ears and personal taste obviously are a factor too. I saw an old post where someone thought the 7509's were the bomb with the TD-10 prompted me to buy them (plus a need for a second set of phones for my stereo). I don't regret the purchase but they didn't work out according to plan.

[masterbeater]

Forget spending money on a headphone amp.

Extreme Isolation Headphones that I bought from a recommendation at this site have a sensitivity of 96.
Don't need much power. They sound as good as my AKG 240's and my fostex that I once used for years.
I can run 4 to 6 pair off of my headphone jack from my multi-track in my home studio and record loud instruments in the same room as the multi-track plus they are comfortable to wear. Everyone that has used them in my studio has bought a pair. I got a deal on 6 pair and need nothing else. You can find them here..... www.drummersheadphones.com www.extremeheadphones.com
www,directsoundheadphones.com

[GRRAVEE]

so master beater,everyone tied to your headphone chain would hear the same mix right?headphone amps are an affordable way for us drummers and those guitarists not to beat each others heads in

[snared]

It seems as though I am never going to figure out which to buy. There is so much info. on them out there and in here. Its getting harder and harder to narrow it down. I do still want to get an amp or some kind of splitter though, because I want to play with HPs on and still have others hear what I am playing. However, I am thinking about other alternatives to HPs requiring amps. So, it is still up in the air.

Thanx for all the input everybody. I think I will continue my research now that I have a few other ideas besides the usual Sony 7506's and 7509's, etc. Not that I have anything against Sony, but they seem expensive for such a mainstream, mass produced product. If I am going to spend that much or more I really want the best.

[snared]

OK. So, will a 100 ohm headphone amp be able to run a 600 ohm headphone? And will it be able to run 3 other pairs of headphones at, say, about 60 ohms each, or so? Or possibly power 4 pairs of 600 ohm headphones?

[This message has been edited by snared (edited June 15, 2002).]

[Enjoy the Music.com]

hifizen and deus62,

As an audiophile (professional magazine editor./reviewer) the Senn HD600 are great BUT dump those stock headphone cords. They are horrible. The ones to replace them with, IMHO, are the Stefan AudioArt. They make the HD600's have cleaner overall highs, tighter, better resolved bass. The difference IS NOT subtle. Tried too many headphones in my life to mention and the HD600 are the ONLY ones i feel have high enough resolution and relatively neutral sound UNLESS you go for BIG $$$ electrostat-type headphones. Still, not a fan of Stat 'phones as when they overdrive some nasty things can happen that might break them.

Also tried the new Senn ?240?. Hated them. AKGs are nice, though lack the smoothness and naturalness of the Senn HD600 IMHO.

Hope this helps. As always...

Enjoy the Music,

Steven R. Rochlin http://www.EnjoyTheMusic.com

[deus62]

Hi Steven,

guess what the first thing was I ran out and bought?