Power headphones with reciever?

all i use is my vintage receivers/amps to drive my 600ohm AKG's and they push more then enough power from the headphone out since with all stereo gear the headphone out is driven from the same power amp section that drives the speakers but occupied by couple dropping resistors in place to ensure no accidental damage that gets done to the headphone in use.

just plug it it and see how you like it.

Heya,

 

It'll work fine. Plug 'em in. The only real worry is that the DAC isn't totally junk or if it has a super high noise floor. Other than that, most receivers should power a headphone without much effort.

 

Very best,

Yes, the headphones will work with such an output. Getting them to sound good is a completely different matter altogether: The output impedance of such receivers is typically extremely high - in the hundreds of Ohms. As a result of this extremely poor damping factor, the typical lower-impedance headphoe that dominates the home headphone market these days will sound like who-knows-what-had-gone-through-them even if they sound good otherwise because their impedance is much lower than the jack's output. And using even 600-Ohm headphones with those receivers will result in a low damping factor of less than 5 - the equivalent of using 32-Ohm headphones with a typical portable player with a 10-Ohm output impedance.

 

No wonder why most headphones sound really murky out of the receivers' headphone jacks, in my experience. Sure, the OP would get sound out of them - but the sound quality would be nowhere near as good as the headphones in question are capable of. In other words, like hammered dog $#*! (pardon my Franglais).

Edited by Eagle_Driver - 9/21/11 at 5:55pm

i kinda doubt that. not all receivers/amps have a high output impedance. lot of newer amps are 120ohm standardized using 120ohm resistors and don't nearly sound as good as an older amp say with something of 680ohm output impedance. impedance matching should only be a concern with power lines and not really any audio gear. it's more dependent on voltage matching then anything else.if the amp sees a lower input impedance than it's output it will try to drop the voltage to match the impedance anyways. damping factor as well has very little to do with headphones since headphones don't vary much at all in frequency(most of them anyhow).

if it sounds different it's more overall on the topology design of the gear i personally think. output impedance is the least of the concern. if it was a major concern everyone must not need an amp since soundcards and mp3 players must be the best things to use cause they have very low output impedance and must be the ultimate for all headphones... kidding aside :P, but yea it overall depends on the end-user. it either sound good or doesn't.

Actually, I have listened to those older receivers with the 680-Ohm headphone output inpedance. Those receivers sound utterly unlistenable with any modern low-impedance headphones whatsoever (the impedances were severely mismatched, with the headphone's own impedance being far lower than the headphone jack impedance). Those receivers really require headphones that never existed at all - those with a nominal impedance of greater than 47 kilohms (>47,000 Ohms) just to sound even acceptable to my ears. But then again, modern headphones are really designed for newer gear with a near-zero-Ohm output impedance, with their relatively elevated bass response (compared to those early ultra-high-impedance 2,000-Ohm headphones that delivered virtually no real bass response whatsoever - their entire bottom end is severely recessed to compensate for the ultra-high output impedances of the day). Try plugging a modern headphone into such a vintage transistorized receiver, and it will sound very similar to the Beats Solo when the latter is plugged into the average low-output-impedance headphone amp. And many high-impedance headphone outs do not lower the impedance at all even with low-impedance headphones. That results in a sound that's extremely loose, severely distorted and almost completely uncontrolled.

 

By the way, the receivers that you have listened to that are "good" have valve (tube) amps. It's the transistorized (solid state) amps with high output impedances that you have to watch out for.

 

And among the OP's receivers, the vintage Fisher receiver has the best chance of sounding good with decent headphones. All three of the others were manufactured after the receiver manufacturers started cutting corners on headphone out quality (which began some time in the 1970s).

 

Edited by Eagle_Driver - 9/22/11 at 12:29am

Which ones have a 680 Ohm output?

My understanding is that most solid state receivers use voltage-dropping resistors to take power off the speaker taps.

I'm not aware of any transistors with an output impedance that high. Output impedance is usually in the single digits. If not, then the receiver would have to have output transformers to handle speakers.

So if there are designs like that out there, please give us some more information. It's something I don't know about and want to read up on. I often tell people that vintage receivers work fine and they have a measure of popularity here, too.

Uncle Erik,

 

The resistors actually do substantially raise the output impedance of the headphone out - in this case, the output impedance would almost always be higher than the value of the resistors used in the headphone out. If the headphone out impedance of a transistorized receiver were near-zero Ohm, the output would have blasted the same amount of voltage as the loudspeaker out - a disaster for headphones, especially those that cannot handle anywhere near the voltage input that such outs deliver. In the case of 32-Ohm headphones plugged into a receiver headphone out that's near-zero-Ohm impedance and connected to the loudspeaker amp of a 100-watt-per-channel (at 8 Ohms) receiver, that would have resulted in an input going into the headphones of a whopping 25 watts per earpiece (at maximum output)! Unfortunately, most audiophile headphones are rated to handle only 0.25W (250mW) per earpiece. That would have resulted in very little headroom between the volume setting that starts producing sound at all through those headphones and the volume level that starts overdriving (putting too much power through) those same headphones.

Edited by Eagle_Driver - 9/22/11 at 12:51am

that is very interested. i really don't own any low impedance headphones besides my AKG studios and Pioneer Monitor 10's. i wouldn't say solid state high impedance outs are bad cause i enjoy using my sansui 5000x which has an output impedance of 680ohms and not only sound clean with my 240 sextetts and 240DF's but sound great with lower impedance like my pioneer monitor 10 and akg 240 studios. i even had a chance to test an othodynamic yamaha hp-1 which sounded great as well with no muddy bass response. if there is problem with the amp then it means caps need to be changed or something else needs to get fixed. but this is from my experience of course and not everyone else experience is the same that i do understand.

i wouldn't say not all older headphones with high output impedance lack bass control either. my sextetts lp i tested can have very powerful deep bass response down to 20hz no problem if fed with right amount of power and can still feel the vibrations of 10hz on your ears. my 240DF's tho start to roll off at around 30hz and can't dig as deep as my sextetts lp can.

i agree tho the fisher would probably be the best for the op cause i do as well love older fisher amps. i just wouldn't discount any vintage solid state receivers and power amps really just yet. also in my opinion i don't see how comparing older headphones to newer modern headphones makes any difference(besides the difference way they're tuned now for modern equipment and music) cause to be honest not much has changed the past 30 years in headphone technology.

older amps usually used 680ohm and 560ohm resistors but that all depend on how powerful the amp itself was. usually amps 60wpc and above had 680ohm output impedance but there was some exceptions on certain amps. the reason also the headphones are driven from the same power transformer as well and lot of bigger amps were known to have massive power transformers(or dual transformers) and pretty beefy power transistors and caps to also handle low-impedance speaker loads cause designers knew back then about impedance dips under 4ohms with speakers so they always made sure the power transformer can handle the loads of current when impedance dips. headphones go through the same transformer but power is cut of course through dropping resistors.

In my experience it's quite random how headphone will act when plugged in to high impedance outputs on receivers.

I have a Harman/Kardon PM665, with the DF's it sounds fine, with K242HD's it sounds fine, with 120 Ohm HD555's it's extremely bassy and muddy.

Now why does the 55 ohm K242HD's sound fine, while the HD555's with their higher impedance do not? something to do with sensitivity/efficiency rather then impedance maybe?

Edited by Adda - 9/22/11 at 3:37pm

If that's the case with vintage receivers having high headphone output impedance...then why do vintage headphones only have 8-ohm impedance in some cases?

 

My set of vintage Sansui SS-20s is exactly that. Eight measly ohms of impedance. Pretty sensitive from what I can tell, too; I can drive them straight out of a typical sound card or portable device without any volume issues, though without a dynamic headphone amp to use, I can't compare. If anything, I'd expect them to match up well with the old Sansui 8080DB receiver we have packed up...

 

On another note, I actually am using a not-so-vintage receiver as a headphone amp right now (Onkyo TX-SV515PRO)...but not in the manner that you'd expect. I need the speaker amp to drive a Stax SRD-7/SB. It's rather bulky for that, but it works. The SS-20s and AD700s show no improvement going through it instead of being fed directly by the sound card, as far as I can tell.

those were mainly cause they were consumer products or low-end. lot of radio broadcasting and studio gear was 600ohm standard. the sennheiser hd414 and h424 also known was the first to use microphone drivers instead of your typical dynamic paper cone driver and reason for it's 2000ohms. also most of the 8-16ohm headphones reason why they sounded so bad is cause they basically just took cheap speaker parts and used them as ''full-range'' drivers most of the time so if you wanted to you could actually rewire them with speaker wire and use them off the speaker outputs but really won't make any difference really besides solve volume issues with your typical 8-16ohm paper cone driver.

there is exceptions tho like the pioneer monitor 10. that was design for live recording and monitor in the 70's and used large 57mm polyester film cone divers and an aluminum voice coil instead. the pioneers were rated at 4-16ohms but they do benefit from more power cause aluminum is more resistive to copper and can handle lots more power since it dissipates heat much faster. that's why high-end subwoofers and full-range drivers are made with aluminum voice coils. same goes for the famous beyer dt48's which used aluminum voice coils. i think the dt880 was around same time as 240df's in the 80's and were 600ohms till later on they decided to design more consumer friendly versions.

you also got electrostatics,electrodynamics and planer magnetics to consider as well.

sensitivity maybe. i'm not sure and can't say really. just bad synergy maybe. who knows. also akg headphones are known to be infamous for big impedance spikes for some reason. i remember reading somewhere they tested multiple driver impedance and akg's were known to typically spike and dip the most especially around the 100hz and 1khz region.

I've always used stereo recievers with headphone along with speakers since i was a little kid thanks to my Dad owning a television and audio shop. Not once have i had any problems with bad sound quality. Currently am using an Onkyo TX-8555 stereo reciever for headphone and speaker (2) use and it really adds a just the right oomph fullness to my Audio Technica Ath-AD700 headphones without distorting the sound.

 

Only time i had a problem was with a humming sound when i purchased a RadioShack PA system. Though it made the headphones sound more full it also started giving them a very annoying hum after awhile. Now i have it in storage and stick to my Onkyo with some Insignia Bass Reflex speakers when not using headphones.