[Barber_91]

I don't know what to do, so maybe someone here can help.

I have a Harman Kardon AVR100 reciever and a set of Sony headphones that are about 5 years old. (Sony MDRCD-270).
Both worked very well but my headphones started losing their ear pads so I asked for a new set for Christmas.

My girlfriend ended up getting me a set of SONY MDRCD-380 and I was pumped. So I went upstairs and plugged them in only to hear a faint HISSING noise. Just enough to piss you off, and it changes pitch every few seconds too! That's also just plugged into the amp with the CD player off!

I then tried my new headphones in different stereos. They are fine in my dad's amp, and same for my brothers. (Older Pioneer amp, HK AVR125 respectively).

So I tried plugging in my old headphones to see if I was just deaf before and never noticed this hiss. As it turns out it does hiss a LITTLE bit, but I can only hear it now because I know what to look for.

So what could be the problem?
Why is this hiss only occuring with any great noise in a specific set of headphones?
Do you think it's the amp or the headphones??
It can't be the headphones if they work perfectly in everything else can it??

I emailed HK and they told me to send it in, but I'm afraid they will just tell me everything is fine!

 

[wallijonn]

Welcome to Head-Fi. Sorry about your wallet.

you may want to look at this thread: http://www4.head-fi.org/forums/showt...threadid=23483

you didn't notice the hiss before because the old headphones couldn't reproduce that high a frequency. if your new headphones work on the vintage amp, the problem is probably your new amp which probably has an op amp headphone output.

marantz 1060 amps are going for about $100 on Ebay. ask the marantz 1060 owners if they detect hiss on their equipment.

 

[Barber_91]

So the problem is my headphones are too good?
Sorry, I'm what people like to call a newbie! HAha

Is it anything that HK can fix if I send my amp back, or am I just going to have to live with it?

Why would an old amp work better than my new HK amp for these headphones?

Please explain, you have me interested now =)

thank you for the help by the way

 

[wallijonn]

actually, i am more worried about the hiss fluctuating. why not try it at 3 am when everything else in the house is turned off? the power cord is probably polarised so it probably won't help to reverse it.

a little hiss won't hurt you. especially if they are low inpedance headphones. by the time that you have turned up the volume to hear the hiss, either your ears will be bleeding or the headphones will have gone up in smoke. if you're really serious, a dedicated headphone amp is the way to go. But before investing $200 on an amp, you want to try a $100 receiver (or at least listen through your father's amp.)

does it really bother you while listening at moderate volume levels? if it does, see if you can swap receivers with your father.

do not think of buying an headphone amp just yet. listen to your headphones for awhile. enjoy them first. there's no hurry. i probably get more hiss listening online (the classical section of digitallyimported.com) than through a cd player. try to keep your RCA cables as short as possible. see if monster cables help (borrow a set from somewhere or someone before spending the $20 - $100. why don't they make 1 foot rca cables?)

 

[Barber_91]

The hiss isn't bad at all when listening to a normal song. the music seems to drown it out. I only really get pissed when songs have a very quiet part like the intro to "Nothing Else Matters" by Metallica.

I guess my question is why the static?
I understand my headphones are picking up a frequency that the others couldn't, but why would the amp put out such a noise? I wouldn't expect that from HK =)

- Thank again.

 

[Barber_91]

I forgot, I should mention that the hiss stays at the exactly the same volume until I reach the about 95% of the full power of the amp.

 

[wallijonn]

it may be an impedance mismatch. why i don't know, as the mdr-380s are probably 32 ohms, and the headphone output source impedance is probably 32 ohms or less. you may just have to upgrade the amp if it really bothers you.

well, at least it isn't hum. that's even worse. had you said that you had a hum problem, i would have told you to disconnect the video cable from your TV if the music source was a dvd player.

hey, guys, will grounding the unit cause the hiss to go lower or disappear?

 

[wallijonn]

you may want to make some shorted rca plugs. then install them into the phono inputs, tape inputs, cd inputs, aux inputs, etc., and see if the hiss goes away.

you say that the hiss is there when there is NOTHING connected to the receiver? for all we know this hiss may be coming from the FM section. i used to have fm bleed through on my radio shack receiver. i ended up removing the fm antenna and shorting the fm antenna inputs.

too bad you are not in arizona. i would not mind looking at this unit. (or the one in the onkyo thread). i find that hiss is introduced when cables are connected. upgrading the rca cables to something more substantial usually cures that problem.