[Anaxilus]

Interesting thread.  Just dusted off an old Sansui 5000 that's been idle for about 45 years.  I know what poor damping factor sounds like and am quite sensitive to it.  680ohms output z or not the Sansui is driving the LCD2, HD800, T50rp like a champ.  Tight, controlled and more accurate than many revered headphone amps around these parts.  I'd love to have it explained how that's possible.  

 

[Sophonax]

I've had better luck with headphone amps than with receivers, although my headphone amps have all been Class A versus Class AB on the receivers, so apples and oranges...
 
Does anyone know -- are headphone outputs on receivers / preamps supposed to follow the IEC standard 120-ohm output impedance?  If not, then why does this standard even exist, if no one really seems to use it?

 

[Adda]

Quote:

I've had better luck with headphone amps than with receivers, although my headphone amps have all been Class A versus Class AB on the receivers, so apples and oranges...
 
Does anyone know -- are headphone outputs on receivers / preamps supposed to follow the IEC standard 120-ohm output impedance?  If not, then why does this standard even exist, if no one really seems to use it?

Some receivers/integrateds might have 120 Ohm outputs, but most will not, more likely 400-600 ohms or more.
As for preamps, it'll most likely be a rather low output impedance, less then 100 ohms, active preamps and headphone amps are very similar.
As far as I know, the Naga devices have 120 Ohm headphone outs.

 

[sexiewasd]

I'm new to this whole talk of impedance matching, I do know that my 701's sound fantastic with my Yamaha A-760 integrated amp (solid state)
but sound completely rubbish with my much newer pioneer receivers (vsx-515).  They also sound really terrible on the phone jack on my Nakamichi Rx-202.

 

[plexxx]

I just recently purchased Beyerdynamic DT-990 600Ohm headphones with the intention of using my AV receiver to drive them.  The quality out of the receiver is disappointing.  There is a hiss and they sound muffled.  They sound a lot better driven by my external USB sound card (lexicon alpha).
 
Nick

 

[RexAeterna]

Interesting thread.  Just dusted off an old Sansui 5000 that's been idle for about 45 years.  I know what poor damping factor sounds like and am quite sensitive to it.  680ohms output z or not the Sansui is driving the LCD2, HD800, T50rp like a champ.  Tight, controlled and more accurate than many revered headphone amps around these parts.  I'd love to have it explained how that's possible.  

the sansui 5000 is all discrete unit. reason why no dampen issues is cause of the power transformer inside. the headphones go through the large power transformer first and the transformer lowers or higher it's voltages to match the impedance at the output. the 680ohm output is for safety issues when using lower impedance headphones. they put high output impedance so it won't drive too much current and voltages to the headphone all at once and the power transformer is allowed to do all the voltage and current matching if needed. the speaker outputs the headphone is tied to is rather low(close to 0 impedance) for speaker driving but has resistors for safety reasons which give the headphone output it's 680ohm impedance. you can swap them for 10ohm resistors but that'll probably give you gain issues and can kill any headphone that is not an electrodynamic or electrostatic design

 

[RexAeterna]

I've had better luck with headphone amps than with receivers, although my headphone amps have all been Class A versus Class AB on the receivers, so apples and oranges...
 
Does anyone know -- are headphone outputs on receivers / preamps supposed to follow the IEC standard 120-ohm output impedance?  If not, then why does this standard even exist, if no one really seems to use it?

preamps usually fellow the 1/8 rule. meaning there is always a low output impedance but has high voltage output at that impedance. that's why voltage matching is more important than impedance matching if you want proper gain and proper frequency response. so say headphone is 600ohms you'll want a pre-amp with a 75ohm output impedance and is capable of delivering above 1-2v at least at that given impedance for proper damping and proper FR.

 

[monoethylene]

Quote:

I've had better luck with headphone amps than with receivers, although my headphone amps have all been Class A versus Class AB on the receivers, so apples and oranges...
 
Does anyone know -- are headphone outputs on receivers / preamps supposed to follow the IEC standard 120-ohm output impedance?  If not, then why does this standard even exist, if no one really seems to use it?

This standard exists because there is almost everywhere a standard for everything..at least in Gemrany and it says that an output impedance of 120 Ohm leads to the same SPL over the whole frequency range for headphones from, if I remember in the right way, 5 Ohm - 2000 Ohm.. or in other words the subjective hearing difference of loudness would be minimal over the frequency range.. I will have a look tomorrow at the DIN in your language if you need it

 

[Sophonax]

Nah I don't really need it -- it was more just curiosity.  I've read that a lot of headphones are designed with this 120-ohm IEC standard in mind, and yet there doesn't seem to be very many consumer electronics that follow this standard.

 

[Tomppa]

I don't quite understand what is going on with the impedance matching and such. I've ordered MS-1i and I was planning to use my Sony STR-232L receiver to power them. MS-1i are 32ohm, Sony claims the STR-232L has output impedance of 8ohms for the headphones, but in reality there are 270ohm resistors inside. So I am assuming the output impedance is at least 270ohms, will this cause some kind of problems?

 

[RexAeterna]

I don't quite understand what is going on with the impedance matching and such. I've ordered MS-1i and I was planning to use my Sony STR-232L receiver to power them. MS-1i are 32ohm, Sony claims the STR-232L has output impedance of 8ohms for the headphones, but in reality there are 270ohm resistors inside. So I am assuming the output impedance is at least 270ohms, will this cause some kind of problems?

they're probably paired in parallel to allow an output impedance of 8ohms maybe. lot of yamaha receivers and amps did this as well cause they were designed and marketed with their orthodynamic headphones in mind so they usually had 2 headphone jacks with 4 resistors in parallel instead of typical receiver/amp design of running the resistors in series. you should be fine cause the power transformer will match the impedance of your MS1i but you liking the sound of the combination is entirely up to you.

 

[Anaxilus]

Quote:

the sansui 5000 is all discrete unit. reason why no dampen issues is cause of the power transformer inside. the headphones go through the large power transformer first and the transformer lowers or higher it's voltages to match the impedance at the output. the 680ohm output is for safety issues when using lower impedance headphones. they put high output impedance so it won't drive too much current and voltages to the headphone all at once and the power transformer is allowed to do all the voltage and current matching if needed. the speaker outputs the headphone is tied to is rather low(close to 0 impedance) for speaker driving but has resistors for safety reasons which give the headphone output it's 680ohm impedance. you can swap them for 10ohm resistors but that'll probably give you gain issues and can kill any headphone that is not an electrodynamic or electrostatic design

Thank you very much. 

 

[livilaNic]

Just wondering if I should use the preamp out spec. as the Headphone jack spec.: 1V/470 ohms, or...?
 
Pioneer VSX-5600:
 
Block Diagram: http://tinyurl.com/3sy2zzp
 
Specifications: http://tinyurl.com/3p97gmd
 
Also, if so, what type of headphone spec. should I look for to pair up with this receiver?
 
Cheers.
 
 
 
 

 

[Rawrbington]

ive gone through a handful of receivers.  for me its been hit and miss with headphones.  i found the pioneer sx i bought when i was 8 to be the best match, others just produce this confused sound.  either WAY too much highs or big BLOATED mid bass or just absolutely lifeless sound.  i have no idea how to figure out what is being pushed out of the HP jack on these receivers but it either sounds good or bad and you know pretty much instantly