Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Many AV Receivers/Stereo Integrated amps do NOT use opamp powered headphone jacks
New Posts  All Forums:Forum Nav:

Many AV Receivers/Stereo Integrated amps do NOT use opamp powered headphone jacks - Page 7

post #91 of 211
7/1/08 at 3:44pm
Quote:
Originally Posted by chesebert View Post
Problem with integrated amps with R divide: 1) by having an extremely high output Z, the amp, the power amp is effectivly restricting voltage output as its necessary since most integrated are at least 30dB in gain. Now when your Zload >> Zoutput, you are making the load less sensitive to the input voltage and therefore you lose alot of the fine detail and you also loose control. If you look at damping factor (DF), you will see that in a R divide headamp, you have a very very tiny DF; and a tiny DF means lack of control, sloppy base, and loss of details.
Well, I can't tell you that you're wrong, because I'm not an electrical engineer. But if you're right, why don't the resistors in stepped attenuators, and multi-gain headphone amps have exactly the same negative effect? These are features built into some of the most expensive, most resolving headphone amps.

Or I could just ask the simpler question. Why do my HD580s reveal lots of detail and exhibit great bass control when played through my Harmon Kardon integrated amp?

This goes back to the old problem I had when veteran head-fiers were trying to tell me that 580s couldn't possibly sound good through a battery-operated amp. I was sitting here reading that while listening to the 580s through a Headroom Airhead. And it sounded good. Great? No. But thin, lifeless, no dynamics, sloppy boomy bass? Nope. None of the above. And yes, I know what good audio sounds like. It created a bit of a credibility gap, as you can imagine.

Tim
Reply
post #92 of 211
7/1/08 at 3:44pm
Quote:
Originally Posted by chesebert View Post
If you look at damping factor (DF), you will see that in a R divide headamp, you have a very very tiny DF; and a tiny DF means lack of control, sloppy base, and loss of details.
.
Warming up the tubes of the XCANv3 to see if these effects are easy to hear compared to my Pioneer A449 power amp...
Reply
post #93 of 211
7/1/08 at 4:18pm
Quote:
Originally Posted by tfarney View Post
Well, I can't tell you that you're wrong, because I'm not an electrical engineer. But if you're right, why don't the resistors in stepped attenuators, and multi-gain headphone amps have exactly the same negative effect? These are features built into some of the most expensive, most resolving headphone amps.
cuz you are at the other end of the chain; I don't even know why you are confused...seems trivial that the traditional volume control does not contribute to maximizing the voltage transfer of the output stage.

Quote:
Originally Posted by tfarney View Post
Or I could just ask the simpler question. Why do my HD580s reveal lots of detail and exhibit great bass control when played through my Harmon Kardon integrated amp?

This goes back to the old problem I had when veteran head-fiers were trying to tell me that 580s couldn't possibly sound good through a battery-operated amp. I was sitting here reading that while listening to the 580s through a Headroom Airhead. And it sounded good. Great? No. But thin, lifeless, no dynamics, sloppy boomy bass? Nope. None of the above. And yes, I know what good audio sounds like. It created a bit of a credibility gap, as you can imagine.

Tim
what can I say? lack of experience? havn't heard better? easily satisfied? bad hearing? bad music? wrong music? lack of expectation? ...etc. (HD600 sounds like POS with TAH..I had one..thin, lifeless, no dynamics, sloppy boomy bass? YES!)
Reply
post #94 of 211
7/1/08 at 4:21pm
chesebert,

What is Z? I've seen it used in DIY threads, but I've never seen a definition. By context here, it looks like impedance? Is that correct.
Reply
post #95 of 211
7/1/08 at 4:29pm
Quote:
Originally Posted by scompton View Post
chesebert,

What is Z? I've seen it used in DIY threads, but I've never seen a definition. By context here, it looks like impedance? Is that correct.
right..its basicly the AC version of R, rather R is the real[Z]. That's what people normally talks about.... To add a little complexity, Z does not mean resistor only, because other circuit elements can be transformed into Z via the laplace transform (awesome for circuit analysis), so now instead of dealing with C and L, you only have to deal with Z and no phasors! But for our simple discussion of the R divide, real[Z] should be the resistor value.
Reply
post #96 of 211
7/1/08 at 4:35pm
I'll be playing two tunes that would reveal the problem at once, if present.

Track #1: **** Buttons - Bright Tomorrow (Street Horrrsing CD, 126kbit vbr). This is bascially a slow melodic repetitive drum (bass) and noise (detail) track. Perfect for A/B comparison.

Track #2: Jason Forrest - Inkhuk (The Unrelenting Songs Of The 1979 Post Disco Crash CD, 256kbit). This is an extremely fast paced and varied drum track (bass) with various other fast paced instruments in the background (detail).

Track #3: The Hidden Cameras - Death Of a Tune. A normal pop song.
(the third track here would probably not reveal the problem at once, but if it does...)
Reply
post #97 of 211
7/1/08 at 4:44pm
Thread Starter 
chesebert-Either in this thread or the other one that is circling the same topic, tfarney brought up the problems of impedance mismatches. I'm aware of some of the different theories of why a resistor powered headphone jack shouldn't be as good as a dedicated.

However, that is not what people are experiencing. Some people actually prefer their integrated amps to their dedicated and seem to have no issues with flabby bass and everything else you mentioned. The majority of experiences seem to be with high resistance (300 ohms Sennhesiers) headphones. Perhaps, since resistor headphone jacks have lower impedances than this, people don't see the issues you mentioned. There aren't many reports on low impedance headphones.

As for the dc offset issue, I take the example of experience again. People have been using their headphones with their resistor powered off headphone jacks for a long time - no issues to speak off. I think Sennheiser even states that you can plug in your HD600/650 into your "hifi system" in the manual. My guess it that many headphone manufactures operate under the assumption the average buyer will be plugging into a receiver. Many people listen to headphones - few have even heard of a headphone amp.

I don't mean to dismiss you. I'm just looking for personal experiences as opposed to theories of impedance, reactance, etc.

Defective - Are those Monitor 10s low impedance (60 ohms or lower?). If so, can you test those as well.
Reply
post #98 of 211
7/1/08 at 4:51pm
Quote:
Originally Posted by odigg View Post
chesebert-Either in this thread or the other one that is circling the same topic, tfarney brought up the problems of impedance mismatches. I'm aware of some of the different theories of why a resistor powered headphone jack shouldn't be as good as a dedicated.

However, that is not what people are experiencing. Some people actually prefer their integrated amps to their dedicated and seem to have no issues with flabby bass and everything else you mentioned. The majority of experiences seem to be with high resistance (300 ohms Sennhesiers) headphones. Perhaps, since resistor headphone jacks have lower impedances than this, people don't see the issues you mentioned. There aren't many reports on low impedance headphones.

As for the dc offset issue, I take the example of experience again. People have been using their headphones with their resistor powered off headphone jacks for a long time - no issues to speak off. I think Sennheiser even states that you can plug in your HD600/650 into your "hifi system" in the manual. My guess it that many headphone manufactures operate under the assumption the average buyer will be plugging into a receiver. Many people listen to headphones - few have even heard of a headphone amp.

I don't mean to dismiss you. I'm just looking for personal experiences as opposed to theories of impedance, reactance, etc.

Defective - Are those Monitor 10s low impedance (60 ohms or lower?). If so, can you test those as well.
The issue is not imp mismatch, its actually not desirable to match imp from amp to headphone because the goal of a good headamp is not to maximize power output (although that's important), but rather to perserve the very complex and fine voltage swings; having a large output Z hampers that effort.

Personal experience? look in my profile..been there..done that...moved on...integrated with headphone out is good for what it is (free headphone amp that can compete with sub $200 dedicated in some limited areas), and nothing more, not withstanding any personal taste differences.

Another point on the int amp...I have only seen headphone out on mid-fi stuff...the good int don't have headamp out....
Reply
post #99 of 211
7/1/08 at 5:10pm
Quote:
Originally Posted by chesebert View Post
The goal of a good headamp is not to maximize power output (although that's important), but rather to perserve the very complex and fine voltage swings; having a large output Z hampers that effort.
You mean that in this sticky thread,
http://www.head-fi.org/forums/f4/hea...8/#post3454398

The 1/2/3 are only for sound level purpose? For example, a 1-headphone (no amp needed) would sound loud enough from an integrated, but would not sound better in this setup than a 3-headphone (amp needed)?

Edit : Reading myself again, I guess I'm not clear enough... Based on what I understand from your recent posts, an integrated will "damage" the signal anyway. It would it be the same for a 1/2/3 headphone, because it's not a matter of impedance mismatch, sensitivity or whatever... it's an amplifier problem! The 1/2/3 could help for sound level only... Correct me please If I'm wrong... Thanks,
Reply
post #100 of 211
7/1/08 at 5:12pm
Quote:
cuz you are at the other end of the chain; I don't even know why you are confused...seems trivial that the traditional volume control does not contribute to maximizing the voltage transfer of the output stage.
I'm at the other end of the chain? In all cases the resistors are attenuating the output of the amp. I'm not sure I understand what you mean.

Quote:
what can I say? lack of experience? havn't heard better? easily satisfied? bad hearing? bad music? wrong music? lack of expectation? ...etc. (HD600 sounds like POS with TAH..I had one..thin, lifeless, no dynamics, sloppy boomy bass? YES!)
OK. This part I understand. I don't see any point in dignifying it with a response, but I understand.

Tim
Reply
post #101 of 211
7/1/08 at 5:19pm
Quote:
Originally Posted by Headdie View Post
You mean that in this sticky thread,
http://www.head-fi.org/forums/f4/hea...8/#post3454398

The 1/2/3 are only for sound level purpose? For example, a 1-headphone (no amp needed) would sound loud enough from an integrated, but would not sound better in this setup than a 3-headphone (amp needed)?
you are a little confused by that thread...

1) there is alwasy an amp...its always needed and its always there; whether you decide to have a dedicated external amp is the purpose of that thread

2) output power and damping factors are 2 different issues and you need to keep them separate. int has no problem doing the former but fails with the latter.
Reply
post #102 of 211
7/1/08 at 5:21pm
Quote:
Originally Posted by tfarney View Post
I'm at the other end of the chain? In all cases the resistors are attenuating the output of the amp. I'm not sure I understand what you mean.
Tim
volume control (attenuation) happens at the Vinput NOT Voutput.
Reply
post #103 of 211
7/1/08 at 5:22pm
I've used both the well-known HD580, and the less known older Pioneer Monitor 10 (about 8 ohms matching impedance, whatever that means...).

The thrid song, Death of a Tune, to begin with the normal pop song, did not reveal anything clearly, with either can. It has no extreme passages to speak of either.

The first song, Bright Tomorrow, in particular with the Monitor 10s has a passage with low bass beneath a carpet of noise. Here, the low bass was much more hidden through the A449 than with the XCAN. With the XCAN I could hear it thumping clearly in the background. Also with the HD580 the bass was less distinct. The effect was more obvious with the Monitor 10. The HD580 sounded a tad boomier with the A449 overall.

The next song was a tad more distinct in the difficult passages, again most obviously with the Monitor 10 but also with the HD580.

Disclaimer: My subjective comparison (no blind test even) between one particular power amp and one particular headphone amp reveals almost nothing about the matter at hand. But maybe if more people join in?

(I actually started the comparison while writing my first post about comparing, because I had time to write only after starting to listen...)

I think that all in all this test confirms my initial impression, that the Power Amp does a very good job with both headphones.
Reply
post #104 of 211
7/1/08 at 5:38pm
Quote:
Originally Posted by chesebert View Post
you are a little confused by that thread...

1) there is alwasy an amp...its always needed and its always there; whether you decide to have a dedicated external amp is the purpose of that thread

2) output power and damping factors are 2 different issues and you need to keep them separate. int has no problem doing the former but fails with the latter.
Thanks for your answer. I'd say that I'm still confused period, by that thread and more, but I don't give up So a 1-headphone can be played without a dedicated amplifier, the sound level will be ok, but the sound quality won't be very good, because the amp won't have enough grip on the drivers (not enough damping factor remaining at headphone out)...
Reply
post #105 of 211
7/1/08 at 5:51pm
Thread Starter 
Quote:
Originally Posted by DefectiveAudioComponent View Post

The thrid song, Death of a Tune, to begin with the normal pop song, did not reveal anything clearly, with either can. It has no extreme passages to speak of either.

The first song, Bright Tomorrow, in particular with the Monitor 10s has a passage with low bass beneath a carpet of noise. Here, the low bass was much more hidden through the A449 than with the XCAN. With the XCAN I could hear it thumping clearly in the background. Also with the HD580 the bass was less distinct. The effect was more obvious with the Monitor 10. The HD580 sounded a tad boomier with the A449 overall.

The next song was a tad more distinct in the difficult passages, again most obviously with the Monitor 10 but also with the HD580.
Thanks!

I think this supports tfarney's earlier statement (in this thread or the other) that the issues with resistor powered headphone jacks will tend to show up more with low impedance headphones. That is assuming the A449 headphone jack is resistors off the main speakers. How old is that amplifier? I've been trying to find info on it but haven't had much luck.

Just so we have more information regarding that bass behind the noise section in the second track, how does it sound through speakers? Do you get that same feeling, that the bass is hidden? I'm trying to figure out if that is the character of the amp or if we are talking about issues only with the headphones.

Sorry for all the questions. I'm just trying to get as much information as possible before this thread dies.
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Many AV Receivers/Stereo Integrated amps do NOT use opamp powered headphone jacks