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Topic: Is a headphone amp needed? (Read 44223 times) previous topic - next topic
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Is a headphone amp needed?

Reply #50 –
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Heh, you would have to have expanded an acronym, which happens in your mind and not here on the forum.  Anyway, you continue to neglect the importance of power supply capacitance in responding to dynamic peaks, so I just assume you need more education in basic electronics... no reply necessary.

P.S. I suggest you look up what the go-vibe website means when it lists:

"2 x Panasonic 1800uF power supply caps"

Hint: What are these parts used for?
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I am breaking my promise of silence to remind you of an important technical matter: One can add all the capacitance that they wish, but it will not increase the rail voltage beyond the battery voltage. Simple review of my posted data demonstrates voltage limited distortion. One can not exceed the rail voltage.

-Chris

Is a headphone amp needed?

Reply #51 –
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I am breaking my promise of silence to remind you of an important technical matter: One can add all the capacitance that they wish, but it will not increase the rail voltage beyond the battery voltage. Simple review of my posted data demonstrates voltage limited distortion. One can not exceed the rail voltage.

Your measurements with a particular amp at 9v still don't prove a thing with an entirely different (op)amp at 9v.

There are several amps out there that run on 3v or less... would you like me to point them out?  If they had clipping on dynamic peaks (which is a dead-obvious distortion that a completely uneducated ear can hear) they would have been returned in droves and redesigned to use a higher voltage. 

What voltage do PCI sound cards use?  How many people here have used HD580s directly from their soundcard without distortion?  I assure you, there are some.

Bottom line -- I do not accept your assertion that 9v is inadequate for higher impedance headphones, sorry.

However, it does look like 9v is inadequate for the amp you tested.  If it were me, I would return it to the builder and complain VERY loudly until s/he refunded my money.  Just because an amp is portable doesn't mean that it should be limited to low impedance cans.  I meant what I said, if it distorts at 9v with high impedance headphones then it is a piece of **** (unless maybe its limitations are clearly indicated to the would-be purchaser).

Is a headphone amp needed?

Reply #52 –
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There are several amps out there that run on 3v or less... would you like me to point them out?  If they had clipping on dynamic peaks (which is a dead-obvious distortion that a completely uneducated ear can hear) they would have been returned in droves and redesigned to use a higher voltage. 


You can use any op amp that you wish, but regardless of cost, brand or reputation, it can not create voltage that does not exist. Their are exactly two ways to increase the amplifier's output voltage beyond the battery's inherant limitation; (1) use a DC-DC convertor [or] (2) use an output transformer on the audio outputs.

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However, it does look like 9v is inadequate for the amp you tested. If it were me, I would return it to the builder and complain VERY loudly until s/he refunded my money. Just because an amp is portable doesn't mean that it should be limited to low impedance cans.


Return an amplifier on the grounds that it can not create voltage beyond the rail voltage? That does not make sense.

-Chris

Is a headphone amp needed?

Reply #53 –
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Return an amplifier on the grounds that it can not create voltage beyond the rail voltage? That does not make sense.

Return it for not performing properly as an amplifier -- which means, amplifying headphones without distortion.  You mean, you would really keep it? 

Is a headphone amp needed?

Reply #54 –
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Return an amplifier on the grounds that it can not create voltage beyond the rail voltage? That does not make sense.

Return it for not performing properly as an amplifier -- which means, amplifying headphones without distortion.  You mean, you would really keep it? 
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Illogical comment[because there is no evidence to support the amplifier is at fault or defective] based on the available data. Refer to previous posts, especially my analysis, that outlines the rules of available RMS voltage.

-Chris

Is a headphone amp needed?

Reply #55 –
This is nuts.  I'm contacting the maker of the go-vibe to investigate your claim.  He has multiple years of experience building a wide variety of amps (not just DIY stuff, but his own designs).

If I'm wrong, I will say so openly here (and go have my ears checked).  If not, I will discredit your claims.  Perhaps he'd be interested in joining the discussion (although I doubt it, he has a day job in addition to building amps).

Is a headphone amp needed?

Reply #56 –
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This is nuts.  I'm contacting the maker of the go-vibe to investigate your claim.  He has multiple years of experience building a wide variety of amps (not just DIY stuff, but his own designs).

If I'm wrong, I will say so openly here (and go have my ears checked).  If not, I will discredit your claims.  Perhaps he'd be interested in joining the discussion (although I doubt it, he has a day job in addition to building amps).
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What is it that you question from me exactly? That you can not exceed the available rail voltage of the amplifier?

-Chris

Is a headphone amp needed?

Reply #57 –
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What is it that you question from me exactly? That you can not exceed the available rail voltage of the amplifier?

"There's a guy on a forum I frequent who is insisting that nine volts is not enough to amplify high impedance headphones like the HD580 or DT880 without distortion, given very dynamic music."

Satisfied?

Is a headphone amp needed?

Reply #58 –
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What is it that you question from me exactly? That you can not exceed the available rail voltage of the amplifier?

"There's a guy on a forum I frequent who is insisting that nine volts is not enough to amplify high impedance headphones like the HD580 or DT880 without distortion, given very dynamic music."

Satisfied?
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'Highly dynamic music' should be specifically defined as music with a RMS average power of -30dB, with 30dB peaks/crest factor that max out at about 0 dBFs, since that is what my example defines. Otherwise, he may not be able to predict the specific values you mean by 'highly dynamic music'.

-Chris

Is a headphone amp needed?

Reply #59 –
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'Highly dynamic music' should be specifically defined as music with a RMS average power of -30dB, with 30dB peaks/crest factor that max out at about 0 dBFs, since that is what my example defines. Otherwise, he may not be able to predict the specific values you mean by 'highly dynamic music'.

Fine, I'll point that out and refer him to this thread, if he wants to read it. 

Enough discussion for me tonight... have a good one.

Is a headphone amp needed?

Reply #60 –
I have an idea in the meantime: Supply me with a clip of the music in question in FLAC format.  I'll loop it back through my soundcard with the amp in the chain, driving 300 ohm headphones, and post the resulting D->A->D file.

Is a headphone amp needed?

Reply #61 –
Well WmAx... you convinced me to not take any chances, so I modded the go-vibe for 18v operation.  No harm in it anyway, the PS caps are 25v.

P.S. I didn't get a straight answer from the Go-Vibe's builder, so I guess people can just decide for themselves based on their own measurements and/or listening tests.  Based on my understanding of electronics (which is admittedly not at Ph.D. level) I still disagree with you -- there's nothing magical about some particular voltage, it's the design of the amp that counts.  But why take chances.

Is a headphone amp needed?

Reply #62 –
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I still disagree with you -- there's nothing magical about some particular voltage, it's the design of the amp that counts.  But why take chances.
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Nothing magical about it. My music requires voltage beyond the amount available with a 9VDC supply. Maybe your music does not have the same magnitude of peaks. Or maybe the peaks are at or near the same magnitude, but are short enough in duration that it is hard to hear the clipping when it occurs. Unfortunately, I have several examples in my music where the peaks are sustained frequently enough that the clipping is very noticable and distracting.

-9VDC supplied amp can pratically supply about 2.4 VRMS, or 2.76VRMS under absolute ideal conditions(which involves a brand new fresh battery).

-The DT880 requires 1.72 VRMS to reach 96dB.

-The very dynamic work that I used as an example has an average RMS level of -30dBFs in most of the content, with several continous significant peaks at about 0dBFs.

-If I listen to the music at an averaged volume level at 73dB(this now means that -30dBFs is 73dB), that means I need to be able to reach 103dB to accomodate the 30dB peaks. Note: I did not even listen at 73dB on average when I set the volume for cofortable listening in the analysis. I was trying to find an absolute minimum acceptable volume level. But 73dB is perfectly reasonable, and if my environment had not been totally silent I would have wanted to listen at about 73dB average for this particulare selection.

-Refer back to the 1.72 VRMS =  approx. 96dB on the DT880(as the actual measured response to that voltage)

-To reach 103dB requires over 4 VRMS

-4VRMS is not availabe on a 9VDC powered amp(unless DC-DC convertor is used internally to boost voltage, or a transformer is used on the audio outputs).

-Chris

Is a headphone amp needed?

Reply #63 –
So let's sum up in layman's language: You played extremely dynamic and loud music at an earsplitting volume, and found that the amp didn't react well.  Crank practically anything up and it will distort.

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DT880 on a G0-VIBE?

Yep.  No problems here, and neither will most people it seems.

Is a headphone amp needed?

Reply #64 –
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So let's sum up in layman's language: You played extremely dynamic and loud music at an earsplitting volume, and found that the amp didn't react well.


I was not aware that 70-73dB was considered ear-splitting.

-Chris

Is a headphone amp needed?

Reply #65 –
You are an intractably stubborn fellow.  You honestly don't believe that the design of the amp plays *any* part in this experience of yours? 

Is a headphone amp needed?

Reply #66 –
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You are an intractably stubborn fellow.  You honestly don't believe that the design of the amp plays *any* part in this experience of yours? 
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The only limitation evidenced is one of voltage.

-Chris

Is a headphone amp needed?

Reply #67 –
BTW... could a moderator move this part of the discussion to a separate thread? 

It's an interesting claim extending to people using their high impedance cans with soundcards, portable players, and any other device that supplies 9v or less to the opamp (or so I gather), but it is somewhat off-topic to the thread title and starter post IMO.  If I'm wrong, then just deleting this post would do. 

Is a headphone amp needed?

Reply #68 –
Huh. I didn't know you post here, MirrorSaw. Yeah, you need a headphone amplifier to adequately power high- and low- impedance headphones; low impedance headphones require more current to accurately reproduce bass frequencies (and thus benefit more from large coupled capacitors, such as the 2200 microfarads found in the PA2V2 or the 1800 microfarads in the Go-Vibe), while high impedance headphones require more voltage to excurse the drivers and avoid op-amp clipping.

Is a headphone amp needed?

Reply #69 –
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An 'optimal' headphone amp need not be costly. For less than $80, one can get a Behringer UB1202 small size mixer which has a superbly performing hedphone amplifier


looks pretty coolish, how would this work in a case of:

sources:
- 2 computers
- 1 mic
- 1 dv tape device

output:
- boxes - yamaha msp3
- headphones

as permanent solution?

i just need something like that to defeat the cabling issues - for listening.
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Is a headphone amp needed?

Reply #70 –
Quote
Quote
An 'optimal' headphone amp need not be costly. For less than $80, one can get a Behringer UB1202 small size mixer which has a superbly performing hedphone amplifier


looks pretty coolish, how would this work in a case of:

sources:
- 2 computers
- 1 mic
- 1 dv tape device

output:
- boxes - yamaha msp3
- headphones

as permanent solution?

i just need something like that to defeat the cabling issues - for listening.
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It would work perfectly for that situation, since you have multiple input sources(12 channel inputs, 4 of which have mic preamps) and outputs(a fixed tape line out can be used to the msp3 and then you have the seperate headphone amped output with it's own discrete volume control to use with headphones).

-Chris

Is a headphone amp needed?

Reply #71 –
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Huh. I didn't know you post here, MirrorSaw. Yeah, you need a headphone amplifier to adequately power high- and low- impedance headphones; low impedance headphones require more current to accurately reproduce bass frequencies (and thus benefit more from large coupled capacitors, such as the 2200 microfarads found in the PA2V2 or the 1800 microfarads in the Go-Vibe), while high impedance headphones require more voltage to excurse the drivers and avoid op-amp clipping.
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The current provided by a typical portable audio player is sufficient to function properly with the overwhelming majority of low impedance headphones. In fact, such devices are designed with low impedance headphones in mind. Such excessive capacitance value as listed by your example serves no functional purpose in a normal headphone amplifier. The real purpose seems be one of marketing.

-Chris

Is a headphone amp needed?

Reply #72 –
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Quote
Huh. I didn't know you post here, MirrorSaw. Yeah, you need a headphone amplifier to adequately power high- and low- impedance headphones; low impedance headphones require more current to accurately reproduce bass frequencies (and thus benefit more from large coupled capacitors, such as the 2200 microfarads found in the PA2V2 or the 1800 microfarads in the Go-Vibe), while high impedance headphones require more voltage to excurse the drivers and avoid op-amp clipping.
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The current provided by a typical portable audio player is sufficient to function properly with the overwhelming majority of low impedance headphones. In fact, such devices are designed with low impedance headphones in mind. Such excessive capacitance value as listed by your example serves no functional purpose in a normal headphone amplifier. The real purpose seems be one of marketing.

-Chris
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The current provided by a typical portable audio player is usually less than 15ma per channel, which can lead to notable distortion with low impedance headphones that require more current draw - I'm not sure to which headphones you refer when you say "overwhelming majority;" I'm sure many of the exceptionally sensitive cheap headphones designed specifically for volume headroom and tuned for bass resonance are more than adequately driven by a portable player's voltage swing of less than 2v at less than 30ma total output current, but I wouldn't want to use less sensitive 32ohm headphones with any less than 50ma per channel available. Further, the capacitors are there primarily for dynamic headroom; they supply current for particularly taxing excursions where an op-amp's steady output would be insufficient. That's the "real purpose" of coupled output capacitors, nothing nefarious there (although I agree that 2200microfarad is rather in excess of what is necessary, especially with a low voltage op-amp, but it extends the flat response considerably beyond the audible spectrum and into sub/hypersonics).

Is a headphone amp needed?

Reply #73 –
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The current provided by a typical portable audio player is usually less than 15ma per channel, which can lead to notable distortion with low impedance headphones that require more current draw


My typical audio player(Zen Extra) as a real-world example, has zero trouble providing 27mA per channel of continous current, when driving 32 0hms at it's full scale approx. 0.86VRMS. Distortions as measured under this condition are below any known audible thresholds.

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- I'm not sure to which headphones you refer when you say "overwhelming majority;" I'm sure many of the exceptionally sensitive cheap headphones designed specifically for volume headroom and tuned for bass resonance are more than adequately driven by a portable player's voltage swing of less than 2v at less than 30ma total output current,


I refer to the overall 'vast majority', regardless of price, because there are few exceptions that are both low impedance and low sensitivity. Examples of low impedance headphones that are not cheap, that operate perfectly on the output voltage/current of a typical portable audio device on most musical tracks: Sony MDR-R10, Sony MDR-CD3000, Grado RS-1, Sony MDR-010, Audio Technica ATH-900. In the case of very dynamic music, as my prior example, some may not have sufficient volume level, rendering the music too quiet. But no clipping should occur in these closed systems, because the gain should be limited to under the voltage driving ability of the internal amplifier when at 0dBFs.

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Further, the capacitors are there primarily for dynamic headroom; they supply current for particularly taxing excursions where an op-amp's steady output would be insufficient. That's the "real purpose" of coupled output capacitors,


No one is claiming that capacitors should not be used in the power supply. But I am not sure what you are referring to as coupled output capacitors, because the 2200 uF caps in the amp you suggested, for example, should be power supply capacitors, not output coupling capacitors. I suspect you made a typo here.

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nothing nefarious there (although I agree that 2200microfarad is rather in excess of what is necessary, especially with a low voltage op-amp, but it extends the flat response considerably beyond the audible spectrum and into sub/hypersonics).


I am not sure what you mean by this. Back to the typo, I think. Most portable amplifiers do not use coupling capacitors on the outputs. Many portable audio players do use output coupling capacitors, however, that may cause very low impedance(<30 ohms) cans to have a slight audibly attenuated low frequency response. Output coupling capacitors server as safety devices, protecting the transducers from DC related problems/amplifier shorts/etc.. The capacitors act as high-pass filters when used in series on an AC signal, such as the configuration of output coupling capacitors.

-Chris

Is a headphone amp needed?

Reply #74 –
I've gotten a reply from someone I consider an expert on these matters (who will remain unnamed, unless they wanted to join the thread themselves).

Quote
Under demanding conditions, 9V is inadequate for any high impedance headphones with any opamp.

So WmAx, it seems I owe you an apology for calling your amp a piece of ****, and for being confrontational.  I apologize.  It was something of a shock to find this out, given my own listening experience and the sheer number of lower voltage amps out there.  I'm going to be much more selective in the future with amp choices (including built-in amps in devices like soundcards, portables, receivers, etc).