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[Impression] JDS Labs C421 (OPA2227 vs. AD8620) featuring cmoyBB, O2, T5 and UHA-4. - Page 2

post #16 of 51
Thread Starter 
Quote:
Originally Posted by rhapsodicboom View Post

would the jds c421 be "good enough" to drive the he-500 ?

 

I don't have a HE-500 to confirm, but I know it has a very low sensitivity. C421 might do the job but the new C5 is probably a better choice.

post #17 of 51

What happens when lets say you have an amp which has a frequency response of 20-20kHz jds c4and headphones are of different responses like 14-29kHz. gradops500 Would that amp not be suitable for the headphones since its only giving 20-20 range and headphones not driving those higher frequencies because its connect to that amp ?

 

looking into getting the grado ps500 but think my amp jds c421 may be limited 

post #18 of 51
Thread Starter 
Quote:
Originally Posted by rhapsodicboom View Post

What happens when lets say you have an amp which has a frequency response of 20-20kHz jds c4and headphones are of different responses like 14-29kHz. gradops500 Would that amp not be suitable for the headphones since its only giving 20-20 range and headphones not driving those higher frequencies because its connect to that amp ?

 

looking into getting the grado ps500 but think my amp jds c421 may be limited 

 

Nothing will happen.

 

Any well designed amp can outdo 20Hz-20kHz, but they only list 20-20 because that's what is important to human hearing and it is convenient (*and because many customers expect a number, even though most of them have no idea what that number actually mean).

 

The so called 14-29 is also a marketing trick. First, you likely can't hear pass 20kHz, so what good 29kHz does to you? Second, the headphone is likely never be able to produce even 20kHz in enough loudness to make it to the +/-3dB (reference to 1kHz) tolerance. So why list 29kHz? Well, it looks good on paper, and most people will not consider it a fraud when a manufacturer exaggerate the actual performance in headphone (or at least they don't know about it). That's why the officially listed frequency response for most headphone are totally useless, and only intend to mislead the public who lack the knowledge.

post #19 of 51

Thanks that was really helpful i guess its similar to marketing peak watts to RMS watts. So what exactly do you look out in an amplifier to pair it with a headphone which is meaningful, guessing it would be the power output listed. Or would it just be the matter of trying it out and hearing what you feel pleasing. 

post #20 of 51
Thread Starter 
Quote:
Originally Posted by rhapsodicboom View Post

Thanks that was really helpful i guess its similar to marketing peak watts to RMS watts. So what exactly do you look out in an amplifier to pair it with a headphone which is meaningful, guessing it would be the power output listed. Or would it just be the matter of trying it out and hearing what you feel pleasing. 

 

The first few things to look for are the headphone impedance and sensitivity. These often are enough to tell you whether a headphone can be driven well by a portable source or an amp might be beneficial. High impedance (i.e. 80ohm or over) or very low sensitivity (under 90dB) means higher gain / volume might be needed. Too low of an impedance (under 16ohm) means more current output is likely needed. High sensitivity (110ohm or over) means you want to look for an amp or source that is hiss-free and low in gain. Of course, sometime synergy also matters if you are looking for a particular sound signature.

 

Most of the time it is not what is needed that dictates what gear to get, but what we believe that is 'missing' that makes us want to upgrade. Unfortunately there is hard to know whether what we believe in is actually real or not.

post #21 of 51

Are these suitable for CIEMs ?

post #22 of 51
Thread Starter 
Quote:
Originally Posted by hilosxdd View Post

Are these suitable for CIEMs ?


Most CIEM have too low of an impedance to be used with C421 because of the possibility of coloration. Unless we are talking about single driver, I'll suggest the new C5 instead.

post #23 of 51
Quote:
Originally Posted by ClieOS View Post


Most CIEM have too low of an impedance to be used with C421 because of the possibility of coloration. Unless we are talking about single driver, I'll suggest the new C5 instead.


I see , thanks for the tips , since when they're out ? Have not seen these models before , only have seen like O2 and C421 . Are o2 suitable for CIEMs too ?

post #24 of 51
Thread Starter 
Quote:
Originally Posted by hilosxdd View Post


I see , thanks for the tips , since when they're out ? Have not seen these models before , only have seen like O2 and C421 . Are o2 suitable for CIEMs too ?

 

O2 will works with CIEM without any problem. C5 has been out for a few months now, replacing C421.

post #25 of 51
Quote:
Originally Posted by ClieOS View Post

O2 will works with CIEM without any problem. C5 has been out for a few months now, replacing C421.
Is an odac relevant for a (frequent) traveller ?
post #26 of 51
Thread Starter 
Quote:
Originally Posted by hilosxdd View Post

Is an odac relevant for a (frequent) traveller ?

 

That depends how much you value a good sound out of your laptop and how much improvement there is going from the internal soundcard to ODAC. It will be easier just to look for a portable amp with built-in USB DAC even though it might not be as good sounding as ODAC + amp for the same budget.

post #27 of 51
Quote:
Originally Posted by ClieOS View Post

 

That depends how much you value a good sound out of your laptop and how much improvement there is going from the internal soundcard to ODAC. It will be easier just to look for a portable amp with built-in USB DAC even though it might not be as good sounding as ODAC + amp for the same budget.

Do any of the JDSLab amps have a Odac+amp ? Do all ODAC's need power supply ?

post #28 of 51
Thread Starter 
Quote:
Originally Posted by hilosxdd View Post

Do any of the JDSLab amps have a Odac+amp ? Do all ODAC's need power supply ?

 

ODAC is powered directly from the USB connection, and it is a standalone unit. You can buy a O2+ODAC combo (where ODAC is fitted into the O2 casing) from JDS Lab, but it is non-portable and must be powered by a wall adapter.

post #29 of 51
Quote:
Originally Posted by ClieOS View Post


Most CIEM have too low of an impedance to be used with C421 because of the possibility of coloration. Unless we are talking about single driver, I'll suggest the new C5 instead.

 

As a multidriver balanced armature iem user (Shure SE420, Westone UM3x, Shure SE535) i wonder what's the ear sensivity to frequency response deviations caused by output impedances drving swinging impedances.

 

I wonder if is there any well established convention that states 1 decibel, 2 decibels or...kind like the 1/8 rule.

post #30 of 51
Thread Starter 
Quote:
Originally Posted by elfary View Post

 

As a multidriver balanced armature iem user (Shure SE420, Westone UM3x, Shure SE535) i wonder what's the ear sensivity to frequency response deviations caused by output impedances drving swinging impedances.

 

I wonder if is there any well established convention that states 1 decibel, 2 decibels or...kind like the 1/8 rule.

 

That really depends on the impedance interaction between the amp and the specific IEM. Since every IEM has its own impedance curve, interaction will be different as well. But the general consensus is that 1dB variance is enough to be noticeable for most human. Of course, whether the coloration is a good or bad thing is largely a personal opinion. But in the quest of fidelity, the goal is try to avoid unnecessary colortion as much as as possible.

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Head-Fi.org › Forums › Equipment Forums › Portable Headphone Amps › [Impression] JDS Labs C421 (OPA2227 vs. AD8620) featuring cmoyBB, O2, T5 and UHA-4.