High output impedance player with low impedance cans
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MarkCavendish

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im going straight to the topic , i have a zishan z1 which have 100 ohm output impedance (correct me if im wrong with the specification) , what if im using low impedance cans lets say earbud which have 16 or 32 ohm with 106 dB/mW sensitivity , does it any effect to drive my earbud with high output impedance player like zishan z1? im worry it cause negative effect in long term like imbalance for my earbud or it may damaging my cans , thank you in advance.
 
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MarkCavendish

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100 ohm output impedance is absolutely unusable for almost all headphones. Are you sure that spec is right?

http://nwavguy.blogspot.com/2011/02/headphone-amp-impedance.html?m=1
im also not sure there is no have exact information even at sale site like aliexpress it only describe Signal Noise Ratio:≥89dB and from shopee malay/philip says PO (earphone out) with high power @ 12V max output, driving 300Ohm below easily. and i got information from another thread https://www.head-fi.org/threads/new-zishan-z1-dsd-player-thread.844417/page-53 , which knudsen said : "I've stumbled upon the post here, where "Uncle Eric" says that

"When it comes to headphones, you generally want an output impedance lower than the headphone impedance. This is called the 'Damping Factor'."

and also

"an output impedance higher than the headphone impedance loses control of the bass".

Afaik the z1 has a 100 Ohms resistor in the signal path just before the output, so output impedance will be at least 100 Ohms. Since I use earbuds with an impedance of 32 Ohms that does'nt sound too good.

So would it/could it be beneficiary to change that tiny thing (100 Ohms SMD resistor) to maybe 10 or 20 Ohms? Or have I misunderstood everything? :k701smile:

There is a guy at a russian forum here who has changed it for 10 (bullit no. 4), but he's doing all kinds of crazy stuff so I don't know if the resistor alone is meaningful.."
well since they thread has been locked and i couldn't reply their thread so i want to ask in here
 
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castleofargh

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honestly I looked rapidly at the topic you link, and I'm not sure they all know what they're doing. several seem fine enough to go and change stuff themselves, but I couldn't find one who would clearly say that he bothered measuring the output impedance of the device(obviously I might have missed it). unless the resistors is directly in series before the plug(which seems like a pretty dumb idea), there is actually nothing to say that the output impedance will be at least 100ohm.

so I don't know what to tell you. you need one guy to measure the impedance properly. did any of those who changed the resistor provided measurements under various loads? that would provide some answers, the 3 pages I read provided none.


now for the theory, yes damping ratio is a thing and in general, modern headphones are made to work following impedance bridging designs. with the amp close to zero ohm and the headphone's own impedance limiting the current flow.
it's not a 100% thing, and the consequences can go from irrelevant to massive change in sound. it really depends on both the device and the headphone.
the safe rule is to have the headphone's impedance to be at least 8 times the amp's impedance output. that way you stay away from various things that could alter the sound. again it's not a must, more like good practice to stay away from bad surprises and have the electrical damping of the headphone fairly strong for good control of the driver.
now is it a good idea to go and remove something on a device to lower the impedance despite how it was probably soldered there for a reason? my general answer would be "don't touch anything". but for a 30$ device, if you wanna have so fun and try stuff, worst case scenario you lost 30$. you might decide that it's not a big risk.
 
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If your low impedance headphones have a flat impedance curve, then the effects of having a very low damping factor won't be much of a concern.
You won't be able to get the whole power of the amplifier, but more often than not, you won't need it anyway.

If you're using low impedance headphones with a winding impedance curve, such as most multi-driver designs, then you'll get frequency response coloration in the shape of the impedance curve.
The bigger the amplitude of the variation in the headphone's impedance curve, the more the sound gets colored. Similarly, lower damping factor means more colouration in this scenario.

You can safely pick low impedance headphones with relatively flat impedance curve or high impedance headphones.
You won't damage low impedance headphones with winding impedance curves (for having a low damping factor), but you won't hear them the way they were designed to sound.
 
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Putting a 100 ohm resistor on the output of a headphone amp seems plain nutty to me, all I can think it that they do it to affect the sound - ie less damping. An 'impedance adapter' is an audio transformer, bulky, and likely a pair to do this would cost more than the DAC, if they even exist. I've never heard of them being used in this way, except for tube gear.
 
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I am also wondering if my DAC/Amp has higher source Impedance than the headphones, if this could damage the headphones (I did read that somewhere in the past and since then this is bothering me). I couldn't find an exact answer in the posts above, so it would be nice if someone could make it more clear.

My personal hardware is the PreSonus AudioBox 22VSL: Technical Specification here

It states 60 Ohms on the headphone output. And common headphones have about 16-32 Ohms.
So is it possible, that i damage my headphones when connecting them via TRS?
And does the volume I choose on the AudioBox matter? It goes from 1-11 (no idea what unit)

I am probably totally wrong here, but I imagine this like 1 is 0 Ohm and 11 is 60 Ohm. So with a pair of 32 Ohm headphones I shouldn't go higher than ~50%.

Please enlighten me. I tried to find some info but nothing seemed to state this explicitly.

Thanks in advance
 
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I am also wondering if my DAC/Amp has higher source Impedance than the headphones, if this could damage the headphones (I did read that somewhere in the past and since then this is bothering me). I couldn't find an exact answer in the posts above, so it would be nice if someone could make it more clear.

My personal hardware is the PreSonus AudioBox 22VSL: Technical Specification here

It states 60 Ohms on the headphone output. And common headphones have about 16-32 Ohms.
So is it possible, that i damage my headphones when connecting them via TRS?
And does the volume I choose on the AudioBox matter? It goes from 1-11 (no idea what unit)

I am probably totally wrong here, but I imagine this like 1 is 0 Ohm and 11 is 60 Ohm. So with a pair of 32 Ohm headphones I shouldn't go higher than ~50%.

Please enlighten me. I tried to find some info but nothing seemed to state this explicitly.

Thanks in advance
It's actually the other way around - the resistors are used to prevent excessive current from being delivered. Usually, amps are overbuilt so so 'tone' it down they shove an in-line resistor to bring down the effective gain. They're also used to minimise the consequences of overvoltage conditions.
 
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Thanks for the fast answer.

So in easy words:
If i use my headphones with a human ear healthy music level I cannot damage them with a "non-matching" DAC/Amp?
But the Amp should not run at 100% of its power at all times since as for all technical equipment a 100% load isn't ideal over long periods of time?
 
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dazzerfong

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Thanks for the fast answer.

So in easy words:
If i use my headphones with a human ear healthy music level I cannot damage them with a "non-matching" DAC/Amp?
But the Amp should not run at 100% of its power at all times since as for all technical equipment a 100% load isn't ideal over long periods of time?
Headphones break when put too much power into it. That happens if:
- Set volume too high (but I'm talking about extremely powerful amps into very sensitive earphones).
- Poor design (see Lyr 3 for an example of bad relay design)
- Power surge (lightning storm)

As for the second one, it shouldn't run at 100% of its power ever as you'll most likely go deaf before that happens. Most amps are more than powerful enough for most headphones.
 
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