Can external amplifiers damage IEMs that have been built with battery powered portable personal audio devices in mind? How?
Sep 22, 2018 at 2:06 PM Thread Starter Post #1 of 5

deafmutelame

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I'm considering the purchase of the Campfire Audio Atlas IEM. I found this reading the manual:

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These are the specs of the Atlas:

Specifications

5Hz–20 kHz Frequency Response
105 dB SPL/mW Sensitivity
19 Ohms @ 1kHz Impedance
Less than 1% Total Harmonic Distortion


I have got a NAD C370 amplifier that I would like to connect the Atlas to.

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In the C370 manual it says that the Output Impedance of the headphones out is: 220 ohms.

Given these specs in the headphones and in the C370 amp, would I be safe to connect the Atlas to the C370 provided I listened to it at moderate levels or could I damage the Atlas no matter at which level I listened it to?

Where it says "Atlas" read any other IEM.
 
Sep 22, 2018 at 2:10 PM Post #2 of 5
I'm sure CA means the one you are intending try (that disclaimer is just trying to avoid people from situation they can cause damage). You just have to set the volume all the way down, and increment it very tiny bit at a time. Just get a portable player. LOL.

What if you forgot to set the volume down low? Kablooey!!!!

The big stuff like you pictured has large gain for speakers. You will likely run into hearing noise floor.
 
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Sep 22, 2018 at 2:17 PM Post #3 of 5
Yep, I assume that the correct way to listen to it would be to start turning the volume up slowly. I have got an old but trusted FiiO X1 for portable player at the moment, which I'm looking to replace too, but I spend a lot of time in front of the C370, hence I'd love to be able to connect the Atlas to it, for it's such a good amp, but I don't know about the headphones output...

What does the 220 ohms OI imply vs. the typical OI in a of <2 Ω(32Ω loaded) [on the FiiO M7, for instance].

There's quite a bit of difference between 220Ω and <2Ω, but I don't know what does it imply, also in terms of hiss/noise and SQ. (n00b alert :) )
 
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Sep 22, 2018 at 2:21 PM Post #4 of 5
Yep, I assume that the correct way to listen to it would be to start turning the volume up slowly. I have got an old but trusted FiiO X1 for portable player at the moment, which I'm looking to replace too, but I spend a lot of time in front of the C370, hence I'd love to be able to connect the Atlas to it, for it's such a good amp, but I don't know about the headphones output...

What does the 220 ohms OI imply vs. the typical OI in a of <2 Ω(32Ω loaded) [on the FiiO M7, for instance].

There's quite a bit of difference between 220Ω and <2Ω, but I don't know what does it imply, also in terms of hiss/noise and SQ. (n00b alert :) )
That 220 ohm is for the headphone safety I think. So, I think the headphone jack probably be ok. You just have to start at lowest volume and see how the range is.

It's a dynamic driver so my guess is, it won't by effect by output impedance for frequency response. But I believe distortion goes up based on output impedance.
 
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Sep 22, 2018 at 3:31 PM Post #5 of 5
I'm considering the purchase of the Campfire Audio Atlas IEM. I found this reading the manual:
These are the specs of the Atlas:
Specifications
5Hz–20 kHz Frequency Response
105 dB SPL/mW Sensitivity
19 Ohms @ 1kHz Impedance
Less than 1% Total Harmonic Distortion
I have got a NAD C370 amplifier that I would like to connect the Atlas to.
in the C370 manual it says that the Output Impedance of the headphones out is: 220 ohms.
Given these specs in the headphones and in the C370 amp, would I be safe to connect the Atlas to the C370 provided I listened to it at moderate levels or could I damage the Atlas no matter at which level I listened it to?
Where it says "Atlas" read any other IEM.
The C370 uses the same amplifier(s) to drive the speakers and the headphone jack.
Which was fine in the old days when (i guess) people would use studio type (high impedance, 250-Ohm to 600-Ohm) headphones with their speaker amplifier.
If the C370 headphone jack has a 220-Ohm output impedance, it would not damage a 19-Ohm IEM (Atlas) unless you turn the volume control way up, on the C370.
But because of impedance issues, the IEMs will not sound very good, like you would get a bloated (louder, less detailed) bass or other sound issues.
Headphones in the 250-Ohm to 300-Ohm range would be best for plugging into the C370's headphone jack.
150-Ohm should ok.
For IEM (or low Ohm headphones), you could connect something like the Schiit Magni 3, to the line-output (RCA jacks) on the C370.
The Magni's headphone jacks output impedance is less then 1-Ohm,so good for low Ohm IEMs (or low Ohm headphones)
 

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