A question about amplifiying IEM-s
May 8, 2015 at 4:48 PM Thread Starter Post #1 of 4

lakiozoon

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Is there a benefit in using additional amplification (CMOY and such) with IEM-s?
 
I have a Sennheiser cx 300 ii (16 ohm) and a CMOY. As a source I use my smartphone.
The smartphone itself has a good volume level, so I am not adding CMOY into the chain to increase the overall volume.
I was wondering does adding CMOY bring anything into the overall sound quality.
 
From what I am able to tell:
- If i set my smartphone volume to half and bring the volume up by using CMOY, it adds a noticeable level of white noise.
- If i set my volume to max, the level of white noise is about the same.
 
Is the added amount of white noise normal?
Are there any benefits in using CMOY?
 
May 9, 2015 at 12:13 AM Post #2 of 4
  Is there a benefit in using additional amplification (CMOY and such) with IEM-s?
 
I have a Sennheiser cx 300 ii (16 ohm) and a CMOY. As a source I use my smartphone.
The smartphone itself has a good volume level, so I am not adding CMOY into the chain to increase the overall volume.
I was wondering does adding CMOY bring anything into the overall sound quality.
----
Is the added amount of white noise normal?
Are there any benefits in using CMOY?

 
An additional amp is only necessary if the device is distorting on it or lacks dynamics. As it is, generally nearly all IEMs including a lot pf CIEMs with multiple drivers don't need any dedicated amplification. Most of the others only benefit a little.
 
I have the Aurisonics ASG-1.3 and the bass is bloated on the SGS3 (they actually are boosted by design, but the Samsung distorts); my Ibasso D-Zero sounds cleaner and tighter but not enough for me to strap it on. Fiio X1 has the same benefits and in a more convenient packaging, but the trade off is not hearing any incoming calls.
 
 
 
From what I am able to tell:
- If i set my smartphone volume to half and bring the volume up by using CMOY, it adds a noticeable level of white noise.
- If i set my volume to max, the level of white noise is about the same.

 
You don't hit those volume levels without the CMOY, so you never get the noise out of the phone; adding the CMOY means that with its gain it just makes that noise worse.
 
May 9, 2015 at 12:16 AM Post #3 of 4
Amplification is not just about getting more gain. Sensitive headphones or IEMs may only require a few millivolts to be loud enough, while your phone's headphone jack or DACs line output can generate over one volt. The CMOY could have lower output impedance, lower distortion, and the ability to drive more current. All of these things are important for your relatively low impedance IEMs because the output impedance is more significant, and they require relatively more current than higher impedance headphones.
 
Your phone, or any other components before the amp, will generate some level of noise. There may be noise generated at the input of the amp as well. By turning the amp's gain up, you are amplifying the noise more. It is best to set the volume on your phone higher, so that the gain on the amp can be set lower, reducing the amount of amplification that is applied to the noise. The same amplification is applied to the signal as well, but since you set the signal volume higher, you get a higher signal to noise ratio.
 
You can listen and compare them for yourself to decide if there is a noticeable improvement.

 
May 9, 2015 at 4:46 AM Post #4 of 4
I can't hear much of a difference in sound quality, so I won't be using Cmoy.
It's better for my ears anyways, since sometimes I tend to overkill the volume.
 
Thanks for the replies, you both explained it well.
 

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