[Matez]

Few days ago I made my first Cmoy (yupi!

) and I have a small problem with it. Everything is working perfectly except one thing: when I set the potentiometer (Alps) to nearly max (90-100%) ,plug the amp to my PX100 and source iAudio U2 the strange thing occurs. When i listen to the music while the U2 is laying on my desk - everything is OK ,when i gently hold it on my palm - it's OK ,but when i hold it in my fist I hear strange hiss and sometimes even drop of volume in my PX100. In addition when i turn potentiometer down a bit the sound is perfect - no distorions at all. I guess it's a grounding problem cause while the distorions occurs ,when I touch something connected to the ground or the ground itself the hiss disappears... Strangely ,when i connect the amp with another MP3 player the sound is ok

...

THX in advance and sry for my English

BTW. The pot is mounted to the board.

 

[peterpan188]

Did you try when you connect the headphone directly to your iPod? Does the distortion occurs when you hold it tightly?

Peter

 

[Matez]

Quote:

Originally Posted by peterpan188 Did you try when you connect the headphone directly to your iPod? Does the distortion occurs when you hold it tightly? Peter

1.I don't have an iPod - my second mp3 player is Qoolqee X2.

2.Yes ,when i hold it gently the sound is OK.

 

[ozshadow]

You should not be turning the amp up to 90-100%. Turn the source up to 90% and use the amps volume to control.

 

[Matez]

Quote:

Originally Posted by ozshadow You should not be turning the amp up to 90-100%. Turn the source up to 90% and use the amps volume to control.

I know ,but im curious why this phenomenon occurs

BTW. What is the "best" combination of position of source's volume control and amp's pot? I generaly use iAudio X5 (20mW per channel) + cmoy (gain 5.7) + PX100 (32Ohm).

 

[NeilR]

Could be oscillating. See my post in a recent thread, where this was discussed with a PPA V2, and the followup discussion.