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LME49720 opamp in CMOY senstitve to RF/EM interference?

post #1 of 5
11/18/11 at 11:59pm
Thread Starter 

When I put LME49720 in the socket of my BSG CMOY I am getting quite heavy inerference (about as loud as the actual sound) when my android phone (wether it's connected to it or not) connects or disconnects from WIFI. Apart from that, I was very pleased with the sound.

 

I do not have this issue with OPA2227 and OPA2604 opamps.

 

Anyone else has had such issues?

 

I did not expect such a difference in this aspect

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post #2 of 5
11/19/11 at 12:58am
in my amp i also have a 49720 and get interference, but i do with all opamps i think. I just try and keep my phone away from my amp. The 49720 is great also
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post #3 of 5
11/19/11 at 7:26am
Thread Starter 

My phone is my portable source and the amp is also used in my desktop setup (quite close to a router) so this sensitivity means that this opamp won't do it for me. Quite a pity because I do like the sound signature.

 

The difference in sensitivity with my BB opamps is quite drastic. It happens at the length of my connection cord (about 70cm) so keeping it further away from my phone is not an option.

 

 

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post #4 of 5
11/20/11 at 12:19am

thats because its probably getting in by the phones ground connection as well as through the air. since its a cmoy you should be able to fix the problem by placing a low pass filter in the opamps feedback loop or at the input to the amp, i'd say the cmoys layout has stability issues, ive never had this problem with the lme49720

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post #5 of 5
11/20/11 at 4:30am
Thread Starter 

Thanks for the input.Unfortunately my modding skills don't exceed rolling socketted opamps and tubes.

 

I think it may have been a seating issue. I rolled it back in and I am unable to reproduce the interference. I need to put the amp on top of the router to get a hint of interference now.

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