Help with LM4950 base amp

[Pablo]

Please help,

i'm trying to build an amp based on an LM4950 (similar to the one javacody posted a while back) with a ROG Supreaux for the front end. i had it running great with the amp (on perfboard) running at 12v and the the Supreaux (on breadboard) running on 9v but when i try to run them both on 12v it works but i get an undesireable distortion/noise in the background.  

now the questions:
1. what components do i need to change to run the supreaux on 12v?
2. my power supply actually puts out 13.85v, is this to much?
3. the trimmers are adjusted to half the supply voltage, right?
4. could the higher voltage on the breadboard be part of the problem?

Thanks for any and all help

[Lonestarjohnny]

You can do that, the fet's can handle up to about 20 volt's, so 13 should be ok, you'll have to rebais your fet's for 6.9 volt's if you run it on 13.8 volt's, bias is half of your B+,
and your Capacitor's on your circuit board will have to be rated for 14 volt's or more to be on the safe side.
alway's check your data sheet to see how much voltage your fet can handle.
Johnny

[dolhop]

You most likely have a grounding issue of some sort.    Probaly a massive ground loop.  Ensure that all of your grounds are brought to one spot, preferably closest to the input jack.    

Are you supplying these circuits from wallwarts?  Were you using individual wallwarts before and now a single unit?  If you are using an unregulated wallwart, you could be drawing too much current and getting a lot of ripple on the supply lines casuing some noise.