Is this all RF interference?

[smoguzbenjamin]

Hey all!

To boost my wireless reciever I used an LM386 preamp I had in a plastic box. BUT my boss octaver gets totally confused and when I turn my metalzone on I get nothing but a low buzzing noise and LOTS of staticy noise. What am I hearing? I run the preamp from a seperate 12v wallwart and it's got a neat diode in it to prevent ground loops. But still this noise!!!!

Would moving it to a metal container help at all? :?

[Paul Perry (Frostwave)]

Maybe the 386 suffers from ultrasonic oscillation?

[smoguzbenjamin]

Nah I used a tiny 1nF or so cap from pin 7 to ground to stop it from doing that. I get the same hum with my LPB, but the LPB just doesn't get near the right volume. I'll get a metal case and see.

[Peter Snowberg]

It still could be ultrasonic oscillation. Sound like it's time for a scope!
Now that you can work, it's time to start saving those Euros to get one.

Take care,
-Peter

[puretube]

yep, you hear your plastic box (or at least that what`s creeping into it)....