Murata regs + Caiman = Problem??

[mcebrian]

Hi! I just upgraded my Caiman with Murata regs, and I'm a bit sad with the upgrade. Both new regs (5,12v) are in place (correctly soldered).

It works, but, there is a high level background noise that was not there before. Very annoying!!

Steps already taken:

• Use a medical-grade PSU 16V (instead of 15v because of Vdrop from the diode) :: Result: NONE. Same noise.
  
• Try to put two caps 100uF 25V between pin 1 and 2 of the regs (as described in datsheet). :: Result: NONE.

Same noise is at the headphone output as at the fixed line output. Noise is the same with the GATOR on or with the original PCB.
In my (bad quality) scope it appears as a constant 20-24mv wave when you generate a test signal (-120db no matters frequency) with the computer.


I paid for the Muratas and at the end it turns out that they perform worse?? At lest regarding noise performance.

On cans, background noise is perfectly audible from 12 o'clock knob volume position.

Parts involved:
Murata 7805SR-C 0.5A max Part n: B036C
Murata 7812SR-C 0.4A max Part n: B046C