hum

[Marius Kaizerman]

Hi,

I've build the riaa preamp from here:
http://www.paia.com/riaa.htm
and the dual power supply that feeds it from here:
http://www.albertkreuzer.com/psu01.htm
(I've used 7809 and 7909 instead of the 15v regulators)

If I feed the preamp with two 9v batteries, all is ok.
However, using the above power supply there's a
strong hum noise.

Anyone can help ?

Thanks!