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!

 

[John Woodgate]

I read in sci.electronics.design that Marius Kaizerman
<marius@kaizerman.org> wrote (in <newscache$d0731i$yg2$1@news.actcom.co.
il&gt about 'hum', on Mon, 19 Jul 2004:

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.
 
See my other reply. Have you taught it the words, though? (;-)

--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk