Help with Soul-O-Tube breadboard

[recoverysounds]

Hello- Trying to problem solve this Soul-O-Tube 12AUZ tube preamp breadboard I'm working on. It passes a very light signal, but there is more hum than signal. I'm using a 12dc power supply. I think the problem lies somewhere outside the power supply though. Any of you mind taking a look and offering any suggestions?

http://theanimalsatnight.blogspot.com/2009/10/tube-preamp-breadboard-in-progress.html

Thanks!

Graig Markel
www.twitter.com/recoverysounds

[Mick Bailey]

Graig,

The pictures are not clear enough to see where everything is connected and I can't see the connections to the pots and valve base.

My advice would be to simplify the build at this stage by removing the tone circuit - this is all of the components to the right of the output capacitor C5 on the diagram. If you can get it working this way you at least know that the basic circuit is operating. Make sure you leave C5 in place, though.

The hum could be coming from your power supply if it is an unregulated wall-wart. You may need to add a regulator to the input (just a 7812 and 470uf capacitor) or use a regulated power supply. 

The signal level should be pretty loud from this preamp.

Mick