Thanks for the very quick response from teemuk. Looks like just what I needed and also introduced me to what looks like a very useful site in http://www.about-guitar-amps.com

Thanks again.
Tomcat

Question from a newbie! Have G50R CD and use it at relatively low level with guitar sound primarily from house PA. At the volume I use the amp I find the line out level too low to feed the mixer (Excess noise etc) Does anyone know where I could get my hands on a schematic for this amp so I can look at modifying this part of the circuit. Obviously a lot easier with a schematic than "bush-ranging" without.
Cheers,
Tomcat