22 plus Volume changes when switching

[super_su44]

Hi, greeting to all the guru's here.Usually I can find most of my questions in the already posted posts,but this one I can't find.I'm on my second studio 22 plus with eq. and having a problem while using the foot-switch to change from 'lead' to 'rhythm',he red light on the foot-switch comes on slowly (about a second) , during which time the volume of the amp fluctuate up and down (a little, but you can hear it), before settling to the normal volume.My foot-switch is home built using the schematic you can find on the net.I've tried changing the tubes with no result.Can anybody help me to what and where I should look into? Thanks.

 

[super_su44]

There's no volume loss when the amp is on either the "lead' or 'rhythm' mode,just when switching from 'lead' to 'rhythm' mode.I've tried connecting the 'send'and 'return' for the effect together but it doesn't solve the problem.Any help will be much appreciated.