Tourmaster OD1 channel sudden gain increase

[jaws99]

Hi!

I have recently aquired a Tourmaster, which i just love!
To my surprise I experience a sudden unnatural gain increase on OD1 channel, turning the volume taper from between 1 and 2 o´clock.

Have any of you experienced the same? I run the amp on half-power, OD1 20 W.

Any help and/or explanation would be helpful.
Thanks!

 

[Dopethrone]

yep. the volume jump is normal.