Firmware: v2.71.0, but I think non only
OS: Windows 7
Global Settings: factory defaults (Helix with a complete factory restore)
Bug: Suspected malfunctioning of the Channel Volume, introducing unwanted parallel distortion.
(Step by step description of how to reproduce bug)
A little introduction is necessary before the description of the problem, the following steps should demonstrate not the problem but a trick to solve it partially an temporarily.
VERY IMPORTANT NOTE:
DURING THE PROCEDURE, PAY ATTENTION MANAGING THE VOLUMES LEVELS, WRONG SETTINGS CAN DAMAGE YOUR HEARING!!!!!!!
BE CAREFUL
Create a completely new preset;
Add a AMP+CAB block (one you really know well how it works, one you use very often, better if you start with a distorted one);
Set the CHANNEL VOLUME parameter at 0
Add at least 2 stereo GAIN blocks after the AMP+CAB, each one settled at +12db;
Set the output level of the OUTPUT block to comfortable level for you (I used +20 db);
Play with the AMP+CAB varying the parameters at your taste.
After this, first of all is very important you understand if the chosen amplifier is working really so much better than ever, for me certainly, otherwise it could not be a bug forwardable to Line 6.
As rebuttal do the following steps:
Disable the two gain blocks;
Rise very carefully the CHANNEL VOLUME continuing to play.
Finally I want to say, only to know I'm not a newbie, that:
I have a very big experience with Line 6 product;
I have been playing for 35 years;
I had a multitude of different amplifiers and multi-effects in the past;
I have a large knowledge of musical instruments and surroundings.
So, let me know your experience, to understand if I found something very useful or it's only a dead end.
Personal note:
I have the suspect that CHANNEL VOLUME is working in parallel for the processed and unprocessed CAB block signal, so in fact lowering at 0 the parameter you reduce at minimum the unprocessed signal intervention.
I'm very interested in your opinions so be free to comment.