Hi Rich,
in my opinion, the problem described (volume "instability") cannot have anything to do with the fact that you initially used
balanced cables.
• As you have correctly stated, the output jacks of the T5 are
unbalanced. If you use a balanced (TRS) jack plug, the middle contact (Ring) does not receive a signal because the Ring contact is
not connected inside the T5 output sockets. A balanced input on an active speaker or mixer then only receives "half" the signal (only the
plus-phase on XLR pin 2). This basically leads to a much quieter signal (-6dB) and can also lead to hum, as the input for the
minus-phase (XLR pin 3 = Ring contact of the TRS plug) is OPEN.
• By the way, you
don't necessarily have to use DI boxes to connect the T5 to balanced inputs. If you are using relatively short cables (maximum 3 - 5 meters) it is usually sufficient to work with unbalanced cables. To do this, the XLR pins 1 (ground/shielding) and 3 (minus-phase) simply have to be bridged. This can be done either in the XLR plug or in the jack plug. When using a TRS plug, it is sufficient to connect the Ring contact to ground/shield contact and the cable is unbalanced.
In addition, unbalanced cables should not be laid parallel to mains cables, if possible, in order to avoid hum interference. And to avoid hum caused by potential differences, the keyboard and speakers / mixer should be connected to the same power strip.
• First I recommend using the AUX OUT sockets as a test (instead of the Line Out Main sockets). The AUX OUT sockets have a
fixed volume, so they are not controlled via the Master Volume dial. Please make sure beforehand that "AUX OUT" is activated in the Mixing Console > tab "
Line Out" (not "Sub 3-4).
If the volume remains stable when using the AUX OUT sockets, there is probably a hardware problem (e.g. on the Master Volume potentiometer or in the signal path of the Line Out main sockets, or maybe a loose contact (bad solder joint) on the Line Out Main sockets).
Another way to isolate the problem would be to test whether the volume at the
headphone socket fluctuates at the same time as the volume at the Line Out Main sockets: If not, it is probably NOT due to the Master Volume potentiometer.
• If the "volume instability" occurs when playing with STYLES, it could be due to the following setting:
Please make sure that in the Style Setting display ("FUNCTION> STYLE SETTING / SPLIT POINT / CHORD FINGERING> tab STYLE SETTING") the parameter "STYLE TOUCH" is set to Off. (When this is set to "ON," the Style volume changes in response to your playing strength in the chord section of the keyboard.)
• Please also make sure that the current firmware is installed on the T5 (V1.13). This ensures that the Sliders are correctly calibrated (so that the values of the assigned parameters do not change "by themselves").
• If you have connected a Volume Pedal (FC7) to one of the Pedal sockets of the T5, I recommend configuring it so that only the RIGHT parts are controlled in terms of volume (not the entire keyboard).
• Please also check the assignment of the "Assignable Slider": Press "[Direct Access] and then move the Assignable Slider slightly. If "Keyboard Volume" is assigned here, there is a risk of accidentally changing / limiting the volume of the Keyboard parts. If not required, I therefore recommend setting this Slider to "Off".
Hope this helps!
Best regards,
Chris