1
1/4 inch unbalanced
amp output
(this one is on the rear for the Mk II). This is just a buffered instrument input. Having low output
impedance, it is suitable for handling long cables without any problems. It doesn’t go through the tube, EQ or the transformer. Do not plug in
an instrument here.
Important information about the 60Hz (or 50Hz, depending on the country) hum and buzz:
It can occur if the unit is connected to both
a line level device and an instrument amp. This is a case of a ground loop caused by a double ground and cannot be cured by flipping the
ground lift switch.
The solution is either to lift the ground off of your amp by using a ground adapter (only
AFTER
you have connected it to the 2di4 with ground
switch set to “Ground ON” and plugged into a grounded, 3-prong outlet), or by using a signal cable that has the shield disconnected from one
of the jacks (in which case you LEAVE the amp grounded). The idea is to have the amp grounded at ONLY one point, either through its power
cord, or through the signal cable connecting it to the 2di4, which IS grounded. If you have lifted the amp’s ground, be sure to switch it off
before disconnecting the signal cord (so that it is NEVER operated ungrounded), and remove the ground adapter if the amp is to be used
standalone.
2
¼” unbalanced instrument input. Good for guitar, bass or keyboards. The impedance is 2.2MΩ.
