A challenge came when a friend of mine wanted to expand his
guitar setup with an effect processor. This lead to a new
problem. In some songs he needed to switch a preamp channel
and change the effect at the same time.
We came up with a solution, but it required some special
electronics. His preamp is a H&K Tubeman. An analog
tube preamp with three channels. The idea was to develop a
midi interface that will be able to switch the channels.
The switching is initialised by receiving a program change
command from the effects unit. The midi interface can save
for each program change command the desired preamp channel.
The saved preamp channel is recalled when the program
change is received again.
You can see my friends setup here.