Radial Engineering Ltd.
PowerTube™ Preamp
True to the Music
®
Omniport™ instrument input
If you are using a Radial Workhorse, Cube or Powerstrip, these are equipped with a ¼”
TRS jack identifi ed as Omniport. This jack changes function depending on which module is
connected.
With the PowerTube, the Omniport is an unbalanced
instrument input. This input has been purposely
‘tamed’ to sound good when recording an instrument
like electric bass or acoustic guitar direct. In other
words, we have rounded out the frequency response
to warm it up. If you want more of a glassy tone, simply
compensate by depressing the AIR switch.
As soon as you plug in the instrument to the Omniport,
it will engage a relay that will shut off the XLR mic
input. This ensures only one input is active at any one
time. Disconnect when done and the PowerTube will
automatically revert to normal ‘mic’ mode.
Changing the tube
Inside the PowerTube is a 12AX7 tube. This is mounted on a separate circuit board so that
it can fi t within the limited space afforded inside a 500 series module housing. Removing the
tube is easy. Carefully wiggle the tube out of the socket by gently moving it back and forth as
you pull it away from the socket. If you are not familiar with changing tubes, we suggest you
bring your PowerTube to your dealer and have them show you how it is done.
Changing the tube will of course change the character of the sound. The PowerTube comes
shipped with a select low noise tube. We also include a second Tonebone distortion pedal
tube for fun. These changes are often subtle as tube performance varies greatly. Try different
tubes and see how they sound. Whatever you do – do not tell anyone how you got your
secret sauce! This is part of the fun with owning a PowerTube.
7
INPUT
OMNIPORT
FEED
LINK
1
OFF
OFF
CARD SLOT 1
OUTPUT
OUTPUT
INPUT
OMNIPORT INPUT
(WORKHORSE)
