User Manual

CHANGING THE TUBE

Your Tonebone has been designed to provide years of perfor-

mance before ever needing the tube changed. In fact, it is unlikely

that a tube change will be necessary for two to three years or more,

depending on use. Change the tube only when a degradation of

sound is noticeable.

Disassembly

1. Remove the rubber knobs by pulling them straight up. These

pressure-ﬁtted knobs should be removed with care to avoid

damage.

2. Remove the nuts and washers securing the potentiometer,

footswitch, and input/output jacks using an open-ended wrench

or socket. Please use caution so as not to mar the ﬁnish.

3. Remove the 4 bottom screws that hold the top and bottom

chassis halves together. Carefully separate them. Note that the

chassis top and bottom ﬁt snugly, so a little careful force may

be needed to clear the two side-mounted ¼” input and output

connectors. Watch you don’t lose the nylon washer between

the footswitch and the chassis top!

4. Remove and replace the tube. To do this, gently loosen the

12AX7 tube in the socket by wiggling it back and forth.

Reassembly

1. Install the PC board to the chassis top. Carefully align the

potentiometers, LEDs and footswitches with the holes in the

chassis and assemble through the top. Don’t forget the nylon

footswitch washer!

2. Attach the pot, footswitch washers and nuts (just ﬁnger-tight

for now), to allow alignment of the jacks when the bottom is

attached.

3. Carefully push the chassis bottom on, spreading the sides

slightly so as not to stress the side mounted ¼” input and

output jacks.

4. Attach the side ¼” jack washers and nuts. Do not over-tighten

the plastic isolation jacks as they can strip. Attach the 4 chas-

sis screws (don’t over-tighten). Now you can tighten up the

potentiometer shaft nuts.

5. Re-install the knobs... ﬁrst rotate the potentiometer shafts fully

counter-clockwise. Place the knobs over the shafts so they

point to 7 o’clock and push straight down.

6. Test the pedal to make sure it works… plug in the power. The

LEDs should light when you depress the footswitches and you

can see the tube ﬁlament light up through the side vents.

Radial Engineering

Classic Trimode

True to the Music