Excelsior Tone Control
The second version of the Excelsior tone control is now available! Go to the end of the Mod Kits and Services page if you wish to order it.
This is the second version of the “real” tone control, and it gives you a full range of tones, from dark and thick to very bright. You can pull up on the tone control to bypass it completely and get the amp’s raw tone. You can hear this version of the control in the video at the bottom of this page.
Here’s a little background:
The Excelsior was designed to be an offbeat, oddball amp from the start. The bright-dark switch is just one of the goofy design decisions that makes the amp fun, but also limits it.
One of my first mods was to substitute a 500K pot for the switch, to make the transition from the bright to the dark setting continually adjustable. You can hear the effects of that mod in this video:
It’s not bad, but the range of tones is somewhat limited, especially on the bass end. I felt there were better-sounding versions of the single-knob tone control. In the videos below, I test two versions of the same control. I designed it so all the components are mounted on the control, and there’s a pull-up to bypass the control and get raw tone. The control attaches to the existing circuit with two wires. Other than removing the switch, there are no other modifications required.
It’s hard to capture amp tone with a camcorder, but I also don’t have the time to properly mic the amp and mix it into the video. (I tried an external SM58 plugged into the camcorder, but there was a lot of hum.) To hear these recordings properly, you need earphones or good speakers. From the emails and messages I received, the votes were unanimous for the second version.
Installation of the tone control is fairly easy. All of the components are mounted on the control and pull-up switch, and it attaches to the Excelsior with two solder connections. You don’t have to remove any components from the circuit board. There is no clipping or cutting. Just desolder the switch, enlarge the slot slightly with a file, and install the control according to the provided instructions. I supply the brown vintage-style knob with the kit.
By the way, the white lines on the knobs are 1/16 inch pinstriping tape. I got tired of not being able to see the molded pointers.
Here is the first version:
And here is the second version: