Aleph Null
Well-known member
The Weeble is my take on Tim Escobedo's Wobbletron, a true phase vibrato. Phase vibrato has a depth and dimensionality that I don't hear in delay based vibratos. Because the amount of pitch bending is frequency dependent, where you play on the neck, pickup selection, and tone controls can all effect the depth and quality of the vibrato.
I used "sea breeze" for the enclosure color and a Japanese wave theme for the pattern.
I used through-hole JFETs because I had them, but the PCB will accommodate surface mount as well.
I've added a second phase stage which allows for extra depth as well as more vibrato at slower speeds. The LFO is left unchanged other than allowing half the minimum speed of the Wobbletron because it's already giving about as much as it can. The capacitors in the all-pass stages really do make a difference in the tone of the effect. With Throb and Chop off, you get a magnatone kind of sound simillar Tim's design, but with much more depth available and the option for going half as fast. Throb changes the knee frequency of the first all-pass filter. When engaged, it can get a little into Univibe territory. Chop changes the knee frequency of the second all-pass filter. This is more dramatic a change than the Throb control and almost sounds like tremolo at faster settings. The first half of the Depth control provides a smooth warble. Beyond that, it starts to get choppy at most speeds.
Despite being close to unity gain, this is not a high-headroom effect. Sending the signal through two JFETs limits the dynamic range. For most guitar signals, this shouldn't be an issue, but this won't handle a proper line level output. That said, when it does saturate, it's pleasing; it sounds like a cat purring. Overall, I'm pleased with the range of wobbly sounds this circuit makes.
Here's a demo:
As always, if anyone would like to build this, I have extra PCBs. Just DM me.
I used "sea breeze" for the enclosure color and a Japanese wave theme for the pattern.
I used through-hole JFETs because I had them, but the PCB will accommodate surface mount as well.
I've added a second phase stage which allows for extra depth as well as more vibrato at slower speeds. The LFO is left unchanged other than allowing half the minimum speed of the Wobbletron because it's already giving about as much as it can. The capacitors in the all-pass stages really do make a difference in the tone of the effect. With Throb and Chop off, you get a magnatone kind of sound simillar Tim's design, but with much more depth available and the option for going half as fast. Throb changes the knee frequency of the first all-pass filter. When engaged, it can get a little into Univibe territory. Chop changes the knee frequency of the second all-pass filter. This is more dramatic a change than the Throb control and almost sounds like tremolo at faster settings. The first half of the Depth control provides a smooth warble. Beyond that, it starts to get choppy at most speeds.
Despite being close to unity gain, this is not a high-headroom effect. Sending the signal through two JFETs limits the dynamic range. For most guitar signals, this shouldn't be an issue, but this won't handle a proper line level output. That said, when it does saturate, it's pleasing; it sounds like a cat purring. Overall, I'm pleased with the range of wobbly sounds this circuit makes.
Here's a demo:
As always, if anyone would like to build this, I have extra PCBs. Just DM me.
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