Mark Hammer's Ultraballz


  • F1
    controls the cut-off frequency of filter 1
  • F2
    controls the cut-off frequency of filter 2
  • Sens
    controls the sensitivity of the effect to the input signal
  • Att
    controls the attack speed of the filter
  • Fuzz
    turns the fuzz on and off
  • Decay
  • Split
    switches between normal mode (2 filters, 1 output) to a mode where each filter has it's own output


Mark Hammer

The "Ultraballz" is just a clone of the Electro-Harmonix Baseballs circuit, with a few modifications:

  1. The trimpots used to tune the filters in the original are replaced with pots mounted on the chassis. They let you revoice the sound of the filter very nicely staggering the filter sections by different amounts produces lots of different sounds.
  2. The original uses the distortion from the envelope follower section built around a 1458 dual op amp for its "fuzz". There is a passive resistive divider to bring the signal level to about what the non-fuzz signal is. I thought the fuzz sound wasn't very good so I replaced the resistive divider with a 2 diode clipper to ground for a more consistent and intense fuzz sound.
  3. I inserted a variable resistor to adjust the attack time from slower than stock to faster than stock. The stock one uses a relatively fast attack time which makes the rise of the filter hard to hear. Even though it does not have a reverse sweep like the Mutron, it *sounds* like it does. Extending the attack time makes the rise part of the sweep cycle more evident.
  4. I have a 2 position switch that adds another cap in parallel with the existing decay cap in the envelope follower. This extends the decay time for a gentler, more ripple-free fall/decay. It also can extend the attack time.
  5. I have a "split" function, which sends the two filter outputs to different output jacks. This permits stereo processing of a sort, but also functions as a kind of pick-your-favourite-filter-range function, and also mimics a Dr. Q, which has the same filter topography but only one filter section.

All in all, it results in a much more flexible unit capable of a broader range of tones and uses.

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envelope-controlled envelope follower amplitude controlled fx pedal stompbox stomp box guitar effects pedal filter eq/excite/filter distortion/fuzz/overdrive dirt grit bandpass bp bpf band-pass filter
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