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x0x:vcftesting [2007/12/03 05:12] spandex |
x0x:vcftesting [2016/01/28 18:05] |
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- | ===== Testing and Calibrating the VCF ===== | ||
- | |||
- | ==== Testing ==== | ||
- | - Re-attach the power supply (with J4) | ||
- | - Apply 3volts to R90 (either with 2 AA batteries or a benchtop supply) | ||
- | - Probe the resonance pot with either a cheap pair of headphones or your oscilloscope. With the cutoff all the way anti-clockwise, you should see mostly a sinewave. If you're probing with headphones, you should hear a low, soft tone. When you turn the cutoff up, you should see a waveform similar to the one you have selected on the VCO. Using headphones you should hear a lot of higher overtones to the sound, and it might be buzzier and more 'acidic'. | ||
- | |||
- | ==== Calibrating ==== | ||
- | |||
- | According to the [[TB-303]] service manual, the resonance frequency should be at 500Hz. | ||
- | |||
- | - Set the waveform to saw | ||
- | - Set Cutoff to 50% | ||
- | - Set Resonance to 100% | ||
- | - Apply 3V DC to the VCO (or press the lower C key if your sequencer is done) | ||
- | - Ajust TM3 so that the resonance frequency is 500Hz | ||