Finished Pieces

ST808







    This piece is based on the following schematic with the following changes.
    -I’ve replaced the 4016 IC with transistor switches.
    -I only installed one channel
    -I didn’t use the 7408 ICs shown in schematic.
    I’ll include an updated schematic when I finish the piece.

    This model uses the ubiquitous 555 timer IC
    and the ultra simple, super useful 4017 counter IC.
    The effect is a glitched out sounding, programmable sequence.
    There are 8 steps in the sequence and each can be turned ON or OFF.

    As the sequence runs, it advances one step at a time, 1 thru 8, then repeats.
    When a step is set to the ON position, it activates 2 effects in the Speak&Spell for the duration of that step. The 2 effects are a tone generator and a “hold” effect.

    The schematic above shows how to locate these bends.

    “Hold” grabs whatever sound is playing and loops a snippet of that sound. So, if the Speak&Spell was saying “Spell the word PONY” and you activate the “hold” effect in the middle of “PONY”, it would sound like…..”Spell the word POOOOOOOOOOONY”.
    One of my favorite SpeakandSpell bends is the “loop” effect (see schematic). This generates random loops that repeat indefinately.

    I’ve found that interesting rhythms can be created by activating the “loop” effect, and then pulsing the “hold” effect over it. The “loop” provides a tonal backdrop and “hold” grabs bits of sound from the “loop”. If “hold” is rhythmically pulsed (using the 555 timer) it will grab sounds at regular intervals and make a constantly changing, rhythmic effect.

    The tone generator effect accentuates the rhythm and can sound nice if the sequence is changed often. If it just pulses regularly (without any variation) it starts sounding like an alarm clock.
    The sample below should clarify things a bit.

    Sounds

    5 Responses to “ST808”

    • 1

      Patrick said:
      April 1st, 2010 at 12:02pm #

      would there be a possibiliy of getting a pars list?
      Where and how does this circuit get attached to the speak and spell?
      thanks!

    • 2

      casper said:
      April 11th, 2010 at 12:31pm #

      @patrick: I’ll work on posting both of that info.

    • 3

      kitsophrenik said:
      July 28th, 2010 at 7:39am #

      i would really like to own this…. best circuit bent speak and spell ever!

    • 4

      martin said:
      September 3rd, 2010 at 9:57am #

      how do you get the speak & spell to power up without a battery compartment? i’ve tried using the power jack with 9 volt adapters with no success. does it need 6 volts?

    • 5

      Mats said:
      October 2nd, 2013 at 8:40am #

      Hi!
      Would be really interested in getting the schematic and BOM for this little beauty. Care to share with us?

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