Scott Stites KLEE 2 Sequencer
This page is dedicated to the KLEE2 i plan to build. It's a supercool project and there is even a set of PCBs available soon. Check out the electro-music forum for further information:
This project is still in progress so schematics and/or frontpanel design may be amended as long as you see this words! You can build it the way the current schematics suggest.
The following schematics are from scott stites revision 3 and offer different scaler and output options to choose from.
This circuit allows one to:
1. Externally clock the Klee
2. Manually step the Klee
3. Program the Pattern Switches
4. Externally load the pattern
5. Manually load the pattern
6. Automatically load the pattern under control of the Gate Bus
We'll start at the clock input. It's ripped straight off of Ken Stone. A signal applied at 'Clock In' will produce a high out of U1B when its voltage exceeds the reference voltage of approximately 2V. This means you can use any waveshape as the clock source. This signal is inverted , converted to a negative going pulse, and the pulse is inverted again before it is applied to pin 1 of U3. This process produces a very narrow positive going pulse, which is used to generate the 'RClock' signal, which clocks the shift register ICs. With each RClock pulse, the shift registers shift their contents right. It's handy to be able to manually step through the sequence when tuning the various steps. Once you tune one step, you advance the sequence to the next step, tune that, and so forth. SW19 is provided for that, it's a momentary switch that, when held down, is debounced by U4. When the Manual Step switch is pressed down, it causes pin 3 of U4 to go high. As long as the switch is held down, this output will be high. This high is ORed through U3 with the high or low output of the clock in comparator to produce the signal 'Clock'. So, if the clock input is high, and/or the Manual Step switch is pushed, 'Clock' will be high. 'Clock' is used by the gate bus to form the output gates and triggers. On this board, it is used to illuminate the Clock LED as a visual cue of how fast the input clock is ticking. So, either a positive voltage transition at the clock input and/or a push of the Manual Step switch will shift the contents of the shift registers right.
The shift register is 16 bits long. A normal sequencer would have one bit high and the rest of the bits low in the shift register. The Klee can do that, but it can also make more than one bit high - you can have all 16 bits high if you'd like, which wouldn't get you anywhere, but you can. The Klee2 uses two CD4034s as its shift register. The Klee configures the CD4034s so that they each have 8 parallel inputs and 8 parallel outputs. That is the key to the programability of the Klee. Each of these parallel inputs (16 total because two CD4034s are used) can be either high or low. Lets say the shift register is empty:
and you have all of the parallel lines low - *except* the first line, which you've set high:
The output bits of the shift registers are all still low - you have to tell the shift register to load your one bit. So you hit 'load' and the output of the shift register is now:
Now RClock clocks the shift register, and, behold, you now have:
RClock clocks the shift register again, and now you have:
And so on. On the 17'th count, that one bit would loop around back to position one. It's a normal sequencer.
Now, each of those bits has a pot associated with it. Lets say the first four bits have pots set for the following:
Bit 1 = 1V, Bit 2 = 2V, Bit 3 = .5V, Bit 4 = 3V
So your sequencer output is:
Step 1 1V, Step 2 2V, Step 3 .5V
Let's say you've selected more bits to be loaded, i.e. you set switches 1 and 2 'on' and hit the load switch: your shift register now has this pattern:
Now RClock clocks the shift registers and you have:
Again RClock clocks the shift registers:
And so on, with the bits looping around to the beginning once they run out of register.
But wait a minute: what's the voltage output now? The voltages of the active stages adds together! Now you have:
Step 1 = 3V, Step 2 = 2.5V, Step 3 = 3.5V
This is the "Klee" experience.
So, back to the circuit. The Load In input is supplied so that external signals can initiate a load of the bit pattern selected by the pattern switches. It works the same way as the clock in. Manual Load SW18 is a momentary switch that is debounced and produces a narrow positive going pulse when it is pressed. U3 allows a pulse supplied by an input signal or a press of the Manual Load switch to be passed on to pin 8 of U3. Pin 9 of U3 accepts a signal that originates from the bus matrix (Bus 1). When the Bus 1 Load switch, SW17, is closed, any stage that is directed to bus 1 will initiate a load when it goes high. It's function is as a sort of reset/reload. With 1 bit patterns, it allows one to have a count anywhere from 1 to 16, with more than one bit loaded, it truncates the pattern even differently, but the main point to remember is that this allows the pattern to reload itself before completely looping around. So, a transition to high on the Load In Input, a push of the Manual Load switch, or a high selected from the gate bus will all produce a pulse that causes the shift register to load the pattern selected on the Pattern Switches.
Paul Klee:
Der Paukenspieler
scaler v1?scaler v2?scaler v3?
cv output v1gate bus?cv output v2
cv output v3
merge function off for both busses
one bit active in register
merge function on for both busses
one bit active in register
It will look like this.
his site...frontpanel designconstructionschematics
know the klee (manual)Glossary (mnemonic table)?schematics rev 3
Synth DIY
last update 16 SEP 08