twisted electrons MK2 TherapSID MKII Desktop SID Synth User Manual

twisted electrons MK2 TherapSID MKII Desktop SID Synth User Manual

Thanks! Overview

Thank you for adopting Therapsid, the ultimate SID synth!

About the SID chip:
The MOS Technology 6581/8580 SID (Sound Interface Device) is the built-in Programmable Sound Generator chip of Commodore’s CBM-II, Commodore 64, Commodore 128 and Commodore MAX Machine home computers. It was one of the first sound chips of its kind to be included in a home computer prior to the digital sound revolution. Read more: http://en.wikipedia.org/wiki/MOS_Technology_SID.

Connectivity & Power (rear view)

TherapSid features from right to left

DC input 15V
1/4” audio inputs and outputs for both chips (mono TS)
MIDI input & output
CV pitch input, Gate input (1/8” TS mono) (only active when in monophonic mode) 3 LFO override CV inputs (1/8” TS mono)

The Audio in enables you to run any audio signal through the SID’s filter path.

Please use the supplied power supply!

TherapSid requires a centre positive DC voltage source of 15v at least 200mA.

Preset load/save

Therapsid can hold 99 presets in its EPROM.

Load
Press the up/down buttons to scroll through the presets.
Preset number appears on the display.
Save
You can store the current sound to any preset slot:

1. Press both preset up and down buttons simultaneously activate save mode.

2. The destination slot number will flash, press preset up or down to choose a
   destination slot.

3. Press both preset up and down buttons to save.

Preset reset
Press reset to return to preset 1 at any time.
Preset randomizer
Hold reset for 2sec to randomize the preset.

Therapsid comes loaded with 99 assorted presets to get you started

These presets are just to get you started, they are all re-writeable!

Note: The presets were created using the 6581 variant of the SID chip. They could sound different on other SID variations.

Voice Section

Therapsid’s 3 voices are laid out across the top half of the control panel. The 3
voice strips are identical in functionality, explained from left to right:

Waveforms

Each voice each consists of 4 waveforms: Square ,Triangle ,Sawtooth and Noise.
Press the corresponding button to enable or disable a waveform (indicated by
LED).
Note: Multiple waveforms can be active at the same time.

Pulsewidth
The pw knob adjusts the duty cycle of the square waveform.
Note: this has no effect on the other waveforms, only square.
Tune
The tune knob transposes the voice in semitone increments. The tune ranges
from -12 to +12 semitones (2 octaves), indicated by the 7 segment LED display. Twelve ‘o clock knob position is zero.

Fine
The fine knob fine tunes the voice (+/-1 semitone range) Twelve ‘o clock knob position is center.

Paraphonic Mode
You can activate paraphonic ( 3 voice) mode at any time by holding a waveform
button on voice 1 for 4 seconds. The LED displays PA indicating Paraphonic
mode. Voices 2 and 3 and now mirror the parameters of voice 1 but can also be
changed individually.

TherapSid always orders notes from voice 1 to voice 3 so you can hold a 2 note
chord with voices 1 and 2, and play a melody with voice 3 for example
Hold a waveform button on voice 1 again for 4 seconds to go back to
Monophonic Mode.

Glide
Adds glide aka portamento to the synth’s pitch.
More glide=longer portamentos/slides.

Sync
When set on voice1, Synchronizes the fundamental frequency of Oscillator 1 with
the fundamental frequency of Oscillator 3, producing “Hard Sync” effects. Varying the frequency of Oscillator 1 with respect to Oscillator 3 produces a wide range of complex harmonic structures from Voice 1 at the frequency of Oscillator 3. In order for sync to occur Oscillator 3 must be set to some frequency other than zero but preferably lower than the frequency of Oscillator 1. No other parameters of Voice 3 have any effect on sync.

Ring Mod
When set to voice 1 or 3, replaces the Triangle waveform output of that voice
with a “Ring Modulated” combination of Oscillators 1 and 3. When set to voice 2, replaces triangle waveform output of voice2 with a “Ring Modulated” combination of Oscillators 2 and 1.

Varying the frequency of Oscillator 1 with respect to Oscillator 3 produces a wide
range of non-harmonic overtone structures for creating bell or gong sounds and
for special effects. In order for ring modulation to be audible, the Triangle
waveform of Oscillator 1 must be selected and Oscillator 3 must be set to some
frequency other than zero. No other parameters of Voice 3 have any effect on
ring modulation.

• Attack time is the time taken for initial run-up of level from nil to peak, beginning when the key is first pressed.
• Decay time is the time taken for the subsequent run down from the attack level to the designated sustain level.
• Sustain level is the level during the main sequence of the sound’s duration, until the key is released.
• Release time is the time taken for the level to decay from the sustain level to zero after the key is released.

Filter

The SID chips are equipped with a multimode resonant filter.
The filter is the analog section of the circuit and its warm/dirty sound is what give
the SID its authentic character.

Filter Modes
Press the filter button to toggle through the 4 filter states:
Off, Low Pass, Band Pass, High Pass, Low Pass+ High Pass (notch)

Cutoff
The cut knob adjusts the filter cutoff frequency

Resonance
The res knob adjusts the filter’s resonance

Note: Depending on the type of SID chip installed, resonance can have more or
less effect.

LFO Modulation

Therapsid has 3 LFOs to bring your synth to life!
Note: the LFO values are also sent as midi CCs so you can modulate other
synths with therapSid

LFO Waveforms
There are 4 LFO shapes to choose from:
Square, Triangle, Saw, Noise and Env3 (ADSR envelope of voice 3).

• Move either of the 3 LFO’s depth or rate knobs to select that LFO.
• Press the lfo shape buttons to change the selected LFO’s shape.

You can also assign no shape at all by pressing a readily lit shape. In this case the LFO’s depth knob becomes a manual controller.

Assigning LFOs to knobs
The 3 LFOs that can be assigned (aka linked) to the following knobs:

Filter Cutoff, Filter Resonance,
Tune1, Tune2, Tune3, Fine1, Fine2, Fine3, Width1, Width2, Width3,
Lfo Depth1, Lfo Depth2, Lfo Depth3, Lfo Rate1, Lfo Rate2, Lfo Rate3,
Arpeggiator Scrub, Arpeggiator Range, Arpeggiator Rate

Assigning an LFO to a knob is very easy:

• Wiggle the target knob (choose from the above list).
• Press an LFO’s chain button to link
• The chain icon is now lit indicating that the LFO is linked to your target knob

To unlink the LFO, simply press the link button again.
The chain icon will go dark again.
Note: You can assign multiple knobs to the same LFO!

Re-trigger & Loop

The LFOs don’t necessarily have to loop, you can also use them as “one shot”
envelopes, useful for pitch decay of percussive sounds for example.

The LFOs can also be re-triggered on every key press. Press the retrig button towards the bottom right of the control to toggle the retriggering On/Off

CV Override
The LFOs can be overridden by external control voltages. Simply plug a 1/8”
mono jack into a cv input to override that lfo. The expected CV range is 0-5v DC

Arpeggiator

Therapsid MKII has a brand new arpeggiator that is easy to use but can become
wild when modulated by LFO!

When active, the arpeggiator re-triggers LFOs The arpeggiated notes are also transmitted via MIDI

Arp Modes
The arpeggiator has five modes: OFF, UP, DOWN, UP/DOWN, RANDOM
press the mode button to toggle through the available modes (displayed on the 7
segment LED display).

Scrub
You can use the scrub knob to jog through the arpeggiator notes. This is particularly powerful when linked to an LFO. Note: The arpeggiator has to be in OFF mode for Scrubbing to work.

Rate & Range

Use the rate knob to adjust the speed of the arpeggiator and the range knob to
set the octave span (1-4).

Note: the arpeggiator syncs to MIDI clock.

MIDI

TherapSid can transmit and receive MIDI. A little dot at the right of the first LED
digit indicates incoming MIDI, a dot at the right of the second LED digit indicates
outgoing MIDI.

MIDI Channel Selection

TherapSid can receive and send MIDI on the channel of your choice. You can individually change the input and output channels at any time by following these steps:

• To select MIDI input channel: Hold Arp Mode and press Preset Up Now the input channel is displayed on the led display. Change the MIDI input channel (1-16) with the Preset Up/Down buttons When done, confirm with a final press of the Arp Mode button. Display goes blank and the channel is saved to EEPROM.
• To select MIDI output channel: Hold Arp Mode and press Preset Down
  Now the output channel is displayed on the led display. Change the MIDI output channel (1-16) with the Preset Up/Down buttons When done, confirm with a final press of the Arp Mode button. Display goes blank and the channel is saved to EEPROM.

Triggering Voices Separately

If MIDI channel input is set to 1 you can trigger voices 1 2 and 3 individually on
MIDI channels 2, 3 and 4 respectively. When the input is set to another channel therapSid on responds to that channel.

MIDI Preset Management
You can transfer all presets to and from a computer via MIDI System Exclusive
(SYSEX) transfers. This is handy to back up or share your presets with fellow
TherapSid owners.
To transmit (dump) SYSEX:
Hold Preset Down during startup. The SYSEX is automatically sent out of the
MIDI port.
To receive SYSEX:
Hold Preset Up during startup. TherapSid will enter SYSEX receive mode,
indicated Re on the LED display panel.
You can now send the SYSEX you previously dumped to therapSid.
At the end of the transfer, the Eeprom will be updated. This takes around 13
seconds. The progress % is indicated 0-99 on the LED Display.

MIDI Controller Implementation

Note: the knobs and buttons (AND LFOs!) send their corresponding MIDI CCs
out too, so you can double therapSid as a powerful MIDI controller for other
synths!

Firmware updating

Therapsid supports firmware updates via MIDI system exclusive messages (sysex).

The firmware version is displayed for 1 second on the 7segment led display during
startup.
Please check the therapSid page online for the latest firmware:
http://twisted-electrons.com/therapsid/

To enter update mode aka boot-loader:

unplug the unit’s power cord.
hold the filter type button down (bottom left of control panel) while plugging the unit power back in.

Every other LED on the control panel will be lit indicating that boot-loader mode is active and ready to receive the sysex from your computer.

Pc

For a windows pc, we recommend MIDI-OX. It is a free and very useful app!

1. Launch MIDI-OX
2. In the Sysex window, choose Command > Window > Load File and navigate the location where you stored the file.
3. Choose Command Window > Send Sysex.

Mac

For a mac, we recommend SysEx Librarian. It is also free!

1. Launch SysEx Librarian.
2. Select your MIDI interface in the drop-down menu at the top (if it’s not already selected)
3. Drag the MIDI SysEx file from the Finder into the frame of SysEx Librarian (if it’s not already in there).
4. Select it with the mouse.
5. Click Play

Multi SID

Although TherapSid is fully functional with a single SID chip. TherapSid supports a second chip. There are 4 Fat Modes to better take advantage of the dual chip setup:

To toggle through the Fat Modes, hold arp mode for 3 seconds.
Fat Mode is then displayed on screen and saved to EEprom.

• F1 Mirror Mode: Both Chips have the exact same data transmitted.
• F2 Octave Mode: Chip #1 is one octave above Chip#2
• F3 Slightly Detuned Mode: Very slightly out of phase leading to some nice panorama effects
• F4 Super Fat mode: Killer 6 Saw fatness!

SID Access and Configuration

Ensure that therapSid is powered OFF.
Remove the 6 screws from underneath the unit using a 2mm Allen key.
You can now remove the bottom part of the chassis to access the SID chip(s).

IMPORTANT: Be careful not to cross thread the screws upon reassembly!
Use the Allen key to recenter the brass posts within the holes if necessary.

If you are having difficulty removing or replacing the bottom chassis try releasing the 1/4” Jack nuts a little…

When installing the chips make sure that the C shaped notch is pointing to the left.
The print on the SID chips should be oriented like on the above photo.

Use the DIP switches to configure the chips as follows
8580/6582: 6581:
123 UP:   123 DOWN
456 DOWN:   789 UP

PLEASE SET THE SWITCHES TO THE 2 ABOVE SETTINGS ONLY!

To remove a SID chip gently lever the chip up on one side, enough to lift it about 30 degrees, Then sliding a flat blade screwdriver under the chip can help lift it straight from underneath.

References

• Commodore CBM-II - Wikipedia
• MAX Machine - Wikipedia
• Digital sound revolution - Wikipedia
• Programmable sound generator - Wikipedia
• TherapSID | Twisted-Electrons

Read User Manual Online (PDF format)

Download This Manual (PDF format)

Download this manual  >>