Thursday, July 11, 2019

Korg Poly-800 mkII mod

Before my experiments on creating multilayered and multitimbral samples for new presets for the SynthScaper app, I made some modifications the one of hardware synth that I would like to use for this. This is Korg Poly-800 mkII.



In standard form, the Korg Poly-800 is a pretty decent synth. Widely considered to be Korg's answer to Roland's affordable Juno series, the Poly-800 employed similar digitally controlled oscillators to offer early 80s consumers an alternative to Roland's budget model.

>>> More about Korg Poly-800 (Vintage Synth Explorer)



There are two most popular and relatively straightforward mods for this synth. The first adds knobs for low-pass filter cutoff and resonance to the front panel and also switch between 12 / 24 dB modes. This is the so-called Moog Slayer mod. The name probably should be taken with a pinch of salt, but there is no doubt that the filter really comes to life with additional controls.

The second is the so-called FM800 mod, which adds frequency modulation of the filter cutoff by the output signal from DCO.

Click on image to enlarge



Cutoff & Resonance knobs: This mod can be found around the net under several different names and versions but essentially it adds knob controls for the low-pass filter cutoff and resonance parameters for realtime control. The resonance knob can take the resonance well into self oscillation and far beyond what is programmable from the front panel. This can produce the kind of screaming top end and subsonic bass that gives these machines a whole new range of sonic possibilities. The filter cutoff knob allows you to perform long filter sweeps for those squidgy burbling analogue lines that you knew your Korg was capable of but could never actually program. Both parameters are still also controlled by the normal programming methods which can set the range of the knobs control.

12 / 24 dB switch: Somewhat mysteriously the filter chip used in these machines has both 12 and 24 dB/Oct outputs but only the 24 dB one is actually used. This mod adds a switch to select either a 24 dB or less drastic 12 dB filter response.

>>> Korg Poly-800 Filter mod details

In addition to the instruction above you can also add 12 / 24 dB switch for the LPF. For this just add two-pole switch that will select signal output from pins 5 or 6 of IC1 to capacitor C103 on the main PCB. You can desolder C103 and add wire from these pins to the switch on front panel.

For any connections between PCBs and controls on the front panel I recommend use only shielded audio cables where each shield connected to the GND on PCB. This will significantly reduce unwanted interference.



Filter modulation: This mod consists of  switch to select a source and the modulation amount knob. Essentially this mod allows you to modulate the LPF cutoff by the audio frequencies from DCO and create all kinds of clanging cross modulation and bizarre alien splatters & sweeps. This effect works best with the resonance cranked up into self oscillation which is where the new resonance knob mod comes into its own. The switch allows you to select DCO1 or DCO2 as source for the modulation. The source three pole switch also has an central position to off this mode.

>>> Korg Poly-800 Filter cutoff modulation details

In addition to the instruction above you can add three-pole switch which will be select the source for the LPF cutoff modulation. In the instruction above, the one pin of the modulation amount potentiometer connected to pin 7 of IC4 and resistor R74. Add three-pole switch that will be select output signal to the modulation potentiometer from DCO1 (IC4 pin 7 - R74) or DCO2 (IC5 pin 7 - R76). On the central position this switch will off the modulation mode. Also you can use for the modulation amount the linear taper potentiometer up to 10K.

The "Noise level" and "Delay feedback" knobs it is just potentiometers that were on the main PCB and on the delay PCB, desoldered and connected to the same value potentiometers on the front panel. Noise level - VR3 (1M) on the main PCB, Delay feedback - VR1 (4.7k, but can be use more, up to 10k, for more fun) on the delay PCB. 



In case you want to replace a dead battery on the main board, keep in mind that you will lose all the patches stored in memory. Look at the instructions below how-to replace battery and download factory default presets.

>>> Korg Poly-800 II Battery Replacement

>>> Korg Poly-800 mkII factory default patches



More about this project:

>>> SynthScaper experimental presets (announce)

>>> Korg Poly-800 mkII mod



SynthScaper - Soundscapes synthesizer specially designed for creating and experiments with ambient soundscapes in wide range from noises to melodic instruments and everything in between.

>>> More about SynthScaper app






Thursday, July 4, 2019

SynthScaper experimental presets (announce)

I want to try create some new experimental presets for SynthScaper app. The samples for these presets I want to make from sounds of my hardware synths (Roland Juno-60, Korg Poly-800, Korg MS2000, Moog Slim Phatty, Clavia Nord Lead, Yamaha DX, Quasimidi Sirius, etc) but with pre-processing on hardware effects. So for in result it should be multilayer presets something like drones or deep soundscapes. Or maybe something others :) Any way it will be very experimental and unusual way to use synths and effects.

These presets and samples will be available for free without any limitations and can be used with SynthScaper and SynthScaper LE. Use advanced version of SynthScaper you can completely rebuild these presets or use its samples with your own presets.

With SynthScaper LE you can use these presets in your tracks and compositions and easily vary its sounding by gliding thru layers, control the tone offset, and change attack and release with special "Tune" panel in this app.

I will try to show some key moments of this process in my blog. Interesting?



More about this project:

>>> SynthScaper experimental presets (announce)

>>> Korg Poly-800 mkII mod



SynthScaper - Soundscapes synthesizer specially designed for creating and experiments with ambient soundscapes in wide range from noises to melodic instruments and everything in between.

>>> More about SynthScaper app






Wednesday, June 26, 2019

SynthScaper LE ver. 1.2 has been released

This update fixes the AU sample rate problem and brings several improvements.

What's new:

- Fixed problem with sample rate in AU instance.
- Sound engine is updated as in the advanced version.
- Improves IAA synchronization.
- Improves MIDI synchronization.
- Audiobus SDK 3.0.6 updated.
- Ableton Link SDK 3.0.5 updated.
- Several minor bugs fixed.









[ SynthScaper LE - Tune panel ]

[ Complete description of SynthScaper LE 1.1 (pdf) ]

[ List of auto detected MIDI keyboards (pdf) ]


Demos and reviews:

SynthScaper LE - Detailed tutorial (video)

The Sound Test Room - SynthScaper LE - AUv3 - Running in Cubasis - Demo for the iPad (video)

First try with Synthscaper LE from Rodolfo Ruiz - Sound demo (video)










Wednesday, June 12, 2019

SynthScaper ver. 1.7 has been released

Synthesizer specially designed for creating and experiments with ambient soundscapes in wide range from noises to melodic instruments and everything in between.

This update improves user interface and adds new modes that make it more convenient to use with MIDI keyboards.

>>> More about SynthScaper






What's new:

  • New presets inspired by sound of vintage synths.
  • Separate ADSR when changing address mask for each voice.
  • Sequencer can use range of keys defined by keyboard scale.
  • Marks for hold keys mode for virtual and MIDI keyboard.
  • Added counter that indicates use samples in presets and scenes.
  • Visual meter of velocity for MIDI keyboards.
  • Visual meter of modulation wheel for MIDI keyboards.
  • MIDI keyboard meters can be disabled in settings.
  • Oscillators controls have different color labels.
  • Added text labels on oscillator controls.
  • Optimization for use on iPhone XR, XS, Max.
  • Audiobus SDK 3.0.6 updated.
  • Ableton Link SDK 3.0.5 updated.
  • Built-in description updated.
  • Several bugs have been fixed.



Tutorials and guides:

[ SynthScaper - Detailed tutorial. Part 1 (video tutorial) ]

[ SynthScaper - Detailed tutorial. Part 2 (video tutorial) ]

[ SynthScaper - Wide and deep sound with the single preset (guide with pictures) ]

[ SynthScaper - Natural chorus and Spatial effects (guide with pictures) ]

[ SynthScaper - How to assign "LFO" to parameters (guide with pictures) ]

[ SynthScaper - How to use "Effect" parameters (guide with pictures) ]

[ SynthScaper - Two-Voiced Drone (guide with pictures) ]

[ SynthScaper - Start with your own samples (guide with pictures) ]

[ SynthScaper - The Designer tool (short description) ]

[ SynthScaper - Arpeggiator / Sequencer overview (video demo) ]

[ SynthScaper - Automate pitch shifting (video demo) ]

[ SynthScaper - One shot sample demo (video demo) ]

[ SynthScaper modules connection diagram (big picture) ]

[ Complete description of SynthScaper 1.7 in one PDF file ]










Thursday, March 28, 2019

FieldScaper ver. 2.1 has been released

Advanced field recorder combined with a sound warp engine and a collection of ready to use dynamic presets for iPad and iPhone.

With the FieldScaper app, you can easily record the sound of the environment and instantly transform it into something unusual and very atmospheric. This app is great for sound design and create special sound effects for movies, games and audio books.

>>> More details about FieldScaper







With using internal sequencer and Ableton Link option the FieldScaper app can transform usual melodic loops into rhythmic broken ambient sound synced with other apps like drum machines.






The FieldScaper supports complete MIDI control for all faders, knobs and many buttons. You can change the parameters of oscillators, filters, delays and mixer by using any external MIDI controller or MIDI apps like sequencers. With the MIDI controllers this app becomes very comfortable to use at live performance.

Look at DIY MIDI controller designed special for FieldScaper

>>> FieldScaper DIY MIDI controller



Video demos:

>>> The most comprehensive tutorial for FieldScaper

>>> Demo of the sample editor and creating new preset

>>> Make preset with step sequencer

>>> Demo of creating soundtrack

>>> Live performance with single sample

>>> Live improvisation ( more details about used setup )








Wednesday, February 6, 2019

SynthScaper LE ver. 1.1 has been released

First update of new app SynthScaper LE. This update improves the app when used as an Audio Unit and adds new modes. SynthScaper LE continues to develop and improve.

What's new:

- Fixed problem with presets list in AU instances.
- Added hotkeys bar when full screen keyboard.
- Help panel opens on full screen.
- Added mode when sequencer knobs use "Scale" range (in standalone).
- Fixed problem with BPM sync when work with some AU hosts.
- Improved work in "freeze" mode in DAWs (exclude sequencer).
- Fixed problem with restore last selected scene when start as AU.
- Improved work of arpeggiator when changing keys.
- Added several new scenes and presets.










[ SynthScaper LE - Tune panel ]

[ Complete description of SynthScaper LE 1.1 (pdf) ]

[ List of auto detected MIDI keyboards (pdf) ]


Demos and reviews:

SynthScaper LE - Detailed tutorial (video)

The Sound Test Room - SynthScaper LE - AUv3 - Running in Cubasis - Demo for the iPad (video)

First try with Synthscaper LE from Rodolfo Ruiz - Sound demo (video)










Monday, January 28, 2019

SynthScaper + SynthScaper LE bundle

Bundle of two apps SynthScaper and SynthScaper LE is available. Two synth apps complement each other.

SynthScaper (advanced version) - synthesizer specially designed for creating and experiments with ambient soundscapes in wide range from noises to melodic instruments and everything in between.

SynthScaper LE - The special lightweight version of SynthScaper that let you easily create and modify your own multi-timbral pads and atmospheric soundscapes. You can construct a new sound from built-in library of unique and high-quality presets.




[ More about SynthScaper (advanced version) ]

[ More about SynthScaper LE (lightweight version) ]