Ambika or Juno?

One thing that comes up from time to time over at the Mutable Instruments forum is the IR3109 filter board. If you do not know, this (discontinued) board used the famous IR3109 filter chip that's found in the Juno 6/60/106, SH-101, JX3P, Jupiter 6/8 and some of the later Jupiter 4's.  To say the least, a very popular and recognizable filter.  Since Mutable Instruments discontinued the filter board (mainly because the IR3109 is no longer produced and should be used to fix the synths they belong to), there have been discussions on wanting to remake the boards.  The schematics and board layouts have since been deleted and all traces removed, but every so often someone comes along looking for one.

Now, the standard Shruthi-1 kit comes with the SMR-4 filter board, which, when you look at the schematic, is basically the same design as the IR3109 chip!  There are some differences, but for the most part they are the same.  There is a mod that can be done (a couple resistor changes and a couple diodes added) that gives it an almost identical sound to the IR3109.  Actually, there is a new replacement for the Juno 106 80017A (which was a board that had an SMT version of the IR3109 and some other stuff encased in black epoxy) which uses the same 31700 Op Amp!

But, the problem is, when someone hears the IR3109, it's typically in a polyphonic scenario.  Well, I just finished a build for a customer that has 6 SMR-4 voice cards!  I decided to set it up like a Juno and see exactly how close it is.

The settings:

Osc 1: Saw
Osc 2: Off
Sub Osc: about half way
LFO 1 Triangle (sloow) > Osc 1 (very little)
Filter Cutoff about half
Filter Resonance about half
Filter Cutoff > Envelope 1 about 2/3's

Then I run it through a chorus pedal to give it that "Juno" sound.  Finally a little reverb.

Finished an Anushri & an Ambika with 6 SMR voicecards over the weekend.  Now that I've heard all 3 voicecards, I must say c SVF and SMR are tied to first (slight edge on SVF with BP & HP modes). 4PM is my least favorite. Now, when Tubeohm gets the Ladder Filter Voicecards done, that may take the lead. Stay tuned!

MFOS Soundlab Minisynth MKII MIDI Board

Well, technically this will work with any synth that works on V/Oct or Hz/V but I built it specifically for my SLMSMKII.  I added a 5vdc power supply to the board for the MIDI THRU.  Ultimately the THRU will chain to another midimplant to control a second Soundlab.  Going for an SEM 2-Voice kinda thing, as I believe I have mentioned before.  At any rate, this is the board that can be added to any Soundlab order.  There will also be a push button at the back to edit the settings of the midimplant.  I will probably add an activity LED to the front panel as well (between the Gate & V/Oct jacks).  Once I get it installed I'll post some photos and do a short video of it in action.

Bluethunder III

Just finished and sent off another Shruthi-1 LSW Blue Thunder Edition.  This is our highly modded Shruthi with the SMR-4 MKII filter.  It has the following mods:

• Audio IN Volume
• Audio OUT Volume
• 2/4 Pole Selector Switch
• Low Pass/ Band Pass Switch (BP1, LP, BP3)
• Audio IN/FM Mod Switch (routes the Audio IN jack to either the filter, as intended or as an FM Source to the filter cutoff.  When used as an FM source, the Audio IN volume becomes an attenuator
• Dedicated FM Mod Pot (takes the raw oscillator output from the digital board and routes it the filter cutoff as an FM Source.  Desgined by forum member yewtreemagic)

New to this model is the "IR3109 Squelch" mod (a mod I had made to a previous shruthi and yewtreemagic perfected and improved.).  This mod replaces a 2 key resistors that tames the filters input & output causing the resonance to sound "purer" and "squelchier".  The original issue with this was that the resonance would then become overpowering to the oscillators when the resonance was set high.  The addition of 2 diodes in parallel with a key capacitor tames this issue and results in a VERY Roland-esque filter!

More photos here.

love her sleep - RoyFnBerry

"Off the cuff - first run - not over thought - drum half of new spaceship with 1 drum pattern - plus 1 bassline (a repeating 303 & SammichSID)"

Featuring a SammichSID built by LSW!


and another vid featuring the SammichSID & an MI Shruthi by LSW!

"Not supposed to be a song; demoing some synths and a process; thought I'd film it. Click [show more] for explanation.

Using a MIDIpal (for a sine ccLFO and a random ccLFO) and an Event Processor Plus program (to remap things and whatnot), a SammichSID and 2 Shruthi SMR4-mkII (for stereo), auto crossfade and auto random program change.

A second MIDIpal randomizes the notes of an EF-303 sequence (no audio heard from EF-303).

The SammichSID starts first. You can tell which one's volume is down and receiving random program changes, because its screen will show the patches changing (once the patches stop changing, you'll hear the patch it stops on fade in). The SammichSID makes noise when changing patches (it's a flaw of the old C64 SID chip).

The SammichSID and one of the Shruthi's were built by Adam Armstrong from Mutable Instruments trusted builders list. The other Shruthi was ordered from the Mutable Instruments web-store, built by Olivier Gillet (honestly can't remember which is which).

Audio straight into a ZOOM Q3HD, normalized.

AND the SammichSID sequence patches and drum patches play at their own speed for some reason. I'll figure that out later. Also, since the program changes are random, some of the sounds happen more than once."

New product officially added!

Finally got around to working up a flat fee for the MFOS Soundlab Mini-Synth MKII, mainly because Im thinking of building a 2nd to make a 2-Voice SEM of sorts. I'll also offer the addition of a MIDImplant.    Go to "prices" above for details. It's at the bottom.