Saturday, 15 May 2021

Mogue mixer & VCA - NLC build notes - part 2

 I started this build back in 2019.
Finally catching up. Sorry for the delay.
I blame a combination of slackness and covid.

Part one is here.
Mouge Mixer/VCA- build notes
The Moog CP3 is a classic so its  always interesting to study the circuits.
iT HAS two (inverted) outputs. : a +ve & a -ve 
It also has a passive mix bus without the use of op-amps.
The module uses transistors.

And I was unsure what parts to use. The LM394 is obsolete.
What to do? Should I use some cheap Chinese copy off Ebay , ... or maybe a Russian clone ???
I decided to try some matched some BC547s first.

The LM394 consists of a pair of super matched NPN transistors
The Emitter-base voltage is matched to 50 mV

The BC547 is also a NPN transistor

First , you need to match the BC547s.
Here is some info on the subject of matching

Vbe (base-emitter voltage) matching is the most common type of matching done.
I like using a Atlas DCA Pro DCA75  


Installing headers

pOTS and jacks next.


Still testing the transistors.
They need to be matched as closely as possible.

The mixer actually has 2 outputs: a +ve and a -Ve.
It's what you'd expect from a CP3 mixer.
However, the -ve is fed directly to the switching pin of the VCA input.
This output is somewhat distorted.
The +ve output is the jack directly below IN2

It does work with the BC547's
You don't need to buy clones from Ebay.

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+ official build notes & BOM
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Wednesday, 12 May 2021

Vitalise - Week 7


For week 7 of 9, there are  five live acts: 
Unkle Ho
Loose-y Crunché
Nick Dan
Brendon John Warner
guest DJ: Cinnamon (aka Zimt)
resident DJ: Chris Mountford
resident VJ: ATMM

MST MIDI to CV Converter - sYNTHROTEK - part 1

 Building my first kit in a long time.

Finding a MIDI to CV converter is pretty easy in Eurorack format, but CV to MIDI clock converters
are rarer.
I'm looking for a module that will convert analog clock to MIDI clock.
Hopefully this will do the job.

according to the manual it does:
1. Clock input to DIN MIDI & USB MIDI CLOCK out

Build notes (official)

The official build notes are great.
My notes are just to help me trouble shoot should I encounter any probs.
The supplied kit makes everything easy.
Sourcing parts is often more that half the work.

There are 2 boards: Logic & control.

Diodes first
all are 1n4148s

The 20Mhz crystal.
This is the clock source.

Caps next.
there are six 100nF caps - do these first.
c1, c4,c5,c9,c15,c16.

Four 51pF caps

Two 15pF ceramics
These go either side of the crystal

Electrolytic caps
c10, c13,c14

IC sockets

Spacers - standoffs -- headers

Once you screw in the standoffs, soldering the headers is easy.

Power (10 pin).
Switch & i2c header


The red switch sets the midi channel.
It's kind of a reverse binary number system
offoffoffoff = binary 0 = Midi 1
ONoffoffoff = binary 1 = Midi 2
offONoffoff = Midi 3
offONONON = binary 14 = Midi 15
ONONONON = midi 16 

thAT  square shaped black socket is the header for a i2c connector.
It connects to the expander module.

Time for c12 
The 220 nF capacitor  is pretty big so needs to be twisted a bit to fit in nicely.

transistor voltage regulators
VR1 - 78L05
supplies 5V

This is a shunt regulator or to use its long description, its a
programmable precision voltage reference IC.
It's a regulator diode whose output voltage can be programmed by changing the value of resistors connected to it. It's probably being used here to provide a voltage reference.

To be continued ......


Tuesday, 11 May 2021

Access Virus TI Control Centre - Burning to ROM

My Virus TI was purchased many years ago, and I'm re-familiarizing myself with it.
TI = Total Integration.

This means you can connect it to a computer and among other things, arrange your presets and patches via a VST.
For a machine that it now almost 20 years old, this is still really cool.
The makers in Berlin were way ahead of their time.
The memory consists of 4 banks or RAM and 26 banks of ROM (read only memory).
RAM (random access memory) is where you save any new patches to.

However, my RAM banks are full and I wish to transfer some of those patches to a ROM bank, to free up space for new patches.
I couldn't find much info in the web, but I think this procedure works.

You need to do what's called "Burn To Flash". 
This seems the same as burning to a ROM bank.
Do let me know if there are any mistakes in the procedure.
I'm burning from RAM A to ROM T 

This is a unedited video of the procedure.
There is no sound.
 From the TI quickstart guide:
Burn To Flash allows you to overwrite the content of the ROM banks in your Virus TI. 
As you may have already noticed, the Virus TI memory has been expanded to 26 ROM banks and all the new ones are only filled with INIT sounds. All those unused banks are waiting to be filled using Burn To Flash. 
In order to transfer a bank of sounds to the ROM section you need to select a source bank first. The “Select source bank” menu shows exactly the same choice of banks you see in Virus Control.

Next you need to decide where you want to write the bank to. 
By clicking on the letters A-Z you select the target for the transfer, as well as see the present content of the bank to be overwritten. Once you made up your choice, 
hit “OK” and proceed from the top again in case you want to overwrite more 
banks in your Virus TI.

The user bank icon indicates which banks already have been overwritten in the past. 
To restore the original banks later, see “Advanced Menu” below."

 The first time I tried this my Virus Locked up (above pic).

But with the second attempt all worked fine.

Only issue I found was that the newly burned ROM banks don't show up in the VST Plugin browser, though they are definitely there.
If anyone knows how to fix this, please shoot me a message.

Hope this helps others out there.

Many thanks to Marshal Arnold for his excellent video of the ultimate Virus TI setup in Abelton.
+ Access Virus -The different versions 

Monday, 10 May 2021

Vitalise gig

 Some highlights from the Vitalise gig last Thursday.
It was so good to be able to perform live again.

Hopefully the worst of COVID is behind us.

 This is a nine week run of  live electronic music.
Held Thursday evenings, between 6pm and midnight.
Good Space 
33 Playfair St,
106-108 George St, The Rocks


Friday, 7 May 2021

Alesis A6 Andromeda - Midi , Mix Mode & MULTITIMBRAL SEQUENCING


This is part of my exploration of the Andromeda synth.
It's a wonderful synthesizer, which even after owning it for over 5 years I'm still just scratching the surface of what it can do.
The official manual is really long (as you'd expect) from such a complex synth, so this is my attempt to break things down, into smaller parts for myself. If this helps someone else, that great too. 

I'll constantly add to these posts as I discover more about this wonderful instrument.

The other parts are here:

Midi Clock

The A6 sends and receives MIDI Timing Clock. 
This is usually found only on time-based devices like a sequencer or a drum machine. 
But since the A6 has step sequencing and an arpeggiator it can control other rhythm-type units
or be controlled from an external MIDI source. 
The Andromeda is capable of sending and receiving on up to 16 MIDI channels simultaneously.
Mix Mode is used for this kind of MIDI application.
It is possible for the A6 to assign any Mix Channel to any MIDI channel if desired.
In Program Mode, the A6 sends and receives on a single MIDI channel at a time.
in Program Mode you can play only one Program at a time, 
In Mix Mode you can play up to 16 Programs at once, either from the keyboard
 (as layers or splits) or from an external sequencer.

 Or, you can have several different programs on different Mix Channels responding to the same MIDI channel. This means that if you want to play a layer of several Programs, you don’t have to clog the MIDI sequencer with duplicate tracks and messages.

Mix Mode

Use this mode if you wish to send & receive MIDI on up to 16 channels.

Each Mix channel can be assigned to a specific MIDI Channel with unique MIDI controller assignments.
The row of rectangular buttons just below the display area are used to select the Programs within a Mix. When a Mix Channel is ON, its associated LED will light. When a Mix Channel is currently selected for editing in the display, its LED will blink.

 Pressing the MIX button displays the Mix mode display screen.
The page tabs under mix mode are:

Page 244 of manual
The easiest way to use the A6 with a MIDI sequencer is to use one of the preprogrammed Mixes in the Preset or User banks. 
See the Program/Mix chart for the Mix set up for multitimbral use that’s appropriate for your situation. 
But if you want to start from scratch or edit an existing Mix, here are the steps:
1. Press the MIX button. 
2. Select a Mix to start with using the PROGRAM GROUP/NUMBER, and BANK keys.  
3. Select Mix Channel 1 by pressing the black MIX SELECT 1/9 key. 
     Make sure the right side of the display window has a box that says MIX CHAN 1. 
     If it says MIX CHN 9, press the SHIFT key and press MIX SELECT 1/9 again. 
4. If the green LED above the MIX SELECT key isn’t flashing, press it again to enable 
     the channel. 
     A small box in the display should say ON and an arrow appear pointing to the 
     current Mix Channel. The flashing LED above the switch means the Mix Channel
     is currently selected for editing and is ON.
Set the Keyboard parameters 
5. Press soft button 5 (KBD). 
6. If you want to play this mix channel from the keyboard*, make sure that 
     ENABLE is set to ON using soft knob 4. 
     Set the high and low ranges using soft knobs 1 and 2
Set the MIDI parameters 
7. Press soft button 6 (PROG). 
8. Set the MIDI channel for this Mix Channel by turning soft knob 6 (MIDICH).
9. Press soft button 7 (CNTL). If the first parameter isn’t MID IN , press it again. 
     Set MID IN to ON using soft knob 1. 
10. If you’re going to be using this Mix Channel to send note messages to
       the sequencer*, set MIDOUT (soft knob 2) to ON.

Wine Glass Bay - Freycinet National Park, Tasmania

 Some pics of Wine Glass bay, Freycinet National Park, the Granite Mountains.
The main town is called Coles Bay. It sits at the foot of the granite mountains known as the Hazards and on the edge of  Freycinet National Park and Wineglass Bay.

This is about two and 1/2 hours drive from Hobart and Launceston on the east coast of Tasmania. 

Wine Glass Bay is part of the Freycinet peninsula