Saturday, 10 October 2020
ARP 2500 - 1026 Preset Voltage Module
Friday, 9 October 2020
Online 808 . 303 emulation from Roland.
There is no excuse not to add this to your bookmarks.
Electronic: From Kraftwerk to The Chemical Brothers - The Design Museum
If you're in London, don't miss this:
Wednesday, 7 October 2020
Akai Force - importing Abelton projects
Saturday, 3 October 2020
ARP 2500 - 1005 ModAMP Module - Ring Mods vs VCAs
The 1005 is a really interesting module.
At first glance it seems simple... a ring-modulator (Balanced Modulator) connected to a VCA (Unbalanced Modulator). Actually ARP (and Tonus) often combined different components which would usually
be separated, into a single module. A good example is the filtamp 1006 -- it's a filter+VCA.
The interesting bit about this module is how the two parts interact with one another, how you can control them and how they modulate the modulating VCOs ... but more about that later.
First, a brief description of Ring Modulators & VCAs.
Ring modulators & VCAs are of course related.
Both modules accept two signals and both multiply them together, but in different ways.
VCAs are also called Unbalanced Modulators & Amplitude Modulators.
Ring Modulators are also called Balanced Modulators.
VCAs
A VCA lets a signal pass. How that signal is passed is however controlled by the second signal (The control voltage).
Basically, it's multiplying the input signal by the modulation signal.
If the modulation strength (CV) is at full voltage, all the input signal will get through. In effect, the signal is multiplied by 1. (There is a switch to change the slope of the VCA between exponential & linear).
If CV = 0, out = 0. That is, there is silence when there is no CV.
An important point to remember with a VCA is that the (audio) input signal can be bipolar (+ve & -ve), but the CV can only be +ve. (Any -ve modulation signals are ignored).
So it won't let any audio through if the modulation signal is zero or -ve.
(Because of this, most VCAs have added a DC offset at the modulation input which inverts any -ve voltages to +ve.)
VCAs are classified as 2 quadrant multipliers because they handle bipolar signals on the audio input but allow only +ve multiplication.
You may ask the question "where did the ring modulator get it's name?"
In the early days, the modules used diode rings to change the polarity of the modulation & carrier signals.
Most modern modules have done away with this old technology
So the ring modulator is just a VCA with a special bipolar (+/- ve) input.
Because of the difference , the Ring Modulator is also called a four quadrant multiplier
Convention, states that the audio input ("A" in the ARP 2500) is called the carrier & the modulating / multiplying input ("B" in the ARP 2500) is called the modulator.
The Modulator can be activated or disengaged from the audio signal by pushing the UNMOD/MOD buttons. You can also use gates & triggers to do this.
The obvious modules to supply gates are the 1027 sequencer, or a pulse from a LFO/Oscillator. However, the slow random CV outputs of the 1016 Random Voltage Generator can also trigger these switches. The "internal clock out" of the ARP 2600 (Sample & Hold section) also works.
The ring mod section of the 1005 possibly uses a potted module: the 4014 sub module (I'll check this one day).
This sub-module was used in the 2600.
Here is part of the schematic:
With a RingM you can create a wide range of new frequencies that have no relationship to either of the original inputs A or B. Inharmonic overtones can be produced. This brings us to the lower half of the module.
The 1005, in addition to the ring mod & VCA, contains additional circuits that produce two sets of "Inharmonic Preset Control Voltages". They are named CVa & CVb.
The output of the ring modulator is always passed through the VCA.
I understand that the VCA used in the 1005 is identical to the 1006 Filtamp.
Electrical Specifications
I have never seen one of these.
It offered balanced
modulation without voltage controlled
amplifiers.
The 1035 contained
three balanced modulators and six
microphone pre-amplifiers.
The 3 overload lamps indicate voltages over +/- 10V at the outputs of the modulators. If they are lit, the signals are most likely distorted & clipping... you should thus either reduce the amplitude of the inputs or reduce the gain of the amps.
Links
+ ARP index
+ The ARP 2500 & the 1005 MODAMP module
+ Guitar fool
+ TTSH (ARP 2600 clone) build notes - Ring Modulator
Pemberton WA - Fire Lookout Climbing Trees
We in New South Wales are looked out of Western Australia until this virus is done.
So I can only dream for the moment.
Make Noise - 0-control / 0-coast Patches 3
This is a continuation from patches 1 & 2
10.
11. Overtones & envelop 1 control (of Time)
12. Subharmonics & analog quantizers
Sunday, 27 September 2020
Makenoise 0-coast/0-control - Patches 2
Master clock : clock 0-coast.
2a
3.
Random controls direction.
Random can also be used with overtones, etc
4.
Square wave triggers envelope 1 , which modulates the balance (0-coast mixer)
Balance
Saturday, 26 September 2020
Arp 2500 - 50th anniversary virtual symposium
Wow 50 years
Saturday, 19 September 2020
How to Program a Roland TR-808 - Quick start guide
Roland TR 808 - Quick Start
The 808 is a pretty basic machine that isn't too complicated to program, though it has a few odd quirks that are good to know. Before, you write any new patterns, it's important to clear the old ones.
How to clear old patterns
1. Turn on with the top left power switch
2. Turn the MODE knob all the way to the left, to "Pattern Clear".
3. Choose which memory location you wish to erase by pressing one of the
16 step buttons.
4. The "Basic Variation" switch needs to be in the AB position.
5. Press the Red "Pattern Clear" Button
yOU will see the AB LEDs flash really fast
How to program a simple pattern (1st Part rhythms)
8. Program your beats by pressing the step buttons (step mode) or the TAP button
(Tap mode)
9. If you flick the Basic variation to B you can program the steps 17 to 32.
The B LED will light up. (Keep the MODE Knob on "first Part")
Setting the variation to A/B will play steps 1 to 32.
How to Play existing patterns
1. Turn on with the top left power switch
2. Turn the MODE knob all the way to the left, to "MANUAL PLAY".
3. Choose which rhythm you wish to play by pressing one of the
16 step buttons.
4. You will notice that the LED above the step button will flash.
5. The "Basic Variation" switch has 3 modes (A, B, and A/B) which gives you a total of 32 sixteen step patterns.
5a. Set the Basic variation to A. The A LED will flash.
6. Adjust tempo
7. Press the START/STOP Button
8. If you set the variation to B, steps 17 to 32 will play.
Setting the variation to A/B will play steps 1 to 32.
------------------------------------------------------------------
The Second Part
7. Press the START/STOP button when programming is finished.
How to program two 12 step patterns
If the mode selector is on the 2nd part, then the LEDs will indicate the 2nd part only.
If the mode selector is on the 1st part, then the LEDs will indicate the 1st part only.
11. Press the START/STOP button when programming is finished.
---------------------------------------------------------------------------
I/F Variation Switch
I/F Variation = Intro or Fill-in Variation A or B
This performs the same function as the BASIC VARIATION switch, except it is only used for INTROs and FILL INs and relates to the last four white STEP buttons.
Intros and fill ins are additional rhythms separate from your basic rhythms. You add an intro at the beginning of your main rhythm, and a fill-ins between different basic rhythms.
The selected "White Pattern" will automatically play every 16 or 8 or 4 measures etc
You can turn the Intro/fill function on and off by pressing the TAP button.
When you first turn the mode to "play" you will see two LEDs lit:
a) One from the 1 -12 group (flashing LED)
b) one from the 1 - 4 group (solid LED)
Pressing the start button will play the rhythm as standard.
BUT
If you press the TAP button first, the 1-4 LED will start to flash.
Now press the START button and the selected intro rhythm will play before the basic rhythm.
To disable this function just press the TAP button again, and the LED will stop flashing.
--------------------------------------------------
Setting the Pre-Scale.
If you are playing a pattern and decide to change the pres-cale switch, don't forget to also press the red Pres-cale button.
1. STOP the Rhythm
2. Set MODE to PATTERN CLEAR
3. Press a BASIC rhythm button (1 to 12)
The LED should light up but not flash.
4. Set the Basic Variation switch to A
5. Press CLEAR button
6. Set MODE to PATTERN WRITE 1st PART
7. press START/STOP button
8. Set the Pre Scale selector switch to #3
9. Hold the CLEAR button down & press switch 12 at the same time.
10. Release the CLEAR button
You have just set a 12 step pattern using a #3 Pre Scale.
Example 2: (basic 4/4 beat)
Create a 16 step pattern using the #3 pre scale
Example 3.
You can change the time signature of existing rhythms without erasing them.
1. STOP the Rhythm
2. Select a BASIC rhythm button (1 to 12) to edit
The LED should light up but not flash.
3. Set the Basic Variation switch to A
4. Set MODE to PATTERN WRITE 1st PART
5. press START button
Your rhythm will play.
6. Set the Pre Scale selector switch to #3 (for example)
7. Hold the CLEAR button down & press switch one of the step switches (1 - 16)
at the same time.
8. Release the CLEAR button
------------------------------------------------------------------------------------------
Composing the Rhythm Track
Play/Compose/Track Clear



















































