Saturday, 29 November 2014

The ARP 2500 & the 1005 MODAMP module

The ARP 1005 MODAMP.
The 2500 manual describes this as
" a balanced modulator, a VCA with certain associated circuitry"

It's very much like your standard ring modulator.
There the output consists of the Sum and Difference of the input frequencies
(but contains neither of the input frequencies).

The ARP 2600 used analog multipliers in contrast to the ring of diodes found in many RMs.
I wonder if the 2500 has a similar circuit.???
GuitarFool has the schematics here:
The schematics for the 4014 Balanced Modulator which I think is related to the 1005 modamp
have two 2-Quad Multipliers.

The submodule in the 2600's case was the ARP 4014.
The schematics from ARPtech are here
One of the nice things about the 2600 was its switch that allowed you to select between
AC-coupled and DC-coupled modes.

Anyway, the 2500 manual describes the 1005 module thus:
"The Balanced Modulator" can accept two input signals A & B in the frequency range DC to 20KHz
and will produce the output function (A x B/10)......If f1 & f2 are chosen properly, the output will be a complex wave with inharmonic overtones".

One of the really cool things about the 1005 ModAMP is that it produces two DC control voltages.
(CVA & CVB).
 CVA & CVB - the 1005 outputs control voltages

In this video example (below) I'm using the CVs to modulate the VCOs.

You can download the audio files from the above video here:

Turning the ModAmp is easy with the illuminated on/off button.

 This on/off switch can also be operated with a gate. (the input is marked "Mod Gate" on the bottom & top of the module).

The Mod Gate

At the top, there are an "unmod" & a "Mod" input.

 Upper half of the 1005

The Manual states" a Pulse applied to to either input will switch the operating mode to either"unmod" or "Mod".
The mode will remain as set until a pulse is applied to switch to the other mode,
or until the mode is changed by the button.

Finally, the 1005 has a VCA.
We have a switch to choose between linear & exponential control.

And there are lots on CV inputs from both the upper & lower matrix sections.

Heaps to play with.

Elektron A4 & RYTM - Paradise Lost

Here I'm mainly experimenting with the Scene Mode on the Rytm Drum machine. The Analog Four is just providing some background sounds.

The more I use the Rytm the more I realize that its real power lies with parameter locking. The Scene Mode gives you instant parameter locks.

Friday, 28 November 2014


A Arp 2500, 2600 and two drums.
Vermona DRM & Metasonix D-1000 (Vacuum tubes).

We did a few takes of this.
Here is an earlier one that ended on the cutting room floor.
Though I'd place a link to it as part of the exercise:

Boss DR-550 MkII Dr. Rhythm

Boss DR-550 MkII Dr. Rhythm
This is a great sounding machine Early NIN ???
Nice for techno, rap and industrial. The Mark II model dates from 1992.
The Mark I is from 1990. 
It's small and runs on batteries. A very underrated machine. You can still find these puppies for under $100 on the bay.

She was my old workhorse that I bought back in the 90s.
I used to program beats on this while going to uni lectures via the bus.
....there is automatic quantizing (for when the bus jolted to a sudden stop).

Sadly there is no midi out. There is MIDI sync in so you can hook it up to other sequencers.

There are a number of time signatures ie 4/4 3/4 2/4 etc
The Mark II has pretty much got the whole 808 kit and some 909 sounds.
The samples sound very good (44khz). You can alter their Decay, Color, and Pan.  

For more info on the history of Roland Drum Machines click here

Wednesday, 26 November 2014

Roland CR-78

The CR-78 CompuRhythm is one of  THE  Classic Drum  machines from Roland.
It's quite small compared to a 808 or 909.

300(W) x 280(D) x 205(H)mm
11.8″(W) x 11.0″(D) x 8.1″(H)
5.5 kg/12.1 lbs

It was made famous by its use by prominent pop musicians. The machine  featured in  "Vienna" by Ultravox, "Heart of Glass" by Blondie and "In the Air Tonight" by Phil Collins.

These come dressed either in wood or black
There are 5 sliders, 31 buttons & 5 knobs
5 sliders, 31 buttons, 5 switches and 5 knobs
5 sliders, 31 buttons, 5 switches and 5 knobs
5 sliders, 31 buttons, 5 switches and 5 knobs

Rock 1-4, Disco 1-2, Waltz, Shuffle, Slow Rock, Swing, Fox Trot, Tango, Boogie, Enka, Bossanova, Samba, Mambo, Chacha, Beguine, Rhumba.

Bass Drum, Snare Drum, Rim Shot, Hi-Hat, Cymbal, Maracas, Claves, Cow Bell, High Bongo, Low Bongo, Low Conga.

Cymbal + High Hat, Bass Drum, Snare Drum, Cow Bell + Claves.

It was the second drum machine to use a microprocessor. (That honour belongs to Paia's Programmable drum set).

Ikutaro Kakehashi (The founder of Roland Corporation) says that at the time the only CPU choices were the MOS Technology 6502 and the intel 80 series.The 6502 was difficult to get in japan so the 8048 won out.
  (the 8 bit CPU - NEC D8048-C015)

This was a very important advance in drum machine technology. Users could now program and store their own drum patterns

8 bits CPU NEC D8048-C015Users could now program and store their own drum patterns By tapping you could create your own pattern. You could also combine this with one of the preset patterns.

Start/Stop, Variation (DP-1, DP-2)

8 Beat, 16 Beat, Combination.
The external clock input accepts a clock of 12 ppqn (pulses per quarter note), which adds up to 48 pulses per bar/measure on a four-four time. The signal should be between +5V to +15V, and have a length of min. 5ms. A Doepfer A-146 LFO produces just what you want .... a +5V symmetric pulse wave.

EXT. CLOCK (trig out):
0 to 15V pulses. min. 5ms width

A Pedal Switch DP-2 & Write Switch WS-1 (Roland programmer)
Roland programmer
are useful accessories

You can trigger the CR-78 with the following Eurorack modules :
  • A-146 LFO II
  • A-155 Analog/Trigger Sequencer
  • A-160 Clock/Trigger Divider
  • A-161 Clock/Trigger Sequencer
  • A-180 Multiples
See link 7 below for more info.

1. Fenix I & III (and a Roland CR 78) 
2. CR 78 Midification (AnalogueSolutions)
3. Roland CR-78 CompuRhythm with Modifications - Demo Video 
4. Roland CR-78 non-rechargeable Lithum battery replacement mod
5. Astronaut
6.  Warren Cann from Ultravox  (his experiences modding the CR-78)
7. Triggering, Syncing and Programming a Roland CR-78 with Eurorack
8. CR-78 repairs & internal pics
For more info on the history of Roland Drum Machines click here

Havana Cuba 3

Shopping in Cuba

There is lots on the shelves, just not a big choice.

One of the main shopping centres in Havana.

the oldest building in Cuba

 The Bacardi Building in Havana


Tuesday, 25 November 2014

AceTone (Roland) FR-6 Rhythm Ace / TR-55

The FR-6 is more or less a 1972 Roland Rhythm TR-55. 

Above is the FR-6


Above is a TR-55. The layout is different from the FR6. The TR55 being more portable. And its got that cool touch sensitive start/stop button.

So there are lots of reincarnations of this machine. The Roland corporation began as AceTone.
In 1972 AceTone was sold but continued to make drum machines under that name.
In the UK, these machines were called "Bentleys". 

The FR-6 has the same 6 sounds as the Roland TR 55.  (BD, SD, Cy, low conga, high conga, claves)

There are 20 Presets: waltz, slow rock, ballad, rock'n roll, rumba, beguine, mambo, bossa nova, cha-cha, tango, samba, fox trot 1, fox trot 2, swing 1, swing 2, swing 3, march, haba-nera, bass snare, bass.

The preset patterns are the same on both the FR6 & TR55 (except for the TR-55's "Parade" rhythm which was substituted for "Haba-Nera" on the FR-6).

This machine is dripping with personality. The wooden box with the sloping front face is just stunning. It's all analog of course.
There is no trigger out or in so you will either have to mod this in order to sync with other gear or use something like an envelope follower.

I don't have the heart to touch this baby at all. It's too beautiful and should be left in its original condition.

The Balance Knob varies the sounds between HH & cymbals (higher frequencies) and the lower bass Drums. It's a joy to play with.

You can play more than one preset pattern at once. Combining these with the two Beat buttons opens up lots of variation in pattern.
For more info on the history of Roland Drum Machines click here