Monday, 15 June 2015

Serge TKB Build notes - 9 - Ribbon cables S2 & S3

***Click here for the Index of the TKB Build ***

Now it's time to attach the second & third ribbon cables.
It total there are 3 ribbon cables that connect the main PCB with the front panel.
They are named S1, S2 & S3.

S1 connects the TOUCH PADS (I have already done this).
S2 connects the PULSE OUTS
S3 connects the  POT BOARDS

On the PCB the connectors are our 16 pin male headers.

 S1 is the header on the right. S2 is the lower header on the left. (S3 above this).
The connections on a vintage TKB are exactly the same.

It's fun to read the original 1970's instructions for building this kit.
They read:
"Connect the three ribbon cables to the appropriate places. Note that one is wired along the row of pulse output jacks, one is wired along the bottom row of potentiometers (with the wires which were not soldered in step 3). The ribbon cable which goes to the TOUCH assembly goes through the cut-outs in the panel to the 16 connectors along the top edge of the TOUCH Panel. There should be the absolute minimum of bare wire extending up from the solder connection to prevent shorts when the TOUCH Panel is installed onto the metal panel. The wires from the ribbon cable that are soldered to the small pads going to the large touch pads should not be inserted into the holes. These leads should be cut very short, and soldered flat onto the pad, using a minimum of solder. It won't affect the operation if wires or solder extend through these holes, but for best appearance this should be."

First up, I'll install the S2 cable.
This connects to the 16 red pulse out sockets.

To clamp the female headers I've used a simple bench clamp.

Now it's time for S3


Below are the ribbon cables on the vintage TKB.
Notice that the S3 cable in the centre connects directly to the pots.

Connect the ground pads with some wire.

It's almost time to start connecting the PCB to all those upper jacks & the PSU

The power connections are circled in red (from top to bottom):

Z  -12V (WHITE) 
X  +12V (RED)
W  GND (BLACK)

Starting with the ground first.

 On the other side of the pot boards it looks like you only need to connect one of the pot boards to the ground terminal of the PCB. May as well connect the same wire to the toggle switch (middle terminal).
-----------------------------------------------------------------------------------------------------------

***Click here for the Index of the TKB Build ***

 

Sunday, 14 June 2015

Roland RA-50 (Realtime Arranger) & L.A. Synthesis

The RA-50 is essentially the module version of the E-20 keyboard. 
These date from 1988. The name "Arranger" is shared by the Roland TR-66 (1973)


The heart of it is the MT-32 based sound module which uses LA (linear arithmetic) Synthesis like in the Roland D-50. I far as I know, there are no dedicated drum machines that use LAS. The Roland R-8 & R-5 for example came out just one year later in 1989 and they still used ROM based samples. 
The RA-50 can however be used as a stand-alone drum.


LA synthesis combines subtractive synthesis with PCM-based samples. The synthesis is all digital (linear)
and the sounds are summed (arithmetic). This method should not be confused with additive synthesis.



Lots of music styles ... though you can program your own patterns. There are 30 variations of drum rhythms. There is also built-in digital reverb. 8 Types ( Hall 1 / 2, Plate 1 / 2, Room 1 / 2, Delay 1 / 2 )

At the time (1987), the DX7 FM synth of Yamaha produced excellent metallic, percussive sounds. This was something that Roland's synths, using subtractive synthesis, were not great at. Roland's answer was the D-50
which went on to become one of the best selling synths of all time. Thus, the RA-50 is a unique sounding & excellent drum machine.

Chord intelligence' function allows you to play full chords with just one or two fingers.
 'Chord hold' sustains a chord on the lower 

 The RA-50 (& D-50) use a combination of samples. These were divided into 2 groups.
1. Those for the attack transients.
2. Those intended for embellishing the body of the sound. These were mainly single-cycle sampled waveforms that could be continuously looped.

Melody intelligence: this function creates block chords for accompaniment based on the melody and bass note


 These two types of samples were "summed" and embellished the subtractive sounds that the synth itself produced. So LA systhesis was the best of both worlds ... it was both a sampler & synthesizer.
The synth part sounds very analog with low-pass-resonant filters.

'Sync start' lets you start the performance automatically when you press a note.

I haven't even started on about the rhythm arranging cababilities of this machine.
Though it's not the reason I bought this, it's still a very capable instrument for auto acompaniment.... band in the box duties.The  'intelligent' Arranger section automatically produces a accompaniment consisting of drums, bass, and other instruments ( such as piano, percussion,and horns ). This is based on the chord you play and the music style you choose. there are 32 preset music styles.

Rear Panel: Ext. Pedal jacks x 3, MIDI ( KBD ) In / Out for both keyboard & sequencer.
DC in jack, Power switch, 
Power Supply: 9V DC 800mA PSU required. Centre -ve.( when using supplied adaptor) 



Output Jacks x 2 ( L / Mono, R ), Headphones jack,
Card slot for expanding memory.

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

SERGE Modular - Deep Acid House



Friday, 12 June 2015

ARP 2500 & NLC

Wow - Andrew F of Nonlinear Circuits is restoring this baby.

It's another ARP2500. There are now three of these babies in Australia (as far as I know).
These pics were taken in Japan.

Here is the link to his blog about its restoration.
http://arp2500.blogspot.com.au/
Have fun Andrew.

Some close ups:
 The modules from left to right are:
1023  x 2 - Dual Voltage Controlled Oscillator
1004-T - Voltage Controlled Oscillator
1047 - Multimode Filter/Resonator
1006 x 2 - Filtamp
1046 - Quad Exponential Envelope Generator
1016 - Dual Noise/Random Voltage Source
1045 x 2 - Voltage Controlled Voice
1036 - Dual Sample & Hold/Random Voltage Generator.
1027 - Ten-Position Sequencer
1050 - Mix/Sequencer
1002 - Power Supply.

Notice the ribbon controller...It's a Moog 1150.

Side cabinet 1.
The modules are (from left to right):
1023 - Dual Voltage Controlled Oscillator.
      (It has had 2 switches and 2 pots added to the panel.
       Neither of the switches were wired to anything.)
      More info and pics of this module can be seen here
1006 - Filtamp
1033 - Dual Delayed Exponential Envelope Generator
1027 - Sequencer:
1050 - Mix/Sequencer
1002 - Power Supply.

Side Cabinet 2:
The modules from left to right are:
1004-T - Voltage Controlled Oscillator
1047 x 2 - Multimode Filter/Resonator
1004-P - Voltage Controlled Oscillator
1005 - Modamp
1046 - Quad Exponential Envelope Generator
1002 - PSU

The 1004 VCO comes in two varieties, the T & the P.
The 1004T is the same as the 1004P, except the P also has inverted waveforms.

This is a mystery at the moment. It's obviously a home brew 2500 addition (as if the current system wasn't already big enough). Andrew is currently working out what these modules do.
Some of the DIY modules are just a panel with no PCB behind. So the question is what to
do with the empty spaces?? Maybe add some NLC modules???

So far he has identified (from right to left):
1.  Reverb (extreme right) - the one with the big black dial.
2. Matrix mixer ??
3. DIY modules #4 - dunno - so far a mystery (3rd from the right)
4. Fixed Bandpass Filter (4th from the right)
5.  Clock (5th from the right) - this one uses numitrons -- how cool is that :-)

I love this old skool technology.
Numitron tubes are like Nixies, but instead of the ten number-shaped filaments in each Nixie, Numitrons use eight tiny incandescent filaments arranged in seven to make the number plus a decimal point. When a current is passed through the filaments you want lit up they literally light up just like a light bulb.  
Nixies use high voltages, but Numitrons generally use low volatges.

I'll update this as Andrew unravels the truth.

Finally, on it's way to Australia

Tuesday, 9 June 2015

TKB Build Notes - 8 - Wiring the Touch Keyboard Strip

***Click here for the Index of the TKB Build ***

I've cut the ribbon strip to about 60com..... could prob make it a bit longer to make attachment to the mother board easier in the future.
The 16 individual wires from the ribbon strip were separated and cut to different lengths.
(sorry for the out of focus pic).

To quote the 1970 instructions:
"Cut the ribbon cable so that each wire is exactly 1" shorter than the adjacent wire, as shown in the diagram above. This can be done by peeling the blue wire back to 6" from the plug, then peeling the green wire to 7" from the plug, then the yellow wire to 8" and so on. The longest wire will be the brown wire. The length of the brown wire should be about 22". Usually the ribbon cables packed with the TKB kits ore much longer. Strip away about l/8 of insulation and tin the leads for ease of soldering in the following steps."

On the other end I used a female header.
It attaches to the mother board thus:

 Below is a pic of the header 70's style:
To quote the 1970's building the TKB kit instruction manual:
"The wiring of the TKB is made easier with the use of 16-pin 'header' plugs that fit into IC sockets on the KBD PC board. The main wiring consists of connecting the various ground busses and signal busses to form a matrix with the 64 potentiometers".

This is a pic of the vintage TKB. - also using the 16 wire ribbon. Construction methods between the old and new are very similar. Nice one Zthee.


Next I installed the wires connecting the touch board with the 16 red pulse out sockets
In the clone they run under the pot boards.
 Here's how they did it back in the 1970's:

Finally soldering these wires to the touch board.
First, the connections to the pulse outs.
I've propped this up with some books.

The 1970 instructions read as follows:
"Position the TOUCH assembly on the panel face where it will later be installed, but do not peel away the backing from the double stick tape. Using masking tape, tape the TOUCH assembly so that it is in an open position as shown in the diagram. Now the wires from the red Pulse Output Jacks can be installed, feeding under the potentiometer wiring matrix, through the cut-outs on the panel, to the LED pads on the underside of the TOUCH Panel. These sixteen pads are in the center of the underneath of the TOUCH Panel. The end pads are split into two sections. The wire to pad 17 will be soldered onto one section as seen from the diagram."



Nice.

Next : Installing the S2 & S3 Ribbon Cables
-------------------------------------------------------------------------------------------------------------

***Click here for the Index of the TKB Build ***


Monday, 8 June 2015

Cairo - The Great Pyramid

This place needs no introduction.
Everyone should see this before they die.

The Great Pyramid of Giza (also known as the Pyramid of Khufu or the Pyramid of Cheops) is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact.


 Daniel & I praying to the great architect Khufu. There are approximately 2.3 million blocks..


Serge Variable Q VCF - bubbly water sounds

I've been fixing up an old TKB and revisiting my Serge.


The variable Q filter is just lovely. Some cool samples.


I should play with this more often.


Modules used:
NTO, Precision VCO, Audio Mixer,Variable Q VCF,
Quantizer (TKB), DTG, DUSG, TKB. Universal Audio Processor.