I really like this sequencer. Small but versatile & powerful.
JonDent - Explorations in Electronics, Electronic Music, Coffee, Sci Fi, Art & Travel (but mostly electronic music)
Saturday, 14 February 2015
Korg SQ-1 sequencing a MS-20 & MS-50
Just a few experiements, videos & pics of the new Korg SQ-1.
I really like this sequencer. Small but versatile & powerful.
These demos all use old fashioned CV/triggers. No midi.
The pics are more a record of a patches for future rference. This one used the MS-20 sample & hold.
The MS-50 has just one VCO & LP filter. It's a expander for the MS-20
I really like this sequencer. Small but versatile & powerful.
Friday, 13 February 2015
Korg WaveDrum - WD-1 - The Original 1994 version.
This was one of the first drums to use "true Physicial Modelling".
It seems that only 700 to 800 were manufactured back in 1994 and they sold for a wopping $3K.
On initial examination this looks pretty steep for a electronic drum ????
However, once you realise what this actually is the price is understandable.
What we have under the hood are separate head and rim pickups, an arrangement of sensors and microphones that are used to
trigger synthesized waveforms. The sound to be generated is not a sample. It is computed
using a mathematical model (equations and algorithms) which are based on
parameters that describe the instrument to be played.
For example, a simple drum's mathematical model will consist of the
materials and dimensions of the instrument, it's mass & density,
it's stiffness, the properties of the membrane and how it can be played,
the resonance of the cylindrical body of the drum. We also need to
describe the player's interaction with it, his/her movement over time.
The Wave drum comes shipped with 100 factory patches which you can tweak & edit.
For this to be made easier, Korg produced the RE-1 ---- The Remote Editor.
The
factory patches alone are amazing sonically as their character alters
drastically depending on how you play them. Damping, pressing the head,
striking the rim, scratching, rubbing, etc all produce totally different
sounds from the one patch.
It's steep initial price prevented it reaching a wider audience and samples just can't convey how it sounds when played by an experienced drummer. The head & rim are very sensitive and respond without having to select any special modes. It will respond naturally to sticks, fingers, brushes, etc.
The head can be 'tuned' by means of five tension lugs, to give the required playing feel.
The skin is a Remo Fibre and can be replaced with a natural skin if needed.
So does it look more like a toilet seat or the bridge of the starship Enterprise?
I like to think the latter, but no matter what you think about it's appearance, it's sonic capability makes up 1000 times.
Some useful Links:
1. SOS - 1994 article
2. Korg's official website (global edition of the WD).
3. Original Korg Wave Drum Demo (Video)
4. SOS - 2010 article on the new WD
5. Korg WAVEDRUM Demo Performance (Part 1)
6. Korg Forum on the original WD
It seems that only 700 to 800 were manufactured back in 1994 and they sold for a wopping $3K.
On initial examination this looks pretty steep for a electronic drum ????
However, once you realise what this actually is the price is understandable.
Stereo audio outs on two quarter‑inch jack sockets.
The midi jacks don't allow you to plug this into your midi sequencer, or fix up my crummy drumming. I will just have to practice more.
Although physical modelling was not a new concept back in 1994, it was not until the increase in DSP power which brought costs down and made such instruments feasible.
For this to be made easier, Korg produced the RE-1 ---- The Remote Editor.
It's steep initial price prevented it reaching a wider audience and samples just can't convey how it sounds when played by an experienced drummer. The head & rim are very sensitive and respond without having to select any special modes. It will respond naturally to sticks, fingers, brushes, etc.
The skin is a Remo Fibre and can be replaced with a natural skin if needed.
I like to think the latter, but no matter what you think about it's appearance, it's sonic capability makes up 1000 times.
Some useful Links:
1. SOS - 1994 article
2. Korg's official website (global edition of the WD).
3. Original Korg Wave Drum Demo (Video)
4. SOS - 2010 article on the new WD
5. Korg WAVEDRUM Demo Performance (Part 1)
6. Korg Forum on the original WD
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For more info on the history of Korg Drum Machines Click Here
Jodpur Markets - Rajasthan, India
The central markets of downtown Jodpur are a colourful place to while away the hours if you enjoy people watching.
Jodpur markets with the medieval fortress of Mehrangarh in the background
These panoramas were all taken using a cheap galaxy phone.
Thursday, 12 February 2015
SYNTHACON VCF - CGS 35 build notes
These are some build notes for the Cat Girl Synth (CGS) tribute module
of the Steiner-Parker synth VCF. (CGS module # 35).
My thanks to Ken Stone & Nyle Parker for making this possible.
This filter is so very different from all the other filters that I've used. I first heard this on my Arturia Minibrute. According to Vintage Synth, it can self-oscillate like the Minimoog, but has an opposite polarity so it doesn't lose any volume when resonance is increased as do the Minimoog and Odyssey's filters.
If I'm not mistaken, the original multimode synthacon filter had a knob to change between high, band and
lowpass filtering.
The 4 toggle switches at the bottom allow the VCF to be controlled by Keyboard, Envelope 2, Sample and Hold, and VCO3.To the left the toggle switches select inputs for VCO1, VCO2, VCO3 and Noise. There are 3 knobs for frequency, filter type and Resonance(Q).
Ken's version allows all three to be used simultaneously.
The simplicity & elegance of this filter always amazes me. The circuit seems to be based on your standard non-inverting amp LP / Sallen Key type filter design
= operational transconductance amplifiers can be found in Korg MS-20 type filters & vactrols can be seen in many Buchla filters).
In the Steiner- Parker VCF, a string of eight (1N4148) diodes morphs into this voltage controlled resistor. How ???
And all 3 filters (BP, LP, HP) are obtained simply by injecting the audio signal into different parts of the circuit.
Take the LP filter as an example.
The LP filter is obtained by injecting the audio into the 47k resistor at the top. There it enters the diode string (1N4148) and the 2n2F capacitors.
Those three 2n2F caps are v important.
Also notice the two 2n2222 transistors that sit on either ends of the diode string. They form a voltage differential across the diodes.
The diodes need to be fed current if they are to act like a resistor......
By varying the voltage we can produce different effective resistances in the diode string as we force current through them.
The whole idea of the diode string is based on Ohm's Law & the equation R=V/ I (R= resistance, V= volatge & I= current )
I've chosen to use 3 x 2N2222 trannies.(Mouser).
The pic to the left is the view of a NPN 2n2222 from the underside.
I didn't match these. I wonder if you can use any standard NPN transistors?
Maybe BC 547s ???
In Nyle Steiner's 1972 article it looks like he used 2N5174 transistors instead of the 2N2222 . On Analogue Realitie's site, they use two monolythic matched SSM2210 pairs.
The PNP Transistor 2N2907 - mouser Part No.
Alternatives ??? - 2N5138 or BC 557 - I might try these in future versions of the filter
"Original transistors as per Nyle Steiner's schematic are 2N5138 and 2N5172"
of the Steiner-Parker synth VCF. (CGS module # 35).
My thanks to Ken Stone & Nyle Parker for making this possible.
This filter is so very different from all the other filters that I've used. I first heard this on my Arturia Minibrute. According to Vintage Synth, it can self-oscillate like the Minimoog, but has an opposite polarity so it doesn't lose any volume when resonance is increased as do the Minimoog and Odyssey's filters.
Ken's version allows all three to be used simultaneously.
Sallen Key filter
If the resistors (R1 & R2) are voltage controlled (eg with vactrols or OTAs), then we have a voltage controlled filter. (OTAs In the Steiner- Parker VCF, a string of eight (1N4148) diodes morphs into this voltage controlled resistor. How ???
And all 3 filters (BP, LP, HP) are obtained simply by injecting the audio signal into different parts of the circuit.
The LP filter is obtained by injecting the audio into the 47k resistor at the top. There it enters the diode string (1N4148) and the 2n2F capacitors.
Also notice the two 2n2222 transistors that sit on either ends of the diode string. They form a voltage differential across the diodes.
The diodes need to be fed current if they are to act like a resistor......
By varying the voltage we can produce different effective resistances in the diode string as we force current through them.
The whole idea of the diode string is based on Ohm's Law & the equation R=V/ I (R= resistance, V= volatge & I= current )
The pic to the left is the view of a NPN 2n2222 from the underside.
I didn't match these. I wonder if you can use any standard NPN transistors?
Maybe BC 547s ???
In Nyle Steiner's 1972 article it looks like he used 2N5174 transistors instead of the 2N2222 . On Analogue Realitie's site, they use two monolythic matched SSM2210 pairs.
Alternatives ??? - 2N5138 or BC 557 - I might try these in future versions of the filter
"Original transistors as per Nyle Steiner's schematic are 2N5138 and 2N5172"
Hope I've got their orientation right.
Simple = Beautiful
8 diodes, 3 caps & 2 transistors = a multi-mode VCF.
Some more Links:
3. SynthMuseum
5. Doepfer
Wednesday, 11 February 2015
Roland Rhythm 55 - TR-55 Drum machine
Internally & sonically, its very similar to the Acetone FR6.
Controls: volume, balance, tempo, up tempo, power on-off, touch start
Dimension: 130 (H) x 380 (W) x 235 (D) mm (5.1" x 15.0" x 9.3")
She weighs about 4 kg (8.8 pounds) & has 13 buttons & 4 knobs.
The Start-stop Electro-static touch sensitive switch is a great feature.
You will see these on the Roland TR-77 also.
The diode above the on/off switch flashes in time with the beat.
There are 10 voices (split into 6 channels) & 10 patterns: Bossa Nova, Samba, Mambo, Cha-Cha, Rhumba, Beguine, Rock N' Roll, Ballard, Slow Rock, Waltz.
The variation knob splits the rhythms into two parts.: 2 Beat & 4 beat
- 2 BEAT: bass drum, bass + snare, foxtrot1, swing1, march and parade
- 4 BEAT: bass drum, bass + snare, foxtrot2, swing2, swing3 and tango
The 10 voices are : bass drum, low conga, high conga, cowbell, rim-shot, claves, snare drum, high-hat, cymbal, maracas
bass/snare and hahats/maracas
Sadly there is no way to sync the drum externally.
This is ripe for modding. It's all analog with tons of trimpots begging to be tweaked
If you pull off the backplate and tweak the trimpots you can get that 808 bass and it's decay can be set to last forever !!!!
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For more info on the history of Roland Drum Machines click here
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