Thursday, 5 February 2015

kORG SQ-1 sequencer - First impressions & tests

This (the Korg SQ-1) just arrived yesterday so I'd though it would be fun to test with a few of my Korgs.
I was surprised by just how small it is when compared with its older brother, the SQ-10

Barely the size of a Korg Volca. And it runs on batteries. First a test with the MS-20 mini.No Midi used here. All old school CV/trigger




 .

A comparison of the controls of the SQ-10 and the SQ-1 above.


One interesting observation I made regarding the clock speed of both sequencers.
was that if I connected the multiple pulse out of the SQ-10 into the sync in of the SQ-1,
 the SQ-1 ran at twice the speed of the SQ-10.

Korg equipment (eg KPR-77, DDM-110 & DDM-220) uses 48 pulses per quarter note. I guess the SQ-10 is the same. But it seems that the SQ-1 runs at the Roland standard of 24 pulses per quarter note (PPQN for short)..... thus the doubling of its speed when clocked by the SQ-10.

The SQ-10 is a S-trig sequencer.

The SQ-1 can be both a S-trig & V trig sequencer..
Re Gate out polarity of the SQ-1.
When the Mode button is unlit, -ve polarity (volatge fall) is selected - This is the S-trig.
When the Mode button is lit, +ve polarity (volatge rise) is selected - This is a V-trig.
The Gates output level are 10V.
The Sync Out jack outputs a 5V pulse (15ms long)
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A brief summary of  Sequencers & Sequencing Resolution - PPQN

You will often see the letters PPQN or PPq used in reference to old drum machines & sequencers.

What does it all mean and how does this help one to clock a Roland drum machine to a Korg SQ-10 sequencer? Early sequencers and drum machines had resolutions in the order of 24 or 48 pulses or 'ticks' per quarter note (ppqn).

A sequencers resolution is defined as its ability to divide the beat of a quarter note into
a pulses. The more pulses, the more accurate a sequencer is.

Common divisions used by sequencers are :
24 parts - 24 ppqn
48 pulses - 48 ppqn
96 parts - 96 ppq
192 ppqn, etc etc etc

MIDI clock = 24 pulses, so called "ticks" per quarter note
Roland equipment (606,707.727,808.909) use 24 pulses per quarter note (PPQN for short), known as DIN Sync24.
A notable Roland exception is the CR-78 which uses 12ppqn.

Korg equipment (eg KPR-77, DDM-110 & DDM-220) uses 48 pulses per quarter note.
Oberheim (DMX) & Linn is 96ppqn.
The SCI Drumtraks handles 24, 48, and 96 ppqn
EMU drumulator - 24ppqn - needs a din to 1/4 Y cable,


Links
+ Modular Clocks - Analog, MIDI , PPQN

(To be continued)
If there are any mistakes or omissions, please write to me.
J

Tuesday, 3 February 2015

CGS 86 - Build notes for the Serge Touch Keyboard

Firstly, I'd like to thank Ken Stone of Cat Girl Synths for making this kit possible.
You can find his build instructions here:
http://www.cgs.synth.net/modules/cgs86_trk.html

Useful Links:
1. Muffwiggler Thread
2. That famous Synapse Article by Arpad Benares (care of Cyndustries)
3. PAiA - Touch switches (like those used on their Programable Drum Set)

I'm currently waiting for some pots to arrive for the TKB build.
The Serge TKB also uses a touch keyboard and it seems logical to build the CGS 86 at the same time.
I think these two projects share many common concepts. If I understand this correctly, both use the capacitance principle (not FSR - force sensing resistors).

It looks like the two BC547 transistors on the small driver PCB make up the emitter coupled astable oscillator (Multivibrator circuit). They produce that famous square wave of 100khz. 

The second larger PCB is called the detector since it detects when the output of the astable osc changes. When you touch a key, some of that square wave is shunted to ground and the Op Amp's (The LM3900's) output goes +ve in response.




I'm hoping the CGS 86 will compliment the TKB. Possibly, I'll instal them in the same boat.

Here are the virgin PCBs:

You will need two of the larger green PCBs if you wish to use all 16 touch plates.


IC headers, Resistors, Diodes first.


Sunday, 1 February 2015

Serge TKB build - Part 5 - Potentiometer boards.

This is the fifth stage of the Serge TKB build - Potentiometer boards.

The further I get into this project the more I realize this is not just a clone that I'm building. Like the original TKBs of the 1970's this project also comes as a kit. It has the blessing of Serge Tcherepnin himself and is the real deal brought to 21st century standards.

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

The virgin Pot Boards


The first part of this section involves inserting 64 x 1M resistors.
That's 16 resistors per board..
This is so much easier to do in this modern kit as these 4 boards replace the wires that joined the pots & resistors found in vintage TKBs.

 Can you imagine having to wire this up back in the 1970's ??? :-(

And you will need 4 of these headers.

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Saturday, 31 January 2015

Conn Min-o-matic Rhythm Drum Machine

I picked this up very cheaply. Might be fun to mod.
If anyone has the schematics for this drum and is willing to share I'd be eternally grateful.

 I think this dates from 1966 - all analogue goodness with discrete components.

pretty simple to use with only 9 push buttons and 2 knobs global volume and tempo frequency - See more at: http://www.polynominal.com/site/studio/gear/guest/conn/index.html#sthash.FasTlVLl.dpuf
 A drum machine can't get much simpler than this. Nine pattern buttons & two knobs for volume & tempo.

 There are 5 sounds: kick, snare, conga, Hihat, claves, metronome click.

Sadly there are no seperate outs
If you do decide to mod this please be very careful. Once the cover is removed you run the risk of electric shock. This will KILL YOU.
Rear mounted tone control, 1/4" phono output jack & Hi / Lo output level selector.

This is not the simpliest drum to mod. The Rolands & Korgs tend to seperate their PCBs into PSU, rhythm & voice sections. Not so here. Everything is on one PCB.

The PSU is here. Be very careful !!!


There are 6 pattern presets: Waltz, Ballad, Foxtrot, March,Teenbeat, Latin, metronome.

Here is some info about C.G.ConnInstruments
 
There are 6 pattern presets, no possible variations except the Double Beat function:
- Waltz
- Ballad
- Foxtrot
- March
- Teenbeat
- Latin
- metronome - See more at: http://www.polynominal.com/site/studio/gear/guest/conn/index.html#sthash.FasTlVLl.dpuf

Socceroos - Football's Asian Champions of 2015

Roland (Rhythm) TR-77 & Bentley (FR-8L) Rhythm Ace Drum

The TR-77 was Roland's very first drum machine. It was released in 1972. TR stands for Transistor Rhythm. As it is Roland's first drum machine, its place in the history of Roland and indeed in Electronic music history, is assured.


Officially named the Rhythm Tr-77, it was in reality a updated Rhythm Ace  FR-7 &/or FR-8L
The FR-7 appears to be very very rare (In fact I have never seen one in real life or even a photo). More common is the FR-8L  To make things even more confusing, in the UK, the FR-8L was  re-released as the Bentley Rhythm Ace and in the USA she was sold as the Hammond Auto-Vari 64.

 the Hammond Auto-Vari 64


1972 was the foundation year for Roland, who also released in the same year, the TR-33 & TR-55. The 77 was Roland founder's (Ikutaro Kakehashi) baby as he migrated from the old company, Ace Tone. The Tr-77 became Kakehashi's flagship product. 

Here are the TR-77 & the Bentley Rhythm Ace ....... united once again.
The differences between the two machines appear to be small, however they do sound different. The Bently/FR-8L is also slightly shorter than the TR-77.

The TR-77 has two additional patterns (the Western & the 6/8 March) over the Bently.
and also a Samba 1 & Samba 2 rhythm. The Bentley has only 1 Samba Rhythm.


The Bentley has 5 faders for Volume,Tempo, Cymbal/HH/Maracas, Guiro, Snare, Bass Drum.
The TR-77 has 6 faders for Tempo, Fade Time, Volume, Bass D, Snare D, Guiro & Hi-Hat/Cymbal/Maracas.

As you can see from the pics above, these drums were designed to sit on top of an organ.
The wood finish and the built in music stand indicate their designer's original intentions.
However, I think they are the warmest sounding drums I have. I really dig them.
The voices are generated by "tuned resonance" type circuits. Though neither has the kick of a 808, there is a smoothness to both that I truly love.



The Bentley Rhythm Ace (FR-8L)

Both also have that lovely start/stop metal bar that can be seen on their extreme left.
Why don't more drums have this?

The Roland Rhythm TR-77


The Roland Tr-77 Rear

 TR-77. Start, High Impedance & Low Imp outputs.

Here is a interesting video where a Roland TR-8's handclap is routed to an individual out and then run into the Footswitch stop/start of the TR-77. This allows the TR-77 to start and stop on command via an audio signal. The handclap on the TR-8 were placed on steps 1 and 14 of the sequencer and the TR-77's tempo was hand-adjusted to match. 





TR-77

Both the TR-77 & Bently FR-8L have no sync abilities without modifications.
Nor do they have seperate outs for the individual drum sounds.
 The Bentley Rhythm Ace FR-8L rear

Bentley FR-8L

Bentley FR-8L
These drums are ripe for modding.
Here are some links to start you on your modding and/or circuit bending way.
3. Burnkit2600 TR-77 mods (trigger inputs, External clock Sync,Tone Mods).
4. Warren Cann from Ultravox  (his experiences modding the TR-77)
5. CircuitBenders (FR-8L & the TR-77)
6. Circuitbenders (Tr-77 External Power conversion to reduce hum & background noise)
7. Bently Rhythm Ace with Buchla & Euro (using a envelope follower to sync)
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For more info on the history of Roland Drum Machines click here

Friday, 30 January 2015

Korg PS 3200 & Volca Beats.

I just love mixing up my Korgs.
Here we have a old 1978 Ps-3200 & a modern Volca Beats.
They are sequenced via a Doepfer Dark time.

My thanks to Paul for tweaking the gear. I'm currently waiting for the Korg SQ-1 and when it's here I'll definitely upload more videos.

The Dark time uses the V/Oct standard.

The CV design of the MS-20, MS10, and the PS-3200 always used the Hz/V standard.



This provides excellent pitch stability, however it also limits the number of the step sequencers that are able to correctly control the PS3200. The Dark Time is working well in this instance as it's using midi, not CV and gate. My PS-3200 has been midified.

And yes, GATE OUT Polarity (+ polarity vs - polarity) and SYNC IN/OUT Polarity ie, + (rise), - (fall) can also be a problem  

Korg uses S-Trigger ("short circuit trigger", sometimes called "negative trigger"). This involves keeping the voltage high, and then shorting the trigger circuit whenever a note is played.

The Dark Energy uses a positive trigger which is also called V-Trigger  or "voltage trigger". This method involves keeping the voltage low (around 0 V) and producing a fixed positive voltage to indicate when a note is played.


As a descendant of the SQ-10, the SQ-1 supports the Hz/V standard so it should enable me to perfectly control the MS-20 or MS-20 mini and the PS3200.
Until then, the Dark Time is doing fine.

Flying Fox - Jodhpur - India

What a great way to see the fortress of Mehrangarh in Jodhpur, India.
Flying over these magnificent battlements is so exciting.





Zip 6: The Magnificent Marwar (300m) You fly over two lakes an land on the tip of a fortified tower that rises 30 metres out of Ranisar Lake.

Battlements of Rajasthan

 Flying Fox - cable - over Mehrangarh Fort.


The medieval "Blue City" of Jodpur.

Thursday, 29 January 2015

TKB Build - 4 - main PCB - Semi-conductors

*** Click here for the TKB Build Index ***
 
The diodes (6x 1n4148) are already in. Transistors & integrated circuits to go.
The main board uses 10 transistors:
One PN4250 & nine PN5179. (my vintage TKB uses nine EN5179s)

 This is a pic of a vintage EN5179.

Today the PN5179 and EN5179 are very hard to get, so they have been replaced with the more common 2n3904.



The PN4250 is unchanged from the original.

There are 9 types of ICs used on the main board.
These are:

1. LM324N. We need 4 of these.
     Mouser #: 512-LM324N    
     Manufacturer: Fairchild Semiconductor
     This is a quad Operational Amplifier.

2. 4042. We need just one of these
     Mouser #: 595-CD4042BE   
     Mfr. #: CD4042BE
     Manufacturer: Texas Instruments
    This is a CMOS quad clocked D-type latch.
For more about latch circuits click here:
http://www.dummies.com/how-to/content/electronics-projects-how-to-build-a-latch-circuit.html

 3. 4050. We need 3 of these
      Mouser #:     595-CD4050BE    
      Mfr. #:     CD4050BE
      Manufacturer:     Texas Instruments
     This is a non-inverting hex buffer.
    
Some info on buffers:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/buffer.html

 4   4051. We need 3 of these.
      Mouser #:     595-CD4051BE     
      Mfr. #:     CD4051BE
      Manufacturer:     Texas Instrumen
    
      The CD4051B is a single 8-Channel multiplexer having three
       binary control inputs, A, B, and C, and an inhibit input. The
       three binary signals select 1 of 8 channels to be turned on,
      and connect one of the 8 inputs to the output


5. 4069 - We need two of these.
      Mouser #:     595-CD4069UBE    
      Mfr. #:     CD4069UBE
      Manufacturer:     Texas Instruments
      The 4069 contains 6 CMOS inverter circuits.

     For more info click here:LOGIC INVERTERS
   
    

6. 4081 - We need two of these.
     Mouser #:     595-CD4081BE     
     Mfr. #:     CD4081BE
     Manufacturer:     Texas Instruments
     This is a Quad 2-Input. AND Gate.

For more info on Gates click here: LOGIC Gates
7. 4516 - just one is needed.
    Mouser #:     595-CD4516BE    
    Mfr. #:     CD4516BE
    Manufacturer:     Texas Instruments
    Desc.:     Counter ICs Binary Up/Down


8. 4520 - We need just one.
    Mouser #:     595-CD4520BE   
    Mfr. #:     CD4520BE
    Manufacturer:     Texas Instruments
    Desc.:     Counter ICs Dual Binary Up

9.  MM74C150
     This is a 16 line to 1 line Multiplexer
      Datasheet info

Part 5. Pot boards.
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