Showing posts with label DIY. Show all posts
Showing posts with label DIY. Show all posts

Monday, 9 February 2015

Roland CR-8000 CompuRhythm Drum Machine - Description.

The Roland CompuRhythm CR-8000 came out in 1981.
It's without a doubt one of Roland's classic drum machines with roots that go back to the  famous CR-78 (produced in 1978) & the TR-808 (which came out just one year before in 1980).
The 8000 & 5000 also look a lot like the Korg KR-55 which came out in 1979. There must have been  intense rivalry between these two Japanese corporations and I suspect the CR5000/8000 was a response to Korg's KR-33/55.

The unmodified CR-8000 weighs in at 3.2Kg, with 12 knobs & 32 buttons.
I really like the the digital tempo display. It's very accurate at giving a precise BPM reading.


The digital display was not a feature on the slightly earlier CR-5000 
The CR 8000 also adds the user programmable presets and fills.

Unmodified, the CR-8000 has a trigger out (+5V pulses) so you can clock external gear.
Sadly there is just one audio output, but unlike the CR-5000, the 8000 has DinSync (24ppqm).
dinsync I/O at 24PPQ

DRUM (weight: 3.8Kg) Main panel features a display, a data encoder, 11 knobs and 32 buttons.
- See more at: http://www.polynominal.com/site/studio/gear/drum/roland-cr-8000/roland-cr-8000.html#sthash.bPBX691N.dpuf
DRUM (weight: 3.8Kg) Main panel features a display, a data encoder, 11 knobs and 32 buttons.
- See more at: http://www.polynominal.com/site/studio/gear/drum/roland-cr-8000/roland-cr-8000.html#sthash.bPBX691N.dpuf
Another advantage the CR-8000 had over the 5000 was the "Programmable Rhythm Section".
Here you can program your own beats, one instrument at a time,  in step time. 
The drum uses two 1.5V batteries to store your patterns in 8 slots when the machine is turned off.
The CPU used is a 8-bit micro-controller - a 8049/8048 chip. (40 pins)
CPU NEC D8049C232

There is a knob above that allows you to pick the instrument you wish to program.

To the right of the Program section is the "Voice Level". This essentially is a 6 channel mixer. The Cr8000 has in total 13 sounds so compromises had to me made with the mixer. The channels are:
1. Bass Drum
2. Tom Tom /Rim Shot /Snare
3. Conga
4. Claves/ Cowbell,
5. Cymbal/ High Hat. (the HH is unique...and one of the strengths in this machine)
6. Hand Clap.

Another advantage the CR-8000 has is the "accent" dial.

I think the unmodded CR-8000 sounds like a cross between the CR-78 & TR-808. It's often referred to a the poor man's 808. Though it really shines when you start to mod it.
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For more info on the history of Roland Drum Machines click here

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

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

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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*** Click here for the TKB Build Index ***
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Wednesday, 28 January 2015

TKB Build Notes - Index - The Human Comparator Kit

TKB Build Notes - Index - The Human Comparator Kit.
This is the main Index for the build notes for the Serge TKB (Touch Keyboard Sequencer).
Many thanks to Zthee (The Human Comparator) for making this build possible.

I'm documenting my experiences as I put the TKB together to help me trouble shoot in the future .
Hopefully, this will also help others in their quest to build the TKB & more importantly, to learn the
Art of Electronics & of Electronic Music.

1. Pics of the kit before starting.
2. Some pics and info of a vintage TKB.
3. Starting the build - main PCB -  resistors, diodes, headers, caps, etc.
4. Main PCB - Transistors & ICs
5. Pot boards.
6. The Touch Keyboard (Installing the LEDs)
7. Front panel assembly.
8. Wiring up the touch keyboard
9. Installing the S2 & S3 Ribbon cables.

This index will be updated as the project progresses. 

The official build notes of the Human Comparator
http://build.thehumancomparator.net/ 

The original build notes for the TKB kit from the 1970's are here:
http://serge.synth.net/documents/kit/tkb.html 
Official modifications to the TKB from the1970's are here:
http://serge.synth.net/documents/kit/tkbmod.html  
Intro to the Serge Modular Music System
http://www.serge.synth.net/documents/Intro_To_SMMS_Part_1.pdf

Muffs has a great thread here:
 https://www.muffwiggler.com/forum/viewtopic.php?t=104513&start=575
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Zthee's previous project was the TTSH (Two Thousand Six Hundred).
This is a clone of one of the greatest synthesizers of all time, the mighty ARP 2600.
My build notes for the TTSH are here:
TTSH Build Notes




TKB Build - Part 3A - Main Board

TKB - Touch Keyboard Sequencer - Build Part 3 - Main Board. (Resistors, Caps, etc).

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

Before we begin there are some preliminary pics of the PCB


I'll start of with least temperature sensitive components such as the IC header sockets, resistors & diodes.



Mouser #: 571-5103308-3
Mfr. #: 5103308-3
Manufacturer: TE Connectivity
Desc.: Headers & Wire Housings 16P 2 ROW HEADER LP
These modern headers connect the Main PCB to the rest of the keyboard. In vintage TKBs, the headers used were slightly different:


Notice the silver arrow which is used to check the header orientation.
Vintage TKB headers.

Back to the Modern PCB: 

Looks like the four 22pf caps on the left need to be swapped for 100pf.
According to one of my tech friends, you can experiment a bit here. Serge used 82-100pF,
but you could even go as high as 220pF. Apparently the caps are filtering some unwanted noise from the clock driving the keys, and 100pF suppresses it OK. ....but even higher values might do a better job. The only problem is - go too high and it might start to slew your signal… ????

I'll def do some experimenting with this. (Many thanks to my friend for this advice).

Looks like the surface mount 100n caps need to be soldered to the underside of the PCB across pins 5/4 & 11/10.  of the  LM 324s --- SEE PIC BELOW

The LM 324 is a low power quad Op-Amp


There are 5 surface mount 0.1uF / 100nF caps to solder to the underside of the PCB.
The soldering points are a bit tricky to see at first. They lie across two of the LM 324s -  pins 5/4 & 11/10.
and underneath the LM324 just below the MM74C150


The SMD caps lie under the three LM 324s on the top right

Almost finished the easy part ... soldering the resistors, diodes, caps & headers..
I think its a good time to stop and compare this board to a vintage TKB main board. This one is a unrestored TKB -- also from the late 1970s.

Notice the bud box below is self powered.... in fact it has two PSUs, and was once part of a much larger system.

 Top pics of the main TKB PCBs (vintage on left)

The underside of the PCBs.


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