Showing posts with label Eurorack. Show all posts
Showing posts with label Eurorack. Show all posts

Tuesday, 12 April 2016

Quick & dirty DIY Buchla to Euro conversion

These are my quick and dirty DIY notes for a Buchla to Euro power converter.
This blog is my diary for ideas, projects etc that are on going. It helps me to remember details that I usually loose if I don't write down.

This will probably change as I refine the circuit. if you have any suggestions for improvements, please let me know.

Buchla provides -15,+15,+12,+5.
Euro needs +12,-12,+5.
So we need a -12V for Buchla & Euro modules to exist in the same case.
Using a L7912CV voltage regulator.
 http://www.st.com/web/en/resource/technical/document/datasheet/CD00000450.pdf


This was my first attempt using perf board.
In the first attempt, the caps were both 1uF electros

Attempt # 2 ... using a 1uf & 2.2uf cap.

I built this for a friend about a year ago and he reports that it's still happily chugging along.
It might be a good idea to add a heat sink to the regulator. C1 is required for stability. A tantalum is recommended, though in this mock up I used a straight electro.

If electrolytics are used and you are planning to run lots of euro maybe ten times (or more) value capacitors should be selected.???

AND: a high current diode from input to output (1N4001 or similar)
should be introduced to protect the device from momentary input short circuit.

29/0416
Some new pics care of Cobramatic.
Paul has used tanties and he reports no problems.
This board doesn't use a heatsink -- will see how this goes over time.

The Buchla (BEMI) power board is on the top.


Disclaimer: 
I take no responsibility if this damages any Euro or Buchla modules or starts a fire. 
Modular gear requires care and more that a casual understanding of electronics.
Don't build this if you are not totally confident with your soldering skills.
These are just working ideas that will be refined over the coming years.

Saturday, 2 April 2016

ARP 2500 - Modcan'd

Playing around with some Eurorack sequencers.
The Modcan Touch is shaping up nicely as a partner for the ARP2500

Taking some samples:


It syncs perfectly with the ARP 1027 sequencer.

 The 1004-T oscillator.

The 1047 filter.

The 1046 Envelope Generator.

The patch.

Monday, 25 January 2016

Metro - Cobramatic remix

Some Buchla & Euro sounds.

Enjoy
This new track features the random out custom mod to Mutable Instruments 'Grids' module. Grids plays some of the TipTop module drums and the random out triggers the bass synth gate played by a Verbos Buchla format 262v Harmonic Oscillator.
There is a Intellijel Metropolis sequencing the lead line. An additional sequencer line comes from the Buchla 208.
Everything is remixed in Ableton Live.

Friday, 18 December 2015

Korg Monotron Delay - Build notes for Shock Electronix euro version

These are my build notes for the Shock Electronix Eurorack conversion of the Korg
Monotron Delay.
I remember modifying my monotron back when they were first released. So much fun.

Matt from Rhythm Active has done some great work in producing this kit.
Its very easy to build.
BOM
Resistors:
100R x 1
390R x 1
270R x 1
33K x 1

Diodes:
1N4148

Capacitors:
100n
10uF electros

First open up your Monotron Delay.

Lots of surface mounted components. You could hack from this surface to (a future job) but Korg have helpfully placed the patch points on the rear.

I love the people at Korg. They have even made the schematics freely available.
Delay schematics are here.

Back to the build.
Resistors first.


Wednesday, 2 December 2015

NLC Collude - build notes

These are my build notes for the Nonlinearcircuits collude module.
It's an envelope follower and very very high gain amplifier (from 2x to 20x).
...... so it should be very useful to amplify all sorts of signals no matter how weak they are
and produce useful voltage envelopes for your modular.

Andrew's build notes are here:
http://www.sdiy.org/pinky/data/COLLUDE%20v1.pdf

There are eight 100k SMDs in the build. I'm using 0805s.
Andrew has given the option of using SMDs or through the hole for the remaining
resistors.

Some NLC wisdom to inspire your build.
Thank goodness for that!
Datura is a genus of nine species of poisonous vespertine flowering plants belonging to the family Solanaceae.

I'm a bit old fashioned so most of the resistors are through-the-hole. except for the LED resistors.
I'm trying out 470R ones this time. I used 1K in the last project. ... no real method in this... just experimenting.

 Surface mount components first, then the IC & power headers.

Thru hole resistors next.

Trannies, Caps, diodes, etc ... all the through hole stuff.
The ceramic cap in the front is 10pf. The schematics ask for a 12pf.

The 4 pots are all 100K linear. I like to insert the pots and jacks on the PCB first without soldering
then screw on the faceplate.
Once you are satisfied that everything is in the correct position , then solder.

Don't forget to solder the ground tabs

Pop those LEDs in and you're done.


Useful links
+ NLC blog

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Tuesday, 24 November 2015

NLC - 2 x LFOs - Build notes

These are my build notes for the NonLinearCircuits Dual LFO & difference rectifier (Eurorack version).
It's a easy build as all parts are through the hole.


Andrews build notes are here:
http://www.sdiy.org/pinky/data/WAMOD10%20dual%20LFO.pdf
and his blog notes are here:
http://nonlinearcircuits.blogspot.com.au/2015/03/dual-lfo-with-difference-rectifier.html
Some pics of the virgin PCBs
And the rear.
There are two op-amps used : a TL074 & a TL072




.
 Headers first.


Resistors next.

This LFO uses a combination of integrator & schmitt trigger. It's quite a commonly used combo.

This is a simplified version of Andrew's circuit.
The op-amps "A" & "B" are part of the TL 074. "A" is the non inverting schmitt trigger. "B" is the integrator.
The output of the Schmitt trigger is a square wave. This is fed into the integrator. The output of the integrator is a triangular wave, which is fed back to the Schmitt trigger. Thus first stage drives the second, and the second drives the first..... which came first ???? the chicken or the egg ???

The last part of the module is a diference rectifier which is described by Andrew thus:
"This circuit is a hybrid of two basic op amp ‘building blocks’ .....a difference circuit and a rectifier.
 It takes the triangle waves (from the 2 LFOs) and supplies a signal that is the difference between them"
 http://www.sdiy.org/pinky/data/dif.html

The NLC module uses two standard 1n4148 signal diodes for this rectifier circuit.

"Basically the circuit compares the voltage on the ‘-‘ inputs with the voltages on the ‘+’ inputs. (on the 072 op-amp). The difference between these voltages is fed to the outputs. If the difference is positive  it appears on the ‘+’ output, if the difference is negative it appears on the ‘-‘ output. Again, a great way to mix boring CVs to get something interesting, audio frequency wave - shaping. "



The two electro caps I'm using are rated 25V.
I've used monolithic ceramic capacitors for the two 1uF 105s.
The three 100nF 104s are straight ceramics



I've used 1k 0805 SMDs for the LED resistors. Not really sure of the exact value but they are easy to change if needed.
As it turned out, the 1K resistors seem to work well.


The pots now. I was debating whether to chose two audio 100k pots (for frequency adjustment) and two linear pots for the fine adjustments, but Andrew advised me to use all linear100K pots

I've used scrap resistor wire for the ground connectors


Testing the square & triangle waves.

Lovely !!!

Useful links.
+ Video - VCO using a Schmitt trigger & integrator.
+ Pdx.edu VCO
+ Falstad.com
+ Thomas Henry - The birth of a synth
+ The two amp oscillator
+ Circuits Today
+ What is a schmitt trigger and how it works
+ NLC build notes for the difference rectifier & neuron

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Wednesday, 21 October 2015

Delay No More - NonLinearCircuits build notes.

The saying "Delay No More" is a great ideal to live by.
And for those of you who have spent any time in Hong Kong, you might also recognize it by its local slang meaning.. "Delay no more" sounds similar to the Cantonese foul words (Diu lay lo mo) which translate as "fuck your mother".
Seldom used seriously "Delay no more" appears in writing as a joke among Hong Kong people. There is even a fashion brand in Hong Kong producing T-shirts with "DelayNoMore" on it.


I'm sure Andrew knew none of this when he picked a name for his new delay module. :-)


Here are the build notes:
http://www.sdiy.org/pinky/data/DelayNoMore%20build%20notes.pdf

All the SMDs are passive ... just caps & resistors. So building this puppy should be pretty easy.
(Be careful not to heat the caps too much).

The DNM uses the PT2399 which is a great chip for DIY. It's almost a whole guitar pedal by itself.
According to Princeton (the manufacturer) it is a echo audio processor IC utilizing CMOS Technology which is equipped with ADC and DAC, high sampling frequency and an internal memory of 44K.



It also features an internal VCO circuit in the system clock, thereby, making the frequency easily adjustable.
Cool Man !

First some virgin pics of the PCB.

Both sides require SMD components. Solder these on first.


Headers, resistors, caps next.
Next the BC 547 trannie, the 78L05 (+5v voltage regulator) and the vactrol.
I'm using a Silonex NS 32

K = Cathode.

Now the pots & jacks. There are six linear 100k pots , one 1M linear  and a single 50k linear.

Don't forget to solder the ground tabs with scrap wire.
Lastly do the LED.
Beautiful !!! Time to stand back and admire.
And she sounds very distinctive. esp for such a small module. Another sound effect in your arsenal.

I'm thinking of putting this into one of my Buchla cases. As the CV input is isolated by a vactrol, plugging in 10v - 15v Buchla voltage levels should be fine. This module is not just for Eurorack.
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