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

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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You can find more NLC builds here.
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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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Click here to return to the NLC Build Index: 
 http://djjondent.blogspot.com.au/2015/03/non-linear-circuits-ncl-index.html

Sunday, 22 November 2015

CGS 38 - Saw pitch shifter & wave multiplier

These are my build notes for the Cat Girl Synth shifter & wave multiplier.
(CGS 38). A very easy build.

Ken's notes are here:
http://cgs.synth.net/modules/cgs38_saw_pitch_shift.html


And the reverse.

IC headers first.

Resistors, caps,  beads next.

I'm waiting on a few components.
TBC.

Monday, 16 November 2015

Saturday, 14 November 2015

Master Pulse Divider - CGS 22 - Build notes

These are the build notes for Ken Stone's master clock divider. Cat Girl synth 22
The incoming clock signal is divided into successive clock signals to drive EGs, sequencers, etc ... lots of nice poly rhythms.


Its more than just a simple clock divider though.
There are four outputs each for divisions of 2, 4, 8 and 16.
Altogether there are 16 outputs.
ie : each division had 4 variations that are phase shifted from each other.
The first is a straight division. As far as I can work out, each successive is shifted by 1/2 the frequency of the last. (please let me know if this is BS).
 
HEADERS, Beads, the odd cap & diode .



 Resistors first.



I've followed the suggested values for the resistors:
RA = 1k8
RB = 1k
RL = 2k2 (for the LEDs).



Most of the decoupling capacitors are mounted directly to the solder side of the board. Pads are provided on pin 7 and 14 of each of the 4070 for 100n the decoupling capacitors. 

 I've added heatshrink to the cap legs to avoid shorts.

 Most of the decoupling caps are surface mounted 805s.
Trannies next. These are common BC 547s


There are 4 types of IC used : the TL072,CD4024B, CD 4070B.


 It's a dual op-amp.


The CD 4024 - its a general purpose binary up counter with clock input, reset, and 7 outputs (only 4 of which are used in this circuit - Q1,Q2,Q3,Q4). The binary outputs count up on the negative edge of the clock. It counts out a binary sequence and makes the bits available on the output pins (pins 5,9,11,12).  So we clock this counter (pin 1) and this produces a binary count N bits wide. Hitting the reset (pin2) with a logic signal of 1 resets the counter to 0.

This chip is very useful if you wanna generate square waves from a oscillator.

The 4070 is the logic network which accepts the counter output bits as input.
It's a quad 2-input Exclusive-OR gate. There are 4 of these in this module.


Initial tests indicate that the pulse outputs for the CGS22 are +5v. OK for Eurorack, though my aim is to use this in Buchla land. So looks like I'll have to boost this to 10V to drive the sequencer on my 208.
The Dual Lopass Gates on the 208 do however trigger with the 5V pulses....interesting.


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Update ; The Buchla 208 sequencer can be triggered with 5V pulses from the CGS 22 if you go via the Easel program card. The program card seems to accept much lower trigger voltages.
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The panel is a bit rough around the edges.
The LEDS are mounted straight onto the PCB. I hate wiring things up. Couldn't avoid having to wire the bananas though. Lots and lots of flashing lights. :-)
Gotta love that.

I've wired the bananas according to divisions. The top (left most) four are division2.
The next four are division 4, and so on.... the last being div 16.
It would have been nice to mount the LEDs next to the corresponding banana, but one can't have everything.esp if you decide to mount the LEDs directly onto the PCB.

From top (left in the pic) the LEDs are labelled:
1B - Division 2 Phase 3 (clock XOR Q1)
1D - Division 2 Phase 1 (clock XOR Q1)
1C - Division 16 Phase 4 (Q4)
1A - Division 16 Phase 2 (Q4)
------------
2B - Division 4 Phase 3 (Q1 or Q2)
2D - Division 4 Phase 1 (Q1 or Q2)
2C - Division 2 Phase 4 (Q1)
2A - Division 2 Phase 2 (Q1)
----------------
3B - Division 8 Phase 3 (Q2 XOR Q3)
3D - Division 8 Phase 1 (Q2 XOR Q3)
3C - Division 4 Phase 4 (Q2)
3A - Division 4 Phase 2 (Q2)
-----------------------
4B - Division 16 Phase 3 (Q3 XOR Q4)
4D - Division 16 Phase 1 (Q3 XOR Q4)
4C - Division 8 Phase 4 (Q3)
4A - Division 8 Phase 2 (Q3)

You can see a pattern developing.

 Links:
+ CGS 22 build notes
+ Schematic
 + CGS version 1 
 + MOTM - Richard Brewster 
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For more CGS builds, info, etc click here.