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

Tuesday, 7 November 2017

Greyscale Algorythm - Firmware 2

This module is a 1 to 8 channel step sequencer.
It can be a 1x64 step, 2x 32 step, 4x16 step or a 8x8 step sequencer.
 
The new firmware is a bit tricky to decipher initially.

There are 3 global menus
(access these menus by holding the Start/Stop button for about 450ms.)
 
1. OVERVIEW MENU (Loop/End switch)
2. MODE RESPONSE MENU (Seq/Rand switch)
3. CHAINING MENU (Gate/Trig switch)
 
Tap any of the right top white LED switches (excluding the left most Start/Stop LED switch) to change to a different menu.


 
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1.OVERVIEW MENU (Loop/End switch)
 The Overview menu always appears when the module is powered on.
It displays what's happening with each of the 8 channels.
 
The 1-8 LEDs flash brightly when an output voltage is high, and glow dimly when an output voltage is low. 
 
You can also mute channels from the Overview by tapping the specific channel button really quickly (just a light tap). 
 
Holding the button down for longer will allow you to see what steps are on/off for that specific channel.
To return to the Global view/menu, hold down the "Start/Stop" button.
 


 
Muted channel LEDs still flash (albeit less brightly) during playback so that you can keep track of what muted channels are doing before un-muting them. Mutes are applied on a per-segment basis, meaning that you can mute any segment within a chain while the other segments continue to play.
 
 
2.MODE RESPONSE MENU (Seq/Rand switch)
controls whether or not a channel will respond to a pulse at the Mode input jack,
 


 
3. CHAINING MENU (Gate/Trig switch).
( Switches 2, 4, and 7 have no function in this menu.)
 
Tap switch 1 for a 1x64 chain, where each of the 8 segments play in series. 

 
Tap switch 5 for a 2x32 chain.   (Switch 1 & 5 are lit)
 

 
Tap switch 3 for a 4x16 chain (switches 1,3,5,7 are lit)
 

 

tap switch 8 for an 8x8 setup, where each channel is independent (chaining is off). 

 

 
All the 8 LEDs are now lit.
 
 
Pattern Editing
You can change between channels/segments at any time, from any menu, by holding down one of the 1-8 switches for 450ms.  
you will then enter the editing mode and see the LEDs light up sequentially.
video 6
 

 

To return to the global view hold the Start/Stop button for about 450ms.

Links
 
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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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Thursday, 26 October 2017

Buchla Easel - Portabellabz bob expander.

These are my build notes for the Bucha easel BOB by Portabellabz.
You can find the docs here .
It's quite a neat little unit. And it's expandable.



The two ICs are a TL071 op amp and a CD 4093. The TL071 is I think used to invert the EG.... the second left output jack.  The 4093 is I think used for converting gates to triggers ???... for the pulser trigger out ???

The trimmer sets the voltage level of the pulse trigger out. ... If using eurorack the voltage level of the pulse out can be reduced to 5V


Papz has left a section on the right blank to add your own circuit.
I'm putting in a square wave LFO/audio oscillator which you can find in the build notes.
I first tested this on some bread board.

Used just one 741 op amp, one capacitor (220nf) & 7 resistors.
The uber basic circuit is here
It's about as simple a circuit as you can get. An op-amp with positive and negative feedbacks.
The inverting input is connected to a RC (resistor capacitor) network. The non-inverting input is connected to a voltage divider.
It's classified as a astable multivibrator which has two states, neither of which are stable. It is constantly switching between these two states with the time spent in each state controlled by the charging or discharging of the capacitor through a resistor. The op-amp works as an analogue comparator... comparing the voltages at its two inputs.
The full schematic is here:

 Yup. It works both as a modulation oscillator and a audio oscillator.

Now to build it into the board.





So the the connections from left to right are:
- sequencer pulse in
- envelope inverted out / envelope trigger out (switchable)
- pulser pulse in
- pulser trig out (the internal short pulse occuring at the end of its cycle, not the ramp on yellow bananas)
- MO modulation switch CV
- LPG1 mode switch CV
- LPG2 mode switch CV
- LPG2 signal routing switch CV
- extra oscillator - switchable between LFO & Audio.


Saturday, 21 October 2017

EHX Big Muff - Basic build

This must one of the most studied, rebuilt, cloned, copied circuits ever.
The Big Muff Pi (π), often known simply as the Big Muff, is a fuzzbox produced in New York City by Electroharmonix (and their Russian subsidiary , Sovtek). These are mainly guitar pedals.

 
The famous Mike Matthews Electro-Harmonix Big Muff guitar pedal. Pink Floyd used it. So did the Smashing Pumpkins. Jimmy Hedndrix gave it immortality. The list of artists is endless.

There are countless variations too. You can buy kits on the net with PCB & parts supplied to save you the hassle of understanding the circuit. But I like to know how things work. I'll build this on perf board.
So here is the basic circuit.

So how does it work?
The signal comes in through R2 and C1 before hitting the first stage, a basic transistor signal booster (Q4). Once the signal is boosted, it goes through C4 and enters R24 (the sustain potentiometer). This controls the gain. 

The signal goes through C5 and R19 before hitting the next stage, which is doing 2 things. Boosting  and clipping the signal. The clipping is achieved via the diodes (D1 and D2) & C6/C12.

The signal then goes through C13 and R12 before hitting the next stage : tone control.
It's identical to the previous diode clipping stage apart from the tone pot (R25) which pans between a high-pass and a low-pass. This explains why when you turn the tone control down the sound is very bassy, while turning it up cuts the bass, and it gets very bright.

After leaving the tone pot, the signal goes through C3 and enters into the final signal boosting stage before exiting through C2 and going out of the volume control into the pedal’s output.

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Many thanks to Kit Rae for a wonderful website.
If you haven't visited it yet here is the link:
http://www.kitrae.net/music/music_big_muff.html
This is the site to go to for everything you could ever need on this topic.

The first pedals came out in the late 1960s and over the last nearly 60 years the designs have barely changed. It says a lot about how good the basic design is. Of course there has been lots of tweaking over the decades. At one point the four transistor design was changed to op amps. And for another one of those decades Electro-harmonics transferred production to Russia.

Today the company is strong and still building Big Muffs. I highly recommend the modern versions (I own a few and love them) but I think it is fun and educational to explore the older variations. These go for astronomical prices on Ebay & Reverb today. Vintage "Triangle" and "Foxey Lady" pedals regularly change hands for over $1500.
If you can afford the real vintage thing go for it as I think nothing really beats vintage components. They have a persona which only the years can give. But probably the only chance I will have to experience something like the vintage sound will be to build my own.  So below is a brief comparison between the different variations. It's a great way to explore the evolution.

Starting with the early "Triangle" pedal

Triangle V1


Circa 1971 Circa 1971/2 Circa 1972-73
R1


R2 33k 33k 33k
R3 100K 100K 100k
R4 2.7K 2.7K 2.7k
R5 33k 33k 39k
R6 10K 12K 12k
R7 390K 390K 390k
R8 33k 33k 39k
R9 470k 470k 390k
R10 150R 100R 82R
R11 15K 15K (or 12K) 22k
R12 8.2k 8.2k 8.2k
R13 15K 10K (or 15K) 22k
R14 100K 100K 82k
R15 470k 470k 390k
R16 100K 100K 82k
R17 470k 470k 390k
R18 10K 10K 12k
R19 8.2k 8.2k 8.2k
R20 100K 100K 82k
R21 100R 100R 150R
R22 100R 100R 82R
R23 1K 820R 820R
R24 100K 100K 100k
R25 100K 100K 100k
R26 100K 100K 100k




C1 0.12uF 0.1uF 0.1uF
C2 1uF (or .1uF) 0.1uF 0.1uF
C3 1uF 0.1uF 0.1uF
C4 1uF 0.1uF 0.1uF
C5 0.12uF 0.1uF 0.1uF
C6 0.12uF 0.1uF 0.05uF
C7 1uF 0.1uF 0.05uF
C8 0.01uF 0.01uF 0.01uF
C9 0.004uF 0.004uF 0.004uF
C10 500pF 500pF 500pF
C11 500pF 500pF 560pF
C12 500pF 500pF 560pF
C13 0.12uF 0.1uF 0.1uF




Q1 2N5133 FS36999 FS37000
Q2 2N5133 FS36999 FS37000
Q3 2N5133 FS36999 FS37000
Q4 2N5133 FS36999 FS37000




D1 1N914 1N914 1N914
D2 1N914 1N914 1N914
D3 1N914 1N914 1N914
D4 1N914 1N914 1N914
 

The values seem to have changed slightly over those 3 years.
There is a lot of scope to do some tweaking to find that sound that's right for your needs.
Maybe play around with carbon vs metal resistors? In the 1970s those carbon resistors would have been 10% tolerance or more ???

R24, 25 & R26 are the pots.  
Vintage USA Big Muffs (V1, V2, V3) used single-gang, linear taper, 24mm,100k pots.
A possible future mod could be to use B100K for R25 & R24 & A100k for the Tone (R25).
Log pots (A-100K type) have a longer usuable mid position and less at the ends. ... better fine tuning.
Could be useful for the tone section.

 Leakage current for the 1N4148 as 5 µA .... I think the same as the old 1N914

What transistors to use???
They need to be NPN bipolar
BC549C, BC550, BC239, SE4010, and 2N5210 work according to Kit Rae.
2N5088, 2N5089, MPSA18, 2N3904, 2N4401 are possible candidates.
It might be best to use sockets to allow experimentation.
Were the transistors matched in the early pedals?

Kit Rae's valuable diagnosis identifies three sets of components which alter the BMPs the most.
1. The clipping blocking caps. (C6, C7)
2. The feedback / filter caps. (C10, C12, C11)
3. The Tone stack filter. (C9, C8, R8, R5).

The clipping blocking caps
" C6 & C7 determine the bandwith to be clipped by the diodes". They are usually identical in value and have a great effect on the sound. The smaller the value, the more bass. From the photos I've seem it looks like these are ceramic.

Feedback Filter caps;
C10,C12,C11 usually have identical values. They determine how buzzy/fuzzy the pedal sounds. "They filter the amount of high frequencies. Larger values roll off more highs and smaller values give more crunch and buzz to the sound. The better sounding vintage Big Muffs tend to have the larger values and sound smoother and warmer. Modern Big Muffs tend to have the lower values and sound a bit more buzzy/fuzzy." (Kit Rae).

The pics of vintage units indicate ceramics.

The ToneStack filter.
These 4 components surround the tone pot (R25).
 
C8, C9, R8 & R5. This section influence the mid frequencies. The more mids that are removed, the deeper & darker will be the sounds and the more the muff will probably stand out in a mix. The two resistors determine the amt of mids removed. Looks like 33K was the most common value for R8 & R5.
"Higher values have less mids scooped out and lower values have more mids scooped. This resistor also works in conjunction with the high pass tone capacitor (.0004uF in the example above) to affect the treble at low tone settings. Reducing this cap to .003uF alters the range and scoops slightly more mids. Increasing to .004uF reduces the scoop. Combined, a larger high pass cap and smaller resistor decreases the treble at low tone settings." (Kit Rae)

The pics of vintage V1 boards suggest C8 is a polyester  & C9 be ceramic.

Links:
Muffs Guts (Kit Rae)
Electro-Harmonic's Time Line

To be continued......


Thursday, 14 September 2017

Numberwang - NLC - Build notes

These are my build notes for the Numberwang Eurorack module by nonlinearcircuits.
The Numberwang is a 4:16 decoder using the CD4514 CMOS logic chip.
I plan to use this for triggering drum modules.
It takes 1-4 gate signals and converts them into a 4 bit number, the corresponding output goes high.
It means you can mix clock signals to get complex timing structures and patterns.
There is also an overall sync input.

This is not to be confused with the Wangernumb module which I built earlier .(See previous notes).

The Numberwang is a 4:16 decoder. I plan to use this for triggering drum modules.

The Numberwang is also great for triggering the ARP2500's envelope generator module .. the 1046.
It appears to output gates with sufficient voltage. (The 2500 usually needs between 7V & 10V gates).
It also triggers the ARP 2600's ADSR envelope generator.
My voltage measurements from the Numberwang - Gates of approx 7V.
Use a Gate booster if your ARP doesn't trigger.

Andrew's build notes are here:
http://www.sdiy.org/pinky/data/Numberwang%20BOM%20guide.pdf


...




The CMOS 4514
I like to get the passive SMDs in next
The through hole stuff.
Jacks next:

Now the LEDs. They are loosely placed. I'll only solder when the panel is on.

Yah, it works.


 Links:
++Andrew's build notes are here:
    http://www.sdiy.org/pinky/data/Numberwang%20BOM%20guide.pdf 
++ NLC Blog


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Null A - NLC Build notes.

Here are the build notes for the Nonlinearcircuit Null A module.
This is in Eurorack format.
It's a reasonably big build so probably not good for a newbie.
Though it has all the major modules one would want so if you feel game go for it.

 2 VCOs, 2 LFOs, 3 VCAs, 2 filters,  1 sequencer, 1 clock divider, 1 mixer, 1 S&H, 1delay, 1 headphone amp and a chaos generator.

Andrew's build notes are here:
http://www.sdiy.org/pinky/data/NULL%20A%20build&%20BOM.pdf
His blog notes are here:
http://nonlinearcircuits.blogspot.com.au/2017/03/null-a2.html

There are lots and lots of SMDs and 2 PCBs.






I've seen the golden goat.
 These lyrics are from the band "The residents". From the album "Our Finest flowers"

I've seen the golden goat
He would like to lick my throat
I know he's mean and poor
And he waits at my door

He's too weak to do me harm
But he has a big long arm
It fills my dreamy head
Then I shake and wet my bed

Well, there's something I must tell you
I need something I will swear

The only perfect love
Is the one that isn't there
Yeah, the only perfect love
Is the one that isn't there

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More NLC wisdom.


Traditionally, in Aristotle's logical calculus view, there are only two possible values
(i.e., "true" and "false" or 0 & 1) for any proposition. 
This is also known as Boolean Logic and is the basis of modern computers.
But in multi-valued logic, there are more than two truth values.
For example, Łukasiewicz and Kleene accept the values "true", "false", and "unknown".
Fuzzy Logic is another example of a non-Aristotleian view of logic.
Here the truth values can be any real number between 0 and 1. It is employed to handle the concept of partial truth, where the truth value may range between completely true and completely false.

Not really sure what this one means.
DPT = Dipropyltryptamine ?
N,N-Dipropyltryptamine (DPT, also known as "The Light") is a psychedelic drug belonging to the tryptamine family, first reported in 1973.
Back to the build:
First components. The 074 op-amps

...

Using 4 x LM13700MX/NOPB
Mouser NO:  926-LM13700MX/NOPB


The module uses one PT2399. Its a guitar aUDIO processor/delay chip.
Mouser doesn't stock these. So found some on ebay.
Look for SOP 16 size.

There are three CMOS chips.
4024,4029, 4052.
Mouser numbers:
595-CD4024BE  
595-CD4029BM
595-CD4052BNSR

I'm using sizes SOIC-14/16, SOP-16
SOIC = Small Outline IC
SOP = Small Outline Package 

"A Small Outline Integrated Circuit (SOIC) is a surface-mounted integrated circuit (IC) package which occupies an area about 30 to 50 % less than an equivalent dual in-line package (DIP), with a typical thickness that is 70 % less. They are generally available in the same pin-outs as their counterpart DIP ICs. The convention for naming the package is SOIC or SO followed by the number of pins. For example, a 14-pin 4011 would be housed in an SOIC-14 or SO-14 package."
(Wikipedia)

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RL = resistor LED.
R176, R199, R217,261. These set the brightness of your LED. I'm using bipolar LEDs so picking 5k1 .... see how this goes..

 ----------------------


Q11,Q12 & Q29
I used a MMBFJ108 replacement.
Mouser no. 771-PMBFJ108-T/R


1K Tempcos.
Right side of main PCB  
 Centre of main PCB

 Left of main PCB


 Installing headers.

 Lots and lots of jacks n' pots


A NSL vactrol. cheap as chips. K = cathode = white dot on the vactrol.




Couldn't find a SMD 10M resistor. So a through hole had to do.



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