Thursday, 29 August 2019

Jaipur - Hawa Mahal - The Palace of the Winds.

Jaipur.
It's a beautiful city with wide boulevards. It's the capital of the state of Rajasthan.
Founded in 1727 by Jai Singh II., it was designed during the British Colonial Period.
It's also one of UNESCO's world heritage sites.

It's often know as the Pink City because it was pained that colour to welcome Albert, Prince of Wales in 1876. Albert, later was crowned King Edward VII. One of his many titles was Emperor Of India.

There are lots of attractions to see when visiting Jaipur.
It's also a good base to visit other parts of Rajasthan such as Jodhpur (348 km), Jaisalmer (571 km), Udaipur (421 km)

A must see when visiting is the Hawa Mahal


This is the front. It's constructed of red and pink sandstone.
There are 5 stories. to this pyramid structure.
Built in 1799 by Maharaja Sawai Pratap Singh, the grandson of Maharaja Sawai Jai Singh, who was the founder of Jaipur

Its been described as a behive. There are 953 windows (Jharokhas). Notice the fine latticework..
Royal ladies were not allowed to be seen by the public without face coverings. This latticework allowed them to view the street, and not be seen.

These pics are the inside
Hans A. Rosbach (Attribution ShareAlike 3.0)
 
Sameer Goya


Ziaur Rahman 

Midi triggering the 1010 bitbox


I'm loving the bitbox.


It's a great sampler ... reminds me of the Roland SP 404 or a AKAI MPC
I've been searching for the best midi sequencer to pair with this module.
I've had success with the Arturia Beatstep Pro (the drum sequencer section) and the Roland TR-8

Midi note numbers output from the tr 8.
The Roland TR-8  outputs midi from channel 10. The midi note numbers are as follows:
Bass Drum - 36
Snare Drum - 38
Low Tom - 43
Mid Tom - 47
High Tom - 50
Rim Shot - 37
Hand Clap - 39
Closed HiHat - 42
Open HiHat - 46
Crash Cymbal - 49
Ride Cymbal - 51

Luckily, the bitbox also responds to midi on channel 10.
Midi input can also be used to modulate some parameters in the bitbox.

Ive seen the cirklon sequencer also used very effectively on the 1010.

Let me know if you of any other sequencers that pair well with the bitbox

 

note
TRS MIDI B
Arturia (e.g. Beatstep Pro and Keystep) and Novation (e.g. Circuit and Launchpad Pro) , Music1010 (MX4, blackbox, bitbox, synthbox) use ‘TRS MIDI B 

 

Synthesizer Power Supples ----- Linear Vs Switching

When building a synthesizer power supply, there are two choices:

1. Regulated Linear Power supply
2. Switch Mode Power Supply (SMPS)

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1. Regulated Linear Power supply.

These are quite simple in design.
Low noise ... most supply types produce no high-frequency interference.
But they are inefficient when compared to a SMPS . Output voltage is regulated by dissipating excess power as heat resulting in a typical efficiency of 30–40%.
Often uses heavy line-frequency transformers

It's hard to find AC Linear Wall Warts larger than 2A. This is a problem if you are building a large modular.
 This is a NLC linear power supply. It's very easy to build.

 aND ANOTHER example of a DIY linear PSU. One advantage is their ease to build. The components are cheap.

I use a 2A  AC brick with both of these.
Something like this:
I find that powering 3U to 6U (max) of Eurorack is OK with these ... check your modules power requirements of course.

You could of course use something like this if you needed more juice:
 This is a power one HCC 15-3A
This transformer based design has a center tap to give the centre ground. Both voltage outs are rectified and regulated to create dual voltage rails

Its very very heavy and would be hard to fit into a eurorack case. I used this in a Serge case.


Above is a doepfer A-100PSU2
Its a Linear PSU with ring core transformer
Output voltages/currents: +12V DC/1200mA, -12V DC/1200mA
Input voltage: 230V AC or 115V AC

Below is the L1 linear PSU
 It's a great kit.  1.5A per rail. 5V regulator on busboards.



2. Switch Mode Power Supply (SMPS) 

These first came out in the 1970s They are very efficient and their performance is much higher than linear regulators. SMPSs use PWM (pulse with modulation) to regulate the output voltage.
Their efficiency is very high, but the process is extremely complicated & creates high frequency noise.
They use diodes & capacitors to produce high voltage DC. This high DC voltage is then decreased and converted into a steady DC output using a system of transistors, capacitors, diodes, inductors & ferrite transformers.

The power bricks (wall warts) are a modern example of SMPSs. You will find them powering computer laptops and mobile phones.

This is a ATX SMPS from a desktop computer.


The advantages of this type of regulated PSU are that its smaller. There is very little heat generated.
Noisier due to the switching frequency of the SMPS. An unfiltered output may cause glitches in digital circuits or noise in audio circuits.
Above is the Doepfer A-100SSB. Its a small switcher PSU, suitable for up to 8 modules. (380mA)

Below is the Doepfer A-100PSU3
It's a +/-15V switching supply (wide range input 100...240V for mains voltage) followed by a linear regulation circuit that generates +12V and -12V. The +5V is a pure switching supply without linear regulation.

Really interesting design as it combines both linear & switching supplies. The black boxes are
Meanwell switching supplies. They create +15v, -15v, and +5v. The +/-15V must be passed through linear regulators to get +/-12V. I can't see the regulators in the photo ...maybe they are under the heat sink fins ???

The transformer in a switching power supply is also smaller than a traditional line frequency (50Hz or 60Hz depending on region) transformer,

If you need a high current wall wart a SMPS PSU will be easier to find. I use a 10A brick to power one of my Buchla cases.(though the OEM brick is expensive).


------------------------------
Meanwell RT65B.
Mouser

A great switching PSU which seems ideal for a small eurorack case (around 200HP)

5 VDC(5A)
12 VDC (2.8A)
- 12 VDC  (0.5A)

You can use a Bus board with filtering  to remove the PSU ripple noise.
Use something like a LC filter.
This consists of an inductor ( represented by the letter L) connected in series with the power flow and a capacitor (represented by the letter C) from the filtered voltage to ground.


I guess before you do this you need to ask the questions;
  1. Are you better off filtering the noise, or preventing noise in the first place?
  2. Is there actually much noise ?
  3. Is the LC filter making more noise than it is removing?

------------------------------------------------------------------------------------------------
Below is another example of a switching PSU
Its a Meanwell PD2515
Mouser: 709-PD2515



 It supplies : 24W 15V/0.8A -15V/0.8A 
iTS ok FOR a small buchla system

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Finally, this is the PSU for my amalgamod Eurorack system:


Plenty of juice for  this:


Links
+ NLC Build notes - Linear PSU 

Monday, 26 August 2019

Portishead - dummy - 25th anniversary

A landmark album.
This was part of my growing up
I can't believe its 25 years.

The group comprised sampling guru Geoff Barrow, guitarist Adrian Utley, and vocalist Beth Gibbons.
The album is all about atmosphere and texture.

Some of the tracks used material that was first recorded to tape, then pressed to vinyl which was stomped on and kicked around to give that crackling sound.
It seems they recorded a lot to tape which imparts compression & frequency distortion.

No.    Title            Length
1.    "Mysterons"    5:02
2.    "Sour Times"    4:14
3.    "Strangers"    3:55
4.    "It Could Be Sweet"    4:16
5.    "Wandering Star"    4:51
6.    "It's a Fire" (not on vinyl LP or original UK & Europe versions of album)    3:48
7.    "Numb"    3:54
8.    "Roads"    5:02
9.    "Pedestal"    3:39
10.    "Biscuit"    5:01
11.    "Glory Box"    5:06

Some of the synths used on the album were the  :
Roland 808 drum.("It Could be Sweet")
Akai S 1000 sampler
Roland SH 101 ( "Mysterons") ???
Fender Rhodes (Roads, "Biscuit", "It Could be Sweet" )
Vox Continental Organ ("Numb," "It's a Fire," and the end of "Wandering Star." )
Hammond Organ ("Numb," "It's a Fire," and the end of "Wandering Star." )
Roland Space Echo - RE 201 ( "Mysterons", "Pedestal", "Numb")

This is by no means a complete list...
(I haven't of course mentioned any of Adrian Utley's Guitars)

Saturday, 24 August 2019

NLC Mixer & Headphone amp

This is a 3 input mixer with a minijack and 1/4" output as well.
Its in Eurorack format.
The headphone amp has its own input and volume control. This way you can monitor a single patch and set it up whilst other patches are fed to the PA. 

This is a really easy build. Ideal for someone who is new to DIY eurorack.



If nothing is inserted into the headphone input, then the mixer output is routed to the headphones.

 All the pots and minijacks are mounted on the PCB.




BOM & Build notes 

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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

Marrakesh Morocco

Some pics of Marrakesh.

 Great Markets






sNAIL soup





Yves Saint Laurent Museum

Friday, 23 August 2019

Buchla 261e - notes

Revisiting the Buchla 200e.
I'm slowly working my way through the 200e manuals and re-writing my notes.
I'll update this as I go along.
This post is mostly about the 261e, however I can't help to notice its similarities with the old 259

Of course the 261e is just 1U ...Don has packed a lot into a small package.
Both have modulation & principal Oscillators.
In the 261e, the oscillator core is now a digital sine wave.
I understand that the 259 had a triangle core (analog of course).
For more about oscillator cores read here

 

Modulation Oscillator:

The modulation oscillator on the 261e can be switched between 3 settings: Low, Hi & track
In "Low" or sub audio mode it oscillates between 0.25 Hz and 64 Hz.
In "Hi" or audio mode it covers a frequency range between 27 Hz and 7040 Hz.
In "Track", it follows the pitch of the main oscillator and can be shifted relative to it regarding pitch.
The offset will be zero when the modulation frequency is set to 440 Hz. (indicated by extinguishing the bicolor LED).

An F.M. input for the Modulation Oscillator provides for frequency modulation.
The waveshape of the MO is voltage controllable. This ranges from sine through square and pulse;.
There is also a multiplying input (the centre banana in the above picture). This varies the degree and direction of waveshaping.

The output of the modulation osc is internally connected to the the principal oscillator
The Amplitude (AM), Timbre & Pitch (linear FM or frequency modulation) of the Principal Oscillator are the main targets.

You can apply this modulation either singly or in combination.

Under Amplitude, there is a point where it acts like a ring modulator.

The Timbre section has 3 parameters: Timbre, Symmetry (direction) & High Order (magnitude).
Symmetry and high order have variable offset and are voltage controllable.

If all the pots are set to zero, the output wave shape will be a sine.
1. The Timbre (Top left knob) knob adds harmonics as you increase the value.
    It's the wavefolder
2. Symmetry controls how different one half of the waveform is from the other.
    As you turn it from zero, it will change the sine wave to a square wave.
3. High Order acts a little like a high pass filter.
    As you turn it from zero, it will change the sine wave to a spike wave.

Note that pitch modulation responds only to sinewaves.

Sync Facility of MO
This permits synchronization of the Modulation Osc to MIDI note-on messages, or to subdivisions of the principal oscillator.
Hard sync truncates the waveform; soft sync uses a phase locked loop to achieve synchronization.

 

Principle Oscillator

 The core is a digital sine wave.
 The frequency ranges from 27 to 7040 Hz,



There are attenuators  and jacks for both the pitch CV (banana) and the audio-FM input.
----------------------------


Internal Buss settings for the 261e & a 225e preset manager.

Bus I.D. for the module is set with two board mounted switches IN THE LOWER left corner


The module ID can be displayed on the 225e preset manager by holding the remote enable switch on the 261e for about two seconds. 

You should see something like this:
Here, the 261e is on Buss C.

The normal settings start at A and go for as many modules as you have (up to D, or four).
The 261e responds to pitch & fine tune messages via the 225e.

 MIDI Fine tuning


To respond to MIDI fine tuning messages, the “Ft” field in the 225e’s display must contain something other than a default value of “An” for the bus of interest (buses A – D).
The fine tune data is in cents (a cent is 1% of a semi-tone), and can range from –49 cents to +49 cents. It can be set for each bus, and therefore for each of four oscillators.

Note that if fine tuning is enabled for a particular VCO that oscillator’s pitch knob will be incapacitated, as will its F.M. input and control voltage input. Pitch will be completely determined by MIDI signals.
So if you want to use the VCO knobs as normal, keep the setting on "An".
"An" I believe stands for analog

To be continued.................