Thursday, 27 October 2016

NLC BaDum TISS - drum module

These are my build notes for the nonlinearcircuits Badum TISS.
Badum Tisss is a snare/hi hat eurorack module.

 it mixes the sound from a VCO & noise circuit into a ring modulator.

The VCO is triggered with an envelope follower.
This EF also triggers a VCA further down the circuit.

Check out Andrews build notes for further info.

Sneaky Nuts??? s this a reference to Angry Boys?

Anyway, where did the name Ba Dum Tiss originate ?

The Urban Dictionary defines badum tish as
 "an onomatopeia for a drum technique normally accompanying the conclusion of a cheesy joke or a comedy pratfall (where someone is made to look like an idiot by their own devising - such as falling on a banana skin they earlier discarded). It consists of two fast rimshots and a splash cymbal - producing the sound "badum tish".

Firstly, get those pesky SMD ICs out of the way:

Rest of SMD next.

Just 2 transistors:
one BC847 NPN (marked by the "n") & one BC 857 PNP (identified on the PCB by the "p")

Now for the through hole stuff.

I had to drill an extra hole in the panel to accommodate the LED

Sounds Great!
Thanks Andrew.
You can find more NLC builds here.

Kinkakuji (Golden Pavilion) - Kyoto, Japan

This is a Zen Buddhist temple in Kyoto, Japan.
The golden pavillion is so beautiful. It's part of a larger complex of buildings set in the most
Japanese of Japanese gardens.
Address: 1 Kinkakujicho, Kita Ward, Kyoto, Kyoto Prefecture 603-8361, Japan
Kinkaku-ji is officially named Rokuon-ji.

The site dates from 1397. It started off a a villa but was converted to the Kinkaku-ji complex
by the Shogun Ashikaga Yoshimitsu.

The Pavillion is very important to the Japanese. It is on the world heritage list and is
designated as a National Special Historic Site.

During the Onin war (1467–1477), all of the buildings in the complex aside from the pavilion were burned down. This golden pavillion remained in tact for nearly 500 years until 1950 when it was burned down by a 22-year-old novice monk,
 Hayashi Yoken, who then attempted suicide on the Daimon-ji hill behind the building.
 He survived and was jailed. He died of tuberculosis in 1955.
The temple has been rebuilt but one can only feel sadness for this lost of a national treasure and what pain it must have caused the Japanese People.

For more travel pics:

Tuesday, 25 October 2016

NLC Doof Drum Module - Build notes

These are my build notes for the Nonlinearcircuits Doof drum module.
It's Eurorack format.
This is a very different circuit from the 808 & 909 clones doing the rounds today.
Can't believe I would ever tire of those sounds but its great to have something different.
This circuit uses a trimmed down NLC dual OTA VCO and the VCA from the NLC matrix mixer
(a future build).

 I built the OTA VCO over a year ago.
That VCO used a OTA or Operational transconductance amplifier.

The topology is common enough in many drum synths: Trigger circuit, envelope follower, VCO, VCA.

Get started with some tanning. It's the Aussie way.

Firstly the virgin PCBs & faceplate:

First get those !Cs in.
Now the rest of the SMDs
I'm using a 10K on the RL ... LED resistor
Stuff in the through hole stuff:
pOTS & jacks next.

Now the LED. Get the orientation right. The anode is the long lead.

initial tests:
Initially, with a headphone, I found the volume very low and the LED didn't light up.
The LED resistor I used was a 10K. This is for super bright LEDs.
I swapped it for a 1K and noticed a sudden increase in volume & that the LED lit up.
I decided to do another swap. This time for a 510 R.
Much much better !!!
Very loud and the LED lights up nicely thanks.
Andrew F suggested that in order to get a bigger output, I change the 220k next to the TL072
He has taken it to 4M7 ...which is way OTT, ....bounces off the power rails.
Maybe a more sensible range would be between 1M5 & 2M2.

For the moment I'm really happy with the standard Doof module.
Other mods include
1.  CV control of decay instead of freq... see build & BOM pdf
2. replacing the 10nF capacitor on the input with a link to
create 808 style extended drum hits with gates rather than triggers.

1. NLC Build Notes
2. Muffs : adjusting output level of the Doof
3. NLC blog spot 
You can find more NLC builds here.

Friday, 21 October 2016


How times have changed (thank goodness). 
I came across this pic the other day. Is this for real ? 
It's a drawing of a "cat organ".
Cruelty knew no bounds in the 17th century.

 Many credit Athanasius Kircher with the original design of this instrument. He was a German Jesuit scholar.

"The musician selected cats whose natural voices were at different pitches and arranged them in cages side by side, so that when a key on the piano was depressed, a mechanism drove a spike in the appropriate cat’s tail. The result was a melody of meows".

Synth lovers today respect all animals, especially cats.

This is what Spike has to say about all this:

Thursday, 20 October 2016

All about JFETS - matching for synthesizers

This is a very good introductory video on JFETs - junction field effect transistors.

JFETs can be either N or P channel.
The channel conducts current moving from the source to the drain.
A voltage at the gate increases the channel resistance and reduces the drain source current.
Therefore, the FET can be used as an amplifier or a switch.

This is an excellent device.....Peak Atlas DCA Pro.
The bits about JFETS are around 7mins & the PC applications are at 14:20.

We often want to use a JFET as a variable resistor, particularly in phasers.
The problem with JFETs is that it is much harder to make consistent JFETs than to make consistent bipolar devices. Therefore matching them is important.

 These are screen shots taken of the readouts from my Atlas Pro of one of the JFETS.

 Try to match the curves for each JFET along with as many other specs as possible.

I tested twelve J112s.
measuring VGSoff, Idss, VGSon in that order.
 These were the results:

1. Vsg (off) = -2.97V
    Idss = 0.51v
    Vsg (on) = -2.04V

2. Vsg (off) = -3.14V
    Idss = 0.50V
    Vsg (on) = -2.04V

3. Vsg (off) = -2.98V
    Idss = 0.51v
    Vsg (on) = -2.05V

4. Vsg (off) = -2.71V
    Idss = 0.54v
    Vsg (on) = -1.80V

5. Vsg (off) = -2.99V
    Idss = 0.51v
    Vsg (on) = -2.06V

6. Vsg (off) = -2.68V
    Idss = 0.55v
    Vsg (on) = -1.77

7. Vsg (off) = -3.60
    Idss = 0.46v
    Vsg (on) = -2.63

8. Vsg (off) = -2.90
    Idss = 0.53v
    Vsg (on) = -1.98

9. Vsg (off) = -2.66
    Idss = 0.55v
    Vsg (on) = -1.76

10. Vsg (off) = -2.89
     Idss = 0.53v
     Vsg (on) = -1.97V

11. Vsg (off) = -3.17
     Idss = 0.50v
     Vsg (on) = -2.24

12. Vsg (off) = -3.15
     Idss = 0.50v
     Vsg (on) = -2.22V

A huge variation in results from just twelve J112s
I'll go with 1 & 3

1. Vsg (off) = -2.97V
    Idss = 0.51v
    Vsg (on) = -2.04V

3. Vsg (off) = -2.98V
    Idss = 0.51v
    Vsg (on) = -2.05V

1. Stompville
2. Learning about electronics
3. Geofex

Sunday, 16 October 2016

Tokyo Akihabara Radio Center

This is where you can see some old school electronics.
.... the stuff that rebuilt Japan after WWII.
 Akihabara ‘electric town’ is famous for tiny retailers selling radios and electronic parts at cut-rate prices under the Sobu line tracks.
 It's a shade of what it used to be in the 50's & 60s but some of those "tiny hole in the wall" shops are still here, crammed together. It's worth a visit just for the historical aspect.
DIY old school with parts in open boxes and plastic containers.
Analog, digital, LEDS, knobs, jacks, resistors, capacitors, etc etc... the way it used to be before
the internet came along and killed off the little shops.
Most of thehe electronic shops that used to crowd both sides of this street have been displaced by game centres and animation shops. It’s also a great place to treasure hunt for old games.

 Akihabara is centered around Akihabara Station, located on the JR Yamanote, Keihin-Tohoku, and Chuo Local lines. Take the "Akihabara Electric Town" exit. (ラジオセンター), 1-14-2 Soto-Kanda.

 By subway : travel to Akihabara Station by the Hibiya line (H15), or Suehirocho Station by the Ginza line (G14).  

For more travel pics:

Friday, 14 October 2016

Bonsai - Narita, Japan

Some trees that just wowed me as I was waiting for that plane to take me home.
Mountain Maple ... 80+ years old.

 Chinese Juniper ... Over 100 years old.

The literal meaning of Bonsai is "potted plant".
But these are more than just potted plants.  It's an art form that is alive and constantly
changing..... an attempt to represent nature in miniature.

Bonsai, their growth, flowers, fruits and leaves are so beautiful.

Paintings of bonsai can be found in picture scrolls of the Kamakura period (1192-1333).

For more travel pics: