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
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).
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.
:-)
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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
http://www.sdiy.org/pinky/data/Doof_Build&BOM_vers1.pdf
2. replacing the 10nF capacitor on the input with a link to
create 808 style extended drum hits with gates rather than triggers.
These are my build notes for the Nonlinearcircuits eurorack version of the Aries 329 Phase Flange.
"Circuit is based on the Aries 329 phase/Flange, which is not the same as
but shares some similarities with the Arp Quadra phaser and the Tau
pipe Phaser. This version is nearly all smd and uses BCM847 matched
transistors."
The old Aries brochure:
Some pics of the NLC panel & virgin PCBs
Andrew supplied this board with the matched 847s already soldered onto the PCB.
This row is of the 22nf caps. Don't use cheap ones.
Install the rest of the SMDs
It's time for the JFETs
JFETs can be either N or P channel.
The BOM specifies either a J108 or J 112. Both are N-channel.
The module needs two of these matched FETs.
G= gate, S= source, D= drain.
A voltage at the gate controls the channel resistance (between the S & D).
Andrew reckons that you do not need to match them to 1μV. Just buy a
batch of at least 10 or so and find the 2 closest to each other. Maybe
with in a few mV is okay. ??
I purchased a batch of J112s from Mouser and tested them using my Atlas DCA Pro.
Its a wonderful device which will make your job so much easier.
It's important to match the FETs as closely as possible. In my batch of 12 the results varied greatly.
I tested for VGSoff, Idss, VGSon in that order.
If you can get VGSoff very close and Idss in the ballpark, you should be ok.
Main components are in.
Now its time for the jacks, switches & pots.
This is what the final module looks like:
Calibration is very important.
When I first turned the phaser on I was confronted with a loud continuous screech.
Adjustment of the trimpots eliminated this problem.
The main one is the 50K pot near the phase jack.
It also controls the amt of clipping at the outputs. A lot depends on the FETs chosen
Check out Andrew's NLC build notes for further info regarding calibration.