Adventure in Soundland

30/6/09

Last night I did the Vit S thing and had three of my instruments set up and using the mixer I built I was cycling through them and trying to make it work. It’s an interesting concept but quite difficult to do well. On one hand I could carry on with this idea and I’m thinking of how to incorporate a looper in this context but on the other hand maybe two at a time is enough, or even one instrument, as one has more time and focus to concentrate on the possibilities thereof as opposed to just trying to keep a wild animal under control with smaller gestures.

This is the stuff I had ready and it all worked for me. New to the arsenal is the mixer, the power supply, and the guitar. The mixer and power supply allow me a sense of tidiness and scale that has been missing using the big Behringer mixer with it’s myriad of functions but tiny knobs while the power supply is good for about an amp, at least, of 9V duties. The guitar building is in Current Bits and Bobs and its finished, well it works, and in my world thats what usually amounts to finished as I’ve yet to find the time to go back and properly finish stuff, paint, oil, coat,etc, after it works. The wring for it was kinda experimental and it doesn’t actually do much at all but I’m loathe to change it as theres alot of stuff going on in a very small space and I’m actually quite proud that its so minimal and functions, the wiring and the fact that all those switches and knobs don’t actually do much is beside the point.

The big steel sheet, and that should suffice as a name for it I suppose, is completely dry, straight to the mixer and kinda suffered by not having enough boost to keep up with the other stuff. one way would be to cut the other inputs back but that lifts the noise floor so I’ll have to do a plain old booster to lift its output without FX.
The things that looks like two bra cups, others idea, is a dual theremin or the minimum theremin by Mr Harrison (just search for Minimum Theremin and you’ll find it easy) is made with 4049 chips as opposed to the specific 4069 chips he specifies and is a prick of a bloody thing… I’m going to break it down into two separate modules any day now or use the other half as a volume control because at the moment two separate pitch oscillators is just silly as they have to be tuned against each other and to every room they are used in. Thats radio frequencies for you. That then sends signal to a harmonic perculator, which is just a kinda octavy boost, then to the uglyface which is a story unto itself but suffice to say the mixture of an envelope controlled oscillator with a blend control and an LFO for good measure is lots of fun. In last nights performance the theremin, untuned really, was just used as a voltage trigger for the uglyface. So thats two channels and the third was the guitar through the clari(not) which is a delay with the delay speed controlled by the input envelope. Changes voltage to resistance so the delay speed changes depending on the input envelope so you get lots of weird pitch fluctuations and the note decays.

Then we come to the mixer which performs almost as exactly as I wanted it too but with a little tweaking will do exactly as I envisaged it would. It’s just three channels and each has an input fader and wet and dry cuts. The signal comes in, is amped then splits to dry and wet and I can cut each one or mix the two with each other. The wet gets sent out and the return mixes with the dry then amped one final time then theres an output volume. In this instance the send goes to a delay and so on each input I could have either entirely delayed signal or entirely dry or any combination thereof I was quick enough to make.
25/6/09
Just spent the afternnon finishing up a wah based on… actually the infos up above. The Earth Space Wah. Designed by Earthtonesaudio whos name says it all and I thought I’d do something special because hes such a nice chap, Alex is his name.

I’ve used it as a warm-up, which is needed ’cause it’s pretty cold at the mo’, for a guitar thats been laying around unfinished for ages… I need to get back playing those things but I’m kinda over using O.P.D.(other peoples designs)
24/06/09
The mixer is finished but untested and today I started in on a ducker. Duckers are used in radio so that when the announcer speaks his signal causes any background music or voice to drop away. Duckers, though, can be used creatively by using a signal to seemingly control two others like using a rhthym guitar to duck a drum signal so the bass shines above the drums at the guitars strumming envelope, etc. So I’ve wanted one for a while so that when I play something like the theremin its signal envelope is used to cut the signal from an instrument thats either a drone or constantly playing feedback’d delay. I started a few days ago with the deisgn which is a hodgepodge of other circuits and this morning I found a healthy dose of feedback from DIY stompboxes to simplify my design.

The top left input is the slave input and what I want knocked back goes in here. Below left is the master input which splits off into the 386 mini 1watt amp IC so that the signal can be rectified, which isn’t actually needed because the swing from rail to rail is all positive but it helps to define each section of the LED drivers, and then stored in a capacitor which then drives the LED which in turn effectively grounds the signal on the slave section because the brightened LED drops the resistance in the LDR to a few kilo ohms while the LDR in the master section is in series and the brightened LED lowers the series resistance of the LDR and passes signal. The capacitors off the end of the 386 are important because they create a time constant where the signal from the master charges up the cap and discharges into the LED. Smaller caps will have almost no effect on the envelope whereas bigger ones will lengthen the envelope so this is why different combinations are available on a rotary switch. Twisting it about while two drones are going should be quite interesting.
This morning I etched the board but I’m outta cash again so I’m going to have to put it on hold but I may be able to do it before monday as I have most of the parts on hand anyways… just have to search them out though I do want to find a 25k slider pots for the mix control as I found a choice old aluminium bowl yesterday which is well beaten up and today looking at the bunch of sliders I do have was pleasantly amazed to find that I’ve already got two, just two mind, 1k sliders that can be used for the tracking pots for the LED’s.
So the blend/mix control allows me to mix whatever portion of master and slave that I want, the tracking pots allow me to chose how much envelope of the master affects each channel and the rotary allows me to set the time constants for each envelope. Should be an interesting box. If I’m uninterested in doing all the above then grounding the tracking pots will see it working at a simple two channel mixer. Well, overly complicated but essentially a two channel mixer with quirks.

Oh and I’m also buildind the earth space interface wah by Earthtonesaudio and have finished the Fuktave by Nelson, both regulars at DIY stompboxes. Things sometimes (sometimes?!) lie about for a while half finished then I finally get round to finishing them… mostly. The earth space interface wah is like a seek wah by z-vex or suchlike which is a wah wah where the envelope and sweeping of phase shift (I think thats what they do) is controlled by a radio frequency oscillator shifted by body capacitance through an antenna that is converted to a shifting voltage which drives an LED/LDR combo. What that means is that instead of a mechanical rocker we now can move our foot to and away from an antenna plate to get the wah to wahwah. The circuit is all soldered up and hardwired to outside world stuff and the bit of wood is done. Just some plates to be made and putting it all together.

Nelsons Fuktave won the monthly comp at DIT stomp a month or two ago and he posted the schematic and some clips and I fell in love. It’s an over the top fizzing fuzzy octave pedal that ring modulates between gating itself in and out. Very dirty and sleazy! and its mainly 30c transistors without an opamp in site.

So in the foreground, on my tidy bench, is the wah stuff, and in the background, shining like gold, is the etched PCB for the Ducker.

Here we have the ducker box and a few bits for inside (lower left and going anti-clock), the power supply for at least an amp of 9V, both neg and pos, the mixer and last but not least the N.F.S.(Nelsons Fuktave Stompbox) or not for sale which is me making fun of the art world I so absently inhabit.

18/6/09
So for a while I’ve been using a mixer given to me by SJD, who I work for as a builder now and again, but it’s a big and bulky Behringer with one input channel slider a little on the dicey side which, though it does the job, doesn’t fit in with the aesthetic that pervades my electronic stuff.

It’s, then, been on the cards to build my own little mixer and the other day I started drawing up what I wanted and ended up with 10 opamps, 2 x tl074’s and a tl072, which just looked like too much work so I decided yesterday to do it with straight transistors, which aren’t so easy to tailor to specific gains and inversions, but are cheaper and easier to design and make PCB’s for. And given the general lack of a need to be precise with this form of sound creation, in the sense that higher noise floors and high gain circuits open to the elements can do some weird and interesting things, then transistors are the way to go.

Also I’ve been wanting something that allows me easy control for what I want to acheive and as you can see from the diagram below, not neccessarily the schematic but the drawing of the box, I’ll be able to have three inputs that I can easily turn on or off with the slider, then adjust the wet and dry signals to whatever levels of mix that I want. I’d have usually either a delay and/or looping pedals in the send/return loop.

Last night I drew it out on some copper clad board, two sided originally but I taped off one side with sellotape and into the acid it went to remove the otherside totally, and this morning I etched this up.

Checked my email this morning and Felix is coming up from Raglan to do a surplustronics shop so I don’t know how much work I’ll get done today putting the pots and hardware into the enclosure but, as usual, I’ll start into the headlong rush to get as much stuff as possible built and working by 7.45pm Monday night.
Meanwhile heres a photo of my workspaces.


And an old photo of the workshop proper.

It’s been re-arranged since then and is now much easier to keep tidy and work in. Still needs the really big cleanup though.