Category Archives: DIY Synth

DIY Synths, basic oscillator circuits

DFW Synth DIY Meeting in Dallas, TX 8/9/08

DFW Synth DIY Meetup

This Saturday 08/09/08 in Dallas TX a meet-up will be held for DIY’ers interested in Synth building, Circuit bending and making all kinds of glorious noise. The top secret location is at the Bar of Soap (3615 Parry Ave Dallas, TX 75226 USA). 2PM to 5PM – No Cost. The organizers are planning regular meet ups (maybe monthly) for sharing ideas, playing with circuits and showing off latest creations, and ALL LEVELS are welcome.

“If you have never even held a soldering iron, you might learn about an easy project to start with. Maybe you know how to make abrasive noises using an old television and a garden hose….but need a little inspiration on how to apply it. Have you ever J-B welded a window break sensor to a ball ping hammer and directed it straight to your guitar amp? * (btw..its like firecrackers!) Have you ever wanted too? Can you repair guitar amps? Can you program VSTi plugins? Wanna impress somebody with your new Tenori-on. Its all something we want to talk about and share. ”

For more information, contact at www.myspace.com/dfwsynthdiy or dfwsynthdiy@yahoo.com

Can someone say Geek-out? Let me know how this goes, and please post some pics in the comments! Good luck. Thanks Robert for sending this in.

Ohm LoFi Cardboard Samplers

 Ohm Sampler Cardboard Boxes

Ofir sent in some very nice pictures and links to his Ohm LoFi Samplers built completely out of laser cut cardboard with stenciled on conductive paint. The instruments were constructed as a design studies project directed by designer Barak Asher during 2008 at the Shenkar College of Design, Israel. Pretty Fucking Rad! Enjoy.

More information as the story develops…

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Website has lots of building photos – Link.

Strange Folktek competition

getlofi_folktek.JPG

The ever controversial craftsmen of very nice looking Folktek instruments are putting on some sort of a competition via an eBay auction. The premise is that after buying a mystery sound circuit for $44.44 you will be entered into a competition to create a sound art piece with that circuit. The best entry will receive a custom Folktek instrument. Deadline for submission is August 30th and the winner will be chosen and made example of by last day in September. Any takers?

How to Make an Easy Dub Siren from a Circuit Bent Keychain

In the previous post we established what a Dub Siren was. Now it is time to make one and start the journey to become a Legendary Dub All-Star.

First you need the parts:

8 Sound Keychain – available here in packages of 12 for $9.50 plus shipping! There is plenty of other sound generating circuits out there which are cheap and in the next few days I will do a keychain roundup. There is also a COB (Chip-on-board ) version of this sound generator without the button traces that would be a lot easier to work with. This particular keychain just sounds so good, its got your sirens and machineguns, which everyone instantly recognizes as being Atari like or 8-bit, plus it loops!

Rotary Switch –  this will be the sound selector. 8 position is ideal, however 12 position ones seem to be most common and are the cheapest from Jameco. This is what all the sound buttons will be wired to and the center pin will be going to a push button that will trigger the sound by completing the circuit with the Ground.

1 Mega Ohm Linear Potentiometer – to control the pitch of the sound being played back. Obviously the sound circuit has to have a pitch resistor, most cheap keychains do. Lets try to stick with just Jameco for the source.

2 Momentary Push Button Switches – One button will connect the ground to the rotary switch and the other one will be used as a Mute by sending positive output from the instrument jack to the ground. Jameco once again.

AA or AAA Battery holder – Mine was from the SAW III sampler toy, you can improvise as long as you don’t go above 3 Volts. Jameco has a good deal on these.

Plastic Enclosure – Plenty to choose from, but I would recommend reusing something and helping to keep the trash out of the landfill. A Cigar box would do nicely.

Output Jack – 1/4 inch seems to be the industry standard.

Rasta Graphics for the front panel – free on the Internet.

2 Knobs – lots to choose from and scavenge if you can, otherwise get some chicken heads from Jameco.

Rubber feet – so the Rasta Box doesn’t slide off that table when the Bass is bumping.

Solid Core wire – stranded core will be a pain to work with, it splinters too easy.

The total for parts should be under $20 and possibly even cheaper if you are resourceful and can strip components from discarded electronics, etc.

Dub Siren Construction

The construction process:
Get everything together in one place on a work surface in a well lit and properly ventilated environment.

1. Connect the battery compartment to the 8 sound keychain board. ( Probably best to keep the batteries out for now, so there are no shorts ) No need for power switch because this particular keychain powers down automatically and instantly comes ON when the any button is pressed.

2. Solder the output jack to where the speaker was connected on the sound board. One wire to the Transistor Buffer and the other to the positive terminal? I dunno seems like that’s how they had it. Normally you would connect the Ground to the outside ring of the instrument jack and the Positive output to the tip.

3. Remove the pitch resistor and replace it with a 1M potentiometer. Center and one of the outer taps should go to where the resistor legs used to be. Very important, connect the remaining outside tap to Ground, this will give you the low pitch drop!

4. This step is perhaps the most tricky and easy to mess up, solder 8 wires to the button connection traces. These are very thin traces that interlock and if you build a solder bridge the sound will be stuck in the ON position. It will be hard and the only thing I can recommend is that you lightly sand or scrape the green protective layer and possibly cut the traces that go to Ground from those buttons. Solder with caution and be careful not to pull hard on the wire because the entire trace may come off. At this point you can probably plug in the batteries and test the soldering job making sure that if you connect the Ground to any of the button wires the sound gets produced. If the soldering checks out, drench that thing in hot glue so nothing moves or falls off!

5. Take a break then drill some holes for the controls in your plastic box. Make sure the knobs are spaced such that there plenty of room for them to rotate. After that you should overlay the graphic and then cut the holes on paper for the controls to slide through. To hold the paper in place I just use packing tape, but there are other plastic sheets and laminate options if you want to get fancy with it.

6.  Mount the push buttons, the potentiometer, and the rotary switch in the case if it is big enough to work inside. Otherwise solder wires to the components first and then mount them. Please note that there will be more solder lugs on the rotary than button contacts. I typically just use every other one the first round. The trigger button needs to have a wire going from the center tap of the rotary switch to one of its legs. The other leg needs to be connected to Ground. The Mute button will need to be connected to the tip of the output jack with the second leg going to Ground as well. The potentiometer should just have to be wired to the ground. If you are clever you can make all the Ground connections meet at the same place saving on wire. Mount the output jack and test everything. Makes sound? No…try setting the potentiometer to center and maybe resetting the batteries. Still no? Go back and recheck your connections.

7.  If everything works, use copious amounts of hot glue to hold stuff in place. Close the enclosure and start jamming out. The gate switch should chop up the sound when pressed, doesn’t get much simpler than that.

Next plug this into a delay pedal, turn up some Dub Reggae on YouTube, and start Toasting! The only thing to watch out for is  overusing these sounds because they eventually lose the magic. However the first 30 minutes will be a pure blast! Enjoy.

Easy Dub Siren

P.S. Here is the rough schematic of the circuit with the keychain board in the center, note the red Xs, those are to indicate that if you are soldering to the pads make sure they are not connected to any other pads via Ground. I can post a picture of exactly what I’m talking about soon.

* Updated *

I will be making another schematic and a new version of the siren using the Chip-on-board sound circuit. Also if these keychains are not available in your area, for whatever reason, feel free to order them from GetLoFi here.

abelincoln live looper

abelincoln live sampler
In continuation of my previous post on the Yada Yada Yada samplers here is an instrument that I threw together in one evening. The “abelincoln live sampler” utilizes 3 Yada Yada Yada voice recorder circuits and simple passive 3 channel mixer for the Output signals. I only went as far as summing the resistors and didn’t do anything with the powered section in the schematic. Maybe in the future builds.

The Inputs of all 3 boards are wired in parallel so each sampler receives the same signal, either the Mic or Input via 1/4 inch jack with a switch to select between the two. The signal from the instrument jack is not attenuated, however a single potentiometer should be able to do the trick or if you really want professional quality a simple 20db pad can be constructed. I thought about wiring each sampler individually, but unless you want to sample 2 different things at the same time there is really no need. One improvement maybe to add a 3rd option of sampling whatever is being played back by the other two samplers to “bounce” tracks. The playback buttons were all wired to switches for continuous loop playback. If you want one shot playback, toggle the switch back and forth. The record buttons were replaced with heavy duty panel mount push buttons. Something to note about the controls is that they are activated by connecting the Ground signal to designated spots on the board. This makes wiring a bit easier because the Ground can be made into a common bus. Things that share the Ground are: Buttons, Mic element, the – Power connection (obviously), and the Line In jack, but not the Speaker, at least I haven’t tried wiring it to the Ground. The output is carried via two separate traces and there must be a good reason that. I just picked the same trace on all the boards as the common for the mixer inputs.

abelincoln live sampler back

All 3 circuits are powered by a single +5 Volt LM7805 Regulator with a 9 Volt Battery going into pin 1, Ground on pin 2 and Pin 3 is connected via a bus to all of the Positives on the boards. YYY boards appear to only power ON when the Play or Record buttons are pressed, but the same does not apply if you are using a Vreg connected to a battery. In that case its always ON and will drain eventually, so a power switch with an indicator LED would probably be a smart idea.

The pitch control knobs work fairly well. One only controls the Playback and the other controls the Recording and the Playback. It is possible to slow down the recording speed and get a lot of grainy loop-able time. The playback of that recording can be either speed up or slowed down even further, making things very low bit rate sounding. During the lower recording rates the entire CPU will slow down and the recording will not start until the LED is illuminated. The pitch of the recording tone is usually a good reference for what the speed is. It is also possible to record the pitch changes during while the LED is on, which puts another interesting spin on things.

This is the first stab at a looper device, the construction was done quickly and with as few components as possible. Lots of things could be done differently in version 2. More images are located here.

Possible improvements would be:

  • Attenuator pot on the input.
  • Separate Voltage Regulator for each sampler ( pitch drops slightly when you engage more loops. ) May help with distortions and crosstalk.
  • Cue output for listening to what is being sampled.
  • Switch to pipe the output into the input for bounding sounds between the samplers.
  • Try connecting the pots in the same way that Warp Wheel was soldered, with center and left pins wired together to +5 volts.
  • Battery Power switch with indicator LED.
  • PCB board design with pots, switches, and buttons. Eliminating the point to point wire.

Here are a couple of videos demonstrating the device. Enjoy!
http://video.google.com/videoplay?docid=8645880348464924659&hl=en
http://video.google.com/videoplay?docid=-5886100544585004545