This little monster is a Dub Siren I made for DJ DRM (Aaron Schultz) of Bastard Jazz Recordings. If you’re unfamiliar with what a dub siren is you might guess by its name that it sounds like a siren. There are many varieties and a good deal of folks make their own:

One
Two
Three

But the tying thread is that they are usually just square wave oscillators with minimal tone and a couple controls to vary the speed and pitch of the siren. Check the sound samples at the bottom of the page for an example of this one.

This dub siren revolves around a couple of 555 timers and has four main controls. A speed control which changes the speed of the siren, a pitch control which changes the, well, pitch of the siren. A range control which changes the siren’s range and lastly, a modulator which, when engaged, alters the smooth sweep of the siren to a more asymmetrical ambulance type siren. There are two LEDs: one that flashes in synch with the clock cycle so you can see the speed in the dark and another that oscillates gently when the momentary switch is engaged. Both RCA and ¼” jacks are available and the RCAs are only active when there is not a ¼” jack plugged in. This was to prevent ground noise from accidentally coming into the circuit by inadvertent contact with the jacks. Check the full build on Flickr by the link below.

More photos, comments, and the schematic can be found on Flickr here:

SupersetSiren

Sound Samples:

Dry, without Effects

Wet, with effects

 
This is a square wave tone generator based around three 555 timers wired up as oscillators. I took some inspiration from the dub siren and figured if two were good then three would be better. This was mostly true. Several unlabeled pots control the oscillators impact on each other and then two signals are mixed at the final stage. Just as a note I get these pots by buying damaged internal boards of Mackie mixers. With a little time you can remove these great center detent pots for pennies. A schematic isn’t available right now but I will get something together and post soon.

There were a couple problems that I didn’t really notice until after the circuit was wired up. I used a pot to control the balance of the two signals going into and additive mixer at the output. This causes large swings in output volume depending on how far from center the pot is. When jamming it all in the box with a battery something happened  and one pot has no impact on the sound. These problems aside, the tone generator makes some great chirps, bleeps, bloops, and squeals.

I’ve recorded a string of the sounds you can generate with this tone generator, chopped it up into a couple dozen samples and included them for your use. If you end up using them in something I’d love to hear what you do.

You can see the complete set of photos here on Flickr

and samples:

This is a Ring Modulator or similar sounding effect box based around the AD633 (Analog Devices Four Quadrant Analog Multiplier). The original design is taken from Roman Sowa. His website has further details on his design and the schematic I used as a starting point. The above photo shows the finished version albeit without knobs. This is mostly because I, despite better judgment, bought pots from Radio Shack, and didn’t want to waste them. As you can see the shafts are just a bit long. No matter; they work.

I made a few modifications. The first was to remove the option to select AC/DC coupling. I felt that I had no need for DC coupling so I hard wired it up AC coupled. Secondly I added some gain on the clean channel. The clean signal was coming through a little light which I personally didn’t like. Lastly, I added a LED meter on the output volume which you can see in this picture. Using a LB1403N I made a level meter which increases as you turn the volume up. This doesn’t actually monitor signal level but the position of the pot. There’s no real purpose other than I like blinking, flashing, pulsating and adjustable lights on all my gear. Who doesn’t? It’s wired through a dual ganged pot with a trim pot to adjust sensitivity. The detailed photos can be seen at the full Flickr photo set.

From a distance the paint job looks OK but as you can see in the first photo there’s definite room for improvement. Wet sanding, Clear Coat, and Polish would definitely help but it’s not a bad first run. The fluorescent paint however had a tendency to get ‘powerdery’ and presented some problems. Check the sound samples below to hear what it sounds like.

Many more photos and comments on the build can be found on Flickr here:
AD633 Ring Modulator

Sound Samples:
Before & After Number 1
Before & After Number 2
Before & After Number 3
Before & After Number 4

This is my second design from scratch that I put together for DJ Paul Diggs. He mentioned to me he wanted to add some fuzz to his Fender Rhodes and this seemed like a great chance to take a stab at an original design. Well, almost original. The distortion circuit is a portion of a larger circuit which I found on the web but unfortunately did not document. The remainder however, the sweepable low pass filter and second tone control I added in myself. Overall this is a pretty versatile sounding fuzz box with a pretty wide range of tones. It utilizes diode clipping so it still can be a little harsh although with the filter and clean/dirty mix you it can be tweaked for a nice sound. This is hopefully only the first version, I’ll be working with Paul to refine the tone and the layout to hopefully make this a perfect compliment to his Rhodes and bring about the sounds of classic rock years gone by like those from Joe Zawinul and the likes of Weather Report… though that’s just my taste, I’d bet it will end up a bit different.

This time I actually took notes and threw together a schematic. I’m hardly an engineer and my understanding of analog circuits is elementary so I welcome suggestions and criticisms from anyone familiar with these types of things. As with the other projects you can see detailed photos on the build at Flickr.

More photos, comments, and the schematic can be found on Flickr here:

Paul’s Fuzz

Sound Samples:

Unfortunately I neglected to sample this box before popping it in the mail. Version II will definitely have samples. That will be better anyway.  Incedentally I’ve repalced this fuzz with a better one.. the Big Muff Mod.

The Crash Sync is a John Hollis design who’s schematic can be found here. There are dozens of examples of these on the web.  They’re pretty popular among DIY enthusiasts and not terribly difficult to throw together.  John’s site has a number of great projects that center around Op Amps and are very affordable to complete.

I typically use whatever components I have available, either bought or raided from old gear, so when putting a project together there are some inevitable changes.  In this project I used different Op Amps and added in a bypass switch (with lights of course) to pass the original signal.  As far as I can tell using a different op amp hasn’t had a noticeable impact on the sound of this awesome little box. Lastly, like all of my boxes so far, I haven’t wired them up for use with a 9V… which is fine for me, but others might find it an inconvenience.   See the full flickr set for detailed photos.

Many more photos and comments on this build can be found on Flickr here:

The Crash Sync

Sound Samples:
Before #1
After #1

Before #2
After #2

This is the first distortion “box” I designed myself. Admittedly it was a haphazard process of jamming parts together with only minimal understanding of what I was doing. It uses a couple diodes and an LED as well as a couple of op amps to give this guy some seriously gut busting distortion.

Looking back I now know I have some bias problems which cause some unpredictable behavior but my poor design notwithstanding, this is well suited for sound-design/sampling. It however is not functional as a typical signal processor. I neglected to label the inputs and the knobs so I always have to f with it to get it working, an amateur move, but I think it adds a little something… like a what-the-hell-does-that-do kind of something.

The most noticeable feature is the enclosure. As you could guess by the name it’s all tossed in an Oregano spice jar. Even if you don’t like the sound you can’t deny it smells delicious.   Not to mention there’re some LEDs in there but, no battery operation.  I don’t know why; that would have been pretty easy to accomplish. I recently went back to draw up a schematic of this circuit. armed with more knowledge of what i was doing I realized half these components weren’t doing jack and i was just overdriving an unbiased op amp.

Be sure and check the full photo set on Flickr and listen to the sound samples below.

Sound Sample:  Before the spice, and after the spice.