Custom Hardware

tone generators, pedals, circuits and fun noise manipulation devices

Custom Hardware, Fuzz/Distortion

Hot Fuzz

By Dave on April 13th, 2009

Previously I’ve posted on a fuzz box that I made for Paul Digs. Recently Jamie Roberts asked me to build him a custom remake of the old Electroharmonix/Sovtek Bigg Muff fuzz pedals. I was speaking with Paul and the fuzz I made for him didn’t really suit his needs so I decided to design and build two fuzz pedals. Starting with any number of the dozens of Big Muff Schematics available on line I tested the circuit and made a couple small modifications… asymmetrical clipping. I used Eagle Cad to draw up the schematic and generate the gerbers and then sent out the custom boards for manufacturing through Batch PCB. They have an exceptional service and are extremely easy to deal with. I highly recommend them.

muff-breadboard

That was essentially the most difficult part. Upon receiving the boards back I mocked up the enclosure layout, drilled my holes and then sent out the enclosures for chrome plating. This was expensive, $80+ per enclosure, which was more than half of the entire cost of each pedal but it was worth every penny. They came out stunning. Exceptional knobs, custom silk screening, and pots with 11 detents. Up to 11! Having finished I would only have changed two things. I would have included a power on LED and included a 9v battery clip instead of just a DC power supply. Nearly all parts were sourced from mouser. The only exceptions were the footswitch, jacks, enclosure, and knobs.

muff-interior

Unfortunately I don’t have sound samples but these things squeal and pump out some serious gain. But, as with anything analog with that much gain you get a significant amount of noise. Not really a problem when you’re playing… just when you stop.

muff-exterior

You can see the detailed photo set here on Flickr.

Custom Hardware, Effects

Alpo Can Ring Modulator

By Dave on February 15th, 2009

This is a ‘ring modulator’ similar to the one used in an ARP Odyssey… this version operates by the input of two square waves into a 4011 quad NAND gate. I didn’t have a 4011 available so in this version I use a 4001 quad 2-input NOR with two inputs wired to ground (low) instead of wiring the 4011 with two inputs wired to Vcc. If I did my logic correctly the 4001 works the same when wired this way. I included the logic tables on the schematic.

Ring Modulator Schematic

The two square wave tones passing into the gates are compliments of a simple op-amp square wave generator circuit. Information on how to wire one of these up is widely available on the web. Here’s one good resource. The original schematic and idea was found on simple-answer.com here. A brief reference to the ARP Odyssey and this ring modulator is mentioned on Wiki here.

Alpo Can Ring Modulator board top

Obviously this is in an Alpo Can. The circuit board can be viewed on Flickr (see link below) but it was pretty small so it had no trouble squeezing in there. The knobs were found on eBay for dirt cheap. The hardest part about modifying this can was getting the sharp edges off the holes drilled into the can. To get the top off without cracking open the dog food… and to be able to take the top on and off the can you’ll need one of these: Kuhn Rikon Safety Lid Lifter

More photos and comments can be found on Flickr here:

4001 Ring Modulator in an Alpo Can

Sound Samples:

Dry, without Effects

Wet, with effects

Custom Hardware, sequencer

16 Step Analog Sequencer

By Dave on February 13th, 2009

A while back Gil Duross over at Philly Techno was talking to me and was thinking about coming up with a analog step sequencer which would cost less than $100. It got me thinking that this isn’t that crazy and it’s likely someone out there has already done something like this. As is it turns out that’s exactly the case. The following video is of my test circuit of a 16 step analog sequencer based on Mauno Tuominen’s schematic for an analog CMOS sequencer based around at 4067n multiplexer/demultiplexer. You can see a DIY version of the sequencer here at studiomanus.com. I had an old sn76477 which I had been planning on turning into something so I started with the basics… indicator lights, tempo, and a simple oscillator. The eventual plan is to expand this out into a large 16 step sequencer/synth based around the sn76477 allowing for extensive sound shaping of each step in the sequence. Although the sequencer is well under $100 by the time this is completely finished it will likely cost well over that but the result should be substantial. In the meantime, take a gander at the initial test circuit. The sounds aren’t the most musical at this time, but it’s function and simple design is more the point.

I’ve expanded on the original design using a simple 555 timer for the clock and the ability to control the number of steps in the sequence through use of the 4063N. This has not been tested… that’s on my to do list. If anyone who reads this is well versed in these components and circuit design I’d love to hear feedback.

sequncer step counter

Custom Hardware, Tone Generators

Dub Siren

By Dave on December 13th, 2008


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

Custom Hardware, Modifications, Resources

FB 383 Freebass Mods

By Dave on November 13th, 2008

Back in 1997 a company called Music and More (MAM) created a tb303 clone called the MB33. They licensed their design to another company called Freeform Analogue Technologies who dubbed the same clone the Freebass FB383. I guess it’s a clone of a clone? Both were identical and affordable during a time techno was all the rage and everybody and their brother HAD to have a tb303. Despite the overused sound and the long past death of techno these little boxes still have a good deal to offer…. Especially at current prices…. Originally around $400… I picked mine up for $10.00 on eBay, albeit broken. Due to poor manufacturing many of these guys are broken these days and don’t produce any sound however, you can still tap into their analogue resonance filter to add some nice tone to just about any instrument and add a excellent tool to your studio. The mods that follow show you how… and it will cost you pennies.

 

FILTER ON/OFF

Assuming you’re familiar with the FB383/MB33 you’ll know there is an external input on the back to patch a signal through the filter section of the unit. Assuming your unit works you know that when you connect a signal the internal synth is disabled which makes racking the unit a major hassle. By adding a filter on/off switch you can keep your unit racked and patched to a patch bay and use the filter easily. If your FB383/MB33 doesn’t work, like mine, then it’s basically a signal on/off switch. I plan on making a cv input for the oscilator and when i do, this mod will still be neceassry if i want to rack the unit.
Filter On-Off

The photo above is a shot of the finished mod. You can see more details, photos, and descriptions at the link below.

The Full Flickr photo set here.

 

FILTER TRIGGER

As with most external filter units, you need to trigger the envelope section before you will hear any sound. So if you have an input signal patched and the envelope is not triggered you hear nothing. To do this you have to supply a voltage to the bias input of the Operational Transconductance Amplifier (OTA). Instead of applying a direct voltage I opted to use a pot to drop the voltage at the base of a transistor controlling flow to the bias input… drop the voltage and current flows to the bias input. With higher voltages you get some gritty distortion which isn’t so bad in some cases. I soldered one lead of the pot to ground and one to an easy to reach lead on the end of a 0 Ohm resistor. That’s what you see in the photo above.
Filter Trigger

As before, you can see the full set of photos by the link below.

The Full Flickr photo set here.

 

RESONANCE BOOST

This one is pretty self explanatory. There is a resistor in place that restricts the resonance a bit. By bridging this resistor you can get some nice thick resonance and even some self-oscillation. Instead of simply bridging it though I added a switch to allow for ‘normal’ and ‘boost’ modes for a variety of applications.
resonance boost

As with the previous mods… photos and details by the link below.

The Full Flickr photo set here.

When initially looking into information on the FB383 I immediately figured out that nobody has any. Nobody. There was virtually no information available on the net with the exception of a brief background on MatrixSynth and some information on possible mods (for a fee) at Circuitbenders.uk. Of course there were reviews at typical locations like hyperreal and harmony central but other than that it was limited. I managed to track down someone familiar with MAM products through the company that ate them, Musonik, and figuring that somewhere someone would have service manuals, design specs, part sources, etc. I was wrong. Nothing.
Circuit Overlay

So given the good number of these machines out there and the likelihood that there were a fair number of folks in need of a signal flow diagram I made a high resolution circuit overlay of the Freebass FB383 (MAM MB33). It’s not a schematic but it’s about as close as you can get. I’ve found it immensely useful and have it available here for any and all to put to good use. Enjoy!

The full high resolution (7920×1587) image here.

Custom Hardware, Effects

AD633 Ring Modulator

By Dave on October 13th, 2008

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

Custom Hardware, Fuzz/Distortion

DJ Paul Digs Fuzz

By Dave on October 13th, 2008

dj-paul-digs

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.

Custom Hardware, Effects

Crash Sync

By Dave on September 13th, 2008

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

Custom Hardware, Fuzz/Distortion

Oregano Crunch

By Dave on February 13th, 2008

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:  oregano_before, andoregano_after.