montreal assembly

Nasa Attribute Finally actually done.

2012-01-30T00:20:00.004-05:00

Finally got a bit unlazy and finish the coding for this. Made a product page for it and also Jaywalking.

Quadraphonic for installation part I

2011-11-08T21:14:00.003-05:00

I was commissioned to build something for an interactive sound installation. The first result is shown. Basically a quadraphonic multi-effect/panner. Effects include delay/phase. The joystick handles the panning and the buttons handle which channel is being manipulated.

I am hoping to get some clips in a mock up of the installation when it returns from over seas. The unit is DSP based so the developement is a bit open ended. Awaiting feedback on what worked/what needs to be changed.

Nasa Attribute Demo

2011-11-08T20:58:00.003-05:00

I was working on an arpeggiator over the summer but did not quite get it to production before school picked up again. Here's a brief demo. More demos soon, hopefully some up for grabs within the next few weeks.

new white fritter vid

2011-06-03T01:32:00.001-04:00

these are available now...

total bad vibez preview

2011-01-22T17:34:00.001-05:00

Heres a short video on the vibrato i was working on. I have also added a page for this project in the index.

total bad vibez mock up

2011-01-20T22:59:00.005-05:00

Here is a vibrato pedal that i built into a wah shell. Its called "Total Bad Vibez". Clips coming by the end of the weekend as well as more white fritter clips.

white fritter/2011/happy new years

2011-01-03T01:57:00.003-05:00

First build of 2011, got the first white fritter up and going. Happy new yerr.

more craigs.

2010-12-15T21:26:00.003-05:00

I put 2 ring modulators into one case (again). whoopedee doo. More importantly i am coming up with was to make things look a bit nicer. This one turned out ok but im working on another one where the lines turned out a bit more crisp.

The White Fritter Fuzz Compendium

2010-12-14T03:12:00.004-05:00

A 3 mode fuzz. One mode sort of emulates something like the Crash Sync (By Jon Hollis) but with an additional LFO added. The other is a more ring modulator type, again with LFO. The last mode is a naive pitch bending algorithm that can be used to generate up to 2 additional pitches at chromatic intervals +/- 1 octave.

At the moment the LFO can provide either square or sinusoidal output. Most features can be controlled by external means (either CV or expression pedal etc...).

glass residence

2010-12-08T01:32:00.002-05:00

The boards showed up for this a few days ago. Here is a mock up of what they might look like. Finalizing the design over the next few days. Video with a sinusoidal input below. More soon...

more tremolo/ring mod

2010-10-28T17:30:00.003-04:00

Here is another video of the newer yet to be named ring mod on the bread board. I removed the LFO from the modulation frequencies because it was sounding a bit too cheesy. Added 'tap tremolo' as well.

another modulator in progress

2010-10-19T20:29:00.004-04:00

Im working on a compact synthy/modulation deal. Conceptually similar to the image below. See video for a basic demo. Experimenting/adding more modulation waveforms at the moment. Has stereo output as well for interesting panned textures.

The input goes to two separate modulator sections. For each section it first has the option of being ring modulated. Each ring modulator also has an independent LFO which can be enabled/disabled/various wave forms. Once ring modulated the signal goes into a panner sending the signal to the two output mixers.

Each modulator can be totally free running, synced to itself (ie LFO and trem synced) or a global sync can be enables (all trems and LFOs controllable from one pot)

Ring Modulator

2010-07-25T01:27:00.002-04:00

I built up the craig anderton design to work with just +9V. It has a decent sound to it. Also added an LDR on a string. Has a wet and dry volume knob and a frequency knob.

Another Uranus Update

2010-07-22T12:37:00.002-04:00

July 2010 update includes:
- 2 new modes (PLUNGER and SH BLISS)
- Improved LFO adjustability
- some tweaking to LFO ranges

A full video demonstration using a keyboard:

blipo

2010-05-10T02:47:00.001-04:00

i added a new mode to the wrong side of uranus called "blipo". Its bit like stairs and a bit like a tremolo. here is a short demonstration.

boats progress

2010-05-06T00:52:00.004-04:00

i am trying to make a totally analog tremolo that can make more complex waveforms than triangle and square. here are some results so far. there is a push button mode to temporarily activate the lfo vs. continuous. the general idea is to make patterns that sort of melt into each other while maintaining some of the previous attributes.

it will have complementary outputs so you can use it as a panner as well. more soon.

more fax machine samples

2010-01-11T20:17:00.005-05:00

I made some clips with a clean guitar into the probability of a fax machine. I have built another small batch of these....

link to original article

Waking up on the wrong side of Uranus

2010-01-11T18:10:00.011-05:00

please note this is an old blog post when i first released this. there is a much more updated video on the actual wrong side page here.

Here is a bit crusher/modulator i came up with.

It operates off 3 knobs: Volume, Rate and Resolution. So far I have about 5 modes that are cycled by depressing the resolution knob. Here are some videos. Sorry the sound quality is not super hot (laptop toooo close to the traynor :(

Introduction video...

Here is a demonstration of the standard bit crusher mode. You can cycle from 1 to 8 bits of resolution and de-rate the sampling period.

Another mode called Autorate. The rate pot controls an LFO that controls the sampling period. The effect is some nice vibrato on the aliased tones.

Folding mode is quite noisy (particularly on this mic) but it creates overwhelming harmonics as the resolution decreases. Makes a nice distortion sound when the bit resolution is high. Blurs to static when the resolution is low.

Stairs arpegiates the sound somewhat. Much more soothing sounds than folding. Makes nice ring modulated type sounds. The resolution knob works exactly as in bit crush mode and the rate knob controls the period of each tone.

DialUp is like folding only the resolution changes automatically. The period of each resolution change is determined by the rate knob combined with the input signal. This makes it somewhat random but around a mean value proportional to the rate knob position. For now the resolution knob is inactive in this mode.

More modes are being worked on but i am trying to keep them somewhat diverse.

Probability of a Fax Machine

2009-10-21T12:27:00.011-04:00

A pitch modulating circuit using a s/h waveform lfo. Generates a variety of sounds from subtle pitch variation to total poop digital breakdown.

Controls:

Period: This knob controls the period of the s/h wave form. (Essentially the speed or rate of the LFO).

Mix: This allows you to blend the clean sound going into the pedal with the effected sound coming out of the pedal. One extreme => just clean, the other extreme => just effected signal.

Volume: A master output level control.

Mean: The end result of this knob is not simply explained and its result is highly interactive with the skew knob. It will affect several things sonically. At min the effect will be subtle and the sound quality will be quite high. As the knob is rotated the probability of glitchy sounds will increase, however their will be some headroom where quite normal sounding tones will be produced.

Skew: This knob is interactive with the mean knob. It will in effect control the variation of pitches that is produced. However this range is also somewhat controlled by mean. An example: Mean somewhere in teh middle and skew quite low will result in just small pitch variations. With skew increased the pitch variation between the output tones will be more varied.

The best way to get a feel for what these knobs do is to watch the sample videos...

sample with clean guitar here

joy

2009-10-21T12:14:00.006-04:00

My friend asked me to make something like this for him.

What it is:

More or less a mixer of 2 effect loops. One loop has the volume control at the effect send and one loop has the volume control after the return. The x-axis of the stick controls one loop and y-axis the other.

Also each channel can be subjected to a feedback loop, which makes it behave a bit like the "total sonic annihilation" pedal (per loop).

red llama clone

2009-10-20T00:24:00.003-04:00

This is the last of the left over boards from a workshop long ago... Built for a friend. Its sort of a mix between the anderton hexfuzz and the red llama. I think the red llama doesn't actually have the additional overdrive switch, but it uses different 'tone' caps than the hexfuzz.

This is sort of the best of both worlds with the switch implemented in stop form and a red/green led to indicate which mode your in.

From the waves you can see the regular overdrive is asymmetrical and a bit soft. IT sounds not bad. People seem to like it.

Heres the led... one button is bypass and one is the 'mode' of the overdrive... knobs are volume and gain.

Heres a look at the signal... order is something like clean, low gain, play with gain knob, play with volume knob, change to high gain/low gain/off etc...

every day is summer

2009-04-28T23:24:00.005-04:00

general myron

2009-02-10T01:09:00.003-05:00

more generation of random frequencies

2009-02-01T02:23:00.000-05:00

one day ill have a camera with video and sound. in the meantime....

higher frequency content

2009-01-31T17:55:00.011-05:00

relative polytone generator. excessive use of precision rectification op amp circuits. wont be perfect due to wave shape but should "work". (f, oct, oct+p5, 2nd oct, etc...).

sine wave through 4 folds. dramatization of new "high frequency content".

f(x) = sin(2x)
g(x) = 2|f(x)| - 1
j(x) = 2|g(x)| - 1
k(x) = 2|j(x)| - 1, etc...

|f(x)| implemented through rectification. -1 or -c (a constant) represents a DC offset, without which running stages in series would be ineffective.

it isn't a strict doubling of frequency, but an approximation of. the shape of f(x) will change unless it is a perfect triangle. but that might be the charm of it. ie the harmonics generated will be waveform dependant, although there should be general trends.

using FFT approximation to see spectrum created...

first fold shows strong second harmonic, subsequent folds show a reasonable fourth then a fair distribution of upper even harmonics.

from this point high pass filters could be used with a sort of subtractive synthesis mentality to move the distribution more in favor of the higher ordered harmonics. not sure if 6 stages are really necessary. probably 4 would be interesting enough.

beyond 2000, one bit multiplier

2009-01-30T14:00:00.001-05:00

block diagram for a more complete implementation of "what we thought the year 2000 would sound like". program selectable lfo and harmonics filter to alleviate "generic" restructuring of any input and other problems.

possibly will be asm three/four etc...

isd interchange

2009-01-30T13:47:00.002-05:00

relaxed implementation of chopping/sampling ideas. burdens and limitations of isd smoothed over by flexible connections with acoustically distracting hardware.

project proposed in conjunction with emilie mouchous.

tribute to 2009

2009-01-01T20:39:00.000-05:00

a somewhat deterministic signal volunteers itself to the consequences of a randomly controled system.

s/h to the mouchous

2009-01-01T16:42:00.000-05:00

random signals...

Zener Type Avalanche Noise Generation:

"Matthew J Bennion, mjb296@soton.ac.uk, pointed out that noise sources are important as random number generators, for situations where you really do need truly random numbers (as opposed to the pseudorandom number generators implemented in software). An example where this is necessary might be encryption and decryption"

"I agree with what you have on Noise Diodes, but I think you overlook the main use: measurement of noise figure. To characterize, for example, a receiver, one adds noise from a noise generator until the observed noise just doubles (or changes by some other convenient factor). Shannon's theorem says that noise always adds (Murphy's law says the same thing). Since the noise generator would typically make a relatively high level of noise that would be attenuated down by precicesly calibrated attenuators, one can know how much noise was required to equal the intrinsic noise of the receiver, and thus infer its performance."

"This white noise generator is based on the avalanche noise generated by a zener breakdown phenomenon. It is created when a PN junction is operated in the reverse breakdown mode. The avalanche noise is very similar to shot noise, but much more intense and has a flat frequency spectrum (white). The magnitude of the noise is difficult to predict due to its dependence on the materials."

Shot Noise Generation:

"Shot noise exists because phenomena such as light and electrical current consist of the movement of discrete, quantized 'packets'. Imagine light coming out of a laser pointer and hitting a wall. That light comes in small packets, or photons. When the spot is bright enough to see, there are many billions of light photons that hit the wall per second. Now, imagine turning down the laser brightness until the laser is almost off. Then, only a few photons hit the wall every second. But the fundamental physical processes that govern light emission say that these photons are emitted from the laser at random times. So if the average number of photons that hit the wall each second is 5, some seconds when you measure you will find 2 photons, and some 10 photons. These fluctuations are shot noise."

The full picture/recent developements and changes in thinking...

http://www.lorentz.leidenuniv.nl/beenakkr/mesoscopics/topics/noise/noise.html

The Poisson Distribution:

http://en.wikipedia.org/wiki/Poisson_distribution

sources:

http://www.maxim-ic.com/appnotes.cfm/an_pk/3469
http://www.avtechpulse.com/faq.html/IV.8/
http://en.wikipedia.org/wiki/Shot_noise

cagibi exposition

2008-09-28T23:52:00.000-04:00

in support of the pop montreal circuit bending workshop there is going to be a small gallery of diy electronics all week at cagibi. i decided to contribute these.
everything makes anything sound like lasers. and the sewing machine pedal is a gain/slight overdrive. none are that recent but they are all quite interesting.

probably more on this later. the vernissage is this wednesday.

Bass Cab

2008-08-27T19:33:00.000-04:00

I made this bass cab with a "sammi sound" speaker i purchased at songbird music in toronto last year. My friend Celidh helped with the sewing.

Because i am paro about the speaker getting punched i put a metal grill behind the mesh. The grill is just held on with velcro. The box is made out of 3/4 inch particle board. I ported the back and it sounds quite nice. It is much tighter and clearer than the other 15" cab i made with an eminence delta.

The upholstering is far from professional but maybe the next one will look nicer now that i sort of have an idea.

Mostly i have been spending time on PIC programming and a soundlab with some extras that will hopefully appear soon.

Sunn 200S

2008-07-04T22:33:00.000-04:00

I did some work i've been talking up for a while on my 200S. Basically two things, implementation of solid state power rectification and replacement of all electrolytic capacitors (from 1967).

The original power cap is one of those jumbo 4 in one caps which i am not interested in sourcing so i replaced it with several separate caps. The 30uf was replaced with 2 x 68uf in series (34 uf @ 800v), the 20uf's feeding A and B were replaced with pairs of 47uf's in series (23.5 uf @ 700v) and the last 20uf with a 22uf @ 450v. Overall this increases the total capacitance of the supply a bit resulting in a decreased power factor. Also to insure that the voltage is shared nicely between the capacitors in series i added dividers using 100k resistors. This will cause a bit more current to be drawn through the power transformer but since it is extremely large i don't think it will cause problems. (2.9mA on the B+, 2.85mA on 570 tap and 2.17 mA on the 433 tap = about 4 watts of power dissipated over the new voltage dividers). The 15k resistor was bumped up to 17k. Ideally the dividers should have been made with 220k and the 15k replaced with a 20k but its what i had on hand and it will work alright. With a 20k the voltages on the preamp taps would remain very close to the original design. with a 17k they are just a bit higher.

The caps on the negative bias voltage supply were also swapped out and replaced with the same type of 47uf mentioned above.

Here is the original supply schematic for reference:

Below is a schematic of the new power supply capacitor section. The voltages are the end result measured after changing to solid state rectification. Unlabeled resistors are 100k 3 watt.

Here are some pictures of the physical layout, first the pairs of 68uf and 47uf.

Here you can see all the electrolytics replaced.

The diode rectification is very simple to convert to. I have seen it suggested 10pf caps be put in parallel with each diode but i do not have any rated at the appropriate voltage so for now i have omitted them. Mostly you just have to make sure that the PIV rating of the diode is about 3 times greater than the rectified DC. In this case the resulting voltage is about 595 volts. And the PIV of a 1n4007 is 1000 volts. 3 X 595 = 1785. So if we use 2 diodes on each half of the rectifier we should be fine.

Here is a picture of the final result with the diode rectifier.

The amp was re biased for the new B+ and so far so good. It seems clearer sounding and punchier. It also seems to have a bit more gain. Possibly from the higher voltages in the preamp or possibly my imagination.

PCB Etching

2008-03-01T03:13:00.000-05:00

This is the second series of etchings i have done. The main difference this time around was the heat transfer method. A problem that keeps coming up is uneven heating of the board when transferring the toner which results in many broken or missing traces.

The previous method involved ironing the copper side of the board with the acetate in between the iron and the board. Pressure is applied on the iron and reasonable results can be had but it not very consistent.

This time the heat is applied to the fiberglass side of the board. This method provides much more even heating to the copper. The transfer is then placed on teh heated copper and a flat surface is smoothed over the surface during heating to put some pressure on the transfer.

Above is the basic setup. The iron is inverted and held in place by a vise. The timer is just to indicate roughly how long the board has been on. The transfer takes about 2-4 minutes depending on the size of the board.

Heres the setup in action. An oven mit is used because it gets real hot on the hands other wise. The aluminum is just a random scrap piece. Anything with a flat surface will do.

The rest of the process is trivial. I used ammonium persulphate to etch. The board is teh "Tube sound fuzz" from tonepad with a few modifications. (Mainly a millennium bypass and a switch for high/low gain.

Above, a sketch of what the extra traces are for/ the modified PCB.

Below, some other pictures from the process.

YBA-1A Re-Cap

2008-02-12T01:47:00.000-05:00

At some point during rehearsal my amp started blowing fuses. So i decided to use it as an excuse to replace the 40 year old caps that were inside and learn a bit about tube amps.

One thing with this amp is that there is no bias pot and the bias voltage is set to -46. This seems to have possibly caused a problem when the capacitors started to dry out. When electrolytics dry out they begin to have resistive quanlities as well as a capacitance. A less negative bias results in a greater current flowing through the tubes. Which could burn them out prematurely, or overload the plate and cause it to glow bright red (seriously shortening the tubes lifespan if not ending it right there).

This is the schematic for my amp. Mine is either a later or earlier revision and has a few less parts plus runs a higher voltage to the preamp tubes.

Basically the main B++ power supply caps were replaced as well as a few others. A bias pot was added as well for a bit more versatility.

Heres a close up of the power supply section. C15, C17, C18, C19 and C20 were all swapped out for 100uF 450V nichicon electrolytics.

But one thing at a time. Going back to the bias problem. When I measured the bias had sagged to -41v.

Looking back at the schematic, if C14 had even a somewhat large resistance, it would be in parallel with R31, effectively lowering its resistance and lowering the voltage drop across it. since the -46v comes from the voltage divider setup by R32 and R31, C14 developing a resistance would cause the bias voltage to become less negative. So i replaced both C14 and C15. C14 with a 10uf and then changed the circuit a bit to have a bias pot that can vary from about -44v to - 55v. Essentially R32 is replaced by a 5k resistor in series with a 10k pot. The wiper of the pot is connected to a 47uf cap and is considered the output voltage. The 3rd leg of the pot goes to R31 which remains unchanged.

Here is a sketch of the old and new bias sections

Here is some math showing the effect of the resistive qualities of a bad cap on the bias voltage

Heres the bias section modified with the pot. Also you can see the replacements for C15 and C19.

Heres C20, C16, C17 replaced. The holes are where the can caps used to be.

I also replaced a few resistors that were floating out of spec. And I changed R16 from 10k to 11k. The reason is because on my version the voltage at c20 is exactly 450 volts (if everything is ok) which is the caps rated limit. Although this is not likely a problem I bumped R16 up to 11k to reduce that voltage just slightly to around 442 volts.

And finally I also replaced C21 with a 10uf 450V xicon electrolytic. While doing this I melted a bit of one of the filter caps being careless with the iron. So I replaced it with a metal film cap of the same value (to the left of the yellow capacitor in the picture below).

Scrambler Clone

2008-02-02T01:03:00.001-05:00

This is a clone of the ampeg scrambler pedal that you may or may not have heard of. Its a pretty high gain sounding fuzz box that can also do an octave up buzz. One knob controls the wave shape and one blends the new sound with the clean sound.

The PCB was made from the tonepad layout. However better bypass circuitry was added.

I perf boarded this pedal about 4 years ago and it worked but the output was so low. I asked about this on a forum and the situation was left unresolved.

the thread can be seen here.

Anyways years later here we are making another one and guess what? same deal. The output is about .6 volts. When you blend to the clean side its going to be at a volume level equal to whatever is coming in. Which in the case of any instrument I have is at least 2 volts and in terms of guitar more like 3 (courtesy of a dimarzio X2N). This works out to around a 12dB drop when the effect is switched on.

Quick searches of the tonepad comments and the DIYstompbox forum revealed that other people have noticed as well.

here and here

If you had low output pickups you might not notice. square waves sound louder than sine waves so the distorted sound will sound louder then a clean guitar signal with the same amplitude. (Rms of a sine wave is approx .707 * Amplitude, Rms of a perfect square wave = Amplitude) .

A lot of people are mentioning building a booster in the same box to bring the volume up. This is poor solution for a few reasons. This circuit calls for 3 high gain darlington transistors and has 2 gain stages and a buffer section. I shouldn't need to add anything to bring the level up.

The problem can be resolved by modifying the final output stage comprised of Q3 and Q4. They are setup as a differential amplifier with a single ended output. Without doing to much math to calculate A (gain) = Rc / re'. Where Rc is the 1K resistor coming from +9v to the collector of Q4.

To calculate re' you must find the DC emitter current and so on. This is not necessary at this point as we can see from the equation in the last paragraph that Rc and A are directly proportional so increasing Rc will increase the gain. It will also however decrease the current through the transistor but this is of no consequence for our purposes.

I put mine up to 39k which gave me about 2.0 - 2.4 v out depending on the wave shape from a 3 v sine. (.707 * 3v = 2.12V so it should "sound" like about the same level). Since the clean part of the blend does not pass through this final differential gain stage its volume is unaffected. It would seem the problem is solved. I would suggest for anyone doing this to use a trim pot to find quickly they're preferred output level, 50k or 100k should be fine.

A millennium bypass was implemented after the board was made so thee are no traces for it.

Heres a video of the effect on a sine wave. The top trace is the output and the bottom is the input measured straight off the function generator. It gives a good idea of how the octave up is generated. First the effect is off. Its switched on when you see the square wave. Then the tone knob is twirled, then blend, then a bit of one and the other.

Variable (+/-) DC Supply

2008-01-20T13:18:00.000-05:00

I started designing thing with +/- 15V mostly instead of the usual 9 volts I was working with before. I don't have a split supply so i built this simple one. It is variable from about +/- 2 to 18 volts DC.

Its based on the LM337 and 317 of course. The transformer is overkill but the point was to build it out of parts I already had.

The circuit is simple enough to perfboard. It is straight from the application notes (using a 1k pot and an 82 ohm resistor) with 1N4004 diodes protecting the regulator as suggested. The large caps off the transformer are 4700 uF.

There is no display of the output voltage. I monitor it with a multimeter.

Probably not the best supply in the world but more than enough for what I need.

DIY Bass Repair

2008-01-12T18:56:00.000-05:00

At some point I bought this bass online:

"you've got mail!"

Ive never seen something get quite so mangled in the mail. Anyways my money was refunded by the seller and they never filed the claim with usps so i still had the pieces of the bass. I asked some local luthiers about a cost of repair but the cheapest i could find was 80 dollars just for the neck. I contacted Dean and they were willing to sell me a new replacement neck for about the same price. so I decided i didn't have much to lose by attempting the repair myself.

I used wood glue and a bunch of clamps to glue both the neck and the body back together. I just used normal wood glue from the RONA near me and it worked perfectly fine. The hardest part was probably clamping the headstock area but in the end it turned out nicely.

this is the part of the fretboard that was originally cracked

the body "repaired"

various neck shots

Also the pickup was smashed so I replaced it with a seymour duncan "basslines" musicman pickup. It required some sort of preamp so I designed a very simple one with the option of some slight asymmetrical clipping using a RC4580 op-amp from texas instruments.

The preamp has 3 controls. A gain knob, a master volume knob and a switch which places 2 leds (used as clipping diodes) into the circuit. Below is the schematic i came up with (note that NE5532 and RC4580 are pin for pin compatible and both high performance low noise op-amps). Also the "volume" pot is Audio tapered not linear taper as stated in the schematic.

Without the preamp the output of the pickup is unbearably low.

The bass is now quite usable. I may repaint the body so that you cannot see the crack
but im not sure if I really care that much.

Microphone Repair

2007-12-30T12:33:00.001-05:00

About 6 months ago I bought a box of broken mics of someone in Toronto while I was working in Vaughan. The only real notable mic is probably the ATM11 which had battery acid all over the inside, and also broken wires connecting the transformer to the battery compartment.

There is also an AKG D1000 but is is missing the xlr piece and will most likely be impossible to find.

There were a pair of "Univox" mics but the stickers are put on rather poorly. I am unable to find a picture of what these mics should look like to compare but I suspect they are not univox, and that they are something else with univox stickers or univox mics re housed? They were also wired incorrectly. The cold wire of the cartridge was wired to chasis ground (pin 1 on an xlr) which is the reason they didn't work.

There is an SM58 fake by "shs" and 3 "voice-craft" which were originally advertised to me over the phone as "electro-voice" (wishful thinking). If you ever want to see an extremely detailed spec sheet take a look at this.

The shure BG 2.0's also look somewhat decent and have a much more sophisticated cartridge with some sort of shock mount. The spec sheet is here.