NT 01
NT02
This is the latest set of NT(noystoise) series novelty synthesizers. following the overwhelming reception of the original NT01 series, it was pretty clear that if i build them, they will sell. the NT02 is simpler in many ways than the original NT01, but the sound and character are a bit more sophisticated than that of the NT01. the NT02 consists of a square wave VCO with chorus/delay, a white noise generator, a ramp LFO, and individual 12db resonant lowpass filters for the VCO and white noise generator. the pitch of the VCO is controlled by one axis of the VCO joystick, while the other axis controls the delay time of the chorus. the chorus circuit is basically just your typical PT2399 delay chip setup, except there is no feedback loop. the VCO is fed to the delay chip, and the delayed signal is recombined with the initial signal before the filter stage. the effect makes the VCO sound much bigger and warmer with the chorusing effect. almost like an old analog poly-synth with detuned VCOs. the white noise generator is your basic two transistor type found in many old synth designs. a common issue with the two transistor noise generators is that they require at least 9 to 10 volts to operate. that's just fine if you are using a plug in power supply, but when using a 9 volt battery, the noise generator usually wont work. in my case, the noise generator wouldn't sound with any less than 10 volts. however, the noise generator doesn't draw all that much current, so i simply used a 555 charge pump voltage multiplier to get the circuit where it needed to be. the problem i ran in to on the breadboard though, was there was some cross-talk from the 555 charge pump oscillator to the VCO, so i only used the 555 charge pump method for the first NT02(revA). for the others i simply buffered the VCO, and made a charge pump out of that. this way, if there was any cross-talk, it would be harmonized and unnoticeable. however, once the NT02 revA was built and working, the cross-talk was gone, so i guess it wasn't necessary. both the VCO and the white noise generator have their own respective filter with resonance control. the cutoff frequency of both filters are controlled by their respective axis on the VCF joystick. the center switch on the joystick toggles either the VCO or noise voice on or off depending on which joystick switch you press. each voice will remain on or off until the switch is pressed again. this feature was not included in the revA NT02. its voices are permanently on. the NT02's LFO is ramp shaped and can be set to modulate one of four parameters, or turned off. the LFO can modulate either the chorus delay time, VCO pitch, VCO filter cutoff, or the noise filter cutoff. on the revA NT02, the VCO pitch setting controls the maximum threshold of the pitch joystick, whereas the revB VCO pitch setting is independent of the pitch joystick. the LFO rate is controlled by the knob above the VCF joystick. the NT02 also has a volume knob, a 1/4 inch switching line out jack that bypasses the built in speaker when plugged in, and a center positive polarity protected DC jack that bypasses the internal battery when plugged in. the internal power supply is regulated, so any DC adapter between 9 and 18 volts will work just fine. unfortunately, unlike the NT01, the NT02 does not have CV inputs or outputs. the NT02 revA(black one) does have two 0-5 volt CV inputs for the VCO and LFO, but the revB models do not because their circuits' operating voltage is 8vdc instead of 5, which is kind of an unusual number... i would have liked to have scaled CV inputs that could turn 0-5 volt CV input to the necessary 1-8 volt CV input that the VCFs, VCO, and LFO require, but space was too limited. the inputs are in there though. i still kind of regret not including the ability to connect CV inputs to the NT02, but it is just safer this way. these were not intended as modular synths. they can be easily modified though, for any advanced users out there. hopefully these little synths do as well as the NT01 did so i can start on an NT03... the NT02s will be available at my for sale page until they are all gone. have a look, tell your friends about this BLOG!!!
Thanks for reading,
Tanner
NT03
Ahhh... internet at last. been having trouble with my connection for the past week or so. haven't had the opportunity to post. the NT03 is the latest of my NT(noystoise) series. i initially started developing the NT03 in early November of 2014. the first of the six was completed at the beginning of December, but a commission came my way, so i put the rest on hold for a month before finally finishing them all. unfortunately the commission fell through. thankfully it was only one month wasted. hoping to quickly recoup my losses, i cranked out the final five NT03's in record time(two weeks), only to find that my 3 month old CenturyLink DSL router was all dried out. one after another, i finally got a replacement that works(for now). now to catch up!
The NT03 consists of two square wave voltage controlled oscillators, a holtek voice modulator circuit, a voltage controlled filter(VCF), and a low frequency oscillator(LFO) that can either/or modulate the filter cutoff, gate the voice modulator transpose sequencer.
The two VCOs are made up of one 74LS124 dual VCO chip. i was able to get a pretty good deal on these chips some years ago, but i haven't really put them to much use. this felt like a good opportunity to use them. i also had a few holtek HT8950 chips that needed to be used. the HT8950 is basically just what you would find in one of those toy megaphones that turns your voice into a robot voice(all circuit benders should know what i'm talking about). the difference in the HT8950 is that in addition to being able to incrementally select the pitch setting of the modulator, there is also a three bit parallel input that can be used to select the chips' eight pitch settings; Robot, x2, x1.6, x1.3, x1, x.9, x.8, x.6. the sample rate(BIT RATE) is resistor set. initially i tried clocking the UP/DOWN inputs on the 8950 with an external oscillator, but found that there is a pretty significant debounce protocol built in. this makes it difficult to achieve faster transitions at lower sample rates, so instead, i built an eight step parallel sequencer from the CD4029 chip. this way the eight pitch modes can be accessed quickly with no debounce(latency/stutter). the sequencer can also advance in either direction.
After the two VCOs are mixed and sent through the voice modulator, they are then sent to a resonant 12db lowpass filter(VCF). the filter's cutoff can be modulated with an envelope derived from the sequencer clock, but the attack and decay of the envelope are preset. the filter cutoff, pitch of VCOs 1&2, and the sequencer clock rate are all controlled by one of four joystick axis. the 3D joysticks are a recurring theme in my NT series. this time i decided to use all white thumbsticks, just because they seem to go with everything. they do tend to get dirty though..
The NT03 enclosures are made from laser-cut plywood and laser-cut acrylic faceplates. everything is made inhouse(in my house) from scratch. when i finished the first NT03, i had originally intended on painting them all primary or secondary 'candy' colors. hence the yellow one. after some time away from the project though, i thought it might be nice to come up with some colors of my own. i ended up mixing all of the colors for the final five by eye. some are a clean wash, and some ended up with some inconsistencies. namely the olive green one that has my big fat finger print in it. i suppose i could fix it or change the color, but despite the imperfection, it still looks really clean. if no one buys it, i'll just have to keep this one for myself.
BUNNY CIRCUIT
NT04
VIDEO
Here is a quick video that covers some basic functionality and sync-ing options.
SEAFOAM
"UH YEAR" REVISITED
BEFORE |
BEFORE |
BEFORE |
BEFORE |
AFTER |
AFTER |
AFTER |
IVAN
The back and bottom plates were pretty easy, but the cheeks gave me real problems. unfortunately i didn't wait long enough for my industrial grade contact cement to set up on the surfaces of the cheeks and wood veneer before i pressed them together. they were still wet a couple of days later when i applied the stain. a couple of days after that i coated the cheeks in polyurethane. it seemed like it went on just fine, but when i came back a few hours later, giant bubbles had formed underneath the wood veneer. i sanded all of the polyurethane off hoping that i could salvage the cheeks. actually, only one cheek was effected, but the wood grain matched symmetrically, so losing one meant losing both. unfortunately it was a losing battle. the stain and the contact cement had combined and somehow dissolved big gooey areas in the veneer. i tossed them, and i tossed that nasty contact cement. well actually all that stuff is still in my basement, but you know what i mean. i laser-cut some new cheeks and headed to Woodcrafters for some more veneer. this time i got some red oak. it's not as subtle as the cherry wood i used the first time. in fact, it's downright DISCO! ok ok, so the next batch came out great. this time i just used good old wood glue and a impromptu press made up of all of the heaviest things in my house. after staining and polyurethane, it was finally looking done. i kept it for about a week or so to make sure there were no other bugs before sending it off to the buyer. all that was left to do is write up an eight page user manual...
YAMAHA PSS-170
upon doing some random research for circuit ideas, i decided it might be time to finally find out what PLL's do. when i started circuit bending some 10 years ago, i remember reading about Phase Locked Loops in a textbook. i think i got about two sentences in before my eyes crossed in boredom. since then i have increased my capacity for understanding electronic applications. i couldn't believe how simple it was to understand. basically, in the case of the CD4046, there is a voltage controlled oscillator that synchronize its frequency to the frequency of whatever signal is inputted to the CD4046. i guess i never understood why you would need to do that. why not just use the input frequency? well, apparently if you divide the VCO output frequency before sending it back in to the CD4046's phase-comparator, the frequency of the VCO will be increased until the divided output frequency matches that of the input frequency. so if the phase-comparator input was set to 1/2 the VCO frequency, the VCO frequency would be raised X2 to match the input frequency to the CD4046. BRILLIANT!!! i remember how exited i was when i learned to divide frequencies, and now i can multiply them!! and not just by 2, 4, 8, and so on. with the PLL you can multiply by whatever number you want. there is one drawback though, at lower frequencies the PLL takes longer to stabilize. it kind of sounds cool though because the frequency stutters a bit before it locks in to sync. hearing something fall in to sync is so vindicating.
after coming up with a decent PLL circuit, i devised a simple bidirectional sequencer that would drive an LTC1799 chip to pitch the YM2413 voice chip of the PSS170. i wanted to add an envelope generator to the keyboard that would be triggered by note-on messages, but unfortunately there was no way to obtain a decent note-on gate from the PSS170 other than to use the audio signal as a gate. and since there are so many different voices in the PSS170, there would be no way to get the envelope generator to respond to all of the voice presets. instead i just synced the envelope generator to the sequencer clock. i also threw in a divider so that the envelope generator could be triggered by 1/1, 1/2, 1/4, or 1/8 the clock frequency.
the envelope generator would be set up to modulate the cut-off frequency of the melody filter before being sent to an echo circuit. while i was experimenting with creating a note-on gate from the audio signal, i realized that the voices coming from the YM2413 sounded really crunchy when you filter them just right and sent them through a frequency divider, so i ran those sub-frequencies through a joystick mixer and mixed them back with the original voice before they get sent to the filter stage. this is when i realized something else... although there are separate outputs for the melody and rhythm voices coming from the YM2413 voice chip, there is some bleed through from the rhythm output to the melody output, even when the rhythm output is fully attenuated. i suddenly remembered this same problem i had with other yamaha PSS models, namely the PSS-30. i think it is due to the fact that the melody and rhythm sections share some similar functions when it comes to the auto-accompaniment. the accompaniment melody comes through the melody output, but the accompaniment volume switch affects both the accompaniment melody volume, and the rhythm volume regardless of the analog volume outputs of the two sections from the YM2413. and of course, the accompaniment volume has no effect on the melody output volume. with all of this in mind, i safely concluded that there was no solution to the bleed through. the only real problem it gave me was that when the rhythm volume was set all the way down, and the melody divider was engaged, the bleed through would get picked up by the melody divider and get amplified quite a bit. the divider seemed to be picking up some aliasing noise too, so to solve the problem, i used a potentiometer with a switch at one end that would disconnect the divider circuit when its volume was set to its minimum. in addition to the independent volume controls for the melody and rhythm sections, i thought it would be kind of cool to have independent echo circuits for the two too.
after about a week of reverse engineering the keyboard and coming up with an overall circuit, i came up with a design plan. the PSS170 has a lot of room inside, but i would need a lot more if i wanted to fit all of the circuits i had built. the first thing i did was replace the huge 6xC battery compartment with a much smaller 6xAA battery compartment. then i cut as much of the front panel off as i could without compromising the structural integrity of the keyboard case. the next step was to clean the hell out of what was left. this keyboard was absolutely filthy. once it was all clean, i took some measurements and started drawing up the new face-plates. after playing around with the orientation of the interface for a few days, i settled on a design, and got to work drawing up a circuit board for the whole thing. rather than using multiple small circuit boards, i decided to be lazy and just put it all on one big circuit board. the circuit board took most of a day just to cut and drill. CNC engraving a circuit board of that size can be slow going. i had to keep going back over it a little deeper each time around the corners to get all of the traces it missed the first time around.
populating the circuit board was pretty fast. the only thing that bothered me was seeing the huge number of parts that this circuit consumed. it's not that i hate ordering more parts, it's when i need parts that i don't have anymore. oh well, i can always pull parts from scrap circuit boards if i get desperate.
once the circuit board was built and ready to go i cut out some prototype face-plates on my laser cutter using cardboard from a cereal box. i have found this to be the best way to connect the hardware to the main-board without having to worry about over abusing the face-plates. then once everything is wired up and working properly, i just swap the disposable face-plate for the real thing. i had originally planned to paint the three face-plates all different colors, kind of going for a crazy candy color scheme, but i kind of liked the way the cereal box cardboard looked with the bright orange buttons. i had a can of krylon that was basically the same color, but i've had a lot of trouble in the past using solvent based paints with acrylic face-plates. i read somewhere that if you reheat the acrylic and let it cool, it will reduce the risk of cracking the acrylic when the paint dries. once the panels were engraved, cut, and i had colored the graphics, i hit the the panels with a MAPP torch for a few seconds on each side until the acrylic started to bow out. i kept heating them up until they wouldn't warp any more, and then i let them cool. once they cool, they return to their original size, and all of the stress in the plastic is relieved. then they are ready to paint. there was a little blistering from the torch, but it is barely noticeable.
i would have to say the most rewarding part of a project that takes so much planning, is when it's time to assemble everything, and it all comes together smoothly. however, being the most satisfying phase of the project can in turn create a perfectly devastating situation. that's usually what happens, and this time was no exception. once all of the new keyboard was assembled and working, and i was putting in the very last screw that would finish the piece using a very powerful screw-gun, i went too deep and cracked a face-plate... i cut out a replacement, painted it, and was able to swap it in by the end of the day. lesson learned.
once the keyboard was closed up i notice a couple of things that i wasn't entirely satisfied with. for one, the envelope generator was biased too low, so it would make this irritating popping noise every time it swept down. not only that but the envelope generator didn't sweep deep enough because the envelope was buffered by an op-amp, so it couldn't reach more than 4 volts. i opened it back up and swapped out the envelope buffer with a couple of transistors to fix both issues. i seem to remember having the same problem with IVAN. why didn't i think of it when i was designing the circuit? oh well, fixed now. while i had the keyboard open, i threw in a little input jack to the CD4046. now the sequencer can accept incoming clock signals and/or the rhythm tempo. i thought about adding a tempo sync output too, but i'll leave it out for now.
RED CLOUD KEYBOARD
RAVE BOX
DRUM SYNTH
FISHER PRICE AXE
NOYSTOISE for MENG QI
(before jacks were added) |
(before additional jacks) |
YAMAHA HS200
This project was a commission for an overseas musician who i have been in touch with for a while. we had talked back and forth for a year or two about having something made, but had trouble coordinating our availability. we were finally able to get a project rolling after all that time though, and ironically enough, the guy happened to be in my neck of the world when the keyboard was finished, so he came and picked it up in person! it is very rare that i get to meet my customers personally. especially since most of them are overseas. it was very encouraging.
YAMAHA PS3 V2
FUN YEARS
BEFORE |
AFTER |
ORIGINAL NOTES |
NEW CIRCUIT |
NOTES |
BROKEN KEYS |
ROUGHING NEW KEYS |
ROUGHING NEW KEYS
|
FACEPLATE DESIGN
|
PCB DESIGN
|
ASSEMBLY |
WIRING IN PCB |
PCB REVERSE SIDE |
WADDINGTONS COMPUTE-A-TUNE
FUNKY GLITCH BUDDY-REVISED
EHX 16 SECOND DELAY MOD
MATATRON!!!
NTSH
The NTSH is a mini joystick noise synth.
It consists of;
- one white noise generator
-one square wave oscillator
-one 12db resonant LP filter
-one Sample&Hold/envelope generator
The controls;
The joystick on the left controls the Filter Cutoff and the Pitch of the Square Wave VCO, while the joystick on the right controls the Gate frequency of the Sample&Hold, and the frequency of the Triangle Wave that is being sampled.
The Gate frequency is also the frequency of the Envelope Generator.
The Gate/Attack Time switch will set the Envelope Generator to either Triangle or Saw waveform.
In Triangle mode, the Sample&Hold Gate time will be at 50% on/off ratio. This will cause the modulation to sweep at the Triangle oscillator frequency between samples.
The Sample&Hold and Envelope Generator modulation sources can each be set to VCO Pitch, VCF Cutoff, or both VCO and VCF together.
The Mixer switch sets the Voice output to VCO, Noise, or both Mixed.
The Mixer switch set to QOSC will turn off the Noise and VCO to the filter, and set the Resonance to self oscillation. The Filter Cutoff sets the QOSC frequency.
In QOSC mode, the Q knob is disabled. In all other modes, it sets the Resonance of the VCF.
The Volume knob sets the output volume level.
The NTSH has a power ON/OFF switch, 1/4 inch output jack, and built in speaker.
The NTSH can be powered by 3 AAA batteries, or with a standard 6-9VDC center positive adapter.
The design;
The NTSH is smaller in size to other NT boxes by about half.
The electronics are all analog, and designed from scratch.
The goal was to design and build a new NT box that was smaller and more accessible for people to buy and support my work. These small boxes are relatively easier to build than the other NT box designs that came before it. They still take several days each to make, but because of their small size and limited function, it is a much less daunting task. I have trimmed a lot of the build time by investing in better power tools for sanding and shaping the boxes, and rather than hand painting the the face-plates, I am using colored acrylic. It costs a bit more, but I just don't have the time these days to do everything by hand anymore. The only drawback is that the colors are pretty limited.
The signal path of the NTSH is pretty basic but it covers a lot, I think. I knew I wanted a white noise generator with a resonant filter. I just love that sound. There wasn't enough space for any kind of sequencer, so I thought a S&H would be nice. The first iteration of the circuit used a bunch of cmos oscillators at different frequencies as a modulation source, because I thought a real S&H would take up too much space, but actually it was the other way around, and the cmos oscillators were difficult to control together in a reliable way. The most difficult but also must interesting part of this build was to come up with as many practical and quality functions as possible with such a small footprint. The end result is such a tight fit in the box, but I think it is perfectly balanced in sized and functionality. The circuitry was also very helpful.. By that I mean, the final circuit seemed to offer up solutions or new features that I hadn't intended using, and usually didn't require too much effort. For one thing, the white noise generator required a charge pump circuit to generate 12 volts to work. However, the current didn't have to be much, so I used the VCO to charge the pump(pump the charge?). Then the S&H gate offered up a perfect synced envelope generator, and the switch to make the gate/attack time 1/1 made both the S&H and envelope so much more dynamic. The Qosc function was something I decided to add after I had already finished the first prototype. It had occurred to me that the self oscillating filter sounded really great without an input signal, and implementing this was literally adding one connection to the Mixer switch! Sometimes things are meant to be.
NT05
The NT05 is a "LoFi RhythmBox"
It consists of;
-Two voices; "Sine" and "Noise"
-Two 128 step pattern banks
-Eight selectable rhythms
-Two "Pad" envelopes
-One LFO
VOICES
The Sine voice has a VCA knob, Distortion knob, and Pitch knob. The Distortion knob effects the waveshape of the oscillator. At the low end, the waveshape is triangular. Midway it is Sine, and at full, the oscillator is squarewave. The Sine VCA knob sets the offset of the VCA, and can be used as a volume mix knob when other modulation inputs are not in use. The Sine VCA can be modulated by any combination of the LFO, Pad EG2, and the Sine Pattern bank EG. The Sine Pitch knob sets the offset of the Sine VCO, and can be used as a pitch control when the VCO is not being modulated. The Sine Pitch can also be modulated by any combination of the LFO, Pad EG2, and Sine Pattern bank EG, however, the LFO and EG2 can only modulate one or the other; VCA or Pitch. Likewise, Pad EG2 can only modulate one or the other; VCA or Pitch. When Pad EG2 is set to Pitch, the Pitch knob sets the depth of the envelope. The Sine Pattern EG is triggered by the Sine Pattern bank. The envelope modulates the Sine VCA, and can also modulate the Pitch. The Bend knob sets the depth at which the envelope modulates the Pitch. The decay of the envelope is controlled with the Decay knob. The decay can be modulated by the LFO via the Sine Decay Mod switch, however the decay has to be set longer, as the LFO can only shorten the decay time of the envelope.
The Noise voice has all of the same VCA, Pitch, and modulation features as the Sine voice minus the distortion knob. The Noise voice is derived from a "LFSR" type pseudo-random-noise generator. The pattern length of the LFSR can be set to one of eight lengths. The shorter lengths are more harmonic, while the longer lengths sound noisier. When the LFSR Select switch is pressed down, the touch pads can be used to select the desired LFSR pattern length. A number below each touch pad represents the corresponding pattern length.
PATTERN BANKS
The two Pattern Banks record and play back 128 steps continuously. There are eight two-channel 16-step rhythms to choose from for inputting into the Pattern banks. The touch pads select the rhythm, and as long as the pad is held, both Pattern banks will record their respective channel. Alternatively, there is a third channel per rhythm that can be substituted to either Sine or Noise Pattern by pressing the Pattern's respective Beat Roll switch. Each of the eight rhythms has a unique Beat Roll that is shared between the Sine and Noise pattern. Both the Sine and Noise Patterns have their own Step Erase switch. As long as this switch is held, the respective pattern will be erased one step at a time. There is also a Clear All switch that will instantly erase both patterns entirely. The Pattern Banks have two settings; Record, and Run. In Run mode, any rhythm input will trigger the Pattern EG's, but will not be recorded to the Pattern. Any rhythms already recorded will be looped continuously. In Record mode, the Pattern will continuously write over itself with any new input, or the looping output. The Pattern Banks are clocked by the Rate oscillator. The speed of the rhythms are set by the Rate knob, but can also be synced to external 5 volt clock signals via the Clk In jack. The internal or external clock source can also be sent out to other devices via the Clk Out jack. The Noise Pattern Bank can also be sent out to external devices via the Seq Out jack. All inputs and outputs are 0-5 volts.
LFO
The LFO can be used to modulate the VCA's, Pitch VCO's, and Pattern EG's as described in VOICES. The Rate and Depth of the LFO are controlled with the joystick. The Rate of the LFO can set to high or low via the HI switch next to the joystick. The rate of the LFO can also be modulated by Pad EG1 via the LFO Mod switch. The Depth control of the LFO can be set to bipolar or unipolar via the Offset switch next to the joystick. In bipolar mode, the LFO depth will rest midway when the LFO is fully attenuated. In uni-polar mode, the LFO depth will rest at zero when the LFO is fully attenuated. While the Pad EG1 LFO Mod is engaged, the Depth control sets the depth of the envelope to the LFO.
PAD ENVELOPES
The two Pad Envelope Generators; EG1, EG2, are velocity sensitive, and are triggered either internally by tapping the unit, or externally via the Pad Input jack. The Pad Input jack was designed to accept any manner of input, but responds best to piezoelectric transducers like the one that is built into the unit. While the Pad Input jack is in use, the internal piezo is disabled. The Pad EG's have independent Decay knobs, and independent Invert switches. The Invert switches invert the response of their respective envelope generator. The Pad Input has a Response control knob to set the sensitivity of the Pad or input. The Response knob can be helpful when inputting stronger or weaker signals from devices such as audio signals or microphonic devices.
OTHER PERIPHERALS
-Built-in speaker.
-Standard Boss style DC adapter
-Master Volume control knob
-Power on/off switch
-1/4 inch output jack
-6xAA battery compartment
GLITCH CAMERAS AND HOW
NTSH BACK IN STOCK
SUZUKI PK-37
Original PK-37 main board |
My schematic |
M112 control main board |
Top side assembled |
Bottom side assembled |
Hole cutting template |
Temporary cardboard faceplate |
Rhythm PCB mounted to hardware board |
Rhythm and accompaniment control section installed |
Temporary faceplates and mini faceplate for Lead section to the right |
Underside view of hardware pass-through holes |
Aligning the panels |
Effects hardware board |
Cut template |
Holes cut |
Cleaned up |
Dry-fit |
Aligning temporary faceplate |
Wiring up LFO rotary switches to modulation destinations |
Bored... |
With... |
These... |
Yet? |
Tucking in |