Tuesday, December 17, 2013

Yoa on Synthesizers Vol. 2

"Why are modular synthesizers so expensive?"

This is a question I get asked pretty much any time after I tell a friend about modulars. Why is a basic VCO $200? Why is a simple mixer $80? Why are mults $50??? There's a simple reason for it. Well, three reasons:

1) Price of parts. A lot of electronics parts are very cheap, often just pennies per unit. Others average about $5 or more. Most modules are built to be high-quality, so panels are thick, jacks are strong, and connections are over-secure. Custom knobs are often employed, as well as silk-screened panels. A normal oscillator, like the Doepfer A-110, costs about $40-$50 to make.

2) Price of design. The real only reason Moog isn't the only modular brand, aside from they moved on, is because other people have different ideas. With this, of course, comes the fact that people should get paid for their time. Often, the people who design electronics for modular synthesizers went to school or have other formal training, and would at least like to make that money back with the skills they learned.

3) Profit. There's no real purpose in running a business if you make no profit. Profit is useful for stuff like, you know, food, and houses, and stuff.

Now, are there some examples of outrageous prices? Of course. Cases in point being anything by Cyndustries and Cwejmann and Modcan and MakeNoise and probably a few other brands. But, then you also have other things, like Apple, that want you to pay $3000 for a computer you'll mostly use for Facebook and cat videos. Or Gibson, who want you to pay $3000 for some wood and metal. But, since they have larger markets and have the same three reasons for their prices as modulars, people buy their products. They still complain about prices, but you also have people who complain about the price of a $1 phone app, which is something I'll never understand.

Am I saying that modulars are cheap? Nope. Am I saying that all prices are now justified? Negative. All I am saying is that usually, there is a reason behind the pricing.

"But why is it I can buy a Minibrute for $500, when that wouldn't buy but three modules?"

It is true that you can get a synthesizer for much cheaper than a modular and be perfectly happy with it. It is also true that, section for section, mainstream synths are cheaper (mainly because they can sell more, but still). But, with most mainstream synthesizers, they have a fixed signal path and few modulators. With a modular, you can design the signal path to be the most crazy, outrageous setup ever. Everything can make sound if you press it hard enough, and everything can modulate and be modulated.

What this means is you get a LOT more out of your $1000 modular than you do with your two $500 Minibrutes. "More bang for your buck" I think is the proper phrase there.

"But I can modify my mainstream synth to have jacks and it will be the same, right?"

If you have the skills and knowledge to modify your instrument with patch points, I say go for it. But, even still you are using what the synth comes with. That means you get that filter, that oscillator, that LFO. Modulars, sure, you can get one type of oscillator, or VCA, or whatever, but you can also get different ones from different people, and they will look, sound, feel, and interact differently. It gets unpredictable, which is usually where the "magic" comes from.

"But it is a lot of work!" or "But I can't save anything I do!"

All I can really say to this is why the **** are you trying to use a synthesizer at all? Yes, it takes half an hour to get your modular in tune, and yes it can take ages to get any sound out of it. No, there are no presets, but you can take pictures or use patch sheets, and you can record the resulting sound. You want easy and presets, either buy a new Moog or go digital. Modulars are about learning and exploration, either you want to do it or you don't. That's what you pay for, the ability to explore.

I'm not sure what the next Yoa on Synthesizers will be, so if you have a topic you want covered, just comment!

Monday, September 2, 2013

Yoa on Synthesizers Vol. 1

"Can't you make the same sounds on any synth?" is a question I get from a lot of people, mainly because most people I know barely know what a synthesizer is. I have already covered that in my 'Synthesis Chronicles' series (which, I know, wasn't the best explanation, but it got the point across), so now I am starting a more general series on one of the more interesting instruments on earth, the synthesizer.

This first installment will focus on the question first posed in this post, "can't you make the same sounds on any synth?" The short answer, as any synthesizer user knows, is no. Due to differences in circuitry (or in the case of digital synthesizers, coding and engine), no two different synthesizers can sound the same. Let's get into more detail, highlighting the main audio components: the oscillator, the filter, and the amplifier. Yup, this'll be a long post.

Before I begin, I would like to note that I am not taking into account various synthesizers that are different by design, but instead keeping it simple by referencing mostly simple subtractive synthesizers (which are by far the most common). FM, Additive, Hybrid, Wavetable, Sampling, and other types of synthesis (I know of about 20 total) will of course have their sonic differences, which are far too great to talk about in one post, and possibly even on one blog. Now, to the content:

Every oscillator is different. Sure, they all have the same general waveforms (saw, square, sine, triangle), but their exact sound is due to exactly how those waveforms are created. Let us look at a few examples of the standard saw wave from different synthesizers:
As you would well imagine, the saw wave we think of is best recreated by the Microkorg. We would expect this because at its core, it is a MIDI-controlled DSP budget synthesizer, and a straight saw wave is much easier to recreate than an analogue waveform (it has a slight curve due to the output circuitry's capacitors). However, Cakewalk's z3ta+ is also digital, however it uses waveshaping as its primary timbral creation technique, so it can more easily recreate capacitor charging, thus the more pronounced curvature. The Roland is also digital, and is still considered a Saw wave despite its odd look. Even looking at the analogue waveforms of the Moog and Oberheim, we can see that they are very un-saw-like, yet still are considered saw waves. Even the half-time saw is very saw-like, even in sound. How can this be? As you probably guessed, they are all very different designs, with different sounds. Now, sadly, I cannot possibly go into the exact makeup of each oscillator and how each part contributes to the sound, so I hope that just seeing these few examples helps you realise the true sonic span of different synthesizers.

Now, let us talk filters. There are a LOT of filter designs out there, each one is different sonically, technically, and, you guessed it, design-wise. In this case I will talk about analogue lowpass filters. I can't really touch digital filters, mainly because I have no real experience with how they work, but I do have experience with analogue filters, so I will talk about those. There are four main filter types that come to mind: RC, Sallen-Key, Transistor Ladder, and Diode Ladder.

Starting with the most basic, an RC filter is just that: a resistor and a capacitor. 
Really, all other filters use this at their core, but in different ways. The standard RC filter has no resonance as there is no feedback path, and is only single-pole. Very, very basic, and not usually used in audio.

Sallen-Key filters are much more advanced filters, containing 2 resistors, 2 capacitors, and an operational amplifier. (don't mind the values)
This type of filter is very popular, namely due to its fairly simple construction, and is 2-pole (aka 12dB/oct), which means you can make much more drastic changes to audio. You can also add resonance by placing an attenuator on the feedback loop. This is the kind of filter used in some Korg, Paia, Roland, and various modular filters, among others. Very, very common.

Transistor Ladder filters are the absolute best-sounding filters you can possibly make. Don't ask why I happen to have original design scans :)
As you can see, transistor ladder filters are far more advanced (thanks Robert Moog!), and even still are very much like RC filters. Each transistor acts as a voltage-controlled variable resistor, and each capacitor is, well, a capacitor. After the first 'rung' of the ladder, each additional rung equals a 6dB/oct filter (the normal Moog ladder is 24dB/oct). Resonance is added much like on a Sallen-Key filter, using the output buffer and an attenuator to the filter input, thus creating a feedback loop. Due to how transistors behave, audio going through it sounds very lush and full. And, since the design hasn't really changed over the years, you can play any modern Moog and hear how it sounds. This kind of filter has been used in Moog (duh), Roland, Arp, and various modular filters, among others.

Lastly, we have the Diode Ladder filter, which is rather unique (another original design scan):
This filter was created by the rather inventive Nyle Steiner. It uses a 'ladder' of diodes and carefully controlled current to make diodes act like variable resistors. This design is also rather flexible in that it can be used for highpass and bandpass filters, as well as lowpass. It has a very unique sound which is very dependent on the kind of diodes you use. Resonance is interesting as well, as it has a fixed feedback path, with resonance amount controlled by varying the gain of the output buffer. This filter is used primarily on Steiner-Parker synthesizers, but it can also be seen in some modules. 

Finally, we are at the amplifier. Really, the timbral aspects of it are very dependent on the components (or code/engine, if we're talking digital) used. However, most amplifiers are controlled in some way, be it voltage or 1's and 0's, and that added circuitry/code makes for additional timbral elements to be introduced. Instead of showing you amplifiers, I will simply tell you to look at various amplifier designs, because (just as with oscillators) there are millions of ways to make them, from analogue OTAs to digital attenuators. 

I hope that this has shed some bit of light onto how synthesizers do vary and how they sound different, despite having similar parts and controls. Next up: "Why are modular synthesizers so expensive?"

Monday, July 29, 2013

Comparators Are Awesome

Ever wonder why people like comparators so much? In various applications they are useful, but being a synth blog, here are some neat ways to use comparators in a synthesizer. BUT FIRST...

~~~WTF is a Comparator?~~~

Simply put, a comparator compares two voltages, an input and a reference voltage. If the input is less than the reference, the comparator will output a voltage near one of its supply voltages. Usually this is performed by an operational amplifier, and the inputs can go in the negative or positive inputs. For our uses, you'll want the reference voltage going to the negative input, and you will want to power the opamp with +-5V.

Now, on to synth uses:

~~~Simple Square Oscillator~~~

You've seen me post about this before, but mate, it's useful. A basic Operational Amplifier oscillator is really a type of feedback-driven Schmitt Trigger. Here is the schematic and output (note that the cap is the general frequency range and the 100k resistor can be varied up or down, I usually use a 1M pot):

~~~Square-Saw-Tri-Ramp-Sine Generator~~~

Now, using the above oscillator, we can derive a few other features using a comparator after an RC lowpass (or highpass, but I'll be using a lowpass) filter. First, filter the output with an RC filter, like this:
The exact resistor value will vary from 10k depending on your frequency range, but make sure you get a generally triangle-like waveform along your whole frequency range. Then, set up a comparator after the filter with a voltage high enough that it only switches near the top of the triangle wave:
And then put another RC filter after that:
You may need an amplifier and DC decoupler stage after this, but once you do you get a saw wave. Now, this section says "Square-Saw-Tri-Ramp-Sine", yet all we have now is square, saw, and triangle. How do we get ramp and sine? Well, one way to get the ramp is to use 2 comparator/filter stages, the second being set to the equal but negative reference voltage as the first. Another is to simply vary the reference voltage, which will sweep the waveform from saw to triangle to ramp (which, by the way, is WICKED FUN).

As for sine, you can simply put a second, low-cutoff filter and amplifier after the triangle wave stage. It won't be perfect, but it will be similar enough for musical purposes... usually. Bear in mind that certain stages may require amplification, decoupling, or buffering, depending on exactly how you process the signals.

~~~Pulse Width/Modulation~~~

I suppose we should start with a couple definitions. Pulse width (also known as duty cycle) is the ratio of time between when a square wave is high or low. For example, a normal square wave is 50% pulse width because half of the time it is high, half of the time it is low. Pulse width modulation is the use of a modulation source to vary the pulse width dynamically.

Now, when I do PWM stuff, I use saw waves for easier control of the pulse width due to having a longer length of wave (from lowest to highest peaks) to work with. For the following pictorial examples I will be using the saw waveform generated using the above generator. All you do is put a comparator (opamp) after it and vary the reference voltage to the comparator.

~~~Unique square waveforms ~~~

If you decide it would be fun to put a comparator on a wavefolder, such as the Lockhart wavefolder, you're in luck. The following image is not mine, however the basic premise is easily replicated:
As you can see, a sine wave (first image) fed into the wavefolder does as you would expect: fold the waveform over itself (second image down) However, adding a comparator to the output (Vref is ground) gives you a unique square waveform. You can alter the reference voltage to get even more unique results, such as PWM. Very fun.

~~~Gate signal from Keyboard/Sequencer~~~

It is always useful to have a gate signal from a keyboard or a sequencer. And, I'm sure you've already figured out how to do it, but if you haven't, it's simple: on the keyboard voltage output, put a comparator referencing ground. If you play legato, you will have a constant gate signal, but if you separate your notes (always a useful thing to learn how to do), you will get a separate gate signal for each note. Cool, huh?


Sometimes, you need a noise gate or similar system. This is also pretty easy to do:
If you follow the schematic, know that I threw in arbitrary values and your needed values will vary. If you don't want to follow the schematic, don't worry. Here's how it works: Audio splits from the input to a VCA and a diode. The diode cuts out the negative voltages from audio. The diode is followed by a lowpass filter, which smooths out the signal, thus making it easier for the comparator to create a stable gate signal. The comparator (Vref is variable as to compensate for noise) outputs a high gate signal when audio passes and a low gate signal when audio is below the reference voltage. That gate signal feeds the VCA, which turns on and off the volume. Yaaay, gater.

Of course, there are more uses than just these. Play around, see what you end up with!

Wednesday, July 17, 2013

Simple ASR

Firstly, THANK YOU! Today this blog broke 18,000 views. That's pretty epic considering what this blog is about. Now on to the subject at hand...

So in my random bout of wanting to solve electronics puzzles at 3am (which I am finding is happening a lot recently), I did something neat and simple: made a simple, no-nonsense ASR envelope generator. I'll give credit where it's due: this is VERY loosely based on not liking how complex Hex Inverter's Postman EG is and thinking of ways to make it simpler. Simple is kinda what we do over here, if you haven't noticed.

Alas, it turns out there aren't many ways to simplify the Postman EG, mainly because it's already a fairly simple device. So instead, I just standardised some values (aka parts I have on hand), removed features that don't really need to be there, and adjusted things to work right with as few parts as possible, yet still giving the features I wanted. So, I came up with this:

Gate in, Attack, Sustain, and Release controls, LED indicator, and normal and inverted outputs. It doesn't get much simpler. And really, you could even ditch the Sustain control, LED, and inverter, and just end up with a REALLY simple AR generator. Or, you could add a manual gate button, maybe a loop function (pretty simple, just put a comparator and inverter at the end and connect that output to the Gate input), whatever you want.

Just bear in mind that this ASR is fairly well tuned, so modifying it may result in you needing to make a few other changes. But, hey, isn't that why we are in the DIY synth gig anyway?

Wednesday, July 10, 2013

Transistor-Output Optocouplers for Voltage Control

I once took apart an old computer monitor (like the ones with CRTs for screens). Among like a thousand other parts, I got 3 Sharp PC123's - that is, transistor-output optocouplers. With a bit of fiddling, I learned that these can be used for voltage control.

If you do not know, this is a transistor-output optocoupler (well, the inside of one):
How it works is this: you apply a current (voltage through a resistor, because resistors are voltage-to-current transformers) to the anode of the LED, and you ground the cathode. This is how you would normally power an LED. The base of the transistor is light-sensitive, and just like applying a voltage to the base of a normal NPN transistor, the collector and emitter act like a directional variable resistor. I say directional because the direction of the voltage going through the transistor has to be moving from collector to emitter (follow the arrow) to properly act as a resistor. I've never had much luck going the other way.

Now, why use this over a normal NPN, or even a FET? Well, mainly because I can never get transistors to work right, but also because optocouplers prevent high voltages from destroying receiving circuit. And, given that you are controlling an LED instead of the ever-so-scary depletion region in transistors, it is far easier to work with.

Before I move on to circuits, I should point something out: my exact opto's (Sharp PC123's) are hard to get your hands on because you either need to get them in a bulk of over 9000 or from older electronics. Thankfully, there is an easier-to-get equivalent: the Fairchild FOD817C (Mouser: 512-FOD817C). It is the EXACT same thing as the PC123 (just compare specs), but you can get them for like $.40 each and can buy as many or few as you want.

Now, on to circuits that allow us to use these optocouplers as voltage-control elements!!!

Here is a test circuit. Vary the input voltage with the pot (100k works best for direct connections to voltage sources), and watch the resistance change on the output side. Be sure to measure with the positive (usually red) probe on the collector side.

Here is a square wave VCO. You can swap out the capacitor to smaller values for higher frequencies; I recommend around 22nF for decent low and high frequency response. This exact circuit is more for LFO speeds. Output is the OpAmp output.

Here's a VCA. You can use smaller values for the input resistor. Note that the maximum gain of the amp is 2, and it has a capacitor on the end to even out any DC offset. Always be sure to put the optocoupler nearest to ground when used as a VCA. You can also do without the opamp stage and just have a voltage-controlled attenuator.

Here is a VCF. Neat thing about this circuit: given the large 1uF capacitor, this lowpass filter actually has some resonance! You can't really control it, though...

There are literally hundreds of different uses for this kind of setup. The above are just a few examples (that just so happen to end up making a full synth: VCO, VCF, VCA). A few things to keep in mind when designing circuits using this form of control:
-The 100k pot can be a CV input as well.
-The optocoupler tends to act the opposite of how you would think: increasing input voltage decreases output resistance. You can use an inverter with a DC offsetter to give you a positive voltage reflecting the opposite of the input.
-NEVER use a negative voltage for the optocoupler's input. You can use a diode facing away from the voltage source to protect from this.
-Using ground as the voltage input may cause problems. This may only be my experience, though.

Happy synth building!

Saturday, June 29, 2013

Modulars and PayPal

The time has come. 

After about a year of dreaming, researching, watching videos, and watching people play modulars at Analog Heaven North East, I will finally be able to enter the modular world myself, starting with the TipTop Audio Tabletop Happy Ending Kit, Blue Lantern Red VCO, and the Xanu Mini-Sequ. I know, it's not much, but I'm like wicked excited. 

I'll probably end up using mostly Xanu modules (mainly because I make them, so may as well use my own modules, right?), but over time I should be able to afford other stuff. I hope. Would love a VCO2RM...

Actually, that reminds me, I am getting ever so close to showing off real Xanu modules. Not CAD drawings, not schematics, the real things. And, once I get this little modular setup, I can show them off, sell them, make money, make more, and maybe after selling like 20 modules I can finally buy a VCO2RM. Or something.

But, you're probably more curious about the second part of this post's title, PayPal. If you look, I've added a Donate button to the sidebar. I know, I know, you're all like, "man youz gotz da zynths n da stuffz wai u need teh moniez??" As I'm sure you know, this world we live in revolves around money, and without it not much can be done. That button will allow you to donate any amount of money to me (even a penny, if you're feeling poor yet charitable), which will help me build more modules, thus both spreading Xanu Modules around the world for your pleasure and allowing me to help pay the bills where I live (synths, audio gear, computers, and lights all cost money to run). Any amount you can donate would be greatly appreciated, and I thank you in advance.

So yeah, I'll tell you when I end up with my little modular n stuff. This is so exciting!! 

Saturday, June 22, 2013

Mad Catz RAT 5 Review


So ever since I got this new Windows 8 machine, I couldn't use my nice (and also wicked old) Wacom Graphire tablet mouse, so I've been using a Logitech M310. Don't get me wrong, that mouse is the toughest mouse I've ever seen and works amazingly, but I decided to step up my game -- literally.

Say hello to my little friend...

So yeah, maybe I went overboard, but it's totally worth it. This is the Mad Catz RAT 5 Professional Gaming Mouse (with random Picasa filters applied in hopes to make it look more epic but instead added random blue stuff). It's kind of a badass:

-Expandable up to 20mm
-4000 DPI max resolution, onboard adjustment
-Weight system (though it weighs 12oz anyway so why bother?)
-Precision Aim button
-3 modes with 6 programmable buttons each
-Horizonal scroll wheel
-Thumb and pinky rests
-High-grip long-range vertical scroll wheel
-Did I cover everything?

First, let's talk about the Precision Aim button: you can program it to be from 0-100% slower than the set resolution. For example, I usually have my DPI set to 1500 x and y, and the Aim to 80%. Thus, when I press this button my DPI goes down to 300, thus making movement slower and making sniping much easier (and if you know me at all, you know that when I can, I ALWAYS go sniper). It can also be programmed to any macro or keypress, if need be.

The two buttons with arrows below them are purely macro/keypress buttons, set out of the box as Internet forwards and backwards. And you can also see the thumbrest, which sticks out a good 1/2" or so, which is an incredible feature to have. I never knew how much drag my thumb had until I got this mouse.

The weight system is something I've yet to actually use, but it is pretty easy: unscrew the back, insert weights from the included weight container, and screw the back back on. Each weight is 6 grams, but the thing weighs 12 ounces on its own so I see no reason to add more.

The expansion system is quite nice. The lever system used is very easy to handle and locks tight, and nearly impossible to accidentally use (it's the little grey button below the rear of the mouse). Sadly, it only adjusts in 5mm increments, but even still it works well. I have mine set to 5mm.

Yes, it is a wired mouse. Yes, it is faster that way. No, it doesn't hurt your game at all. No, it doesn't have a wireless version. Along with the wire, in this view you've got the mode select button (which changes colour depending on which mode you are in), the DPI select rocker switch (pressing on the forward part increases DPI, back part decreases DPI, all the while the LED display on the side changes), and the scroll wheel. The scroll wheel is quite interesting because it has a much longer usable path than most mice, it is very grippy given the rubber sawtooth-like design, and wheel clicks can also trigger a macro/keypress. Most useful wheel in mouse history. Well, except for maybe...

...the horizontal scroll wheel! Yes, I know I already used this pic, but I didn't take a shot of just the wheel. The horizontal wheel has about the same resolution as the main wheel, with one major exception: each click in each direction can be assigned a macro/keypress! To use it as a horizontal scroll wheel, you need to program each side with the keyboard command to horizontally scroll; in Windows' case, CTRL+ALT+LEFT/RIGHT. Otherwise you can just use it as a normal macro/keypress wheel.

Here is the bottom, where you can see that the chassis is indeed aluminum. It also has the usual plastic pads to raise it up, a 4000 DPI laser sensor, and you can also see the weight system a bit more clearly.

It also looks a bit like a Lamborghini :) Not to mention that, like most Lamborghinis, it is REALLY wide. It is not uncomfortably wide, but it is a definite difference, and also feels more stable due to that and its low profile.

And, oddly enough, it is very comfortable, despite its looks. The only comfort issue I have is the rear portion could be lower because I think that extending it to 10mm would be nice, but as with any new mouse I'll probably get used to it. Another thing is that you can't really see the Mode selected unless you put your finger over the button and see what colour it is, which can be hard because two of the mode colours look quite similar. Other than those two issues, I am in love with this mouse. I especially love the price I got it at: a mere $40 on eBay. Not the best deal I've ever grabbed, but still pretty good as they are $70 new.

It eats noobs, it doesn't feel weak and insignificant, it gives you a feeling of empowerment -- oh no, my friends, this is more than a mere mouse... this is *puts on sunglasses* a RAT.

Some of you may wonder how I have it set up, so here it is:
DPI: 1500 x and y on setting 2
Precision Aim: 80%
Mode 1: all default except for above horizontal scrolling setup
Mode 2: designed for AutoCAD, PA is "dimaligned[enter] (aligned dimensioning)", front button is "line[enter] (makes a line)", rear is "pline[enter] (makes a polyline)"
Mode 3: designed for Minecraft, same as Mode 1 except front button is "e (inventory)", rear is [Esc] (menu)"
All 3 modes have full sensitivity

I am thinking of setting up full profile for different programs/games, but that kind of customisation comes with time and use.

Saturday, May 25, 2013


I know I can't be the first person to think of this, but I thought this would make for a neat module idea: use the MIDIMPLANT as a duophonic MIDI-CV converter for a modular synthesizer.

If you don't know, the MIDIMPLANT is a small MIDI-CV device that you can buy. The cool thing about it is that it has two CV outputs as well as two Gate outputs, thus allowing for duophony, among other combinations. And, since any form of polyphony is hard to achieve with any modular synth, it seems to me that this would be an incredible thing to do. Thus, I've planned it all out (this is the 4hp Euro version, but the 5U would be similar):
Pretty simple: MIDI I/O, learn button, and dual CV and Gate outputs. I'm thinking about adding LEDs to the Gate outputs as well. It is also easily powered by the positive bus (as it can handle power up to +15V), and as you can see, the size of MIDI jacks and minijacks just so happen to allow for a rather small MIDI module, which, I should restate, can be DUOPHONIC.

And yes, of course I'm going to say I used MIDIMPLANT on the panel. It's only fair.

If you were curious, this is what the MIDIMPLANT looks like, with pinout:
The device is designed for implanting into old analogue synthesizers so that they are more useful in the modern world. I see no reason why new modulars should be an exception as they are basically doing what older modulars did, just maybe with some newer design decisions and parts.

At the moment is is just an idea as I do not have the parts to build it, but I can imagine this would be useful.

Friday, May 24, 2013

Numark Total Control Customisation

I know, I know, I'm moving more and more away from modulars. You'll just have to wait a bit :)

So I have had the Numark Total Control for about a year and a half or so now (really just a guess, but it's been a while), and I absolutely love everything about it. It's tough, I (almost) never have problems with it, the jog wheels move flawlessly, the knobs and sliders move effortlessly, and its workflow is very nice.
Marketing photo, not my actual unit.
However, recently I had this idea to alter the layout a bit. If nothing else, it is a bit tight, and it could use a fancy new look. The main checklist is as follows:
-install larger wheels (probably lightweight 7" platters for 7" Numark vinyl)
-space out the mixer/EQ section a bit
-make some minor alterations to the placement of each deck's controls and buttons
-of course, make a custom case

I do not know what I will use for platters, but I know that for the top of the platters I want Numark's Ice Blue 7" vinyl, with silver Numark 45 rpm adaptors. All of this will probably simply glue on to the existing jog wheels.
Once for the NS7, now for custom work :)
The case will be a whole different matter. Because I like how it would look, the case will be wood. The actual case will probably be some cheaper strong wood, like maple. But, to make it look cool, first I want to round over the edges, then apply wood veneers to the maple. The sides I know I want to use Zebrawood veneer, just because I love the contrasting grain. The top I want to be some kind of burl veneer, possibly Cedar.
Hey, I think it would look neat.
The only problem with all of this, aside from cost of new materials, is I cannot seem to find a single way to take the Total Control apart so I can see what it would take to do such customisations. I tried removing the rear screws, and found that they were literally not doing anything in the first place. I then removed part of the removable top (it's taped down so I can't get it all without force) and removed what screws I could, and still nothing. Any ideas on how to take this thing apart without damaging the original case too much would be greatly appreciated. I need the original case intact in case I find that I can't do any sort of customisations.

I actually decided to ask Numark how to take the thing apart on Twitter. They referred me to their customer help department, who said this:

"We do not have repair or customization instructions to share, sorry. Although, the screws should be pretty straight forward to get the hardware open. This is not something we will be able to assist you with."

Yeah, sure... well, thanks for replying, at least. It's understandable that they wouldn't want to help anyway.

Now I realise I could save time and get most of the features I want by buying a Numark Mixtrack, but then where's the fun in that?? Besides, I'll have a one-of-a-kind DJ controller. How would that not be cool? Even Kaskade would want one... well, maybe not, but it'll be kinda cool should it be able to be done.

Monday, May 6, 2013

[Gaming] Fallout Radiation

So currently I am playing Fallout 3. I was playing Fallout New Vegas, but made some irreversible decisions and ragequit due to conflicting quests (lol). One thing I love about the Fallout series is the realism: real locations, real possible landscape (given a worldwide nuclear war, of course), real weaponry, et cetera. 

However, today I decided to do a bit of research into how Radiation works in the Fallout series. In reality, nuclear radiation is a real condition, and there is a lot you can read about it online. However, I also noticed some interesting discrepancies between reality and Fallout radiation poisoning, and thought I would share my findings. *Warning* This post is sorta kinda long and has no pictures to break it up. However, it is written to be somewhat friendly with a few poor jokes. 


To start, I'm just a lowly gamer/amateur electronics engineer, so what is stated below may not be entirely factual. It is based on various accounts and medical articles that I found online. Still, an interesting read nonetheless.

In Fallout, the smallest unit for measuring radiation is the rad. This has since been replaced with the Gray (Gy), but for our purposes know that 1 rad = 0.01 Gy. Also know that the maximum amount of radiation you can receive in Fallout is 1000 rads, or 10 Gy. After that, your character dies (thankfully I have no experience in doing so) (Edit: yes I do. Vault 87. 473 rads/second). 

First, let's look at the maximum radiation level versus the amount of time it usually takes to attain such a level. Unless you decide to stand in certain places, the most radiation you will tend to get is 1 rad per second, only around somewhat irradiated objects. Eating irradiated food tends to add to that, usually around 6 rads for one second. With how I play, I tend to get to 100 rads in about 3 in-game days (I eat a lot of irradiated food, yay me!). Using that, it would take about a month for me to die of radiation poisoning, without treatment. 

Also note the various levels of radiation sickness, which occur at 250, 500, and 750 rads. These occur despite how long it took you to attain such radiation. 

In reality, things are a bit different. Less than 100 rads, even attained immediately, will typically produce no immediate symptoms other than minor blood changes. 100 to 200 rads, even delivered in less than a day, will only cause acute radiation syndrome (generally just feeling sick and later weak), but is usually not fatal. 200 to 1,000 rads delivered in a few hours (which, if you manage that, I think you're in the wrong place) will cause serious illness (fever, headache, vomiting, disorientation, weakness) with a poor outlook on the future at the upper end of the range. Doses of more than 1,000 rads are almost invariably fatal, and are usually prefaced with the aforementioned illnesses as well as hair loss, internal bleeding, low blood pressure and slow healing times for wounds. 

As you can see, if you're in the wrong place and get irradiated fairly quickly, Fallout can easily mimic reality. But, since we already determined that radiation in Fallout can be administered rather slowly, it is interesting to note how the real human body reacts to high amounts of radiation in very small doses:

10 Gy = moderate redness of skin

25 Gy = ulcers with slow healing time
100 Gy = severe, quick redness of the skin, blisters/skin breakdown (in Fallout, this is part of ghoulification, see below) in 1-2 weeks, and death in 1-3 weeks.

So, in smaller doses, you can actually take TEN TIMES more radiation in reality than you can in the game. But, then you'll get called a zombie, be banished to the Underworld, be hated by most everyone... at least you'll be friends with any Super Mutants you happen upon! By the way, it's impossible for a human to become a Super Mutant. Sorry. No real-life Hulk for you. Oh, and by the time you undergo Ghoulification, you'll probably be dead. So uh... don't try that.

It's also interesting to note that your character can't actually become a ghoul simply by taking a lot of radiation. This is actually a fairly popular topic among Fallout forums, and it seems no one can quite figure out how anyone could become a ghoul. Here is what I think:

It can be assumed that Fallout Ghouls were initially affected by the atomic bombs dropping, but were able to get to safety soon enough they they did not die immediately. However, the initial nuclear heat and slow rate of radiation caused their skin to dry and flake at the ulcer/breakdown point, thus keeping their flesh from rotting more. Hence, they look half-rotted. Now, how they can live as long as they do, that I do not understand. 

Now that we have covered radiation, how about curing it?

In the Fallout series, there are two forms of radiation medicine: Rad-X and Rad-Away. Rad-X is the equivalent of Potassium Iodide, which fills most of your thyroid with non-radioactive iodine, blocking radioiodine, which is radioactive iodine. However, you are still able to be irradiated via the rest of your body. This treatment can be done in reality by simply drinking or swallowing a pill of Potassium Iodide.

Rad-Away is a bit more interesting. In reality, a protein called "granulocyte colony-stimulating factor", which promotes the growth of white blood cells, can negate radiation sickness on bone marrow. Treatment with this protein-based medication increases white blood cell production, which of course helps in the whole "healing" and "removing some impurities" functions of the body. However, in the various Fallouts you tend to get shot at, so it can be assumed that Rad-Away also contains replacement blood cells. I say this because bone marrow generates blood cells, and if it is damaged your body cannot heal properly. 

However, both the blood transfusion and protein treatment are rather difficult for most people to do successfully, so we can all assume that despite their numerical values, all Fallout player characters have a decent Medicine skill. 

So, yeah. That's all I've got on the subject. Interesting to me anyway! Comment and let me know your thoughts on it!

(And yes, in all this research I did indeed grab a few samples of Geiger Counters. No idea what I will do with them. I also researched the oscillator within said devices and will probably find an interesting way to use it.)

Sunday, May 5, 2013

AHNE 2013

So I went to this thing called Analogue Heaven North East 2013. It's basically a giant synth-meet, and dear god it was heaven. Here's my pics, as a FB album:

Album of holy gloriousness 

I don't think I need to say it, but it was kinda awesome. I'll upload a YT vid later.

Monday, April 22, 2013

Awesome Free Virtual Synthesizers

Now, look, I have like 5,000+ virtual synthesizers (mostly being the random stuff that came with Ableton Live that you can't really do much altering with) but of the plugins I have, there are certain ones that stick out. Obviously Korg's Legacy Collection is incredible. Arturia makes awesome stuff. Native Instruments is industry-leading. But, these are all paid instruments, and if you're like me and working on a budget, you need good sounding free synths.

Free plus good sound usually doesn't work, I know, but there are some that really stand out. Here's my top 12 list in no particular order:

1) Elektrostudio's instruments
Elektrostudio is quite possibly my favourite VST company. All of their instruments model old analogues, like the Minimoog, Moog Sonic Six, Micromoog, Arp Odyssey, Oberheim 2-voice, and the Roland Junos, along with a few others. They all sound great, and model nearly exactly the originals, with a few quirks that you might expect from digital free synths. I really can't stress enough how amazing their stuff is.

2) HERCs Abakos
I don't know what it is with this instrument, but it does the most incredible soundscapes and pads I have ever heard, even trumping giant analogue modulars and certainly any paid softsynth.
http://www.vst4free.com/free_vst.php?id=399 (actual site is under construction, so this is a DL page)

3) Angular Momentum Wavedraw Free
This thing is perfect at everything, mainly because by design it can do everything. It's basically a sampler, but the samples can be drawn waveforms! It uses that sample like a normal oscillator, so you can do all the normal stuff with that, but then it turns into an incredible complete synthesizer with interesting routing and modulation capabilities. AM makes some other neat instruments that I use, as well.

This is another free VST company that sounds AMAZING. They cover literally every need, for every genre, ever. I personally use DSK Choir the most, mainly because I don't have many good choir synths. Actually, I don't have any minus this one. If that doesn't show how specialised DSK is, nothing will.

5) Ugo
This is more of a VST company post, isn't it? Well, Ugo is yet another VST company that sounds great, but they are different in that no one else makes anything close to what they make. I particularly love their Element of Surprise, which guaranteed WILL give you sounds you've never heard. Just shows that limitation can be a good thing. I also use their Texture and Rez (both great for crazy leads, insane basses, and utter dirty sounds), and String Theory and M-theory, which are beautiful pizzicato synthesizers.

6) GTG
GTG makes a lot of neat stuff. Most of it is normally laid out, but they all have a very unique sound that I personally love. It's not all synths, either; the GTG EP 2008 is an incredible electric piano which sounds almost as good as my DX7. Almost.

7) Kamiooka
You love modular synths? You love them so much you want to make your own? YOU LOVE THEM SO MUCH YOU DREAM OF WIRES??? (lol get the reference?) Well, Kamiooka is for you. It's a fairly simple fully modular synthesizer with a possible total of 10 modules. It has all the normal modules: VCO, VCA, VCF, ADSR, LFO, Sequencer, and a combination RM/Noise/SnH/Inverter. Nonetheless, you'll be patching your way to modular bliss for HOURS. In my case, when I first got it, 14 hours and 37 minutes. No breaks.

8) SP-1000 and Blue Synth
Ok, I'm a bit biased with these two instruments. If you have been with this blog for some time, you'll know that I worked on these two instruments. Search around here, you'll see what I think of them :) Blue is free, SP-1000 is only a demo, but you can buy it for $30 (though if you hit me up we can possibly work out a deal). I worked on the presets and some of the sonic and design ideas for both of these, so you know that they sound at least decent for their architecture.

9) Tal-U-No-LX
Along with all the other awesome stuff Togu Audio Line makes, this Juno emulation is just awesome. It sounds like a Juno 106, including all the little idiosyncrasies that exist in the real one. Note that even though there's a buy button, you don't need to buy it to use it. I don't know why that button is there. There's no limitations that I can find, though as you'll see in the next section I have my own ways of dealing with such things :)

10) Muon Tau Bassline (now Tau Bassline 10th Anniversary)
If you're looking for a 303-like sound, scroll down. If you're looking for something like a 303 but different, look no further. Though Tau sounds pretty much nothing like the TB-303 it appears to try to model, it is really good at synthesising bass guitars and other general bass sounds. And, I guess, if you must, you can use it as a fake 303.

11) TS-808
Along with a 303-like synth, who doesn't like an 808-like synth for accompaniment? The TS-808 sounds kinda like a TR-808, but you certainly won't fool anyone into thinking you used a real 808. Still, it's useful :)

12) Gunnar Ekornas' Minimogue va
You know this was going to be on the list. This was my first-ever synthesizer, and to this day is one of my favourites (considering it's in this list). It's basically a model of a Minimoog, but with far advanced features, like a dedicated LFO, arpeggiator, delay, and full ADSRs. And, of course, it has a great sound which is unlike a Minimoog but also unlike a cheap Synthedit knockoff. I fking love this instrument.

Now, there are also some not-so-free synths (infinite demos and the like) that I really love, and will now list here:

1) Native Instruments Massive and FM8
I know, these are normally $200 each, but if you are like me and enjoy meddling with technicalities, they're free. No, I'm not saying to hack them. The way these demo versions work is you can't save presets and it only works for 30 minutes at a time. BUT, if you use Ableton Live (or I'd assume most other DAWs), I found that you can reset this timer simply by activating another track. AND, Live has it's own preset save feature, which I found can work with both Massive and FM8. So basically two of the most powerful synths in the industry are free, as long as you need to work on other tracks within 30 minutes :)
I really don't need to talk about sound with these two instruments because if you've heard just about any harder genre electronic or modern metal music, you've heard them. Modern dubstep certainly makes good use of them.

2) Arturia Moog Modular V
This sort of uses the same principles as the NI stuff. It has the added benefit of essentially being a Moog product, as it was produced in conjunction with Robert Moog. Does it sound like a Moog modular? Yes. Does it work like a Moog modular? No. For whatever reason, Arturia makes use of patch bays and preset interconnections. You can't use it like a real modular, but it's the closest you'll get without paying several dozen grand for a similar system.

3) Audio Realism ABL2
I like all of AR's stuff, but I once heard Joel Zimmerman do a side-by-side of the ABL2 and a real TB-303, and they are IDENTICAL, minus decay times. Just don't use the built-in distortion. Please. This is also a demo, but seems to use the same track-switching rule as the above.

4) Native Instruments Reaktor and Kontakt
Now these really are free, but I included them here because to get much interesting out of them you do need to buy stuff. The free versions do sound good and are useful out of the box (er, .zip), though.

Classic synths are always trying to be replicated in software, usually with little success. Aside from what I've already mentioned, here are a few good classic synths in VST form (again, free stuff!):

1) Cynthia
Know what an EMS Synthi is? No? Well it's basically this really expensive, incredibly hard to use modular synthesizer. Cynthia is the same deal, but if you're up to the challenge it's an incredible free synth.

2) daHornet
The EDP Wasp was a very unique synthesizer, using an electro-static keyboard, pre-MIDI connectors, and was a hybrid subtractive synth. Pretty amazing for the time. daHornet is very similar in sound and function, though not quite as technologically impressive for its time :)

3) Voltkitchen Arppe 2600 va
I don't even need to talk about the Arp 2600, do I? Didn't think so. VK did a decent job with it, though the Xeno Digipatch system is kind of a pain to use. Sounds good, though.

4) ME-80
You like the CS-80? Well, here's your lucky day. The ME-80 has all the same functions as the CS-80 a somewhat similar sound, and of course DrIfTiNeSs!!! Yes, this thing has oscillators that drift EVEN MORE than the original, if you can believe it. It can be controlled somewhat, though, and no matter what it's fun to play with, especially if you don't have $15k to spend on a real CS-80.
As a side note, Messiah and Memorymoon (from the same site) are also pretty amazing replicas of the Memorymoog and the Prophet. I use those too.

5) Syncersoft Polivoks Station
The Russian Polivoks is incredible. The Syncersoft Polivoks Station is slightly less awesome mainly because it looks totally different, but the sound is raw Polivoks power (note: not a sampler, it just sounds similar) Mother Russia FTW. It also adds a few features which make it even thicker and more raw-sounding.

So, there you have it. This list pretty much makes up the majority of the VST synthesizers I use, minus some of the more random ones which I only use for their overly-complicated synthesis engines and ability to create highly advanced wave-sequenced sounds. Maybe I'll blog about those later.

I should also note that your DAW's built-in synthesizers (like Live's Simpler or FL's Harmless) can also be incredibly powerful if you just sit down and learn them. That's an important fact, here: just because I've listed a bunch of instruments, it doesn't mean that you don't need to learn synthesis. If anything, you should learn at least basic subtractive synthesis to near-perfection before getting any of these. Otherwise we'll have a Soviet Russia deal:

In Soviet Russia, synth plays YOU!

And we don't want that, now do we?

Oh, and one final note: I wasn't paid or otherwise asked to talk about any of these. They really are part of my personal collection, and I really do use them in my songs. Granted, my DX7 sees most of my synthesis action (it's just so damned versatile), but I do occasionally use VSTs, mainly these.

I hope you try a few of these at least, and I really hope you like them as much as I do.

Friday, March 29, 2013

Gabotronics XMEGA Xminilab Review

So I know my last post was about oscilloscopes and I never like to post about the same thing twice, BUT I received an oscilloscope today, messed with it, and may as well blog about it since that's kinda what I do aside from Tweet and Post. I should put "compulsive tech/music/electronics blogger" on my resume...

So I decided to show my dad Gabotronics' line of oscilloscopes. Given its price and incredible functionality, he not only got me their Xminilab but also all its accessories: programming header, jumper leads, USB cable, and carrying case. Dare I say, it's one of the best oscilloscopes I've seen.
Before I go much further, I should point out that the USB cable is mainly for powering the unit, though it can be powered via +5V to one of its pins. It's not a USB-centric oscilloscope, however you can export data from the oscilloscope to your computer via USB.
So when I got it into my studio, I slowly unpacked it and pretty much basked in the fact that I finally had a working oscilloscope. Oh, and had Deadmau5 blasting at a decent volume (did I mention I recently sold some random gold and bought some KRK monitors? I didn't? Well there ya go.).
I opened the manual, and one of the first things I saw was the pinout. "Well," I said, "I may as well grab a breadboard to put this on." I then proceeded to use the jumpers to connect grounds to my PSU's ground and use them like permanent probes for the 2 analogue inputs, waveform generator output, and External input.
Without referencing the rest of the manual, I connected the first channel to the output of this simple oscillator circuit (which is indeed my simple op-amp based square wave oscillator with a 1Mohm pot for controlling frequency):
At the time I also had a couple filters after it, so I was messing with those as well. It has nearly all the functionality of more expensive units, including vast zoom capabilities, which is great for either reading idiosyncrasies of even high-frequency audio waveforms or watching LFO's operate (which is quite fun, if you've seen some of the LFO's I've created). This is the oscillator's output:
While playing with the various controls (which are laid out very much like an 80's button-job synthesizer), I noticed the manual stated there was an automatic setup feature. I had already set up the oscilloscope just using my mostly-basic knowledge of oscilloscopes, but because I was curious I tried it. Turn the 'scope on, patch the waveform generator to the channel input and hold K1 (the left-most tactile switch). The result was a super fast waveform scrolling by with no triggering. I reset it so I could actually see the waveform, and got rid of the second channel for clarity:
Nice screen, eh? And as you can probably tell, the screen is highly visible from almost any angle. Which is good, because I can't really take much of a top-down shot. Don't let the small screen scare you; it's very easy to read, and unless you're measuring the idiosyncrasies of noise, the relatively poor resolution is perfect.

Another good thing about this oscilloscope is how the controls are laid out. If you've ever used an 80's button-job synth, or just know how to push buttons in various sequences for a final output, then you will be familiar with using this oscilloscope. Would I prefer per-function knobs? Of course. But, Gabotronics was very smart in their menu layout, and everything is easy to access and figure out. They even have various diagrams of how menus work in the manual!
I've really only had a couple hours with this oscilloscope so far, but I can tell that it will be incredibly useful in making sure my designs work. Everything from voltage measurement, frequency counting, spectral analysis, outputting test waveforms, and of course being an oscilloscope, and I will probably use every single function multiple times a day.

I didn't go through everything it can do, mainly because Gabotronics laid that out better than I could:

So, for around $80 for the Xminilab, including all accessories, you can have all this amazing functionality in a rather small footprint (as you saw, I'm just using a small breadboard, but you could easily have it hanging off the side of a breadboard, or even make a little case for it).

In my opinion, it couldn't have been better.
PS: my apologies, my last computer crashed and now I have a new one (also courtesy of my loving father; damn I owe him a lot), but I don't have Photoshop on it yet so the pictures aren't all pretty n stuff. They looked fine on my camera's screen...

Thursday, March 21, 2013

Finding an Oscilloscope

One of the most important tools a synthesist (or synthesizer builder) can have is an oscilloscope. The only problem is that these are either costly or problematic - well, unless you do a bit o' interwebz searching.

If you don't know, a while back I got this Heathkit Oscilloscope from my dad, who got it from eBay.
The seller said it worked, and it had an image showing it working. As it turns out, all it does is power on (aka not explode when you turn it on). No display, no waveforms. I've checked it over, measuring resistances, capacitances, and so forth, and the only issue is that one of the tubes doesn't light up. Normally, this isn't an issue, except that tube just so happens to be a rare Russian tube that hasn't been made for like 50 years and now, if you can find one, will run you at least $60, which is more than the whole unit cost.

So, I certainly can't fix it, and don't want to find someone to see if they can fix it because they probably cost a lot as well, and can probably get a whole oscilloscope for the price of that one tube which may or may not repair this oscilloscope. Thus, I've done some research and found two things that are incredibly useful in my search: eBay, and Gabotronics.

Let's start with Gabotronics. Among other stuff, they make the world's smallest yet most powerful oscilloscopes. They have various models, but the two I like are the XMEGA Xprotolab and the XMEGA Xminilab. They are cheap ($60 and $80, respectfully), have way more functionality than I'll ever use, but are small and digital. Digital isn't so much a problem except that it means pixels, which means slightly less precise waveforms. Small really just means you'll be using the zoom functions a fair bit.

eBay, of course, is a good place to find cheap stuff. This is true also for oscilloscopes. I had to do a fair bit of filtering, but eventually found a bunch of oscilloscopes for less than $100. By this point you have to really look at the descriptions. Since I've had bad luck with the old Heathkit, I'm pretty much staying away from anything that remotely says it might not work. After that, I just add everything to my watch list and hope they stay affordable!

PC oscilloscope software obviously exists; in fact, I use Visual Analyser 2011 for looking at synth waveforms in my studio. My thing with software oscilloscopes is that you either need an interface or some kind of current and voltage limiting. Most computers don't like raw analogue synth outputs. There are many ways around this, sure, but then you have the problem where my computer is in a totally different room and I really can't move it much. Then, of course, name a computer that doesn't have noisy audio that's actually affordable. I pretty much stay away from using software 'scopes, as you can imagine.

Now, I just need to wait for an affordable oscilloscope to come around (or buy a Gabotronics one) and figure out what to do with my Heathkit. Maybe put it back on eBay. Or, maybe just sell various tubes from it. Or do nothing. I don't really know. I mean, it looks cool, but I'm not a huge fan of giant nonfunctional decor from the 50's.

All while trying to start a company. Where's this supposed "suitcase with $1M in it" I hear about sometimes? Could really use that.

Sunday, March 17, 2013

Stuff n' Stuff

Rapid fire updates, here we go!

I Wub Yew
So my debut album, I Wub Yew, is bound to go to international stores within the next few weeks. The album cover is 90% finished, I've actually added a new song to the tracklist (which I may have uploaded to Soundcloud and is being somewhat popular), and then I need to upload everything to my distributor and give them cash. After that, it's about 2 weeks until you see it in online stores all around the world, and physically through Amazon.

Xanu Modular
The Xanu modular is now stuck at revision 1, meaning that the panel designs and schematics are going to be considered 1st generation. It's in both 3U and 5U formats for now, but of course, custom work is no issue.
And, the good news is I may have a potential start to this whole thing with *drumroll* a sequencer:
No promises, of course, but it looks good.

I can't safely go this week or next without talking about Ultra. If you don't know, I'm talking about the Ultra Music Festival, a two-weekend electronic music event which stars all the biggest names in the industry for a giant rave in Miami, FL. Fking incredible event, really. I can't go, but thankfully they've been livestreaming the whole show on their YouTube page, so I get to see the show with degraded audio but better views!

And, of course, I really can't go much further without talking about the 2nd day closer show. Three words: Deadmau5, epic, and fireworks. Despite the 7 times he trainwrecked epically (that's DJ-talk for being out-of-time), it was an incredible show, both musically and visually. I mean, fireworks. Name a mouse who's had fireworks behind him. Exactly, you can't. Mainly because Deadmau5 is a human, but whatever.
Sadly, I'm only catching a few sets at a time, and today a bunch of acts played that I really wanted to see, but oddly enough reality has prevalence over being high off music. C'est la vie.

If you know me at all you know I'm big on gear. I have an idea to have a semi-public museum of synthesizers, guitars, orchestral instruments - a ton of neat stuff. Yesterday I got to play a really undervalued vintage synth, the Roland JX-8P. Analogue goodness with DCO's, it plays like a dream, sounds like a dream, and was a mere $200! I totally want it, even if it doesn't fully function (aftertouch and LFO bender don't seem to function):
Also, I'm still on the lookout for a pair of direct-drive turntables. Tomorrow I'll be going out to various thrift stores and such. I've only seen two turntables in places like that: one was a fancy cabinet model, and the other was pretty beat. I'm about as pre-addicted to turntablism as I am modular synthesis. Let's hope for the best!

I didn't grab a pic of it, but I finally got to play Casio's XW-P1. I was really hoping Casio had redeemed itself with this, but in fact it's just as bad as their standard "cheap keyboard" scheme. Don't get me wrong, it is musical and can sound good, but good GOD it's built like a piece of paper, has a pretty crappy interface, and it is literally the most digital-sounding synthesizer I have ever heard. What the actual fk, Casio. I was hoping I would want more from you than this little VL-Tone I have. I still want to have a few hours alone with it, but in the 20 minutes I spent with it, that's my verdict.

Ok, I think that's about it. I guess I'll see you next on iTunes, unless something else interesting pops up!

Saturday, March 2, 2013

First Xanu Module EVAR: The Xanu Delay

Before I get started, I'd like to quote an earlier post:
"Q: If you plan to turn this into a company, why do you post all of your schematics and explain how they work?
A: Why not? I mean, I technically own all of my designs, therefore I should be able to use them however I'd like. If you think about it, I'm just saving you time. You can go online and see the PCBs of any module, and you can look at the connections and build one yourself. I'm just saving you some time."

Ok, now, onwards to the subject.

I recently was talking about a module idea I had, a digital delay. Well, after figuring it out a bit and submitting the idea to Muff Wiggler, I'm ready to post a little more about it. It seems like it could be a rather successful delay.

First, general circuit design. What I can post isn't much because the actual delay circuit is rather large and I don't feel like drawing it, but you can get a general idea:
Click to make it larger. Something you may notice is how strangely the delay time is controlled. I used a FET in place of the actual time resistor, which means several things: VC is easy, delay time can be INSANELY long (given the FET is pushed to its limits), and it's really the only way I could have made it VC given the delay line I'm using (PT2399's). The problem with using FETs is that, to use them as resistors, you need to apply a negative voltage to the Gate (hence the inverter). Positively biasing them for a long time may make them melt, and it won't act as a resistor (well, technically when it melts it'll be a resistor of nearly infinite resistance and thus really long delay times, but whatever).

Enough technical stuff. Let's move on to ALL THOSE FREAKING ATTENUATORS WTF. Yeah, so there might be a few attenuators, but it's for a good reason. It means you can mix various signals very precisely and get a ton of different delays. And, given the somewhat high-gain output amp (gain of 11), there can be no volume loss by the end of the chain. You'll also note the input attenuator (the fixed resistors). That's useful because modular signals are typically pretty hot (high-ish voltage) and could probably very easily burn out the delay chip as well as clip through the output amp.

You also have the delay time manual control. This is actually just an attenuator lowering the voltage of the main power source to the FET. The delay time circuit also has a switched jack, so you can use manual delay time or control it via an external voltage. And, as a final note, You'll note that there is a Range rheostat on the same line as the FET. This isn't exactly necessary and could easily be replaced with just a 1k resistor (it needs some resistance), but including the Range control allows finer control on the delay time, which is good for manually syncing it with some kind of clock source. If I figure out how to automatically sync it with a clock, I'll let you know.

Now that that's generally explained, here's the front panel:
It's pretty basic, like most of my designs. But I did label this one and add lines on the knobs. Makes it more awesomer n stuff. The two outputs are exactly identical, I guess just because most people use Delays at the end of their signal chain and it makes it easy to interface with outbound gear. I may make it just mono, though, I dunno. I also grouped things: time controls on top, audio controls on bottom. I may move the Time-CV input to the bottom, though.

Input volume (input signal volume)
Output volume (total effect volume)
Feedback (literally feeds delay signal back through the delay)
Original (volume of input)
Delay (volume of delay, 0% bypasses delay circuit)
Time (delay time within range)
Range (sets max delay time)
CV amount (controls how much incoming CV controls delay Time)

CMOS-based with HQ AD and DA converters
less than -90dB noise
less than .5% THD
44kHz sample rate
Max delay time: ~2 seconds (guessing, will probably be more via the FET)
~15mm deep, will have to check when it's done
currently unknown current draw, but I doubt it's much.

Now, the bad part: everything works perfectly... except the actual delay circuit. It does delay, which is kinda expected, but for whatever reason you can hear the internal VCO and it has constant feedback. So basically it's a constant rhythmic noise source. I blame cats. But, this is more likely due to not having EXACTLY the right parts (digital circuits are so picky), so when I get/find the right parts I'll remake it and try again. I mean, who seriously just has 3900pF, 590pF, and .082uF caps on hand, let alone random resistor values? Though I did just get my Futurlec shipment in (finally), so maybe they're in there.
Now, bear in mind I can't make it or sell it RIGHT NOW, because I still need a few materials (12hp faceplate, jacks, knobs, etc.), but it generally works. I just need to fine-tune it a bit.

Neat fact: I'm literally only using this delay chip because Korg used it in their monotron Delay. And, I mean, it's made by Princeton Tech and has very few external parts compared to other delay lines. You really can't beat that. And before you ask, no, I'm not going to use BBDs and make it analogue, although the general principles can apply. I've never seen them have very long delay times (usually less than 1 second) and they cost a LOT more -- these were like $8 for 20 chips. BBDs are $8 for ONE.