Saturday, February 23, 2013

Triple Fiver Update

So remember way back when I had this idea for a really neat drone synthesizer? Well I've made a few useful additions to it.

The first change is, for each oscillator, I added an attenuator and on/off switch. This is useful for mixing your oscillators together, and makes it more like what it's based on, the Sleepdrone 3.

The second change is I changed the amplifiers to be Op-Amp based. Using LM386's is fun, sure, but they take up more room due to more parts and they cost more. The distortion is still using a 386, though. I could get around that as well, but I have no real reason to.

The third change is a little stranger, though. If you forgot, the Triple Fiver is named such because it used three LM555's as oscillators (ok, really a 555 and 556, but whatever). I decided, using my now-expanded knowledge of electronics, to use Op-Amp-based oscillators, like this:
I did this for several reasons:
1) the pulse width with stay around 50%, whereas 555's vary greatly with frequency
2) the voltage output will be far less (around 6Vp-p), which is perfect/safe for using it with outbound gear like modulars or mixers
3) the 0-9V signal of a 555 was getting oddly offset by the filter's Op-Amp design
4) still a wide frequency range (2Hz to ~10kHz, easily adjustable with a cap swap)
5) FAR less parts

You may be asking how I can use less parts with these changes. The answer is simple: TL084, TL082, LM386. Yes, 'tis true, I have halved the number of ICs from 6. Now, granted, I don't have any 084's right now, but since this first one will merely be a prototype I think I can get by with using 3 082's, which I do have.

This also means I can use half the board space, which will be useful because I could then use the other half for other projects! The actual synth will still be large, though, because it has a lot of controls n such. Just like all good synths should!

I will still call it the Triple Fiver, just because I can't think of anything much better, and for historical accuracy :) One neat thing, though: the filter, as you may recall, is a parallel lowpass and highpass. I never really thought of it until today, but it's capable of creating a phaser-like effect if you separate the cutoff frequencies and move each cutoff knob an equal amount up and down. I simulated this with my MicroKORG today. Very neat effect, especially for a drone synth.

I think I will build this new version as much as I can (c'mon Futurlec...) tomorrow and test it out. The individual parts work alone, but how will they work in series?

Wednesday, February 20, 2013

Modular: Reborn!

So I apparently have great ideas.

I've been working on a few new module ideas for when Analogue Haven gets back to me on when they'll have certain parts back in stock. I won't share these new designs in detail here for a couple reasons, mainly the fact that I never post details about things that may or may not work.

That said, here are two of the neater ideas:

1) Mini-Sequ: this is a small (12hp) 8-step sequencer very much like my full-sized one, minus internal clocking and a few other functions. What's interesting is that I kept per-step reset/on/off switching, added a clock-thru system (basically acts as a mult for the input clock so you can use it for other things as well), and still have transposing and 5th-step gating. It also has the standard clock and reset ins and CV and Gate outs.
2) Digi-Delay: This is a digital delay, which seems to be pretty unique in itself in this modular world, but just about every control on it is very unique: Input volume, Range (max delay time), Delay Time, Delay Time CV, Effect Volume, Signal Thru Volume, Feedback, and Overall Volume. Some of those are unique in that they don't do what you'd think. Feedback, for example, is a literal feedback, taking the delayed signal and inputting it back into the delay.

The interesting part is when I went to Eurorackdb, the ultimate database for all Eurorack modules ever made and to be made.

I looked at miniature sequencers, and found that mine is very unique because it does a lot more than any of the ones on the market, yet will probably be cheaper than most, if not all, other sequencers.

Then, I looked at delays. That's where I found mine would both stick out and be boring. Apparently modular delays are really, REALLY arbitrary when it comes to functionality. They all have a rate control which is voltage-controlled; EVERYTHING  else is totally unique to everyone. However, I can say that mine is kinda like a combo of three or four delay modules, but oddly enough is a totally original design.

When I prove that these designs work, I'll post more about them, but given how unique they are I might keep them partially a mystery. Seriously considering selling my modules, not just because of these, but also because a lot of my modules are rather unique compared to similar modules on the market.

Just thought this was interesting :)

Yoa Answers Your DIY Questions!

I've been asked a few questions about my designs and synth DIY, so I'll answer:

Q: Do these work? I see a lot of schematics and graphs, but virtual isn't physical.
A: Yes, everything I have talked about works - I test them on a breadboard before posting about them. Building them virtually both makes it easier to see waveforms and schematics, and lets you spot problems before blowing up something.

Q: How do I make a nice, easy, simple bi-polar (+ and -) power supply?
A: An easy way to make your own bi-polar power supply is to use a wall-wart (aka those black boxes you plug into the wall) power adaptor that outputs twice the voltage you need (for me, since I use 9V designs, I'd get an 18V adaptor), then use this:
One thing to note is that, though virtual ground is mathematically 0V and will work in physical designs, I've never tried connecting it to a real ground, like on the wall-wart or an actual ground. It's safest to keep it like that, trust me. The capacitors are also just for safety, but may possibly cause problems. Just the resistors will suffice. Oh, and you can technically use other values, but I've found that this creates the cleanest power. 

Q: In your oscillator, you use a lowpass filter to get a saw wave. Does this really work?
A: Yes, but only in a certain frequency range. And it doesn't make a true saw wave, either. I need to figure out a better way to do this. 

Q: How do you read a schematic?
A: Sadly, there are a lot of ways to answer this because everyone uses a slightly different scheme. In general, go to Google and type in "Schematic Symbols". But, for the lazy, here's a good starting place: 

Q: I need a positive AND negative square waveform. How?
A: I had this problem after finding that the 0-9V signal of a 555 was getting oddly offset. What I use now is this (click the image if it shows up black):
I recommend a 1uF capacitor, a 1M rheostat for the upper resistor, and two 10k resistors on the bottom, if you want to make an audio oscillator. Change the capacitor to change the range. And, of course, power the opamp properly.

Q: Should I learn electronics before making stuff?
A: Yes and no. I started building knowing nearly nothing and learned on the way. I learned how to read a schematic and how to breadboard, and learned what circuits did. What I do now is use various basic circuits together to create interesting stuff. But, I do recommend you read about electronics while you build. Here are a few good resources:
Electronics Point - my preferred electronics forum.
Muff Wiggler's DIY Section - Muff Wiggler is a modular synth forum. This is their DIY section. 
Ton o' Schematics - (it's not literally called that) A ton of schematics are here, everything from guitar effects to synth stuff. Not all of it works, though that's pretty normal for free online schematics.
The Art of Electronics - This is my personal copy of The Art of Electronics by Horowitz and W. Hill. It basically is a textbook that explains all the basics of electronics, and several useful circuits. 

You'll find a LOT more stuff on teh interwebz and maybe in local bookstores and such. A good thing to do is to keep a well-organised library of schematics, ideas, pdf books, et cetera. I do. 

Q: Where do I get parts?
A: Most parts (including knobs, jacks, perfboards, and the like) can be had at your local Radioshack or other electronics store. If they don't have what you need or you don't have such a store, I prefer Mouser Electronics for parts. You can also use Futurlec, but they are VERY slow with delivery (so far it's been 5 weeks and I have yet to see a package). As for stuff like panels, power boards, special wires and such, I prefer Doepfer's excess parts. It's all professionally set to the Eurorack standard so you have less to worry about! Of course, if you are building in a larger format, there are other places to get your parts. 

Q: How do you have the time to do all of this?
A: It's a combination of having no job, most of my friends are always busy, and I'm not that interesting of a person :)

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.

So that's about it. Hope I answered your question, and if not keep asking! I'll probably do this again. 

Tuesday, February 5, 2013

This Is a Load of Bull.

The LA Times recently posted this article on how EDM raves+drug use causes deaths (in a nutshell, anyway). Now, I know I'm not huge on the EDM scene (just over 50k fans, according to my Headliner count [and I don't even have an album out yet!]), but I just wanted to put this article into a bit more perspective. And yes, I know Kaskade already did this. This is just my take on it.

First off, kudos to the writer. Though pretty poorly thought out, it's certainly mind grabbing. Now, a quote, which was stated after naming examples of raves where people had died or been injured due to drug use:

"As raves have moved into the mainstream, there have been more tragedies across the country."

Well no shiz. First, if you don't know, raves are what electronic music concerts are called. Now, it's quite obvious that as something grows, the bad will be equally amplified. Say at a concert of 100,000, 1 person dies for whatever reason. The same concert has 1,000,000 people attending at a later date. Given the same ratio, it can be expected that 10 people will die. I know that's not the best example, but you get my point: as the amount of people increases, the likelihood of an injury becomes greater.

In the article, it is stated that "Since 2006 [Yoa's note: this article was written this year], at least 14 people who attended concerts produced by [great LA-based EDM promoters] have died from overdoses or in other drug-related incidents..." Now, guys, maybe I'm a little harsh, but you're saying that over the course of 6+ years, 14 people died of drugs. 14. Aside from being a relatively small number in the scheme of total drug-related deaths in the world, 14 people doing illegal drugs at concerts over the course of 6 years vs millions dying due to drug use outside of EDM... it's just crazy to me to number that few people given the grand scheme of things. It's like they were trying to make this genre look bad. It's like what mainstream media did to metal. And rap. And I think every genre...

Anyway, so the article continues to go on about how ecstasy is the main drug in use and how the concerts are making a lot of money for the cities they are held in. They then link the two together, saying that "The city should have zero tolerance for any activity where drugs are an integral part... A rave without drugs is like a rodeo without horses. They don't happen." Pardon my French, but what the actual fuck. Yes, drugs are taken at raves. But raves aren't about drugs, or sex, or anything like that. I know this gets kicked around a lot, but a lot of the people going to raves really are just there for the music, and to see their favourite artists perform live.

Just a side note, yes I know that a lot of EDM producers simply DJ with a bunch of pretty lights. I don't, and there are a few even big acts that don't, or soon won't.

The rest of the article goes on to talk about the two biggest promoters in the scene and talks concert numbers, so there's not much else going on, but it seems that the LA Times is trying to say that not only are the promoters bad, but that the events themselves are bad. They neglect, throughout the whole 3-page article, to state that the promoters or events never directly influenced these people's behaviour. There's even a quote from a retired police officer on the third page:

 "The promoters need to take responsibility."

No, they don't. The promoters have no correlation to what people do. Do you think that if the promoters wrote on their ads "Hey, and while you're having a good time, don't do drugs!" that the amounts of people being injured would decrease? Of course not. Wouldn't surprise me if it actually increased, just due to certain people's nature to do the exact opposite of what they read or were told.

A man on the board who has approved various raves stated, " far as we could tell, there was no fault of the people sponsoring the event." Thus rests my case. Sure, local cities get a fair bit of revenue (y'know, $14 million, fair bit), but it's not like that is increasing the chance of a person ODing on a drug.

In short, people do stupid things, and there's literally nothing that can be done to stop it.

Xanu Modules Overview: Oscillator, Shaper II, and FIlter

SO I thought I'd tell you more about the three main timbral elements of my modular: the Oscillator, Shaper II (complex waveshaper), and Filter.

The oscillator is a simple device at its premise, but is much more than that once you add the waveshapers, and even moreso if you use it with a mixer. I based my oscillator off of the base waveforms you could get out of older Buchlas. In this image you see the current design schematic with a slightly older design faceplate. In the text I'll tell you what's going on and what I want. CV elements are not included.
So still I'm using a square-core oscillator. For me it just works better than a saw-core mainly because I know how a 555 works and how to use it. Saw-core is just really confusing for me and once I figure it out I can never get the same range as I can with a 555. Anyway, so from that square output you go into the first two shapers: one a highpass filter, the other a mangler. The highpass makes a spike wave, but is adjustable so you can get wider spikes. The mangler produces everything from half-wave saw waves to combination saw and square waves, and even can do filtered clipping. Swapping the cap (or using a switch to swap caps) produces even stranger effects.

On the lower part, you start with a little low pass filter just to get a saw wave. That goes into a rather interesting variation of the Lockhart wave folder. Using the volume crossfader and gain control, you can get everything from distortion to quadruple-folded waves from the "morph" output, and you get square and pulse waves from the pulse output. You can add a bit of upper variation to the pulse by changing the 2.2k to a 1k, and you can control the volume of the pulse with the shunted 1k resistor.

I know, I said earlier I would base this oscillator off of Make Noise's DPO, at at some point I might add some DPO functionality. This is just current progress. I also want the saw wave to be reversible and to crossfade them together to make a triangle, which may end up being a problem. Guess we'll find out. Originally I had a great idea that used a variable slope triangle wave, but it didn't operate slow enough!


The Filter is rather complex tonally, but in reality it's quite simple. Note that in this case I have not included the CV elements. The basic premise of this filter will remain, but I have a new idea for the individual filter components to make them voltage controlled.
This filter is pretty simple at its core: just two filters, a lowpass and a highpass. Each filter is completely non-resonant until you flip a switch and activate the gain structure for each OpAmp. Increasing the gain increases resonance (and clipping at higher levels). Each filter also has feedback. This was based off of older Moog's external audio input: you could route the output signal to the input, overdriving the filter, adding depth and some distortion to the final sound. That is all handled here with an attenuator.

Then you have the HP/BP switch. That switches between using the final highpass filter for highpass or bandpass purposes. Using the original audio signal, it acts as a highpass. You then have both highpass and lowpass outputs. Switching from the audio input to the LPF output, the HPF is then used for bandpass purposes. You'd use both filters to adjust the width and response of the bandpass filter.

This is a good time to talk about the LP>HP output and crossfader. In any case, 0% will be lowpass and 100% will be highpass or bandpass, and of course any point in between. In the LP+HP setup, this is useful for creating a band reject filter at 50%. In the LP+BP setup, you get a similar setup, but you get a very interesting response output at 50%.


Shaper II is rather interesting because not only can it create interesting waveforms, it's the same thing used in the Oscillator!
Though the actual circuit is exactly like what's in the Oscillator, given different shapes it can produce drastically different tones using the same principles. It also has the lower and upper sections separate, but if need be you can use a splitter, mixer, multiple, etc. to get the same signal to each section.

So that's how those work. I'll work on the voltage control portion of things. Won't be surprised if I just use vactrols for everything, really ^_^