Sunday, October 21, 2012

Making the Triple Fiver

So I've started breadboarding my little synthesizer. So far I have a basic square wave going (I can't build the rest of the circuit yet) into a modified Sallen-Key filter. Problem is, well, that filter isn't too happy.

That is a video showing what it does so far. As I say, it's a fancy pulse-width modulatable, frequency tunable square wave oscillator. Except, well...

The output of the oscillator itself (running through a Marshall MG15, no effects, EQ set 10,0,0, mixed with some noise from a mic which was on the same channel) looks like this:

 Obviously, that's effects- and noise-laden, so to show it by itself...
However, though the filter, it looks like this:
So whatever is going on, it's not filtering, that's for sure.

Now, I should note here that this has not been properly tested. The first image was when I first made the oscillator work, and reached for the nearest amp. The second image I took just now, which is directly from the rebuilt oscillator, into a mixer with everything turned down, and into Audacity. The third was using the Marshall setup, but with the filter.

Yes, I said rebuilt. When I initially tried taking that image, there was no sound from the oscillator. It was just noise (of course I thought I somehow blew another 555). I cleared my breadboard and rebuilt just the oscillator :)

To be honest, I won't rebuild that bloody filter, at least not now. I don't have the proper parts, and the ones I do have have problems fitting onto the board because I got a small board.

Here is what I think is going on: the signal going to the filter isn't a square wave, but noise. That goes into the filter, which has improper parts and is possibly built wrong, thus giving a strange sound and unpredictable results.

If I have the time tomorrow, I will rebuild it all, make sure each part works properly, then blog (and maybe vlog) again. I really want this to work, man!!!

The bloody filter:

Friday, October 19, 2012

The Triple Fiver is Nearing Completion!

Yes, I am calling it that. It sounds just cheesey enough for me to like it :)

I'm getting close, anyway. I need to edit the right-most OpAmp (hence the random lines going various directions), change the filter from this boring Sallen-Key placeholder, and add on to the oscillator (allow for sine, saw, and triangle waves), but other than that, this should be a fully functional drone synthesizer!

It also has 10 jacks for input and output. This is mainly for external use (ie, with a modular), but can also be used for the individual effects: ringmod, distortion, filter, and amplifier. Or, you can patch the jacks together and, along with the internal switching, get some crazy sounds. And by crazy I mean complex, not random sounds, though that is possible as well (heck, input to the distortion, split the output into the two ringmod inputs, and you'll have noise!)

Now it's just a matter of getting the rights parts, putting them all together, and hoping for the best!

I made this with Designsoft's Tina-9, TI edition, if you were curious.

Dead 555

Overheating. No output. Smoke. Off and on buzzing. All signs that something is most certainly wrong.

In this case, I was working on building my synth, and I had the oscillator working. I had a 555 diagram all laid out to make a square wave, and it worked! I had to use other parts than what was described (replace a 1M pot with a 50k and a .02uF cap with a .22nF cap). But, using the 50k pot I noticed I couldn't get very low frequencies (I don't care if it can oscillate at 10kHz, I want like 1000 and less), so I thought that a higher rated pot (250k, my highest) would get lower frequencies.

So, I wired the new pot and breadboarded it, but I accidentally messed up the power situation and swapped the negative and positive (oops...). At first, it was sputtering - I thought it was a loose connection. As I let it run while checking connections, I noticed the smell of hot wires (similar to soldering). I wasn't sure what I was smelling. Maybe I had been working with wire and was imagining the smell. But then it happened.

A small, nearly invisible puff of smoke arose from around pin 1 of the 555.

Hoping it was actually a wire and not the timer, I simply released the power and waited a bit. I then put my finger on the 555, and almost immediately burned myself. I swapped the power supply around, thinking that I may have messed that up. It was able to burn me in less than a second. I took everything apart and noticed something: the breadboard under where the 555 was was partially melted! That's hot.

Lesson learned: power is a dangerous thing, even at only 9v, and making sure it's going the right way makes all the difference.

I'll get another 555 later and try it again. At least I know the square wave schematic works!

Friday, October 5, 2012

I'm building a synth! Kinda!

As a synthesist, I want ultimate flexibility. Well, I can't get that, but I can get close by building my own synth!

What it is is, well, a drone synth. In fact, it's like a Skychord Sleepdrone, but only one oscillator, 4 waveforms, a low pass filter, ringmod, distortion, and external input. So basically it's like a Sleepdrone with one voice but way more sonic possibilities.

What do you do with a drone synth? Well, if you hate the technological side of electronic music or you like synths to actually do something other than play a single sound while you tweak knobs, you'd probably use it as a doorstop or paperweight. HOWEVER, if you care to do such things as tweak and such, you'd make epic soundscapes, hard detuned sounds, and you can sample it and play the sound through a sampler!

For instance, take a $165 Sleepdrone3, a simple synth with three analog square waves that you can mix and change frequencies of (that Skychord probably made for about $40). You can sample it with slight detuning and make a heavy bassline, you can make ever-changing soundscapes, and you can produce harmonious harmonies. And we won't mention what you can do if you connect it to a modular or effects rig...

With my idea, though, you'll be able to do so much more. Sure, you can make drones. But you can also make sweeping filters, use it to make Dalek sounds, use it as distortion for a guitar or synth, distort your ringmodded sound, filter your bass for epic depth (the last three can be summed up as 'effects unit'), make coloured noise, or just use it as an amplifier.

However, I am thinking of an alternate idea that will allow for maximum patchability, so you can make it a guitar or vocal synth, have a multiplexed wall of sound (note this has one mono output, so that's saying a lot), still make noise (it's easy), and, well, that's all I can think of right now.

So, how's it work? Well, here's a diagram:
Makes total sense, right? No? Well, it has an NE555P IC as an oscillator with various waveshapers after that. It also has an external input. Both can be patched various ways to a ringmod, distortion, and filter. That goes out to the output to your mixer, effects, modular, amp, what have you.

NAQ (Never Asked Questions, because there are no FAQs)

--"If it's so simple, how can it do so much?" Because analogue synthesis is freaking awesome. It's amazing what a few simple things can do to audio.
--"How will you make it?" Well, I have a 555 and other parts, and with about $10-$20 I can get the rest of the parts.
--"Do you know it will work?" Well, I have the fine folks at helping me out, very slowly. For the most part, though, the ringmod, input and output, and patching are easy. They're helping me with the oscillator, amps, filter and distortion. I'm trying to keep it extremely simple, too. So basically, yes, I know it will.
--"How will you use it?" Didn't I just give a ton of answers to that?
--"Why?" Remember the KereMAX P? This is building up to that. This actually incorporates some of the KereMAX's features: full patchability, multiple waveforms, ringmod, distortion, a filter, and external input for every section. Obviously, the KereMAX has more stuff.
--"What will you name it?" Well, some would call it 'waste of time and money', 'stupid', or 'useless'. I'll call it the 555zYntH for now just because that's close to what all the schematics and block diagrams have for filenames. They're all 555synth or 555synthblk. And hey, if you write it in cursive it'll look neat.

And for those Skychord haters, I used them as an example because Deadmau5 noted one of their synths in a livestream, and so therefore one can imagine that they are at least well-known. I know there are other drone-synth-makers out there.