OT? Oscillator circuits, wave generators - instrument project?

[Branimir]

Hello,

I know this isn't stompbox related, and i tried searching the forums for answers on this topic, but i lack the knowledge of the device that I'm after.

I would like to build a couple of oscillator circuits, in which i can choose the shape of the wave (sqaure, triangle, sine etc.), of course the frequency can be easily changed and maybe a few effects applied also.

I know there are devices somewhat similiar to what I'm after, my guess is that Moog produces them But I'm a total newbie in this so i have no starting point about learing stuff regarding these "instruments". Am I talking about analog sytnhs or some other term? I'm sorry if I'm being stupid, asking these questions, but I would like to learn more about these instruments, and hopefully build some...

Since my english knowledge is limited, I've uploaded a sound sample of my inspiration.

It's a 50 second clip (600kb) from the song Crooked Axis for String Quartet from the band called Earth.

I'm guessing that low freq. sounds are coming from somekind of oscillator circuit and I would like to know more about history and basic desings of it...

Thanks

[christian]

Just google up "synth diy" or "synthesizer diy". You get tons of links, theres even bigger community than with stompboxes out there

ch.

[rockgardenlove]

Just wondering, but how would you trigger these?  Building a simple oscillator is easy, but how would do something like hook it up to a keyboard?

[christian]

Just wondering, but how would you trigger these?  Building a simple oscillator is easy, but how would do something like hook it up to a keyboard?

Well, synthesizers arent that simple. At least those that are usually known as, like Moog's, Oberheim's, ARP's etc..

Oscillator (VCO, Voltage Controlled Oscillator) is constantly emitting tone, frequency dependent on the voltage at its "voltage-input".
Keyboard emits different voltages at each key, and also a "gate" signal, that is usually fed to envelope generator that is used to control VCA (Voltage Controlled Amplifier) whose volume is dependent on its voltage-input.

Google gave this

Nothing stops you from cheating and doing lofi stuff, like just making a simple tone generator that is controlled by just a pot in the RC section on the osc,
then route the output of that to a momentary switch that works as a trigger to emit the tone when you wanna. And then drive that through a wah-wah to get filtered sounds, preferably modify the wah to a lowpass filter like on some EH envelope wahs, or better yet, use an envelope/triggered wah!

ch.

[Branimir]

Thanks for the replies, i found an interesting project that i could build!

http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/soundlab.html

[redeffect]

Check out the XR2206 function generator chip...

[slacker]

If you want something a bit simpler try
your first synth from musicfromouterspace.com, it makes some pretty cool noises and can actually be musical.

[The Tone God]

To be honest I think for the amount of time you will spend on this you could find your local armature radio club (ham radio) and find out where the ham flea markets are then buy one used cheap.

Just a thought.

Andrew

[Branimir]

Heh thanks for your inputs, but I think with my 8 year electronic DIY experience I have capatibilites to build this kind of device... About the ham flea market, heh, my mom works in the national HAM association and my dad is a long time radio amateur, and there is only one HAM flea market worth mentioning and it's once a year, and most of the rubbish that's out there for sale is actually my dad's piles of transmitting tubes along with RF amps and stuff...

Ham scene is relatively bad in Croatia, at least after the 1990. Before, the Yugoslav Ham scene was well developed and there were lots of radio amateurs, and these days, they count about 2000. And most of them are over 50 years old. That's sad, because before 1990, the state invested money in developing HAM radio hobby, along with airoplane modelling, small carts, and all other sorts of technical hobbies...

I think I'm going to finish a few more big muffs and two tube amps that I have lying around to be finished, before I start with synth DIY.

Cheers!

[trevize]

you will get these kind of tones (and a lot more) also with cheap and underestimate 80's synths.
they go for 100$ or so on ebay.

I bought an alpha juno 2 for 80$. it actually sounds very very close to a juno 106 and it has 5 octaves and aftertouch,
can be a good master keyboard and you can do a lot of strings, brass, bass and lead sounds.

Another one could be a korg poly 800. It will cost even less than the previous one and has a very
distinctive sound (very strange and funny sometimes). The architecture of the synth is also very complex
(2 osc, 2 adsr for vco, noise generator, vcf, adsr for vcf and noise, lfo, chorus, midi etc.)

The other choise could be one of the italian string synths (crumar, siel, logan, ....)

I think that buying a synth you could have a very reliable and useful intruments also for live situation.

[Paul Perry (Frostwave)]

http://www.4mspedals.com/
Triwave picogenerator?

[Branimir]

Heh, picogenerator came to my mind too also!

Yesterday I finished Tremulus Lune, and I have nothing bout praises to this tremolo design, so simple, yet tweakable and sounds sweet! Dou Distorotor is already etched and I think I'm going to build all 4ms pedals, they all seem interesting from the electronic design point of view and are all surely good sounding devices.

[moosapotamus]

FYI, Sound Lab Mini-Synth kits are being offered here...

http://www.prodigy-pro.com/forum/viewtopic.php?t=15907

~ Charlie

[brett]

Hi.
For a simple signal generator, there's always old Casio keyboards.  Lots of garage sales and pawn shops have them, usually for about $10 (plus $5 for the parts to make a cable).
A neat thing about them is that you can generate signals corrresponding to any part of your fretboard, which helps fitting input caps for bass cut, etc.
Of course, for $10 you only get about 100 voices and a limited range of effects.
cheers

[col]

Some of the R A Penfold books (see other thread) have tone generator projects based on 555 circuits and filtered white noise produced from a germanium transistor. There are also projects based on treating the tones and noise to get something more useful out of it,

Col