I just breadboarded one of the simplest 555 oscillators out there and got some nice results. I used two pots to mod frequency and made a pseudo-keyboard out of some temporary pushbutton switches using resistors to extract different pitches.
Anyway, it's time to move on. I disassembled an old MIDI keyboard made for some primitive mac editing software, and it's a good platform for my project.
^^ that's the back of it.
Since my existing oscillator runs from 9v DC, I was thinking of +9v to the bottom strip, then the terminal on the other side running to an individual oscillator.
Is there any way I could make this work, with complete polyphony, without having an individual oscillator for each key on the keyboard? If so, how?
Here's the breadboarded oscillator.
Thanks a lot.
Anyway, it's time to move on. I disassembled an old MIDI keyboard made for some primitive mac editing software, and it's a good platform for my project.
^^ that's the back of it.
Since my existing oscillator runs from 9v DC, I was thinking of +9v to the bottom strip, then the terminal on the other side running to an individual oscillator.
Is there any way I could make this work, with complete polyphony, without having an individual oscillator for each key on the keyboard? If so, how?
Here's the breadboarded oscillator.
Thanks a lot.
hmmm, couldn't see the pictures - something about me not having an H:/ drive.
Anyway, most likely the only way to get polyphony is going to be with a small uC detecting the note on and note off transitions and assigning them to a pool of oscillators. There's no easy way to demultiplex the rows&columns switch contacts of the keyboard to a particular oscillator. sorry.
Anyway, most likely the only way to get polyphony is going to be with a small uC detecting the note on and note off transitions and assigning them to a pool of oscillators. There's no easy way to demultiplex the rows&columns switch contacts of the keyboard to a particular oscillator. sorry.
You could, in principle, have an oscillator for every key but in practise this would have some problems. The stability of the oscillator is poor and achieving correct tuning is difficult with standard value resistors so each note would probably require a pot of its own.
It is possible to reduce the number of oscillators but the number of tuning resistances per oscillator remains the same, and now there is an additional problem with switching the tuning resistances into the oscillator in use and selecting which oscillator to use at any time, this further degrades the long-term accuracy of the tuning.
Again, the number of tuning resistances can be reduced to the number of notes, but with the addition of further complications to the switching, the right resistance must now go to the oscillator assigned to that key.
It's enterprising to attempt to make something out of an old keyboard in this way, but I don't think the results will be very satisfactory.
There are two ways you can go with this. You need to understand a bit about switching, so you can dig into logic, keyboard decoding and microprocessors, maybe buy a PIC programmer. You also need to understand a bit more about oscillators, tone and envelope shaping, so you could try building a more sophisticated oscillator and learning a bit of analog electronics.
Somewhere in between these is digitally generated sound. You can have a digitally generated sound or a replayed sample which is assigned to a key.
A lot of people have spent a lot of time working on this stuff, it makes sense to try and catch up on what's already been done so as not to reinvent the wheel, although its interesting to think, 'at least I'm as smart as some guy in the stone age,'
w
It is possible to reduce the number of oscillators but the number of tuning resistances per oscillator remains the same, and now there is an additional problem with switching the tuning resistances into the oscillator in use and selecting which oscillator to use at any time, this further degrades the long-term accuracy of the tuning.
Again, the number of tuning resistances can be reduced to the number of notes, but with the addition of further complications to the switching, the right resistance must now go to the oscillator assigned to that key.
It's enterprising to attempt to make something out of an old keyboard in this way, but I don't think the results will be very satisfactory.
There are two ways you can go with this. You need to understand a bit about switching, so you can dig into logic, keyboard decoding and microprocessors, maybe buy a PIC programmer. You also need to understand a bit more about oscillators, tone and envelope shaping, so you could try building a more sophisticated oscillator and learning a bit of analog electronics.
Somewhere in between these is digitally generated sound. You can have a digitally generated sound or a replayed sample which is assigned to a key.
A lot of people have spent a lot of time working on this stuff, it makes sense to try and catch up on what's already been done so as not to reinvent the wheel, although its interesting to think, 'at least I'm as smart as some guy in the stone age,'
w
Great! Thanks. I was planning on using a trimpot for each key. It's only 37 keys, and shouldn't be too much of a hit on the wallet if I order from Digi-Key.
While I like my square wave, I was wondering where I could find the materials to make a saw/triangle or sine wave. It would be great to have a selector knob to switch between them.
Also, how can you employ effects such as reverb and filters? I've heard of ICs that will do the job, but I'm not too sure where to find them. I envision a slider or even a small X-Y joystick to control the effects.
I'll try and get my images to photobucket. I can't find any way to attach multiple images to the post.
While I like my square wave, I was wondering where I could find the materials to make a saw/triangle or sine wave. It would be great to have a selector knob to switch between them.
Also, how can you employ effects such as reverb and filters? I've heard of ICs that will do the job, but I'm not too sure where to find them. I envision a slider or even a small X-Y joystick to control the effects.
I'll try and get my images to photobucket. I can't find any way to attach multiple images to the post.
SuperSaw
I've tracked down the name of my favorite sound, supposedly it's made with a series of sawtooth oscillators slightly detuned against one another.
Is there an IC out there that produces a sawtooth wave, similar to the 555 timer? If possible, I'd like to avoid having multiple oscillators for each key.
Sorry, but I'm terribly confused as to how synthesizers can produce such interesting sounds. I understand waveforms, the duty cycle, and the area, etc. I'm also up to date on logic and basic electronic principles. I'm just curious how the simple components such as resistors and capacitors can make the sounds that I hear in music all around me.
Thanks again.
I've tracked down the name of my favorite sound, supposedly it's made with a series of sawtooth oscillators slightly detuned against one another.
Is there an IC out there that produces a sawtooth wave, similar to the 555 timer? If possible, I'd like to avoid having multiple oscillators for each key.
Sorry, but I'm terribly confused as to how synthesizers can produce such interesting sounds. I understand waveforms, the duty cycle, and the area, etc. I'm also up to date on logic and basic electronic principles. I'm just curious how the simple components such as resistors and capacitors can make the sounds that I hear in music all around me.
Thanks again.
your 555 oscillator provides a sawtooth - on the timing cap (pin7)
however, you must buffer this with a hi impedance buffer (e.g. jfet opamp) or you'll change the frequency
filtering get very difficult because the filter is different for every key. It quickly becomes easier to do it all digitally.
BTW the old analog synths used a very fast settling voltage controlled oscillators, filters and amplifiers. But to get these to work at the speed of a talented keyboardist requires much skill.
however, you must buffer this with a hi impedance buffer (e.g. jfet opamp) or you'll change the frequency
filtering get very difficult because the filter is different for every key. It quickly becomes easier to do it all digitally.
BTW the old analog synths used a very fast settling voltage controlled oscillators, filters and amplifiers. But to get these to work at the speed of a talented keyboardist requires much skill.
The one I am posting below is fast , uses discrete devices/741
op-amp and can "follow" the lead perfectly. It is not as good
as the VCO's in the ARP/MOOG but it can make music better than a 555.
For more info on analog synthesis and more circuits go:
http://71.203.210.93/pdf1/Electronics/Projects/Synthesizer/
Even has circuits for phase shifting..
To go all the way ,ORION 7 + many wonderful VST plugins
can emulate all the classic analog synths in polyphony,
I have one that does 16 slightly detuned sawtooth's for
a truly "phat" sound.
OS
Attachments
good stuff ostripper
Not to hijack the thread or anything but I felt very educated after reading this website in entirety
http://home.swipnet.se/cfmd/synths/companies/oberheim/
The schematics show a Z80 with a single DAC multiplexing at least a hundred sample and hold circuits driving all 8 voices of dual oscillators, filters and amplifiers. Oberheim used a pretty much custom analog ASIC that are very hard to find now.
edit: dang missed the exit again
I'd check out what the pedal guys do. I know Yamaha has reverb and effects chips but they're a bitch to find and get data on. Basically any delay chip can produce all the effects you describe
Not to hijack the thread or anything but I felt very educated after reading this website in entirety
http://home.swipnet.se/cfmd/synths/companies/oberheim/
The schematics show a Z80 with a single DAC multiplexing at least a hundred sample and hold circuits driving all 8 voices of dual oscillators, filters and amplifiers. Oberheim used a pretty much custom analog ASIC that are very hard to find now.
edit: dang missed the exit again
I'd check out what the pedal guys do. I know Yamaha has reverb and effects chips but they're a bitch to find and get data on. Basically any delay chip can produce all the effects you describe
It sounds like the "transition" phase for electronic music..
with proprietory digital circuits blended with analog voices.
the new MOOG's do this as well , even adding a USB
for additional MIDI control for PC.
I stopped spending mad money on real hardware 5 years
ago and now enjoy 64 voice triple VCO's while even keeping
"classic" analog flexibility. The ARP 2600 in the attachment
even has the subtle nuances of the pearlman filters (I once owned the real unit)..
I even use line in through the VST host to add post
processing effects.
OS
Attachments
Growf911:
I have to ask your interest. You're certainly not in it to DIY an analog synth, that would certainly be a life's work. Is it an understanding of electronics or an understanding of sound and music that drives your experiments?
ostripper is right. A good soundcard and some good software (I use EMU 1616m + cubase/audition) and you can plug in any synth you want, they're all out there. Sure, it'd be nice to have an ARP Odyssey, a Prophet 10, a miniMoog and a LinnDrum but for those of us with small wallets we can still have big virtual studios and get pretty much the same enjoyment.
I have to ask your interest. You're certainly not in it to DIY an analog synth, that would certainly be a life's work. Is it an understanding of electronics or an understanding of sound and music that drives your experiments?
ostripper is right. A good soundcard and some good software (I use EMU 1616m + cubase/audition) and you can plug in any synth you want, they're all out there. Sure, it'd be nice to have an ARP Odyssey, a Prophet 10, a miniMoog and a LinnDrum but for those of us with small wallets we can still have big virtual studios and get pretty much the same enjoyment.
Programming skills certainly don't hurt, as they encourage a disciplined approach, but there's not much use for C++ as systems have to be quite sophisticated to employ objects.
It is a good opportunity to learn assembly language for PIC or VHDL, which are both much closer to the hardware. Since you've got a lot of decision matrices these are best dealt with in VHDL as circuits can be asynchronous and do not have to wait for a clock or 'round-robin' to reach them.
If you want a reverb look at Rod Elliott's (ESP) site. There are a number of instrument circuits there, perhaps one of these might grab your enthusiasm.
If you're more interested in a working instrument then take ostripper and Iain's advice
w
It is a good opportunity to learn assembly language for PIC or VHDL, which are both much closer to the hardware. Since you've got a lot of decision matrices these are best dealt with in VHDL as circuits can be asynchronous and do not have to wait for a clock or 'round-robin' to reach them.
If you want a reverb look at Rod Elliott's (ESP) site. There are a number of instrument circuits there, perhaps one of these might grab your enthusiasm.
If you're more interested in a working instrument then take ostripper and Iain's advice
w
Growf911:
I have to ask your interest. You're certainly not in it to DIY an analog synth, that would certainly be a life's work. Is it an understanding of electronics or an understanding of sound and music that drives your experiments?
ostripper is right. A good soundcard and some good software (I use EMU 1616m + cubase/audition) and you can plug in any synth you want, they're all out there. Sure, it'd be nice to have an ARP Odyssey, a Prophet 10, a miniMoog and a LinnDrum but for those of us with small wallets we can still have big virtual studios and get pretty much the same enjoyment.
Iain:
I've recently come to admire electronic music ranging from the works of Vangelis to Tiësto. Also, I'm pursuing the track of an engineer, and I'm especially eager to learn about the production of electronic sound. I've played with some VSTs which admittedly can produce some incredible sounds, but I'm craving a real, tangible synthesizer. In short, I want to gain more knowledge of both fields. Because they are married in this area, which incidentally I find most interesting, I see it as a prime opportunity to gain a decent understanding.
Ideally, I'd like to make a modular design. One in which new tidbits could be incorporated as I gain knowledge, however, my priority at the moment is simply to make a tunable synthesizer. I coaxed my digital electronics teacher into giving be 37 555 timers, and a trimpot for each should harmonize them well. Unfortunately, RatShack charges $2.50 per pot...
To Digi-Key!
Once more, I give you all my thanks. I'm quite impressed with everyone's willingness to help and these forums as a whole.
I have to ask your interest. You're certainly not in it to DIY an analog synth, that would certainly be a life's work. Is it an understanding of electronics or an understanding of sound and music that drives your experiments?
ostripper is right. A good soundcard and some good software (I use EMU 1616m + cubase/audition) and you can plug in any synth you want, they're all out there. Sure, it'd be nice to have an ARP Odyssey, a Prophet 10, a miniMoog and a LinnDrum but for those of us with small wallets we can still have big virtual studios and get pretty much the same enjoyment.
Iain:
I've recently come to admire electronic music ranging from the works of Vangelis to Tiësto. Also, I'm pursuing the track of an engineer, and I'm especially eager to learn about the production of electronic sound. I've played with some VSTs which admittedly can produce some incredible sounds, but I'm craving a real, tangible synthesizer. In short, I want to gain more knowledge of both fields. Because they are married in this area, which incidentally I find most interesting, I see it as a prime opportunity to gain a decent understanding.
Ideally, I'd like to make a modular design. One in which new tidbits could be incorporated as I gain knowledge, however, my priority at the moment is simply to make a tunable synthesizer. I coaxed my digital electronics teacher into giving be 37 555 timers
, and a trimpot for each should harmonize them well. Unfortunately, RatShack charges $2.50 per pot...To Digi-Key!
Once more, I give you all my thanks. I'm quite impressed with everyone's willingness to help and these forums as a whole.
Not to discourage you , but a 555 is not going to be very musical.
For one, it's waveshape (saw) will change with frequency,
and it will drift with temperature and voltage.
For a much better modular approach, why not go professional...
I found a precision VCO that will track within a few cents (pitch)
over a 10 octave range.. Based on a maxim precision function
generator. Here is the link,:
http://mypeoplepc.com/members/scottnoanh/birthofasynth/id20.html
He has the schema,PCB, BOM ..everything..even tuning instructions.. this VCO can match the best ARP/moog AND
is modern/simple... For the VCF (filter) ,VCA , and envelope
generators precise tracking is not as critical, but the VCO
should be first rate for real music synthesis.
I have all the hard copies (pdf's) in;
http://71.203.210.93/pdf1/Electronics/Projects/Synthesizer/
If you match this vco with some of the generic VCF/VCA/envelope
gens in the other PDF's , you could have a pro (minimoog) type
instrument instead of a kids toy..
OS
right on the money again, ostripper.
I'd add that elektor magazine did a whole modular synth back in the early '80's. If you can get access to the articles (maybe a subscription would provide back issue access) there's a wealth of information there.
Another alternative would be to buy a old mini-moog from ebay and renovate/tweak it.
The 555's are also going to drift - that'll drive you nuts!
I'd add that elektor magazine did a whole modular synth back in the early '80's. If you can get access to the articles (maybe a subscription would provide back issue access) there's a wealth of information there.
Another alternative would be to buy a old mini-moog from ebay and renovate/tweak it.
The 555's are also going to drift - that'll drive you nuts!
Hi Growf911,
I hate to say this, but just 5 mins of Googling will produce loads of links for synth circuits. Try this site, for example:
Yusynth
You can buy ready-made modular synth modules relatively cheaply these days - probably cheaper, in the long run, than designing and building your own. See:
Synthesizers.com
and
Synthesis Technology
I hate to say this, but just 5 mins of Googling will produce loads of links for synth circuits. Try this site, for example:
Yusynth
You can buy ready-made modular synth modules relatively cheaply these days - probably cheaper, in the long run, than designing and building your own. See:
Synthesizers.com
and
Synthesis Technology
Thanks Beelzebub.
Yusynth is a nice site. I'd looked at synthesizers.com and I'm especially interested in their envelope generator. I've grasped a general understanding of these modules, now I'm setting my sights on a controller. I found some circuits on MusicFromOuterSpace for 1v/octave controllers.
Here's one
What do you use for controllers?
Also, would I need multiple oscillators for polyphony?
I've heard that the Yamaha CS-80 uses many oscillators and frequently falls out of tune as a result.
Thanks again.
*EDIT*
I'm proud to say that I'm investing in an oscilloscope.
Yusynth is a nice site. I'd looked at synthesizers.com and I'm especially interested in their envelope generator. I've grasped a general understanding of these modules, now I'm setting my sights on a controller. I found some circuits on MusicFromOuterSpace for 1v/octave controllers.
Here's one
What do you use for controllers?
Also, would I need multiple oscillators for polyphony?
I've heard that the Yamaha CS-80 uses many oscillators and frequently falls out of tune as a result.
Thanks again.
*EDIT*
I'm proud to say that I'm investing in an oscilloscope.
Growf911 said:Thanks Beelzebub.
Yusynth is a nice site. I'd looked at synthesizers.com and I'm especially interested in their envelope generator. I've grasped a general understanding of these modules, now I'm setting my sights on a controller. I found some circuits on MusicFromOuterSpace for 1v/octave controllers.
Here's one
What do you use for controllers?
Also, would I need multiple oscillators for polyphony?
I've heard that the Yamaha CS-80 uses many oscillators and frequently falls out of tune as a result.
Thanks again.
*EDIT*
I'm proud to say that I'm investing in an oscilloscope.
Hi Growf911,
I use a MIDI keyboard, and a MIDI to CV converter. This way, any modern keyboard or PC can be used to control the synthesizer.
Regarding polyphony - don't bother! Use a virtual or modelled synth or, if you have the funds, a modern analog poly synth like the Andromeda A6 or the Prophet '08.
Very few have succeeded in designing and building a workable polyphonic synth - it requires time, knowledge, expertise and loads of money!
Hi everyone.
I recently got an ancient half dead EKO Tiger keyboard.
It generates the sound using twelve oscillators, one for each semitone, and each oscillator produces five octaves of a tone.
Here is the picture of the back of one of the oscillators: http://img15.imageshack.us/img15/4838/picture011uq4.jpg
and front: http://img18.imageshack.us/img18/9859/picture010lb8.jpg
Now, on the rightmost part of the oscillator a row of connection points can be seen. The first one is +15 VDC. next five points are assigned to a specific octave of a tone, so the second point from the top is assigned the highest frequency, and the sixth is assigned the lowest frequency. The seventh point is a master out, and the eighth is ground connection.
When the organ keys are not pressed, each of the frequency determining points is grounded, and no sound comes out of the master output. When a key is pressed, the point is ungrounded and the tone is allowed to go to the master output. The frequency is determined by the inductor on the left side of the oscillator.
Now, I would like to ask for help in solving the problems about this keyboard. none of the oscillators does not work properly, so I can't take one and copy it 11 times. If someone who understands electronics a bit more than I do could take a look at these pictures, and write something about how this thing works, I would be grateful.
I recently got an ancient half dead EKO Tiger keyboard.
It generates the sound using twelve oscillators, one for each semitone, and each oscillator produces five octaves of a tone.
Here is the picture of the back of one of the oscillators: http://img15.imageshack.us/img15/4838/picture011uq4.jpg
and front: http://img18.imageshack.us/img18/9859/picture010lb8.jpg
Now, on the rightmost part of the oscillator a row of connection points can be seen. The first one is +15 VDC. next five points are assigned to a specific octave of a tone, so the second point from the top is assigned the highest frequency, and the sixth is assigned the lowest frequency. The seventh point is a master out, and the eighth is ground connection.
When the organ keys are not pressed, each of the frequency determining points is grounded, and no sound comes out of the master output. When a key is pressed, the point is ungrounded and the tone is allowed to go to the master output. The frequency is determined by the inductor on the left side of the oscillator.
Now, I would like to ask for help in solving the problems about this keyboard. none of the oscillators does not work properly, so I can't take one and copy it 11 times. If someone who understands electronics a bit more than I do could take a look at these pictures, and write something about how this thing works, I would be grateful.
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