teardowns of old electronic instuments like a synth or drum machine - Page 1
Forum section: electronics / general

author: dentaku
author_rank: Frequent Contributor
timestamp: April 06, 2014, 01:40:08 am
content: I'd like to see someone non-musical like Dave teardown a musical instrument like an analog synth (Eurorack module or standalone with keyboard) or drum machineOR do it with someone who knows more about this stuff like when Doug Ford who designed the PA system for trains came over.

author: pickle9000
author_rank: Super Contributor
timestamp: April 06, 2014, 02:21:44 am
content: He's not Dave, he's more repair oriented and music gear is his thing.https://www.youtube.com/user/markusfuller/videos

author: dentaku
author_rank: Frequent Contributor
timestamp: April 06, 2014, 10:34:48 am
content: Quote from: pickle9000 on April 06, 2014, 02:21:44 amI've watched his videos before and I know he's definitely inspired by Dave.It would still be interesting to see Dave do a musical instrument sometime though.

author: sync
author_rank: Frequent Contributor
timestamp: April 06, 2014, 12:41:41 pm
content: Then buy some and send it to Dave.My recommendations:TR-909 (the most dense through hole stuff I ever seen)Memory MoogDigital synths are usually boring. Just a few custom ICs.btw:

author: Blanketduck
author_rank: Contributor
timestamp: April 07, 2014, 03:22:31 am
content: Quote from: dentaku on April 06, 2014, 01:40:08 amPA systems aren't very interesting. As far as modular, I can tell you what's usually in them...Analog Synth: A nice analog synth is built a lot like an arbitrary waveform generator. You can do all of it now in DDS (direct digital synthesis)... The old ones are all RC circuits with linear ICs. You're basically just building a lot of waveforms you'll see in a function generator, and the rest of the device is for modifying them. Most of the time, you can chain 2-4 waveforms in a fixed format based on a selection knob (square/pulse/triangle/sinusoidal)... They can pass through an "oscillator" like an LFO, which more or less changes the phase velocity of the waveform. In RF it would be a value of radians per second for most repeating waveforms, but I can't really imagine it in these, as the final result is mostly an arbitrary type. There are usually 2-4 filters ( slider controls, everything else is a rotary shaft encoder). The difference is almost every stage you can bypass with a switch/button. Since it's an instrument you have a 12 tone system (as far as western music, asian stuff is similar but there's no serious time signature)...120 BPM = Most average/commercial music ( rap and pop )140 BPM = Rock/polka/etc160 BPM = Most metal including speed metal160-300BPM = Neoclassical metal/shredBelow 160 BPM uses an 8th-note/quaver as the base note value. Everything above that is a semiquaver/16th-note (time signature is all about how many notes of a particular value you can fit into a bar.)You usually go by the scale-degree method, because each key only sounds on a certain tuned frequency ( based on A @ 440Hz ), but you can shift them up and down an octave with the octave shift key. There's a half-step/semi-tone, and a tone/step. A full 12 semitones/half-steps, is one octave. The distance between each is called an interval. Not too hard to imagine building with components.Most instruments are 2-3 octaves at max. A guitar is 2 octaves, but there are some 3 octave guitars. The difference between the cheap and expensive midi keyboards is usually the keys, the controls, display, and velocity/aftertouch in the keys. A DIFFERENT BUT RELATED THING: On a western woodwind they use the mechanism/keywork to switch octaves. On an asian instrument it's your lungs/diaphragm ( take for instance dizi, which has around 2.5-3 octaves, or the xiao which is basically a shakuhachi. Octave shift on those doesn't come from the fingering, it's from your diaphragm in your lungs. If you practice zen buddhism, and sit zazen for a few years, they're easy to play. You can learn the breathing without even picking one up. Chinese word is chan, korean is Seon. Most of the best texts on zen buddhism are japanese anyways: mumonkan, shobogenzo, hikeganroku, shin-jin-mei/hsin hsin ming, hannya shingyo, shodoka, sandokai, hokyo zan mai, and basically anything by daichi who lived in 1290-1366, all soto-zen buddhism, etc... Huge emphasis on this stuff. It's not religious, as it came from shorin-ji. If you want religious junk try jodo shin, anyways that was almost off topic, but this is important as far as appropriate answers/sounds...)PCM wave sampler/drum machine/sampling synth: These ones are just MCUs with sound banks, they also have a software sequencer. An "arranger" is usually the same as a regular workstation synth, except for the fact that the sequencing part of it is emphasized... With these it's just a game of polyphony vs monophony. They term it as "voices" on a sampler synth. Monophonic stuff tends to be for instrument simulation. You can make a polyphonic synth that sounds as good as a monophonic one ( omnisphere is an example, but complexity and cost goes up.)The workstation versions of those are the korg kronos (successor to oasys), and roland V-Synth... Those are probably the best/most complex ones you could teardown. I'm sure a $10,000 modular synth is way crazier. I don't think they're worth $10k as far as parts. Too many cables raises the impedance a lot. I bet you could do a lot of those on an FPGA. No one cares though. Maybe $300 in parts, for the best possible one you can make ( not counting mechanical keys )...Note: You can usually buy these in rackmount form and just hook up a MIDI keyboard to them. Basically every great workstation has a rackmount version. You have to browse a little bit more on the website to find them. The rack versions cost waaay less, same sound, but you'll bring your own keyboard. Even those cheap little grocery store ones are fine as long as they have MIDI. I prefer an M-AUDIO axiom or AKAI Pro brand for MIDI stuff. USB has no latency, but MIDI will have latency. If you end up stuck with MIDI, then you'll buy a USB converter for $50 (m-audio uno is the best). Sound cards aren't really used for recording as much now, although DSP cards are really popular. You'll go through an external interface anyways.If you have at least a core I5 3xxx or 4xxx omnisphere is pretty decent. Even then, a lot of people prefer something like this since it offloads all the synth stuff to these DSP cards. This only works with their software sadly. It's not really that amazing for a PCI-E X1 finger. You could fit everything onto one board and add some pericom brand ICs, but most of the designers that make these wouldn't know how to do that...http://www.uaudio.com/uad-plug-ins/uad-2-pcie.html( I wouldn't buy this but it's an example of what's happening )Also: If you're thinking of getting a DAW for a software synth, you'll most likely end up using either: reaper, ableton, sonar, etc (if you get a cheap midi keyboard they tend to come with a budget version of those)... Those are budget ones until you get to the high end DAWs. They're really just front-ends for VST. I don't really mess with software like propellerheads reason 7.x. It is nice and it's standalone (I own an older version which costs way too much). The problem is you can't wire it to a VST without rewire, and even then it's just useless. I can just load up reaper for like $60 and pop in omnisphere, and that one VST does MORE than everything in reason ( the only saving grace is subtractor and thor are pretty decent synths in reason, the rest is junk. The effects and the sequencer are pretty nice, but still you can't use it externally, so it's probably the most retarded thing you could ever buy. Most people who use reason only make rap music with it, so it's just not important. It doesn't say that on the box. Omnisphere, komplete, and other stuff are worth it. Subtractor is terrible compared to lennardigital's synlenth1, which is a standalone analog synth:http://www.lennardigital.com/modules/sylenth1/)

author: dentaku
author_rank: Frequent Contributor
timestamp: April 12, 2014, 03:06:10 pm
content: Quote from: sync on April 06, 2014, 12:41:41 pmThe most dense through hole hardware I've ever seen is old Furuno Loran C equipment for commercial fishing. It's usually build like a tank and crammed with stuff.