jojjelito

If you think that's much then take a look at the AMD/CTS9513 5-output timer at Jameco... You can get the C54 chip at Farnell or Digi-key but you'll end up paying the same. Or spend 3EUR at Reichelt in the EU.

There you go! It starts to sound like a project! At any rate I think it might be worthwhile to design a 82C54 sub-module with one Dout (74HC595) per timer IC. The thing is that I don't know beforehand how many voices can be driven off one core if things like envelopes, LFOs and mod-matrices are run there as well. The soft-synth things can be lifted from the current SID-synth engine and/or MB-FM. Then add one AOUT_NG per core for 8 channels of CV. This will drive the basis of a synth regardless of DCO method chosen. CV multiplexing will eat CPU resources like crazy (think small, but uninterruptible parts of code - jitter is somewhat a concern). If tons of CVs are needed then one can look at MB_NET and several cores a la MB6582, or design an SPI-slave core that contains soft registers for all CVs, takes care of LFOs etc which is updated via CAN or SPI by the main core only when needed. This slave updates all CVs, multiplexers etc. Core offloading achieved. However, one better start small before aiming for the stars. Low part count poly. LOL :laugh: Take a peek at the schematics of analog polys when you have the chance :sweat: The only one that is low-part count (per voice) is the Korg PS-family. There you had full voicing and a complex control scheme (in case of the PS3200) instead. Edits due to somewhat iffy spelling etc at this late hour...

Ahh, you're beginning to grok this :). The base frequency sent to the timer chip doesn't change! You only change the divider value for the timer resulting in different output frequencies. So, new note->fetch the new pre-computed value in a table. Send it to the right timer control register and you're done, unless you do some fancy detune or pitch-bend stuff. The 4051 IC use is just a ghetto (read low-cost) method of multiplexing the DAC output by making a primitive sample-and-hold. I.e, output CV1 from the DAC. Set address one on the 4051 to charge the capacitor connected to output 1 of the 4051. Do the same for all the channels so that the poor DAC has to output new voltages each cycle. If you do this quick enough you won't have too much droop (voltage loss) on each CV between update periods. Normally you use FET-style inputs connected to this SH output in order not to drain the capacitors. See the CEM 3396 PDF or the schematics of say, an Alpha Juno and you'll see it. Edit: This method applied more in the past where DACs were expensive single-channel beasts and lots of CVs were needed to control VCAs, VCFs etc in polyphonic systems. See how the Prophet VS made by Sequential Circuits did it for instance. Its' DAC multiplexing system is a sight to behold! It uses in excess of 68 channels of CV generated by one single DAC.

Ahh, here we go with that project again... the elusive DCO synth. I've been wanting to make something using the CEM3396 wave-shapers but other projects are keeping me busy. The CEMs use a square wave at the right frequency in order to come up with a whole bunch of wave-shapes generated by analogue means. The idea here is the same. The easiest way to get a square wave of the right frequency would be to use the PWM output with a pulse-width of 50%. The issue here is that you don't exactly have a plethora of these outputs using the extant microcontrollers of Core8 or Core32 if you want polyphony. Suppose you want 6 voice polyphony ala Cheetah MS6, Oberheim Matrix6/6r/1000. This calls for 12PWMs at different frequencies for a 2-oscillator per voice synth. The way it was solved in the olden days was to program a PIT (Programmable Interval Timer) that is an old standard 8bit CPU peripheral. See 8253 or the enhanced 82C54. This way you get 3 square-waves/IC. Unfortunately those chips are using parallel I/O (no modern SPI alternatives exist) so you need to stick a 74HC595 chip somewhere close to the timer and program it in the same fashion as the SID. Also, if you go for something polyphonic it might be a good idea to feed the timer chips 1 or 2MHz base frequencies from different clock sources such as high-speed RC oscillators to make the sound less stiff than using a single crystal-derived source. But before you get there it might be a good idea to start with just one PWM from the Core in order to check and debug your DCO... You might want to thoroughly check Tom Wilthire's pages on DCOs if you want to see how Roland made their more digital DCOs and what makes them tick :sorcerer: There's plenty of good educational reading there that needs to sink in.

Mmm, both tapeworms and amphetamine have been sold as over-the-counter diet pills in the past :frantics: I bet that the diet pills of the future won't be as exciting! These guys are more mellow these days, but here's YMO's take on it all: Chill-out version of Sports Men by Haroumi Honono.

There you go. It's that simple in theory. In practice it's always easier to take it easy, snack when not supposed to and all that. Still, Martial arts works for me, YMMV. I think it strikes a good balance between strength, coordination, agility and fitness. Whatever you do, don't expect quick results and don't give up. Also, abandon all ideas of "I just need to get into shape before attempting to do X". That's just tosh! Go for it, you're never going to get into shape without doing some work :poke: Or try swimming, biking or whatever tickles your fancy.

Ahh, sorry for using slang. See Urban dictionary for a definition. Seeing this took my back on a trip down memory lane. My 9090 is finished, but there's still some touching up to do. The Taiwan Alpha pots I got from Futurlec had some issues with the 1M pots so I need to replace those. Also, I need to switch to shielded (grounded in one end) cable for the pots that control the pitch of the digital sounds as those are very noise-sensitive. And yes, slap on the very nice front panel I got from Julian F. But, electronically it's all working. It sounds fantastic! Far better than any samples I've heard :sorcerer:

Hiya. I could scrounge up some 2SA798s if you're really needy. I got them way back when I defensively hoarded "exotics" from Futurlec or Electronic Surplus et al. See 2SA 798. They're only 0.61 US a pop. Do yourself a favor and buy a few if you ever plan on doing more DIY. In Germany you can try HTV-Service The 1SS133 diode over the guarden variety 1N4148 is just being silly. It won't alter the sound. At all. Mouser or HTV-Service carries those if you're fussy. :whistle:

Cool beans. I remember doing this, getting a doh moment since the PSU won't do much without the fuses of course. Enjoy trigging the BD for some fun!

Martial arts, preferably MMA (mixed martial arts) plus walking 30-60 mins per day or running occasionally is a good start. Then cut all the sugar you don't need. :thumbsup:

This morning saw the panel components fitted to the paper copy of the panel in order to check the clearance around the knobs, switches and jacks. It looked promising and photos reside in a Canon somewhere. I hope to put those up later, plus a quick how-to for people using Front Panel Designer - there are some interesting tricks to discover. Then came the time to fit the paper to the rack just below the MB-SEQ. Interesting! Somehow I figured the SEQ was 4U high, but it's only 3U! Guess the 4U came from the idea of SEQ plus outputs from the A-OUT being 4U. It doesn't exactly help that we had already placed the AOUT jacks on the rack panel for the modular... :whistle: So, there's now a full HE more to fill up with interesting gear. A clock module plus clock dividers will round out panel one nicely. This means that rack 2 now has tons of space to spare for the future modules. Plus that I should get back to finishing the MB-6582 I started on earlier this fall. There's a front panel in there too :frantics:

I've gotten away with sticking tantalums in far worse places, but... I was also concerned with the safety of people since this being a DIY forum we shouldn't make assumptions about the skills of various persons building this. Metal oxide vapors are nasty. Have a go either way - rolling your own switcher is a good training exercise :sorcerer:

Hmm, akshually the tantalums are of better performance for this application, but given their volatile tendencies wrt voltage spikes, I'd say stay off them unless you have: a) need for this performance or b) a tightly defined operating environment or c) you can absorb the cost delta In this case I'd say that c) doesn't apply since it's DIY and you won't exactly use thousands. The other conditions still apply though. Guess I just like to play it safe when DIY-ing and use rule of thumb. Please consider not bringing a howitzer to a knife fight :flowers:

Depends on how much space you got on your board. I'd stay off tantalums unless they are *really* needed since they have this tendency to self-incinerate every once in a while. If you can, I'd say use low ESR Sanyo or Nichicon electrolytic caps instead.

Been at it for some time now. I'm building a mystery. :whistle: I figured that it would be nice to combine the awesomeness in a cute little box that is the MB SEQ with my ongoing modular. I snatched a couple of sequencer front panels from Julian F and finished two sequencers, one for me, one for my partner in crime - mr F. After assembling a whole host of modules, both of our own design and PCBs sourced from various people on the electro-music forum it all came together thanks to the Aout_NG module and TK's awesome work. No more external MIDI-CV converters! In fact this modular has 4GB of flash, ethernet and other non-standard goodies. The rest is transistors and chips, some SSM, some CEM, some OTAs and even a light sprinkle of discrete transistors where we could get away with it. At the moment we are filling up the 8U/HE panel that is to host the Aout CV outputs, the gates and some bread-and-butter modules interfacing the system with the real world plus the usual VCO/VCF/ENV/VCA chain in order to make it a complete synth in one rack. All this will sit in a light-weight Adam Hall 12U tabletop racks. The VCO is a Thomas Henry XR-VCO using a XR2206 oscillator with skewed waveforms, the VCF is our own take on the CEM3379 VCF/VCA/PAN that is dual and in full stereo. On top of this we have a noise source from the Thomas Henry Super-Controller that uses the good old SN76477 IC to great effect. This also gives us an LFO and S&H/lag processor. Add a couple of SSM2056-based ADSR modules (we have a ton of these plus we are lazy - sue us!) and some mix/split channels and were good to go. So far it's all panel 1. The preliminary design is printed on paper so that we can make sure that fingers fit between the knobs, there are guard lines around the holes to make sure we don't place any components inside others on the backside. Off to Shaeffer/FPE soon. Not time for POIDH just yet, unless you enjoy nekkid PCBs or similar perversions :geek: Panel 2 and panel 3@12HE must be the targets in line...

Haha, it's a guy thing - function over form. Ivar roxx my living room, but teh females in my home claim I somehow need "real" furniture instead. Just found this: Ikea lets 100 kittehs loose inside a store! Imagine the chaos at WilbaWorks inc should this ensue - You can haz kitteh-sammich!

My gray wegie k1773h Molly claims that Denon iz OK el3ektr0nix: :cat: + Denon 4310 = :hug: Ikea Ivar instead of proper furniture is deffo less OK she claims. She and the other wegie sayz that they might upload p1kkSuRez on Caturday posing with some Midiboxxen, Xoxen or 9090-boxxah. Haha, wonder if catporn is illegal yet?

I'm late to the party, phew! If this should come to pass I would be interested in 60 transparent knobs, and 30 red/black ones. Edit: The picture of the 6582 with transparent knobs looks like teh sex! Cheers :sorcerer: /J

+1oneoneeleven!!!!111 As long as the ST32 outputs the correct timer signals to the 3396's waveform converters we are gold. Me on this: Stalled for now :( Back to Xcode.