To add a little value to my ranting, here's a little video of me creating "live loops" on the fly with SK-1's (actually Realistic Concertmate 500's) and a glorious Boss DR-220 for the sync job. There was a four measure pattern playing w/ syncing pulse at the start, I played the chords in rec mode, then switched on the sync et voilà.
It's another cellphone movie, so please excuse the terrible sound.
(is it ok to post such a video that way ?)
Me again, lucky you, with hopefully useful info. I implemented the sync using an opto-isolator (Sharp PC817 - that's what I had) because I had read things about the logic ground being -5V and the whole thing was unclear to me and I thought that with an isolator there was no risk of sharing unappropriate ground. Perhaps stupid, anyway it worked, so…
Note that the diode on the stripboard is actually an LED displaying the pulse.
One could imagine, at the expense of one DPDT, make the circuit allow the "one key play sync" also, by shorting between KO0>D23 / KI6 (or KO0>D24 / KI5) instead of KO2>D20 / KI1.
[Edit : tried only with +5V pulses]
An easy built to sync SK-1's to your favorite trig/pulse out.
The LED holds the board ! Really pro, no ?
One more superb blurry pic. You can guess where solder joints are though.
This image has been reduced to fit the page. Click on it to enlarge.
Joined: Feb 02, 2010 Posts: 198 Location: California
Posted: Sat Dec 10, 2011 1:07 pm Post subject:
Wow, a thread named after me!
I did that mod very simply - used 1/4 of a 4016 cmos quad analog switch chip (4066 is identical in function).
The trigger input on the 4016 is triggered by + pulse. The switch inputs on the 4016 are wired to the two connections on the "autoplay" button on the SK-1
How to set up a synced beat from the SK-1:
a) With no triggers running to the SK-1 yet, you put the SK-1 in "rec" and "chord" modes with the two switches on the SK-1.
b) You select a rhythm and hit a note on the keyboard to get it going like you would if you just wanted to record chord change sequences into the autoplay.
c) Now, when "autoplay" is triggered, it will reset your chord changes AND DRUM BEAT back to the start.
That can do cool stuff with incomplete rhythms to repeatedly reset it periodically from an external source, but if you want to have the beats really sound fully synced with your external trigger source, then just ride the tempo up and down buttons on the SK-1 until the beats fit within each other. It is surprisingly easy to get them to sound like a good match because they are repeatedly reset back to the beginning on cue with your trigger source.
On my SK-1 I installed a trigger input jack, and a toggle switch which allows you to cut off the trigger input to the 4016, for when you don't want triggers to reach the autoplay (I do this for live situations where I want to enter in things into the autoplay on the fly).
You find the +V and gnd from the SK-1 off of its circuit board, and power the 4016 off of that. Make sure not to send triggers that are greater +V than the power it is running off of.
That is a lot of typing, please ask questions if it is unclear.
Adtnl note: in my SK-1, I also added a trigger input divider out of a 4017, so I can feed it a steady pulse that I use to sync several things together, but it will only trigger once every 2, 3, or 4 pulses that come in (selectable with toggle). Ths is not necessary if you have a different system set up for triggering/syncing.
Here is a video showing it in action. Apologies because I know the sound quality is terrible. The short SK-1 arpeggio you hear is one of the built in rhythms/styles being repeatedly reset back to the beginning by the trigger inputs, the tempo was set to get close to the other instruments by manually fudging the tempo buttons.
In the video the SK-1 is synced with home made drum machine, synth, and sampler.
here is one more showing just autoplay sync (not with the built in beats on the SK-1, just with sequences played into the autoplay record/playback feature). There is a sequence in the SK-1, a sequence from a speak n'music (also modded for autoplay triggering), a sampled phrase (in home made sampler), and home made drum machine. Also, a cat, of course.
Thanks for sharing the details of how you did that mod, Top Top !
I personally definitely prefer using it in normal or solo modes, without a rhythm running (ie chord mode), since you make the music, and you don't have to care about matching any tempo in the SK-1. Thus you can really build live loops on the fly…
More things about this mod :
* Your loop is limited to only 400 notes (2x 199 for solo). Far more than what you'll need.
* To clear a sequence, press reset then clear. (pressing just clear won't work correctly)
* You can't start playback with silence. If you want the melody to start say a quarter note after the beginning of the bar, you'll have to drop the sync pulse then…
* Before recording, I set the SK-1's tempo speed at maximum, thus (I think) making the timing of the recorded notes more accurate. Sometimes you can hear notes still being slightly out of tempo, I decided it was just charming, not a problem. And :
* Easter egg : then, by pressing three times the down tempo button, the speed of what you recorded is more or less divided by two ! (and four times with six more presses, but it's really gross there - unusable)
* You can record a sequence longer than your loop without problem, it'll make an «alternate ending» AND allow gapless loop restart.
* Naturally you can add more notes when the loop is engaged. BUT. Here comes the unpredictable. If you recorded a longer sequence as said above, it might work fine. Sometimes. Otherwise the sound will cut at the end of the last note recorded. Or parts will disappear. No clue why it's so… If you want to go experimental, add layers and layers of notes, you should end up with massive note clusters. Yet another sport then.
* Of course it'd work with any keyboard allowing the recording of notes and/or chords.
Joined: Feb 02, 2010 Posts: 198 Location: California
Posted: Mon Dec 12, 2011 5:47 pm Post subject:
Yea, I also mostly use the solo mode. You can record separate tracks in the two solo lines by moving the switch from one to the other, and clear them out independently. It is a two track sequencer.
In my experience, the timing/resolution has been pretty accurate.
The beats thing I was just explaining because it is kind of interesting that you can use the actual built in beats and sync them to external stuff with a little fudging. In practice, I also do not do it much because it doesn't really fit with the music I do.
What I generally do is shut off the trigger input, then record a line along to the external beat, then flip the switch to get it looping, and overdub more stuff into it on the fly if I want to. _________________ ∆ A. MAGIC PULSEWAVE ELECTRONICS ∆
What I generally do is shut off the trigger input, then record a line along to the external beat, then flip the switch to get it looping, and overdub more stuff into it on the fly if I want to.
Same here. With long envelope and good timing for the switching… Or just relaxed with extra notes to be cut out.
Don't you experience strange behaviours when overdubbing ? I couldn't find the logic of it all. I'd swear I ended up sometimes with different sequences over two cycles… Also disengaging and reengaging the sync can have an effect. And sometimes it just overdubs smoothly. _________________ ::U::N::S::C::H::N::E::L::L::
In solo mode, as long as I overdub in «blank spaces» it works fine. If I happen to overwrite a note it starts to mess up, as you said polyphony limit (one here) is the cause so one can expect such things. In normal mode, the messup can happen with only three notes involved, so it's not the polyphony. And it can happen or not with the same notes… I thought it could be related with the matrix busses but it happened too with F, B and D which are one separate ins/outs. And it's the same on both units here. I just don't get what's going on…
Well, we just have to consider that overdubbing in normal mode leads to unpredictably unpredictable results. Sometimes. One can still switch to play mode and solo above the rest… _________________ ::U::N::S::C::H::N::E::L::L::
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