Hey T..
Btw.: Dan - with a simple trick it is already possible to control all SIDs from the control surface at the same time.
Yeah, nice but i find it easier from within logic atm and using a controller to handle the sid cc’s. I only inc/dec buttons on the SID (no encoders yet :() so controlling stuff with buttons on a prototyping board isnt very productive ;p I should be gettin some encoders soon tho so the proper playtime waits till then…
Ta
Dan
Hey TK,
just finished building my SID (so far with two 6581). Plugged it in and played it. The first time I checked if I hadnt accidentally played my Virus B. Dammit no! It was that SID! Really rocking piece!
Now for some questions:
sometimes if you trigger a note, the SID is playing it kinda false. Kinda very disharmonic. If you retrigger the same note, its still there. If you hit another one, its ok again. Whats that?
With longer Attacks and other things (like pitchchange), it can happen, that the SID “clicks”, again: huh?
I tried out to get an external sound in there (with the Audio In). I hardly heard it on full volume (was a Rm1x Phone Out). What input specs are needed? btw: I did switch to external input already.
Just wanted to let you know these problems.
But still: SID’s rocking well!!!
I had read an article on the engineer who designed the SID (Bob Yannes?). His original intent was to make an inexpensive version of the oberheim 4-voice. Currently, as best I can tell, the SID is only polyphonic by having each of the 3 oscillators play one of 3 notes at a time.
Is it possible to implement 4 SIDs as a single 4-voice instrument, so that if one were to play 1 note, the first SID would play, and if two notes were held down, then the second SID would sound, etc. up to 4 voices?
I’m not sure if this is asking too much of the hardware/firmware but it would sure be cool to make a 4-voice SID! 
Hi Pay_c,
Hey TK,
just finished building my SID (so far with two 6581). Plugged it in and played it. The first time I checked if I hadnt accidentally played my Virus B. Dammit no! It was that SID! Really rocking piece!
Now for some questions:
- sometimes if you trigger a note, the SID is playing it kinda false. Kinda very disharmonic. If you retrigger the same note, its still there. If you hit another one, its ok again. Whats that?
this can have several reasons, but not because of a firmware error, but because of the sound setup. For example, if three voices are oscillating with exactly the same frequency, you will only hear the superposed result, which mostly doesn’t sound very interesting. And depending on the other parameters these effects can occur with different notes.
If it was your intention to play a thin sound, just disable oscillator 2 and 3. Or if you want to play a fat sound (unisono effect like known from the Virus), change the finetune parameters of osc 2 and 3, and assign one or two LFOs to the pitch to prevent the overlay effects.
- With longer Attacks and other things (like pitchchange), it can happen, that the SID “clicks”, again: huh?
thats an imperfection of the SID chip. :-/
- I tried out to get an external sound in there (with the Audio In). I hardly heard it on full volume (was a Rm1x Phone Out). What input specs are needed? btw: I did switch to external input already.
I just tried this with the Line Out of my RM1x - no problem. But I noticed that the polarity of the “Ext” flag is wrong. Means: you have to “disable” the external input if you want to hear the sound. I will fix this in the next release.
Best Regards, Thorsten.
Hi Antman,
I had read an article on the engineer who designed the SID (Bob Yannes?). Â His original intent was to make an inexpensive version of the oberheim 4-voice. Â Currently, as best I can tell, the SID is only polyphonic by having each of the 3 oscillators play one of 3 notes at a time.
Is it possible to implement 4 SIDs as a single 4-voice instrument, so that if one were to play 1 note, the first SID would play, and if two notes were held down, then the second SID would sound, etc. up to 4 voices?
I’m not sure if this is asking too much of the hardware/firmware but it would sure be cool to make a 4-voice SID!
several poly, unisono, layer and split modes are planned
Best Regards, Thorsten.
are you back from holidays Thorsten? ;)
Hey TK, again because of that Analog IN: Tried it on the second SID I built. Still the same: Really not very loud. Hardly hear it.
… … Whats up? I dont get it…
I have decided not to finish the single 4-SID PCB I had started laying out. Thanks for all your help anyway Thorsten, and the answers are still very insightful.
Instead I think I will simply etch all of the layouts required on to one big PCB and just connect them that way.
My reasoning? Well, I decided that if I start to change things around too much then I risk losing long-term compatibility with future advancements to the project / platform. For example Thorsten’s new suggested power supply wiring seems very solid, and if I had created the big board such a modification would be very inconvenient. Also Thorsten recently made mention of possible panning using a forthcoming “AOUT” module, and my design may have omitted a port to plug such a module in on.
I was initially worried that 4 cores and 4 SID modules would be an unmanageably large set of boards, but as has been demonstrated, with a little coaxing they will fit into a C64 case. So there really is no need to try to reduce the component count or increase the efficiency of the layout.
I do have one other little tidbit of info though: my work uses a PCB layout program called “Protel 99SE”, which I decided I would try to learn for this little project. I don’t know what other PCB/schematic software is like for Windoze, but I have decided (based on my weekend’s experience) that Protel ranks pretty high on the stink-o-meter. Part of my decision to stop working on the board is based on about 10 hours of frustration working with this crappy pcb software. (FWIW it seems powerful but has a ridiculous user interface)
Nebula: Should be able to take the 1 MHz clock from one core module and split it between all 4 SIDs, eliminating 4 x 1 MHz oscillators,
TK: this doesn’t really make a difference, but it’s ok. Note that neither the master, nor the slaves are exactly synchronized.
I’ve got some more questions on this topic,
Does every slave-CORE send out this 1MHz clock or only the master ? IOW can each SID have the clock from its own CORE or does it have to come from only the master ?
On the slave PIC’s, is it OK/better to connect all unused pins to gnd or can/must they be left unconnected ?
tnx
Hi,
every SID core module drives a 1 MHz clock, so I think it’s better to use them seperately. In fact a SID slave is a totally independent synth module which could also be used standalone. A master is nothing else than a slave + the control surface with the capability to send parameters to up to 4 slaves…
You could connect the analog pins (J5) to ground, but in fact this doesn’t make a big difference so long as the AIN driver of MIOS is disabled. Don’t forget the pull-up resistors! Don’t connect the remaining free pins (e.g. the LCD port) to ground or +5V!
Best Regards, Thorsten.