Some SID questions

[Benedict]

Hello all,

I came across MIDI Box on the Sound On Sound DIY forum. I'm not entirely new to electronics - I did it at school, but that was six years ago so please excuse me if I ask some stupid questions. I'm really interested in making a SID synth, I want some degree of hands on control so from what I've gathered I need the follow:

1 x Core module

1 x SID module

1 x LCD + 6 (or 10) buttons

1 x DINx4

Is this correct?

I'm also confused by the power supply. I presume these will be separate circuits but I can't seem to find any PCBs or schematics for them. Where do I find them?

If all goes well and I manage to get the above working I think I'd plan to expand to a multi SID. I see from the pictures that the outputs from multi-SIDs are on 4 separate mono outputs. I've got some questions about this:

- Is it possible to incorporate a mixer to mix down the 4 mono outputs to 1 stereo output?

- Would it be possible to incorporate pan information within a patch? Would it be possible to assign a LFO to a pan control for each SID?

- How is polyphony handled by a multi SID? If all SID modules are linked does this mean you can get 12 part polyphony?

Obviously this is just to satisfy my curiosity because I haven't even built my first SID yet!

Thanks in advance

Benedict

[TK.]

Hi Benedict,

the modules are correct, and for the power supply circuit I would suggest the original C64 PSU, a schematic can be found at the MBHP_SID page.

The audio outputs of my SID modules are directly connected to the soundcard (Hammerfall DSP Multiface) which gives me the freedom to apply different effects to the channels and to mixdown them seperatly. For other usecases I cannot provide schematics, but I guess that good working VCA (voltage controlled amplifier) and mixing circuits can be found somewhere in the web.

Controlling pan: thats possible if you add a MBHP_AOUT modules, which gives you 8 analog (CV) outputs. They are part of the modulation matrix, so you cannot only control them with all 6 LFOs, but also with the 2 envelope generators.

One of the CV output can control two VCAs which balance the output between two audio channels. Schematics -> search in the web

12 part polyphony: currently possible with a little effort if you assign the SIDs to different keyzones. However, a real polyphony will maybe be provided sooner or later, but from my experience this will be just a "nice-to-have", but no real useful feature, since each SID only provides one filter channel (which means: complex sounds with filters are not made for polyphony). I myself never needed something like this, so: "low priority"

Best Regards, Thorsten.