Some questions about the SID...

Design Concepts
1

I’m nearing completion on my SID, just waiting on the LCD and a few transistors, and I’ve got a couple questions before I throw everything together.

I think I’ll end up powering everything off of a single 17v DC source, and it seems to be a good idea to run that 17v first throught the voltage regulator on the SID board and then through the core’s voltage regulator. From what I’ve read in the specsheets of the VRs of the two modules, this is a pretty good route to go.

And I’m building the core and SID modules into the same housing (an extruded aluminum box from a really old Motorolla cellphone, pretty big) and attaching the LCD and some buttons and a single encoder or maybe increment/decrement buttons on an external control unit, to provide modularity, and whatever.

Any reason not to route the DIN and LCD lines through the same DB25 conection? Any noise or signalling issues?

And what about cable routing and shielding for the audio portions of the SID? Anything I sould be looking out for, like proximity to digital or power lines?

Thanks all!!

Da5id

2

The DIN and LCD stuff should not be a problem. As to audio, use good analog signal practice during construction. That is, keep all audio well away from digital signals, dont ground the shields to the same point you ground your DC and digital stuff. Dont earth both ends of the audio shielding in the same unit (can set up ground loops…hum)

On gear I build, I usually take all the audio gnd’s to one point and fit a switch between them and the units analog gnd point. This way if I find I get a hum when plugged into an amp or mixer, I can “float” the analog gnd off whatever it is connected to…( I hope this makes sense ::))

3

Humm, I was planning on using some panelmount RCA connectors for the audio  i/o, but they have an all-metal exterior, meaning that the whole case will be analog ground.

Should I change output connectors? Or just go ahead and try it (the piece of aluminum they’ll be in is one I crafted, so if I have to junk it, only a bit of construction time is lost)?

And thanks for the tips on shielding and routing.