SID low noise guide

[Hermes]

Hello everyone

One of the most important issues with regard to the costruction of a MB SID synth is, undoubtedly, how you are going to achieve as low noise output as possible.  Being on the process of constructing my own quad MB SID, I have searched the forum, as well as www.ucapps.de, but I have only found scattered information on this subject. :-/

So I suggest we use this thread to set up the principles one must follow to get low noise out of his SID synthesizer output(s). Some of them can be already found in some threads, for instance the use of TK's  modified C64 PSU or the use of a metal box for better grounding (tip from pay_c)

So are there any specific parts or soldering methods or any other tips in general that result to low noise?

Does the use of the SID inputs affect noise?

I hope something good gets out of this thread...  :)

Best regards

Dimitris (Hermes)  

[pay_c]

OK, here I go. All I remember right now:

- *All* lines carrying audio signals (audio in & out) should be made with shielded cables. Furthermore good caps (e.g. "Styroflex" @ Reichelt) should be used there (no cheap ceramic ones!)

- No "sandwiching" of PCBs! This means no PCB over the other! All ideally next to each other

- Metal case like already mentiones to keep bad stuff out of there and also to have a good shielding underneath the PCBs (also that metal paper of the C64 can be used for that)

- Avoid ground loops! Always connect ground lines star-like      E.g.:  GndSID1-GndSID2-GndCore-GndDIN1-GndDIN2

(NOT!! : GndSID1-GndSID2-GndCore-GndDIN1-GndDIN2-GndDSID1!!)

- Keep lines carrying higher currents away from all audio stuff (also from the PCBs). E.g. following cables: DOUTs, MIDI lines, PSU lines (AC *AND * DC!) ...

If still to bad (e.g. clicks in the audio) shield it away (seperate shielding of those lines/PCBs)

That´s all I remember right now. If I get more like that into my brain again, I´ll write again.  :)