krismosh Posted April 4, 2007 Report Share Posted April 4, 2007 Yes another newbie question. I have populated all pcbs and ready to test. I got Smash T.V.'s kits and was wondering if I still need to build the improved psu circuit? I've read so many posts I think I'm just confusing myself more with each one. If i do need to build the improved psu circuit do I just use the components supplied in the kits? Thanks for any help. Quote Link to comment Share on other sites More sharing options...
dj3nk Posted April 4, 2007 Report Share Posted April 4, 2007 You just need the "onboard" psu. The optimized one is better for SIDs and their background noise.greetz Quote Link to comment Share on other sites More sharing options...
krismosh Posted April 5, 2007 Author Report Share Posted April 5, 2007 please excuse my ignorance, but your saying I should build it only if I get noise from my sid modules? I have two 8580's I don't know if this makes a difference. Is the point of the improved psu to get the circuitry away from the module to reduce the amount of noise it picks up? I apologize in advance if these are redundant or novice but your time is greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Wilba Posted April 5, 2007 Report Share Posted April 5, 2007 It's mainly about using a common ground. If you've supplied your Core and SID modules with separare power supplies (i.e. two plug packs) then the grounds of the two modules are connected (so the logic levels of Core->SID have the same 0v reference). This causes what is called "ground loops" which is a very complicated concept that I don't fully understand, but essentially means there's more than one path to ground... i.e. the current on the SID module could go to ground via the SID power supply or jump across to the Core and go to the ground of the Core power supply.The other issue is digital noise on the 5v/ground supply, to reduce digital noise, the optimized PSU circuit joins them up with common wires rather than each SID module being supplied by the Core to which it is connected.If you have multiple Core and SID modules, the best solution is to have one set of bridge rectifiers/regulators (i.e. for 9v and 5v) and join their grounds together and supply each module from one central PSU circuit... I mean you do not need an actual C64 "brick" PSU with 9v AV and 5v DC outputs... you can use two plug-packs to get your two voltages and copy the rest of the circuit, supplying a REGULATED 5v DC to all modules and a REGULATED 14v DC supply to each SID module (and use whatever regulator on each SID module to drop it down to 12v or 9v as required). Or if it's easier, use a REGULATED 9v DC or 12v DC supply (one 7809 or 7812 for all SID modules!) and connect it to where the REGULATED supply is required on each SID module (i.e. the output pin of the regulator on each module).Whatever you decide to do, DO NOT INSERT SIDS until you check the voltages on the SID socket pins, and also check that ground is ground everywhere... i.e. check difference in voltage between ground pins of the chip sockets and a common ground at the PSU... Quote Link to comment Share on other sites More sharing options...
krismosh Posted April 5, 2007 Author Report Share Posted April 5, 2007 Thanks wilba! You've answered questions for me in the past and once again you've been a big help. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.