Param1 Posted April 13, 2011 Report Share Posted April 13, 2011 I connected my power supply directly to the SID 8580 because the power supply does not deliver enough voltage for use with the sammich power regulators. It works fine tho. I am wondering if there is any disadvantage in doing so. SID Longevity or something, dunno. Quote Link to comment Share on other sites More sharing options...
Flying Panther Posted April 13, 2011 Report Share Posted April 13, 2011 Normally, if your power supply fails or spikes, the voltage regulator will take the 'hit' and smooth the voltage to 9V as much as it can, therefore protecting your SID chip. Also it reduces noise/ripple which you may (or may not) hear back in your audio. The additional capacitors after the voltage regulator are there for the noise/ripple reduction as well. Quote Link to comment Share on other sites More sharing options...
Wilba Posted April 14, 2011 Report Share Posted April 14, 2011 Can you clarify exactly what you are doing? i.e. are you using shunts in JP set to 6581 but using 8580 SIDs? What power supply are you using? I'm not sure if what you are doing is "safe" or makes any sense, actually... the 8580 needs 9V supply, so if you're connecting 9V DC input power directly to the SID, then how is the 7809 supposed to work with input voltage equal to output voltage? Quote Link to comment Share on other sites More sharing options...
Param1 Posted April 14, 2011 Author Report Share Posted April 14, 2011 Guys, I somewhat talked BS. I just had a look at the pcblayout.pdf. What I did is overriding the bridge rectifier by using shunts at JBP. JP is set to 8580. I thought overriding the bridge rectifier meant overriding the whole voltage regulation :logik: But as I can see from the layout, everything is behind JBP, the big condenser, 7809 etc. So I assume I am safe from PSU Spikes and the like, is that right? And my original question needs to be: Is there any disadvantage by NOT using the bridge rectifier? p.s. I use a stabilized psu (NOT switchmode) which delivers 11.5 V. If I use the bridge rectifier the SID only gets about 8.5V. I guess exactly the 0.5V missing at the PSU itself (11.5V vs. 12V!) Board Member rbv2 has the same PSU by the way. He also gets 11.5V although the PSU is advertised with 12V. http://www.conrad.de/ce/de/product/518322/STECKERNETZGERAeT-PA-1000S-LED But I would not care if overiding the rectifier is no problem in the long run. Thanks guys Quote Link to comment Share on other sites More sharing options...
nILS Posted April 14, 2011 Report Share Posted April 14, 2011 If the SID works on 8.5v, I'd prefer not to bypass the rectifier. That way if you ever connect an AC PSU or one with the polarity switched your entire sammich won't blow up. Quote Link to comment Share on other sites More sharing options...
Wilba Posted April 14, 2011 Report Share Posted April 14, 2011 If the polarity is reversed (worst case), it will just short through two diodes in parallel, and they're rated at 1.5A of current. The sammichSID probably won't blow up, and even the bridge rectifier probably won't blow up either. Quote Link to comment Share on other sites More sharing options...
Param1 Posted April 14, 2011 Author Report Share Posted April 14, 2011 OK, I can understand that, but if my PSU and polarity is right - and they are right - then there is nothing bad about it? Quote Link to comment Share on other sites More sharing options...
Wilba Posted April 14, 2011 Report Share Posted April 14, 2011 Yes, there's nothing bad about it when it's working. nILS just likes to put the fear of blue smoking death into you... :rolleyes: Quote Link to comment Share on other sites More sharing options...
Param1 Posted April 15, 2011 Author Report Share Posted April 15, 2011 (edited) Yes, there's nothing bad about it when it's working. nILS just likes to put the fear of blue smoking death into you... :rolleyes: lol, it's mean to scare a noob like me, I am already scared by condensers :nuke: :frantics: :w00t: You know what, seriously, if I short the big condenser of the Sammich with my fingers, after turning the Sammich off, would it hurt or even be seriously dangerous? Or is it to small? Edited April 15, 2011 by Param1 Quote Link to comment Share on other sites More sharing options...
Wilba Posted April 15, 2011 Report Share Posted April 15, 2011 Too small to be dangerous. Quote Link to comment Share on other sites More sharing options...
Trasan Posted April 15, 2011 Report Share Posted April 15, 2011 Param1, I did the same as per an earlier thread (bypassing the rectifier) since I have the same situation. Got a 12v PSU but I measured it to 11.3v, it's not a switchmode PSU but simply not up to the advertised spec. I measured the voltages going to the SIDs after bypassing the rectifier and it was exactly 9.0v. Quote Link to comment Share on other sites More sharing options...
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