Taika-Kim Posted February 10, 2012 Report Share Posted February 10, 2012 (edited) I'm using two dumpstered (one from an abandoned house, the other from a scrapyard) 6581s. I have an used sammichSID 2.0 RC3 I did not build myself. It seems both have broken filters, since cutoff seems to be at max on all channels when playing SIDs with asid. No filter action at all, all songs sound really weird. I know enough of them by heart to hear this :D I have also an encoder problem so haven't programmed yet so much, but if I activate filters on some oscillators, the cutoff seems to be somewhere quite low permanently. This is weird, since it's the opposite of what I hear with SID songs. Resonance does change the sound noticeably though. So is this some problem with the caps, or can filters with broken cutoff action still have working resonance? This would sound a bit strange to me since they're just two aspects of the same response... Here's a pic of one of my caps... Also, does the K in the 470K value mean 10% tolerance, like I read somewhere? I specifically explained that the caps will be part of a lowpass filter in a synth, and I need low tolenrance components... That shop has like the weirdest salesperson of them all, half of the time I'm not sure if he understands me at all :P Anyway, they should be 470pF, as 6581 should have? capsi.jpg: Oh, and I think both chips create a very audible constant note all the time too, is this just a quirk of the MIDIbox/SID-chip interaction, or does this also indicate faulty chips? Edited February 10, 2012 by Taika-Kim Quote Link to comment Share on other sites More sharing options...
Gilesjuk Posted February 10, 2012 Report Share Posted February 10, 2012 6581 envelopes never fully close. It's a bug the 8580 doesn't have. It is worth getting a noise gate for 6581s. I've no idea about your filter problem, im sure others will know. When caps fail they either go open circuit or short. Quote Link to comment Share on other sites More sharing options...
nILS Posted February 11, 2012 Report Share Posted February 11, 2012 That's a 470p cap, yes. if you neither get the filters to work with ASID nor the SID application, then it's pretty likely your SIDs have broken filters. Quote Link to comment Share on other sites More sharing options...
Taika-Kim Posted February 11, 2012 Author Report Share Posted February 11, 2012 (edited) Yeah the filters are not working in ASID... But it's strange that the resonance still affects the sound a lot, so the filters must be active somehow? Anyway, the previous owner was so kind as to promise to send me his old 6582s for free, so I hope I'll be soon rocking :) And, oh, I could use a PCR-300 template for the device, I think spread over several programs most of the functions could be fit there... Or is there a place in some WIKI or something for people to exchange control mappings? Since I hate, hate setting them up :P And, also, Waldorf style mod matrix!! I had microQ some years ago, it's still to this day my favourite digital synth to program... Edited February 11, 2012 by Taika-Kim Quote Link to comment Share on other sites More sharing options...
nILS Posted February 11, 2012 Report Share Posted February 11, 2012 Yeh, the filters may be partially working. Which I'd still consider broken :) Also make sure to change the voltages before using the 6582s. Quote Link to comment Share on other sites More sharing options...
Gilesjuk Posted February 11, 2012 Report Share Posted February 11, 2012 (edited) The filter is the analog part of the SID and so is prone to variation and odd behaviour more than the digital part which often either works or doesn't. I've only had one SID fault in my time of C64 use, one of the channels stopped working. Edited February 11, 2012 by Gilesjuk Quote Link to comment Share on other sites More sharing options...
Taika-Kim Posted February 12, 2012 Author Report Share Posted February 12, 2012 Yeah voltages should be right. Quote Link to comment Share on other sites More sharing options...
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