chromdildo Posted May 4, 2004 Report Posted May 4, 2004 Assembled a MBSID-module, everything is ok.But...I'm not really satisfied with the filters.I tried different caps... * the 470pF (Styroflex) - quite no filter audible... * replaced it by 1nF (Kerko) - very muffled sound, few and unstable resonance... * with the original caps of the C64 box: little better, but not a *FILTER*!Any suggestions witch capacitors are best?MOS 6581 - [0483]btw:...I replaced the 1k resistors with 1k1 5%(couldnt find just 1k's). got anything to do with my filter problem? thanks. ./chrom Quote
chromdildo Posted May 4, 2004 Author Report Posted May 4, 2004 Assembled a MBSID-module, everything is ok.But...I'm not really satisfied with the filters.I tried different caps... * the 470pF (Styroflex) - quite no filter audible... * replaced it by 1nF (Kerko) - very muffled sound, few and unstable resonance... * with the original caps of the C64 box: little better, but not a *FILTER*!Any suggestions witch capacitors are best?MOS 6581 - [0483]btw:...I replaced the 1k resistors with 1k1 5%(couldnt find just 1k's). got anything to do with my filter problem? thanks. ./chrom Quote
pay_c Posted May 4, 2004 Report Posted May 4, 2004 I first used the cermamic caps, too. They are really no hit indeed.Then I used Styroflex ones. I think they´re great. The center frequency is very stable all over the 8 caps!The 1,1k shouldn´t be a big prob. Although I´m asking myself, why you didnt´find 1ks (they´re so f**** standard pieces, you know ) :)Anyhow: I think the Styroflex are the best ones to use (they´re relatively cheap for such a low tolerance). Perhaps you fried yours with soldering them - they´re *extremely* easy destroyed by heat.Greetz! Quote
pay_c Posted May 4, 2004 Report Posted May 4, 2004 I first used the cermamic caps, too. They are really no hit indeed.Then I used Styroflex ones. I think they´re great. The center frequency is very stable all over the 8 caps!The 1,1k shouldn´t be a big prob. Although I´m asking myself, why you didnt´find 1ks (they´re so f**** standard pieces, you know ) :)Anyhow: I think the Styroflex are the best ones to use (they´re relatively cheap for such a low tolerance). Perhaps you fried yours with soldering them - they´re *extremely* easy destroyed by heat.Greetz! Quote
chromdildo Posted May 4, 2004 Author Report Posted May 4, 2004 thank you for the quick reply.witch values did you use for the Styroflex caps?the original 470pF ??I don't think I destroyed mine by heat... (but who knows) :-/regards../chrom Quote
chromdildo Posted May 4, 2004 Author Report Posted May 4, 2004 thank you for the quick reply.witch values did you use for the Styroflex caps?the original 470pF ??I don't think I destroyed mine by heat... (but who knows) :-/regards../chrom Quote
TK. Posted May 4, 2004 Report Posted May 4, 2004 Yes, PayC also uses 470pF so far I remember. Just a reminder: in main.asm, you have to set "CBM8580_FILTER_FIX" to 0, otherwise your 6581 will be driven like a 8580, the result would be a wrong filter characteristicAnd another note: from the three 6581 I own I've only one which sounds good. If your focus is on the filters, I would strongly recomment the 8580!Best Regards, Thorsten. Quote
TK. Posted May 4, 2004 Report Posted May 4, 2004 Yes, PayC also uses 470pF so far I remember. Just a reminder: in main.asm, you have to set "CBM8580_FILTER_FIX" to 0, otherwise your 6581 will be driven like a 8580, the result would be a wrong filter characteristicAnd another note: from the three 6581 I own I've only one which sounds good. If your focus is on the filters, I would strongly recomment the 8580!Best Regards, Thorsten. Quote
chromdildo Posted May 5, 2004 Author Report Posted May 5, 2004 is there any list with differences between the different MOS/SID production cycles over the years?Or a shematic with the inner part of PIN 1-4 (filter)?I got another 6581 and two 8580. will try these...btw: I came across "Captain Hastings" website http://compiler.kaustic.net/fm/ who built a AOUT-kind-of-module (digital pot) with the Analog Devices AD5204....What about driving an analog filter module .... moog style.... :D.... dont shoot, just an idea../chrom Quote
chromdildo Posted May 5, 2004 Author Report Posted May 5, 2004 is there any list with differences between the different MOS/SID production cycles over the years?Or a shematic with the inner part of PIN 1-4 (filter)?I got another 6581 and two 8580. will try these...btw: I came across "Captain Hastings" website http://compiler.kaustic.net/fm/ who built a AOUT-kind-of-module (digital pot) with the Analog Devices AD5204....What about driving an analog filter module .... moog style.... :D.... dont shoot, just an idea../chrom Quote
d2k Posted May 5, 2004 Report Posted May 5, 2004 Hey...That effects box on captain hastings sites looks quite commercial - is it?Would be nice if he could talk about that digital pot MIOS intergration some more - Im sure alot of other mb users wud like to hear too!Dan Quote
d2k Posted May 5, 2004 Report Posted May 5, 2004 Hey...That effects box on captain hastings sites looks quite commercial - is it?Would be nice if he could talk about that digital pot MIOS intergration some more - Im sure alot of other mb users wud like to hear too!Dan Quote
chromdildo Posted May 6, 2004 Author Report Posted May 6, 2004 Yes. I think this would be a really great idea to enhance MIOS with this digital pot.Think about:Quite every analog fx, synth, sequencer circuit could be controlled via midi..../chrom Quote
chromdildo Posted May 6, 2004 Author Report Posted May 6, 2004 Yes. I think this would be a really great idea to enhance MIOS with this digital pot.Think about:Quite every analog fx, synth, sequencer circuit could be controlled via midi..../chrom Quote
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