seppoman Posted February 17, 2008 Report Share Posted February 17, 2008 Hi,some of the chat regulars have already heard about it, but I thought I'd should write a forum post about this project, too :)In the last months I designed a dual SSM2044 filter PCB for use with e.g. MBSID V2. This PCB contains two of the famous SSM2044 24dB low pass filters with the necessary cirquitry, additional LM13700 based Q linearization cirquit and a tiny Omron micro relay for a software controlled (via gate out pins) bypass function. The layout is optimized for use with the AOUT_NG module, requiring the addition of a bipolar option when used with regular V/Oct sources like the original AOUT module.Some pics:Short audio demo: http://www.seppoman.de/stuff/SSMtest2.mp3That's MBSID V2 with 6581 SIDs, "Bassline Demo2" default patch with SID filters turned off. First a sweep without resonance, then a bit of resonance and high resonance. Last a sweep up short before oscillation and down with oscillation (beware of high volume, the end is a bit distorted because of clipping ;))The PCB still isn't final - got the supply connector wrong way for connection to the AOUT_NG, and you might have noticed that I did underestimate the size of 10nF Styroflex capacitors ;)That's it for now,Seppoman Quote Link to comment Share on other sites More sharing options...
MTE Posted February 17, 2008 Report Share Posted February 17, 2008 I love the last 10 seconds, great work man ! :) will this be available as kit in the future ?Regards Quote Link to comment Share on other sites More sharing options...
drsyncenstein Posted February 17, 2008 Report Share Posted February 17, 2008 Looking and sounding good!The 13700 seems to make the resonance a bit more well behaved.I just build your ng_aout and it is a pretty well layed out board,seems this filter will be on the same high level. Quote Link to comment Share on other sites More sharing options...
Wilba Posted February 17, 2008 Report Share Posted February 17, 2008 Very very cool...P.S. I'm glad someone is making use of all those extra headers ;D Quote Link to comment Share on other sites More sharing options...
/tilted/ Posted February 18, 2008 Report Share Posted February 18, 2008 Oh yeah!!The demo is freq in sweet.I'm so glad I have six of these chips...can't wait to build a buncha these. Quote Link to comment Share on other sites More sharing options...
nILS Posted February 18, 2008 Report Share Posted February 18, 2008 Sweet! Very nice :D That'll be a nice addition to the sidLive ;D Keep up the great work, seppo! Quote Link to comment Share on other sites More sharing options...
Sasha Posted February 18, 2008 Report Share Posted February 18, 2008 Great! Must have addon to any SID synth. :)Thanks for samples. Quote Link to comment Share on other sites More sharing options...
seppoman Posted February 18, 2008 Author Report Share Posted February 18, 2008 Hi,thanks for your comments :) I don't think there will be a kit, but I'll find a way to make the PCBs available :)S Quote Link to comment Share on other sites More sharing options...
Sasha Posted February 18, 2008 Report Share Posted February 18, 2008 Public PCB artwork would be fine. ;) Quote Link to comment Share on other sites More sharing options...
/tilted/ Posted February 18, 2008 Report Share Posted February 18, 2008 Public PCB artwork would be fine. ;)...or a PCB... ;D Quote Link to comment Share on other sites More sharing options...
t_xen Posted February 19, 2008 Report Share Posted February 19, 2008 Sounds sweet. :DI'd be down for getting a PCB if made available. :) Quote Link to comment Share on other sites More sharing options...
nebula Posted February 19, 2008 Report Share Posted February 19, 2008 Constructive criticism: would it not be a good idea to make a board that has 4 filters instead of 2? Then if a person decided they only needed 2 filters, they would only need to populate half the board.I'm still really excited and glad you're moving forward with this, but I would need to make 4 of these for my MB-6582, which would mean more redundant parts and more spaghetti.I suggest 4 filters because if you're controlling cutoff and resonance with control voltages, one AOUT_NG would drive 4 filters. Quote Link to comment Share on other sites More sharing options...
Wilba Posted February 19, 2008 Report Share Posted February 19, 2008 I suggest 4 filters because if you're controlling cutoff and resonance with control voltages, one AOUT_NG would drive 4 filters.Yes but for MB-SID V2, you still need one AOUT_NG per Core, two Cores can't share one AOUT_NG to control two filters... although it might be possible for TK to do some magic and make this happen (route one Core's AOUT modulation to a different Core via CAN?) Quote Link to comment Share on other sites More sharing options...
bugfight Posted February 19, 2008 Report Share Posted February 19, 2008 or better: control volume and feedback with the "extra" aout channels Quote Link to comment Share on other sites More sharing options...
seppoman Posted February 20, 2008 Author Report Share Posted February 20, 2008 I'm still really excited and glad you're moving forward with this, but I would need to make 4 of these for my MB-6582, which would mean more redundant parts and more spaghetti.I briefly thought about a quad board, but as Wilba said, MBSid doesn't support more than two filters per core so you'll need to have 4 AOUTs anyway. I don't think sending envelopes via CAN to another core would be feasible without impact on the general performance. Spaghetti factor is actually quite low. Except for the audio and bypass connection, you can put the ssm board side by side with the NG and just have a few short wires. Two is a good number in my opinion, suitable for the SID while not making the PCB unnecessarily big for people building e.g. only a single stereo MBSID.Also, on this PCB there would be virtually no parts to save with a quad version (ok, two polarized capacitors...), it'd essentially be twice the board as it is plus more complicated routing, i.e. more than double the size. And btw, this pcb is 8x5 cm, the few SSM2044 modules out there in the modular world usually are double the size with only one VCF, so I'm actually quite proud on the form factor ;) Except for a few wires less, there'd be nothing to be gained from a quad pcb.If you mean unneeded parts on the AOUTs, you could either build only half of an AOUT or an AOUT_NG with only channels 1-4 stuffed and only channel 1 and 3 with bipolar option.S Quote Link to comment Share on other sites More sharing options...
DrBunsen Posted February 21, 2008 Report Share Posted February 21, 2008 Wait ... those photos ... you have this stuff sitting on carpet??? Have you not heard of static electricity? Quote Link to comment Share on other sites More sharing options...
Sasha Posted February 21, 2008 Report Share Posted February 21, 2008 Have you not heard about anti electrostatic carpets? ;D Quote Link to comment Share on other sites More sharing options...
seppoman Posted February 21, 2008 Author Report Share Posted February 21, 2008 have you not heard that there are carpets that are not made of synthetic junk? :D Plus, I'm not wearing shoes while at home and I never felt any static discharge. Actually, as long as you're not in a large bureau with synthetic carpet while being covered from head to toes in polyester, I believe there's very little chance to damage normal electronic devices that are not specially known for being highly sensitive. I believe all this antistatic thing is a large hype to promote sales of antistatic this-and-that and for electronics manufacturers to be on the safe side (like the American "caution, hot" on coffee mugs - if the coffee wasn't hot I wouldn't buy it ;)). Thanks for warning me, but I know already and am willing to take the risk :)S Quote Link to comment Share on other sites More sharing options...
nebula Posted February 21, 2008 Report Share Posted February 21, 2008 Wait ... those photos ... you have this stuff sitting on carpet??? Have you not heard of static electricity?The real Bunsen Honeydew would never have said that. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted February 22, 2008 Report Share Posted February 22, 2008 hehehe the first thought I had was *omg it's sitting on carpet* then I thought "it's seppo...he knows." so I didn't say anything :) Quote Link to comment Share on other sites More sharing options...
cheater Posted February 22, 2008 Report Share Posted February 22, 2008 I thought static charges in carpets came from the dust contained? ???Demo's great. Great stuff. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted February 23, 2008 Report Share Posted February 23, 2008 The dust would carry a tiiiiny charge...but keep in mind that carpets from natural fibre, which seppo obviously has the good taste to own, won't conduct it anyway. The big concern is with unnatural fibres that generate really big charges in comparison to the dust. Quote Link to comment Share on other sites More sharing options...
widdly Posted March 6, 2008 Report Share Posted March 6, 2008 Does the cutoff frequency track 1v/Oct? Quote Link to comment Share on other sites More sharing options...
Jaicen Posted March 6, 2008 Report Share Posted March 6, 2008 Aout can track V/Oct or V/Hz. I suspect it can be programmed for more esoteric ranges, but i'm not sure of that. EDIT: Actually, if you were referring to the SSM itself, I believe that uses standard V/Octave scaling. Check out the datasheet, readily available via Google if needed. Quote Link to comment Share on other sites More sharing options...
gpmacklin Posted March 31, 2008 Report Share Posted March 31, 2008 Any new information for this PCB? Quote Link to comment Share on other sites More sharing options...
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