ytsestef

:o I haven't thought about that! Duh, scumbug brain got BSOD. :P Of course! Thank you very much. Daisy chaining the CV outs of the AOUT_LC doesn't increase the load? Isn't there any side-effect? As for the special sweeps, I guess I can make each channel sound somewhat different by adjusting static frequency and resonance pots on each channel, thus introducing a sort of "offset", right?

You were very right to clarify that :) I just assume that before anyone even thinks of starting such a project, should read at least the basic stuff (manual, each module's design and build manual etc), and that should be the case, but I am wrong in doing so. Thanks for clarifying my post, you are very polite. No such thing as hard feelings or pissing contest, we are all here to learn and then help someone else :)

Technobreath, when I meant "modifications" I meants not only regulation but also rectifying (9VAC to +9V) and also the trick where the two voltages are summed to give +14V in order to regulate it down to +12V for the 6581s. It goes without saying that 8580s and 6582s need +9V, but these are already on the SID module (that's why I said this PSU works with no mods with MBSID projects, as opposed to C64 PSU). As for the switching noise, I highly doubt that even in 192kHz recording it will be audible, since human hearing performance is well below that. But, I see your point and I agree. Only buy this PSU if you're going to record up to 96kHz, just to be sure. ;)

Well, I edited the following in setup.asm : #define AOUT_INTERFACE_TYPE 1 #define AOUT_LC_RESOLUTION_OPTION_M1 1 #define DEFAULT_F2A_CUTOFF_L_AOUT 1 #define DEFAULT_F2A_RESONANCE_L_AOUT 3 #define DEFAULT_F2A_CUTOFF_R_AOUT 2 #define DEFAULT_F2A_RESONANCE_R_AOUT 4 I hope it works (will have to wait for second filter board to arrive) If 8 bits per channel don't satisfy me, I'm, going to build a second AOUT_LC and stack them up sandwich-style (no more room inside the enclosure)

Is it possible to use an AOUT_LC module in 8/8bit mode to control two filters's frequency? (as opposed to 12/4bit for a single filter - ch1 frequency, ch2 resonance). Can it be done via the menus or do I need to change the firmware and recompile? If so, how do I proceed to do that? And would only 8 bits sound that bad? :P

Thanks! It's almost finished electronically (mechanically it needs a lot of work). Unfortunately I don't have any SSMs, I'd like to buy the 8580 from you, if you want to trade only, that's ok :)

Another major breakthrough today! I received the 8580... MAN this thing is quiet compared to 6581!!! It's so much better that I am starting thinking doing the following changes: - Get another 8580, ditch the 6581 - Forget the whole 6581/8580 mixer thing - Go for a mono/stereo switch that does the following: When in stereo, everything is bypassed and the two SIDs's outputs get routed each to an audio jack (true MBSID stereo) When in mono, the two 8580s are summed (for 6voice polyphony) and that mono signal then gets routed through the fuzz/speaker sim/delay, then routed through a third "mono" output (could also go for duplicating it to both "L" and "R" outputs but It's going to drop in level by -3dB and I'm out of space so I can't exactly build an active splitter). - Get rid of the chorus since in mono I can simply detune/modulate the oscillators which is somewhat similar to a chorus efffect. - Get rid of the noise gate since the 8580 has very good SNR performance. Only with fuzz activated it will be audible, that's why I am also thinking of replacing the Big Muff with a Fuzz Factory which has a built-in noise gate. So I will be able to choose between a true stereo 8580 MBSID and a six-voice mono 8580 with Steiner VCF (with CV control and everything), fuzz, speaker simulator, and delay. This way the interior of the synth gets less crowded (no extra noise gate and chorus) and the front panel (no 6581/8580 mix pots). What do you guys think? PS: I also received Mike's AOUT_LC kit today. Great stuff! Thanks Mike :)

I am building my own version of MBSID, not a MB6582, but you need to put the Meanwell PSU in an enclosure, mount a C64 style socket on it (or any socket for that matter), then make a cable from "whatever-plug-you-have-used" to C64 DIN plug with correct pinout and bypass the MB6582 "optimized C64 psu" circuit by leaving out/bridging any rectifier/regulator etc (you have to check the MB6582 schematics to be sure, I don't know much about MB6582 but if it has a C64 connector I bet it has such a circuit integrated). The Meanwell RPT60-B PSU doesn't need any sort of modification to work with MBSID projects (but the C64 PSU does, that's why you need to bypass it if it's already in the MB6582 board). Cheers!

You're using wires, I see. It can be done that way. I made mine using solder from pad to pad, like this:

That diagonal line beneath IC3 is going to be difficult to solder...

Agreed, making your own linear PSU is no big deal, you just need to calculate the current drain of the whole circuit and then add some more juice ;) All of my previous DIY builds use custom linear PSUs designed and built by me, but I have no idea about switching PSUs, and I needed something small and lightweight for my synth, that's why I bought one :)

This thread is all yours! Long thread, but very useful info in there. I, for one, am using a Meanwell RPT-60B for the MBSID I'm building right now.

Never mind, I fixed it! A trace was ripped off (the Midi+ signal) off the controller PCB. Those PCM mount DIN5 sockets are the absolute horror! Avoid at all costs! :P

Today we had a breakthrough and a major bump on the road. The PSU arrived (btw its beautiful and very small for its power), wired it up. Among the PCBs I have finished populating and wiring at this point: - CORE module works - DINX4 module works - Bankstick module works - SID module works - Minimal CS works Now, I have a very strange problem: The midi controller of the keyboard does not send MIDI data at all (of so it seems) when connected directly from the midi out of the keyboard controller PCB to the midi in of the core module, but when I connect it via an m-audio 2x2 midi interface that I have lying around (in THRU mode, not USB), tadaaaa it sends midi messages and mid SIDs sing... I guess the m-audio midi interface buffers the signal and/or gets rid of noise or ground loops? I'm not sure. I know midi is strange and prone to noise and hum issues due to the optoisolators used and I highly suspect grounding issues here, but I am not sure how to wire it up. So far, my grounding scheme is as follows: Mains ground is connected directly from the IEC connector of the synth to a large metal bar underneath the keyboard, where the jack from the output also connects (the signal comes very clear, when i disconnect it all sorts of noise comes along, so I guess this is right). Also 0vdc from the master keyboard controller is connected to the same bar (I saw this on the original master keyboard enclosure, so I just moved it over to my design. Also different midi pinouts confuse me (where pin2 is NC at IN, but connected to shield at OUT etc), but I guess this is only important when using midi cables (as opposed to wires for 5-6cm from pcb to pcb, which is what I'm doing). To confuse you even more, before I get the PSU I connected them using different PSUs for each device (C64 for mbsid, generic wall-wart for master keyboard controller) and it worked, which only makes it more obvious that there is noise/ground loop introduced when using a single PSU. Any thoughts? Any help would be much appreciated! I'm pretty much at a loss!

Some of the effects need +9V to work and have some 7805 on them, so, it won't handle the +12V output of the PSU AAAND I can't skip the regulators and feed directly +5V, because they need +9V too. If I use a 7809 for supplying 9V to these 2-3 boards, will I introduce any problems (apart from inefficiency)? This would actually mean 7809 in series with a 7805 (on the effect pcb)... but i guess the load will be very low even with three boards (the most power-hungry circuit uses a TL072 and a PT2399 at worst) I would be grateful to any replies :) EDIT: maybe the 7805 will handle +12V input if I use TO-220 and a heatsink?

We'll see if there is any room for that after the main build is finished :D Thanks for the tip!

I think there is already a 7809 on the MB_SID module (specifically for 8580s, otherwise 7812 has to be used).

I believe exactly the opposite. Just a picture is enough to understand that the control surface gives hand-on control for all the basic stuff... To answer your question, I find the MBSID6582 (just like any MBSID w/ full CS) very, VERY easy and quick to use.

Just finished the bankstick module. I left #0 out because I already have 2 banksticks in cartridge form with ID#0, so I have 7 banks on-board and 1 hot-swappable :) Took me a good 4 hours to make on veroboard. Seems simple... ...but it's not!

Seems after all I won't be able to send each SID to either mode of the filter because the mixer has to be before the filter (obviously) and I don't think it's possible to just Y-cable the filter inputs (to be able to send both SIDs to the same filter input), so I guess the active mixer mixes the two SIDs and then I switch the summed signal to select filter mode... Feature Removed!!

I found an MXR Noise Gate on tonepad with a single threshold control (saves up front panel space) and some optional mods for attack/release controls (in case I need them). They have PCBs for sale too :) The only problem now is that I saw other fx as well like a small clone (analog chorus) with rate/depth controls (obvious uses for a synth) and a simple marshall speaker simulator with no controls that might come in handy to smooth out the ugly edges of the fuzz. Am starting to worry I will end up running out of space, money and, worst of all, PSU power :P

Ah yes, I forgot about that. That was the plan at first. But I can't seem to find a verified schematic that can be done easily on veroboard or (even better) a printed pcb (much like the midibox modules that can be bought). Any ideas on that? Is anybody aware of a source with a simple noise gate circuit?

I will post my results when I finish building it :) In the meantime, here is a photojournal of my build

I made this thread as a photo-journal for my upcoming build, to give ideas to other folks who may be interested in something like this and to ask for help for the specific project all in one place (it's likely that I'll stumble upon many problems and I don't want to flood the forum with threads everywhere for each one :) ) Some story: Back in 2007 I had built a not-so-cool MBSID with two 6581s (I never got it to work in stereo, still don't know why, tried everything) that was pretty ugly, had a Minimal CS and was fiddly at best. Had some problems with the C64 PSU and the "optimized circuit" (latching transistors sometimes hang up if caps not fully empty, so the +5V rail failed upon startup), stereo wasn't working, one of the 6581 had a messed up filter, so I ended using it as mono, anyway. I was always frustrated with the terrible SNR performance of the 6581, so when I use it in the studio I always noise-gate it, and when I take it with me live (I play at various bands - mainly synthbass parts) I always ask for the sound engineer to noise-gate it (although same couldn't happen on stage because I usually feed it directly to a bass-amp for monitoring). I ended up not using it regularly (as much as I love its sound) not only because of the beforementioned problems with the build, but also because I didn't want to carry so much stuff with me ("proper" synth, MBSID, extra master keyboard- I don't like layering and splitting, I want to have every single note available to one instrument at a time). So, the other day, a client/friend of mine gave to me an Evolution MK-361c, which is a master keyboard (now discontinued, company bought by M-Audio - I think). "I don't ever use it, I'm a singer, your a keyboard player, so why don't you have some fun with it?", he said. The problem was I already have a (better) master keyboard, so didn't know what to do with it. I am an electronic device hoarder, though, so I thought i'd keep it. :P Then it occured to me: what if I merge the Evolution MK and the MBSID into an all-powerful standalone synth? It would have its own keyboard, and I have plenty of case real-estate to fit some other stuff in there, such as: - an analog filter (as good as the 8580 filter is in comparison with 6581, it will never match a discreet analog filter imho). I chose the Steiner VCF, which is a diode-ladder design, has plenty of character, is multimode, sounds good enough, is easy to build and has CV control. - a simple DIY digital delay with modulation (this one in particular: http://musicpcb.com/pcbs/echo-base-delay/), which I have already made in a stompbox and rarely use it, can't get the LFO behave properly, but I'm hoping to fix it. I am a big fan of "analog-type" filtered delays in pads and leads, as well as some slap delay for fast-decaying sounds - I always thought analog synths sound "dry" on their own. - a big muff (fuzz) clone for that dirty synth bass (I play a lot of synthbass). - an small 2ch active mixer to control the mix of the two SIDs. I'll have one 6581 and one 8580 so I can blend them together and even route each one to a different input of the filter via a switch (LP,BP,HP). This way I can keep the moody/distorted/filtered low end of the 6581 and the sparkly top end or midrange of the 8580 and do all kinds of crazy combinations. Well these are the key features that make it a new twist on the average project. Apart from that it will feature a lot of default stuff: -Knob #1 to #5 as analog pots, directly on core module -Minimal Control Surface -7 internal banksticks #1-#7, a 9DIN input for BANK #0 (I already have a couple of bankstick "cartridges") -AOUT_LC module for controlling the Steiner VCF -Meanwell RPT-60B switching PSU, because I need a -12V rail as well (some modules use inverting opamps). It's small, very likely to be in the synth casing and not in the form of an external brick) -Master Volume control -Pitch Bend and Mod Wheel (kept from the Master Keyboard) -Octave Up/Down buttons (kept from the Master Keyboard) -3PDT switch to route the MIDI IN of the Core Module to either the MIDI OUT of the Master Keyboard Contoller for live playing or the back panel MIDI IN jack for sequenced playback and firmware upgrades etc. (no money or space -and probably use- for a MIDI merger) The only problem is that the Master Keyboard is 5 octaves long, and I don't need that much, I want a compact synth! But when I opened the case I knew it would be easy to cut it down to 3 octaves. SO I DID! (the pcb was cut using a dremel, the keys are interchangable in groups of 1 octave each and the main mounting plate was cut using an electrical saw). AND IT WORKS :D I ordered the wood from a local store, yesterday I build the main casing which is the bottom, side panels, a post to support the keyboard and a front post that fills the gap from the bottom up to the lowest point of the key when it is pressed: VOILA: I'm very happy with it for now, all goes well! If I'm forgetting something obvious that will become a show-stopper later and you find it, please do tell!!! Its difficult to predict everything on my own when I'm disigning such a complex (for me) instrument!

Its +/-12V with a +5V, still very cool, though :)