m00dawg

For my MB-SID, I'm trying to figure out the best method wiring up the audio out. Originally I was going to use 1/4" TRS jacks in stereo (just like the MB-6582). It occurred to me that I have plenty of room so perhaps I should use 1/4" Mono jacks or RCA outs instead? I will be eventually using a sound card that has balanced I/O but offering that for each output might be expensive. So I was going to stick with passive output designs (except for a mix out which will either use a plain op-amp or will offered balanced outs - not sure yet). Just sort of taking a census of what people are doing and how well it seems to work. I know the stereo 1/4" jacks save space but since I don't think that is going to be an issue, and since I don't like playing the adapter dance at RatShack, I'd prefer something that was a bit more straightforward in terms of connections. Advice welcome!

Yet another version, this time using only 1 layer and uses DIL headers for the Mix Out. There is no Mix In because that is no longer required. All I have to do is use ribbon cable and compression-crimp terminals along the cable for each stereo out jack. In this way, one long run of cabling is used instead of having the mixed audio through multiple connections in the chain. That is also what made the board design simpler. I was tossing and turning last night not being able to sleep and one thing I thought of was to mount the jacks on the bottom of the board instead of the top. That way the board sits on the jack instead of hangs off of it. It also means I can put pretty silkscreen messages on the top of the board :) This one is now easy to etch at home as well, though I would still prefer to have them made by a fab house. This way I can at least make an actual prototype at home, though. The tolerances are a bit small - Eagle's default DRC check was complaining a bit about the pads and traces being so close to the board edge but they aren't critical such that if some gets slight cut it shouldn't be a bit deal.

Curious as to why you have so many caps? 3 for positive/gnd and 3 for gnd/negative or something? As far as the heat, you don't appear to have a on those regulators and that should make a *BIG* difference. Be careful not to connect your heatsink solution to both the positive and negative regulators though. For the positive regs, you should be able to even use the metal chassis as a sort of heatsink. EDIT: Aha, I think I figured out what you're doing with the caps. It looks like you are using a multi-out transformer? If so, got a model number? I've been looking for something like that for a while.

Thanks TK! Means quite a bit coming from someone such as yourself! I thought I would check to see how much smaller I can make things using SMD resistors and was able to squeeze quite a bit of space. The GM5 and MBFM projects taught me not to be scared of SMD and, in this case, it's just resistors so I think that should be pretty easy to do. I did undersize the board a bit near the headphone jack - the board won't be flush with the size of the case this way and I'm not sure if that's a good idea or not (should save me a tiny bit from BatchPCB doing it this way). Still need to figure out a good solution for linking them together but I"ll dig around the Mouser and Allied catalogs tomorrow to see if I'm on the right track there. If I can find right angled female connectors I would be all set. The idea is to avoid having to use ribbon cable or wires of any kind and just rely on headers.

Attachment fail :)

Originally I was going to make one large EuroRack style board for all my outs on my rackmount MB-SID. But I got to thinking it might be more versatile across projects to break it up into a modular design and would make it simple enough I could probably etch and drill my own boards without it being a huge pain or could just order a bunch from BatchPCB or even Advanced Circuits probably for cheap. The board has an audio in, mix in, and mix out. Audio in goes into a 1/4" TRS jack. The audio out from the jack is then run through resistors and combined with mix in to a mix out. The idea being that I could use some clever headers to link the modules together, ideally without needing any cabling except for the audio in and the final mix out (which would go to my op-amp module). The boards would be supported by the outside nut on the audio jack. Included is the current board layout - not much to it, really. The right-angle headers probably need to be more thought out since I want each board to be as close as possible, ideally even touching each other. Either way, the interconnect should be simple and avoid having to use cabling, so I was thinking of some sort of male/female coupling of some sort. All the headers have a GND pin but, for linking them together, I was only going to connect GND to the left-most audio jack and have it run through the chain via the mix-in / mix-out connections (to avoid ground-loops). Am I doing it right or does anyone see anything wrong with this? The MB-6582 passive mixer design generally worked for me without much fuss and so I'm using basically the same design. I figure I can compensate for the low volumes via the op-amp. If I wanted to do serious recording of each channel, I can just plug directly into that channel to bypass any downsides of the passive mixer design.

I updated the design a small but by going ahead with the jumper idea. Now it is possible to share JD8 (for control surface designs mirroring the MB-6582) or simply use one of the pins on the jumpers separately, avoiding having to share JD8 with the LEDs. I can't think of a great reason to do it that way unless one was using separate LED and button matrices, but I figured I might as well provide that as an option, just in case. I haven't regenerated the pricing or anything but I wouldn't imagine it would change much. We have 7 orders now - the price for 15(using the old quote) will be about $25 which is lower than having a one-off done via BatchPCB. So I may lower the minimum to 15 if everyone is ok with that pricing.

Received as well and much thanks! Sad to see this be the last GM5x5x5 order!

+1 I could use some as well. In a pinch, they are on eBay, but often for much more than $5.

Holy damn, that's a lot of boards! I'll PM you details but basically I'd be happy with 1 or 2. More if you no longer want them but I assume you'll want to hold on to as many as you can given their scarcity :)

We wrapped up our latest song (Bank Robbery) and posted one of our pre-masters as part of a new contest we're having to give one of our forthcoming songs a name! We had differing opinions about what to name it internally and figured might as well let our fans decide. You can hear the tune here and put in your ideas on Facebook. Like most of our songs off the album, no SID or FM love this time, but we used the hell out of the NES :)

I'm after the SSM2044 boards myself.

Cool thanks folks!

Haha oh ok. Well, I liked the TI option just because it also replaces the need for an op-amp, which I was going to use to boost the mix out anyway. So it's either an op-amp or the TI thing. On the other hand, I do have a mic pre-amp that functions as a DI and was planning on using it for recording some of the time (although more as send / bounce more so than as a DI).

As in you're suggesting I just use a DI box or that's what I use to try to find the part in Eagle? (I did try to search for it, still failed miserably :) ).

Had more time than I thought so I went ahead and uploaded the latest board design to the wiki and create a post for it. Not holding my breath that will hit the minimum order anytime soon but there it is anyway :) I'm still a ways out for likely needing to start ordering boards so there's time yet and if we get more folks interested, I could likely wait a little while longer.

I have been working on an 8x8 LED Matrix board for my own MB-SID synth and figured I would offer it up for a bulk order in case anyone was interested in having a printed version cheaper than having one-off done via BatchPCB or somewhere else. Information about the board itself can be found here. The bulk order page can be found here. Adding yourself to the bulk order page only indicates intent but isn't a full obligation at this point. Please only add yourself to the list if you are serious though! Prices should be about $15 (not including shipping) for 25 boards or about $8 for 50 from Advanced Circuits. 25 is the minimum I am willing to do since, otherwise, folks can just have their own boards made via BatchPCB for about the same price. The design is open - you can grab the Eagle files from one of the above links if you'd rather do it on your own. If you have any suggestions, however, just let me know and I will see if I can implement them if they make sense for the design goals. EDIT (2011-09-13): Added Pic of board layout

Ok I'll go ahead and push out the latest revision (mostly just has some silkscreening on it being the difference) and perhaps look at putting up a bulk order in a few days.

Ah ok. I recall you had some great advice on using blind screw-holes for custom panels and control surfaces which is what this application is for. Unlike for the MB-6582, I'm wanting to attach the LCD to the front-panel instead of to a control board is my ultimate plan. But if the 2-56's work then it should work either way. Was just curious if you had affixed an LCD to a panel before, sort of given our previous conversation (from months ago) in another thread. Either way, thanks for the info!

Don't suppose you have a Eagle library you could point me to that would have one of these things? Been searching the base Eagle library and haven't had any luck. Before I go off and make my own I thought I'd check to see :)

Ah ok, thanks for the info! You actually gave me the idea of blind holes in post a few moons ago :) Do you hook the LCD up the same way (using set screws, threaded spacers, screws on the back of the board)?

Indeed I missed the boat on this as well. Suck.

So I've been distracted as of late while working on my band's album which centered more around the NES than the SID. I plan on picking up my MB-SID design here soon which includes the LCD Matrix. It will likely be the first board I'm going to order. Since it's been a while, I wasn't sure if folks were still interested in a bulk order? If so, I'll go ahead and start one on the proper forum but if not I'll likely add this to my BatchPCB list to have made when I'm ready to pull the trigger. The board design I'm pretty happy with so unless folks want the discrete header for the buttons (the 2 pins shared via JD8 on the MB-6582 baseboard), I can't think of much that needs to be changed at this point. This before, the design is untested so be sure to consider this if interested in the bulk order!

Anyone know the screw-size of the mounting holes for most of the CrystalFontz LCDs? Both my 2x20 and 4x20 seem to have the same size. Looks to be an M2.5 (2.5mm diameter) but I don't have an M2.5 screws to verify. I was thinking about mounting the LCD to my front panel instead of a control board since I can make the actual control board for the buttons and things around the LCD smaller which could cut the cost of fabbing the board in half. Hoping someone has attempted that before, hopefully with good results :)

Oooh I didn't even think about an IC-based solution. Well that would make things pretty easy to do. Correct me if I'm wrong, but the IC basically *is* a DI right? Or did you mean something that might offer better quality? Either way, thanks for the info as that's much appreciated! Didn't think of an SMD solution, but that's probably small enough I could make all outputs balanced (not just the mixed output). I was going to do a euro-rack style thing for the back for all the outputs and I think I should have room to add some chips. The mixed out will already have the op-amp design (now probably replaced with something like the above) so I'll already have a bipolar supply ready to go. That could end up being pretty awesome!