I will give you the final answer next thursday
Thanks very much. I won’t be able to have the layout and part footprints validated before then (Mouser order arrives on Wednesday) so this should work out very well.
-Steve
Earler in this thread Wilba suggested that Vcc, Vdd, and GND for the SID be run back to the power supply on their own. Well, this seems a bit silly on this board, but I went ahead and did that anyway. I also added some shielding around the audio lines.
To see the current state of the layout (this is likely very, very close to the final one) either check the link above, or here: Small - Large
The only thing left to do is validate the physical dimensions of the parts, give everything one last going over, and then I’ll order the prototype boards.
-Steve
It wasn’t really a suggestion… I’m no audio electronics expert at all, only quoting the SID datasheet. Perhaps someone else can suggest whether a ground plane would be better, i.e. even less noisy.
I was hoping that your experience with this PCB design would help me in my own, so I could decide whether to join the SID’s ground to a ground plane or use an explicit track.
It wasn’t really a suggestion… I’m no audio electronics expert at all, only quoting the SID datasheet. Perhaps someone else can suggest whether a ground plane would be better, i.e. even less noisy.
I was hoping that your experience with this PCB design would help me in my own, so I could decide whether to join the SID’s ground to a ground plane or use an explicit track.
I understand. I’m learning here as well… That’s a big part of this project for me. After reading the datasheet, I decided to go for it. It also allowed me to clear up a few other areas as I shuffled things around. I also went with a ground plane encircling the audio lines as more of a safety measure. I’ve seen it done on other audio gear, so I put it here as well.
To be honest with you, I don’t see how the special routing of Vcc, Vdd, and GND could help much, but I figured that it can’t hurt.
I’ve also put up yet another version of the image. Provided all the parts footprints check out (they should) and my checking once again (triple? quadruple?) versus the reference schematics is good, this is the layout I’ll have made into the prototypes.
-Steve
It’s still difficult for me to make the final decision, there are many pros and cons, some of them will be propably mentioned later once I’m very sure…
However, I’ve an important question: are you using a legal copy of Eagle? Because the freeware version is limited to 100x80 mm size and only allowed for non-profit projects. The commercial version is very expensive.
Best Regards, Thorsten.
I could be misunderstanding, but i’m sure c0nsumer said that the board was 180 x 80mm to fit in a hammond project case. Ergo, must be a full version of eagle.
hi c0nsumer,
you probably think i’m a wanker by now but.. do you feel $35 is absolute minimum for you? if i make a quick calculation, your “hard profit” will be around $10 per kit, sell 100 kits and you have made $1000…
of course then you could donate half to TK (development) or TwinX (webhosting) ;D
pls don’t think i’m telling you this stuff, i’m asking… i appreciate your work and contributions, i’m just very kritikal/skeptikal when money gets involved in these things
cheers, marcel
c0nsumer: I’m interested to know who’s doing the PCB manufacture, especially your prototype ones, as I have a need to get some made. I’m thinking of using BatchPCB, but I’d like to shop around first.
Yes, I am using a legal copy of Eagle. I have a license for the non-profit version detailed here. This allows me up to 160mm x 100mm boards. These are actually 159mm x 80mm (to compensate for potential tolerance issues in the enclosure), but that’s besides the point.
Because of this license I would need to upgrade to a commercial standard license at an additional cost of US$273 if I were to sell the boards for a profit. With this taken into account, it’s only after I sold enough boards/kits/whatever with a profit of >$US273 that I would be ‘making’ anything off of these sales. If you take into account prototype PCBs and such, that break-even point of US$273 goes up even higher. But I’m not counting that.
That said, my other option with this license is to simply have a small number of boards made and sell them (with appropriate PICs, most likely, as many people don’t have an easy way of programming them) at my precise cost. Thusly there would be no profit, no commercial sales, and I would be complying with the letter of the license. Accepting payment for the PCB+PIC sets via PayPal, I presume I would figure the at-cost price as follows:
PCB Cost + Portion Of Overall PCB Shipping Cost + PIC Cost + Portion of PIC Shipping Cost + Packaging Cost + PayPal Fees + Final Postage Cost = Final Price
With the aforementioned cost of PICs and PCBs I would see this being somewhere around US$25 + postage. However, I am only likely to offer a small number of these for sale (20 or so). That is because I would want to ensure that *all* of the sets sell, because I do not wish to have money sunk into unused parts just setting around. Perhaps the best way to ensure this would be to ask those interested to pre-order these sets. That way I’m assured that I won’t be ‘stuck’ with unwanted kits. Making a profit isn’t a concern, I just do not want to lose money.
While I agree that the aforementioned calculation by illogik of the potential profits from the sale of 100 kits sounds good, I question how long it would actually take for one to sell that many kits. While I – and many others – think the MIDIbox (and MIDIbox SID) project is great, I’m not sure that there are enough people who would be interested in a kit such as mine to ensure these sales. With an off the top of the head judgement made by reading the MIDIbox SID forum, I would estimate that one or two people begin construction of a MIDIbox SID per week. Presume I had 100 kits available for sale, if every single one of these individuals (based on my estimate) purchased a kit, it would still take 1-2 years to sell through them.
So, I guess at this point I’m starting to re-think my whole idea of selling these. I may be interested in selling a very limited number of sets at cost, if there is sufficient interest. But, we’ll see… I may also just fall back on my previous idea of having only 5 or so boards made – the original quantity intended for myself (I want to build 2 or 3 complete devices) and a couple friends who are also interested.
By the way, now that the design of the main PCB itself is wrapping up, I’ve begun thinking about the PCB for the front panel. That is, the one to which the LCD, six pushbuttons, and rotary encoder intended to be used for Step A – Control Surface. I don’t want a full control surface, just something which will allow easy selection of patches via an LCD and such. My current plan is to use this LCD (it arrives tomorrow) with everything situated similar to how TK did it in Step A. There’s the chance I may just go with all buttons (instead of a rotary encoder) but that’ll be determined sometime later.
Anyway, that’s where things stand now… TK, if you’d like to discuss this out of a public forum, please feel free to email me at the address listed in my profile. I’m also available most of the time via a variety of instant messangers, which are also listed in my profile.
Oh, and illogik, don’t worry, I’m very open to whatever comments. I tend to feel ‘weird’ whenever the idea of making money comes into any project as well. Unfortunately this always comes up when absolutely all of the parts cannot be produced by me, and I need to spend time doing things I rather dislike (packaging / driving to the post office / handling orders) there becomes a desire to make at least a bit of money off the process. If it were just a matter of drawing a PCB, posting it, and everyone could suddenly use it, money wouldn’t come up at all. That part I really enjoy doing.
-Steve
c0nsumer: I’m interested to know who’s doing the PCB manufacture, especially your prototype ones, as I have a need to get some made. I’m thinking of using BatchPCB, but I’d like to shop around first.
I have used PCBFABEXPRESS for my original prototype boards and I was really happy with them. As 5-piece quantities for less than 20 square inches they cost around US$13/each. Fot these prototypes I’ll probably go with them again. Turnaround from order placement to at-my-doorstep was about 1.5 weeks.
If I somehow end up actually needing a large quantity of boards (50 or more) I’ll probably go with Advanced Circuits. They have a very good reputation, good prices, and make the boards in the US. I’m also going to look K&F Electronics, but only because they are located about 10 miles from my house. It might be nice to work with someone local.
For small runs of personal stuff, though, I would strongly suggest you take a look at PCBFABEXPRESS. I can vouch for their boards being quite nice. I’ve got some 600dpi scans of my first prototype PCBs here if you want to see.
-Steve
Yeah, don’t mean to be a smartypants. I do that all the time. I’ve removed my post and I’ll take this one down too if it ends up on its meaningless own, and we can get back to business 
Hey, let me know how you get on with that LCD, as it’s the one I had planned to use for my SID project too! It looks brilliant!
This request is: DENIED
Please don’t see this as a personal attack, it is my error, that I haven’t spent enough thoughts on the general approach for sale requests like yours.
I haven’t considered the consequences good enough - e.g., the consequence, that it won’t be so easy anymore to make small but incompatible changes in the circuits, module interconnections or firmware if they improve the project with an acceptable documentation effort. At the end, I would loose the motivation to do any useful changes in future (partly this is already the case).
But even more I haven’t considered that SmashTV and Mike, who have already spent a lot of money and effort to provide PCBs for best prices to the community, will hang on their preinvestions if other people are trying to do sell PCBs and kits as well. The only right way is to work together with these guys, to distribute new PCBs over the already existing channels, and not to go into competition with people who have already helped the community so much in the last years!
And even if they are not interested in the PCB (maybe because it’s too much customized to your own needs, and not flexible enough for others), you can still contribute by releasing the layout and the documentation for free - midibox.org has a lot of filespace. The board could be a nice inspiration for others to improve your work, maybe the results will inspirate you as well, and at the end we will maybe find the perfect solution, which is really worth for a PCB batch order, and where I also would be willing to support the variant in future.
I’ve now written an addendum to the rules to make my intentions more clear: http://www.midibox.org/forum/index.php?topic=5758.msg45977#msg45977
Best Regards, Thorsten.
TK,
Thanks for the final answer. While I don’t completely understand your reasons for the decision, I do respect your wishes that these PCBs not be made available for sale.
That said, I am continuing to work on this project as I was originally was – for myself and a couple of friends – while making all files / documentation available for everyone to use and share. I have also gone ahead and renamed my project to ‘MIDIbox SID-NUXX’.
I have ordered five PCBs for myself, and once I’m sure they work as desired, I’ll make the Gerber/Excellon and Eagle files available so others may make use of them. Hopefully I will have them within two weeks.
After I have more documentation / final information available I will start a new thread in the SID portion fo the forum to announce it all and make people aware of its’ availablility as a resource. Thus far I am planning on releasing board layouts, case specifications, front / rear panel designs, and all other related documentation. Most of it I just have to finish writing or create. 
Anyway, thanks for getting the MIDIbox project going, TK. This has definitely been an interesting learning experience, and hopefully by the time I am finished building “my” MIDIbox SID I’ll have contribute bits of information to the community which people find useful.
-Steve
Anyone in Europe found a place to have the pcb’s for this project fabricated? I tried Olimex, but the files aren’t up to their specs..
Thanks,
KS