m00dawg

If you're willing to cut tracks and do some interesting things, you could possibly wire the 6581 to your 12VDC input (assuming you have 12VDC coming in) and can just use the 7809 regulator for the 8580. Seems like that would work but I have never even though about doing a mod like that on my Sammich, so it was just a thought :)

Ooooh that's a very good idea! I'll have to play around with that once I finish the rest of the CS boards, thanks for the idea!

Ah yeah I forgot about the Arduino shields! Looks like many of them are secure by multiple pin headers to help provide rigidity? My problem is that the only pin headers I would use are the front headers on the MB-6582 and those are single row. So I was worried about stress caused by the top board only being secured via the single row headers alone.

I came up with an idea to use an intermediate board of sorts between the MB-6582 and my custom control surface to make wiring the control surface easier and avoid an ugly mess of cabling. This allows me to be able to make at least some of the boards myself since a few of them are single-layer or only have a few extra traces on a 2-layer (which I can just use wires for if making my own). I can also make the control surface more modular. Basically, each module has SIL headers that then all go into this CS board. From there, I route all the wires to match the pin-headers on the MB-6582 itself. Originally I was going to use regular ribbon cable (with pin headers) to connect the MB-6582 and the CS board. The thought crossed me mind, however, that it might be easier to wire, and more space efficient to simply connect the CS Board directly to the MB-6582 by using pin-headers, in similar fashion to the Sammich designs. The question is, since those are SIL headers, I was wondering how stable that might be without using another support mechanism? I was wanting to put the board as far forward (up towards the PICs) as I could before running into the SIDs (and leaving some room for the heatsinks and some air circulation) or at least put it so that the headers are centered to the board to sort of balance it. Anything I might need to be aware of? I was worried that this might cause some wiggle and would stress the solder joints, though that might only be an issue while moving the synth around (and it will be rackmount so I don't plan on doing that often). I'm not sure how many people have tried doing such things (other than Wilba and nILS with the Sammich designs) but thought I would ask to see if I am going down the right path :)

Anyone know where I can find an Eagle library for the Neutrik 1/4" stereo switched phono plugs like the ones used on the MB-6582? Eagle (part no NMJ6HFD2)? Eagle has a Neutrik library but none of the audio jacks are even close to the NMJ6HFD2 and equivalents. I am basically making my own passive mixer board and was going to use PCB mount jacks to keep things simple. There's a few reasons for wanting to use my own board. For one, I can use extra filter boards (such as the SSM 2044, yummy!) without needing another set of outputs or anything like that. I am also going to add a CMoy style preamp to the passive mixed output, which I also hope to switch between a front-mounted mixed phones jack as well as a rear mounted one. In any case, before I go spending a lot of time making a layout for the Neutrik TRS jacks (I haven't done that before :) ), I thought I'd check to see if anyone had one for use? Willing to buy you a beer via PayPal :) EDIT: Though it is a bit off topic, for the curious, here is a rough draft of the audio board (I'm simply calling it AudioBus). The 5-pin headers are what I would like to be the PCB-mount Neutriks.

Since the SwinSID supports some additional features, are there any control surface enhancements that can/need be done? I was curious since SwinSID can do some FM synthesis stuff, supports more waveforms (apparently, though I have not been able to find a list of them), among other things. I was planning on using all SIDs but using the SwinSID for drums and other things might be a good idea and I should have room in my chassis either of the SwinSID designs (X2 or Micro). Thanks!

I don't think you'll hurt anything, but you are still supplying 5V to the SIDs even by disconnecting the jumper. So if you want to be certain, I would remove them. To avoid damaging the pins of your SIDs, consider plugging them into a socket and plugging that socket into the MB6582. That way you can remove the secondary socket (with SID) and only risk bending the pins on the second socket. The fan noise may be unavoidable but you may be able to reduce it by making sure you are powering the fan using a separate supply from the SIDs and COREs. In some of the PSU designs, you can tap off the power input (before the regulators) for the fan. As far as the pots go, I believe logarithmic is what you want since you are dealing with audio, although I haven't tried using feedback pots myself so you might want a second opinion there.

Yeah I'm debating on building my own switcher, but I can't imagine being able to do it in a smaller space than I could buy one. I think if I was building my own PSU, I would just go the linear route since I already have that designed and have a prototype board ready to go for it. *shrug* I haven't decided what I should be doing yet :) But I have time anyway since I need to finish my final space measurements and need to start populating a new MB-6582 baseboard.

Yeah but, again, if you're using them as a post filter after the regulation phase of a PSU then it's a non-issue typically because, unless something really bad happens, the voltage past the regulator will be stable or nil meaning it is easy to predict what types of tolerances you will need for the tantalum. The data-sheet for the LM2675 includes a tantalum for the input so I could see that possibly being more of an issue depending on what is being used to feed the regulator. If it's the output of another, regulated, supply, however, then it's basically a non-issue. Again, unless something goes really wrong :)

@olga42: It seems like the majority of folks on this forum hate tantalums :) They are, however, fairly good at filtering HF noise. I think even the low ESR electrolytics were tested (see some of those PDF links earlier in this post, though I'm not sure which page they are on so you may have to do some digging/searching) and tantalums were still much preferred. I think using them past the regulated section of a PSU should help avoid their explosive tendencies since, by that time, the voltage should be quite stable. Regardless, I'll look again at the low ESR electrolytics. I have heard Panasonic is a great brand to go with from multiple places so that's probably a safe bet...as far as aluminum electrolytics go :) @Shuriken I assume you won't have more luck with a US-based store, but alliedelec.com has quite a few tantalums as well as Panasonic (and others) caps. I typically use them for more common parts (mostly since they are close by and shipping is uber fast usually).

The reason I haven't noticed the soft audio is probably because I'm running it through a hardware mixer most of the time anyway. The only time I use the dedicated audio jacks are when I am doing recording or something like that. Otherwise, I don't have enough inputs on my computer or my mixer to be able to use the discrete inputs. I haven't had to really crank up the gain on the mixer though was my point. I've also used the passive audio jack with headphones and it sounded actually a bit loud, though I am sure that depends greatly on the headphones. I suppose a nice benefit of using the Cmoy is I can just turn out the volume pot a bit higher if the audio seems a tad soft. I think 47k is probably a pretty good place to start though. I've seen that value used elsewhere as well, though not in a dedicated mixer design necessarily.

Wilba has a small mention of it on the MB-6582 wiki page: From what I have found while tinkering with my NES and the PowerPak, small changes in resistor values don't change the output all that much, and I suspect that is because we hear loudness logarithmicly. That said, I haven't really found the output of the MB-6582 to be soft really though I am curious to know what good values are as well since I will have to make my own passive mixer for my MB-SID most likely and might as well try to improve upon the passive mixer design. Actually, I will likely mix down to two stereo channels and feed that into a Cmoy style headphone / pre amp.

Ah SMD isn't that bad :) As far as low ESR, what would you folks recommend? I know tantalum tends to offer low ESR. Anything else? Capacitance values matter much here as well? What I have done to this point is based off what I read from the PDFs I linked on this thread a while ago. Seems that Tantalum would do the trick for anything close to the audio spectrum (and perhaps further out though I haven't seen any data on that).

Yep including 3mm mounting holes, although I thought of forgoing it and just using an insulator on the bottom just because the holes account for 1/4th of the space :) By the way, Shuriken is correct - some of the switching regulators I found do indeed switch at 1MHz which is plenty. Looks like in order to get 9V, though, might have to get an adjustable regulator (which is the LM2675 Shuriken mentioned). to switch down to 9V. I suppose that's an option over using the 7809 in my setup, although 12 -> 9V for the SIDs probably isn't bad enough to be worried about heat (I'm going to secure it to the chassis anyway).

Ah wow when you said you were building your own switcher, I was a tad skeptical but I forgot about switched regulators (duh :P). I dunno for me having a PSU that is ready-made and has all the protection built-in seems like a good way to go. I made a tiny board for the extra tantalum filtering caps and a 7809 and it's only 1.25 x 1.30 in which is pretty tiny and may be sufficient. Hell I dunno what I'm going to do :) I already have a linear design that, while it lacks some of the protection stuff discussed earlier in this thread, seems to look pretty solid (and isn't much more complicated than my own PSU I was using previously). I don't like the idea of loosing 50% of my PSU efficiency due to heat - I could bring that down with transformers but then the design gets pretty big. I don't think I can make a switching supply much smaller than my linear design, save for the lack of a big transformer (?) so for me it's other a ready-made PSU + a tiny filtering/regulating board; or a linear PSU option.

Ah good point! I haven't totally decided yet on what I should do :) I am going to design the intermediate power board for the 7809 regulator for the SIDs and filtering caps to see how small I can make that. I suspect that won't take much space at all and would still be smaller than my original linear PSU design (based off your original design) and a lot more efficient power-wise.

Hah yeah I found the frequency stuff right before I was going to buy one as well - so I guess I saved us both. I sent Mean Well an e-mail asking what the fastest switching supply they had was, but I think we have already run into it (TP-75). PFC stands for power factor correction but the wikipedia article is a bit thick to read (for me anyway) in terms of what that means or if it might introduce noise. RPT-60 looks like a winner, though it's about the same price on Mouser as the LPT42 I found. I was looking specifically at Mouser since I was ordering some encoders and things as well. I know there are places to find these types of power supplies cheaper here in the US, however.

Heads up, not all of the Mean-Well switching supplies switch at 132kHz. Some data-sheets do not list a switching frequency while others (such as the T-40) list it at 40kHz. The TP-75 was the one that had the highest switching frequency but also the highest cost :) EDIT: Also found this off Mouser. It's not Meal-Well but meets the specs and has a documented switching frequency of 110kHz.

Ah I see what you mean now. I never knew C64 PSUs even had externally accessible fuses :) I wonder if those are in fewer numbers in the US or if I'm just unlucky. The thing about the safety is the fuse is that it helps my own stupidity. Apart from that I'll admit there isn't much going on a C64 PSU that's different than modern linear PSUs. However, I'd much prefer new electroyltic caps over ones that have been around for 20 years and that's getting close to the shelf life of some electrolytics. I've run into bad caps on gear less old than many of the C64's out in the wild. I would also guess that failure rates among 20 year old regulators over new ones should be taken into account as well. Again, how much are SIDs worth? More than a 20 year old PSU? For me, the answer is absolutely. SIDs aren't going to be easier to find, after all; but all the parts found in a C64 PSU are readily available and can be improved upon.

There's more than a "few" stories, but sure it's less than the majority. Thing is, many (all?) of the C64 brick revisions were filled with epoxy. Good luck digging through that mess to replace a fuse. I believe that's what is wrong with one of my bricks. I was like you, once. But then I had two of those monsters go out on me. One was probably my fault but I'm not digging through mountains of epoxy to replace a fuse. Fortunately, neither have taken my SIDs out (I think one did take a PIC out though but it's been a while since I began refusing to use these things). I figured it would be more repairable to simply build one. The wonderful thing about the Mean Well PSUs (listed in the thread I linked to in my last post) is that, while they are a switching supply, they are way above the audio band (132kHz if memory serves). That's not high enough for those wanting to sample at 192kHz (without capturing some noise), but far above human hearing. For the overly concerned (myself included), using some tantalum and other HF filtering caps may be all that is needed. The Mean Well isn't completely hobbyless - it's not in a nice plastic case, but a metal one you would typically put inside another case. It's a super solid start though. I would love to see a C64-compatible PSU that was an easy to assemble kit (much like CORE) but that idea, while it has been attempted both on and off these forums, has never really materialized in a "kit". It's not difficult to build, though. To each his own, of course. I'm sure many have had good luck with the C64 PSUs. I haven't, and many people haven't either. For me, the value of my SIDs vastly exceeds the cost of building or buying a new, modern, PSU. Building PSUs are, in fact, something I find really fun, but again the Mean Well's look pretty dern solid.

Hehe I was interested but I'm in the US so I figured the savings would work out for me due to shipping.

Your SIDs are precious. The C64 PSU is an evil chip destroying piece of shit, to be frank. forum post has some very good information about a modern alternative without having to build your own PSU from scratch. May be something to consider.

Haha that deserves a real LOL (I really did laugh out loud). I used to work at a place next to a junior college and one of the students had some crazy chameleon paint on his car. The above reminds me of that, but it does look damn good, nicely done!

132Khz is far beyond what humans can hear, yes. It's not beyond what modern samplers can do (I've seen up to 192kHz). For most applications, it's insane to go really above 96kHz. Some might say 44kHz is enough and call me out on the Nyquist Frequency Theorem but having a lower noise floor means that you can do other naughty things to audio without raising the noise floor to audible levels. One example is halving the speed of a drum loop which would cut the sampling rate in half (which ends up being 48kHz when sampling at 96kHz of course, which is still above 44kHz so no problem there). For most practical purposes, 96kHz fills those needs. But when people want to REALLY much with the audio, 192kHz could make some sense, although at that point, your noise floor is really 132kHz when using the above power supply. I can't imagine needing 192kHz in my applications so I never record at that (I do record and highly endorse recording at 24-bit precision, even for old noisy vintage chips like the SID). So, though it's wildly pathological, filtering that noise out is in those applications might not be a bad things to look at. So far, the only graph I have seen is the one I previously. If I am reading that correctly, we know that tantalum can attenuate 10kHz and we could infer from the graph that it can do more since the filtering was approaching zero. That's a large assumption though to go form 10kHz to 132kHz though :) As far as the SID sound, as I said before, I know it's noisy, but it's not a distracting sort of noise and the whole point is to capture the imperfections of the SID - not the PSU :) Long story short, for most people (likely including myself), it sounds like this switch-mode PSU is well worth it by itself without having to do any extra filtering. The exception is those with OCD :) EDIT: Here is a another PDF describing characteristics of different capacitors when uses to attenuate HF noise from switching supplies. Figure 11 shows filtering over 100kHz (if I am reading it right, the ripple is a bit higher than that). Tantalum does indeed filter out a good chunk of the noise at those frequencies. Ceramics can also work well according to the docs, though they may introduce some noise as well (the document does not say what type of noise or at what frequency). So, the takeaway is that, again, for pathological cases, adding a tantalum cap seems like the way to go or perhaps a ceramic. Perhaps even the two could be coupled together *shrug*. I don't even have a way to test the results at those frequencies so, again, it's all very pathological :)