Shuriken Posted May 30, 2011 Report Share Posted May 30, 2011 (edited) It's been awhile since i posted any updates. I finally managed to get all the parts for the PSU. I will be using a LM22675 for the 9V supply and a LM22676 for the 5V section. These baby's are high efficient (85-95% depending on components) and the switch freq is 500kHz. Getting my hands on those regulators took me a long time. I initially was going for an older model LM2676. However after 2 months waiting Futurelec couldn't deliver those. So i started looking for another source. To only discover i could source them straight from National Semi as a sample. Apparently this is quiet popular :wink:, so they charge you 12 dollars for shipping. Which is of course only fair and made me feel less guilty. :angel: After that i used National Semi's online WeBench design tool, to select all the parts. After a hard and long look, i could match selected components with stuff at Reichelt. Only the Power Inductors were not in National Semi's partlist. The WeBench tool has the option to add custom components and it turned out the Power Inductors Reichelt has are up to spec. Only thing i couldn't find was some 0,01 uF ceremic smd in 12xx size. But i found those at Conrad. The schematics are here: LM22676 Schematic LM22675 Schematic I am currently in the process of designing the boards in Eagle. I am sticking to the design layouts in the datasheets. Only tricky bit it that both IC have an exposed pad. Which basically is a small metal surface on the bottom of the IC for heat transfer. You need to solder this to the board. And it has to have vias to the other side of the board for additional heat transfer. If you want to hand solder them, apparently you need to add one big via in the middle. So that you can stick your solder iron through it. Another option of course is to use thermal adhesive. I haven't decided yet. Here is a preview off one of the unfinished boards: Edited May 30, 2011 by Shuriken Quote Link to comment Share on other sites More sharing options...
dreamer Posted July 16, 2011 Report Share Posted July 16, 2011 so if i read this correct. I could use the standard RPT-60B to power my mb6582a instead of the original c64 psu. I only need to get a nice case for it and do some cabeling to it to connect to my mb658. I wonder if the RPT-60B fits inside the original case of the c64 psu. regards Quote Link to comment Share on other sites More sharing options...
middleman Posted July 20, 2011 Report Share Posted July 20, 2011 (edited) The old portable (luggable)c64 used a switched mode psu for all voltages. Personally, I would use a switchmode for the +5v (digital) supply as HF has no effect here, plus you get the benefits of higher efficiency (lower heat and electricty bills) smaller size and more ouput per euro. There is no need to filter when used for this purpose. They normally include over voltage and short circuit protection as standard. I would not take a DIY approach to switchmode design, as the internal voltages are significantly higher than mains levels. Even after switch-off they can deliver lethal currents. In a commercial design, all components are caged for this reason. By all means build a linear psu for the audio portions of the circuit. When building, it is a good idea to first solder up the mains side of the transformer, and then tape off or otherwise insulate the bare tags before continuing. I have used the LM723 voltage regulator in combination with a power transistor for linear regulation in the past. You can set the voltage precisely if you want, and also set your own current limits. It has better line and load regulation than fixed voltage regulators too, which is important with analog synths. Edited July 20, 2011 by middleman Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 20, 2011 Report Share Posted July 20, 2011 While most of the above info is both appreciated and helpful, I have to mention that the C64 PSU looks far more like a linear PSU to me. Check this out. Part of the reason it was so damn heavy was the transformer stuck inside. A switchmode PSU would not have a need for such a big transformer, nor would the bricks be prone to overheating like they tend to be. Quote Link to comment Share on other sites More sharing options...
sidmonster Posted July 20, 2011 Report Share Posted July 20, 2011 While most of the above info is both appreciated and helpful, I have to mention that the C64 PSU looks far more like a linear PSU to me. Check this out. Part of the reason it was so damn heavy was the transformer stuck inside. A switchmode PSU would not have a need for such a big transformer, nor would the bricks be prone to overheating like they tend to be. He's talking about the sx-64 it was a portable commodore with integrated display and disk drive, the granfather of the laptop. Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 20, 2011 Report Share Posted July 20, 2011 Ah yeah curses. That lack of coffee strikes again as I misread the first sentence to read the "luggable C64 power-supply." Oops. I stand corrected! Quote Link to comment Share on other sites More sharing options...
jojjelito Posted July 20, 2011 Report Share Posted July 20, 2011 Interesting this "all the great gear was made in the 70's and 80's and didn't need no stinkeen switch-mode supplies" :) Technology evolves, but a beefy toroid is just like a V8 - it's nice and chunky. Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 20, 2011 Report Share Posted July 20, 2011 I haven't finished building my MB6582-based synth but I have decided to go with a linear. I like most of the ideas behind a switch-mode but regardless of whether I can actually heart the switching I just like the idea of analog equipment to have analog PSUs. *shrug* Plus it's easier to build and building PSUs is something I enjoy. That said, the modern switchmode PSUs are actually quite efficient and switch well above the audible range (most of them - at least the ones in this thread) so it's generally a good way to go. I agree with sidmonster though, it would be unwise to try to build one but the Mean-Wells are pretty good for their size and performance. Quote Link to comment Share on other sites More sharing options...
Hawkeye Posted July 20, 2011 Report Share Posted July 20, 2011 +1 and try warming your average household cat on a switcher Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 20, 2011 Report Share Posted July 20, 2011 Haha good point. The brick-based ones make a great feet warmer on those cold winter days too! Quote Link to comment Share on other sites More sharing options...
jojjelito Posted July 20, 2011 Report Share Posted July 20, 2011 (edited) Great idea - it can double up as a great foot-warmer There's no stopping that gravy train once summer is gone. Edited July 20, 2011 by jojjelito Quote Link to comment Share on other sites More sharing options...
vortura Posted July 20, 2011 Report Share Posted July 20, 2011 Dammit... reading this thread has got me worried about smoking my SIDs and they haven't even arrived yet. Until there's an mb6582 PSU for dummies, I'll have to take my chances I guess. I'm the last person who needs to be playing around with mains electricity. Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 20, 2011 Report Share Posted July 20, 2011 The MB6582 can use the C64 PSU so you have a hands-off option there. I think the C64 PSU is a piece of shit but others on this forum will disagree :) There are, however, some designs and maybe even some places to purchase a C64 compatible PSU so you could try that. The switch-mode PSU would be safer than building your own PSU for the 6852 itself since it already supplies the voltages your SIDs need - you'd just need to put it in a case and cable it up to the 6582 and boom, done. I think the MB6582 also lets you power it with a single wall-wart supply with some work (though I don't think that is recommended due to heat). Sorry I was kinda rambling but hopefully there is some worthy tidbits in there :) Quote Link to comment Share on other sites More sharing options...
Hawkeye Posted July 20, 2011 Report Share Posted July 20, 2011 (edited) As this alternative hasn´t been mentioned in this thread yet... I built mine according to retro-donalds spec and it works - it has four fuses and a crowbar overvoltage protection... and was not difficult to build... http://www.retro-don...wernetzteil.php pics here: Me haz a much better feeling now regarding the well-being of the SIDs :-) Greets! Peter Edited July 20, 2011 by Hawkeye Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 20, 2011 Report Share Posted July 20, 2011 Oh wow that looks really nice! Very very cool! I'm gonna share this with some local folks here as I know they'd be interested in a C64-alternative PSU as well! Quote Link to comment Share on other sites More sharing options...
Hawkeye Posted July 20, 2011 Report Share Posted July 20, 2011 (edited) Thanks a lot - I tested it with my original C64 and played a game of "catalypse" (awesome, btw!), before I dared to plug it into the MB6582 :-). The only thing, I would add to retro-donalds design, is a load resistor right ahead of the 78S05 to relieve it a little - the input voltage is a bit high (9V * 1.41) for a 5V regulator - if a few volts are burned off before, it should run a little bit cooler. Otoh, you can go as insane as you like with oversized passive coolers :-). The unit is nearly twice as heavy as the original C64 PSU :-). As a conclusion, it is linear, easy to build, not too expensive and the crowbar protection also works really nice (tested with a lab PSU). Bye, Peter Edited July 20, 2011 by Hawkeye Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 21, 2011 Report Share Posted July 21, 2011 In my opinion, this should be turned into an official MidiBox project and be the preferred way to power most MBSID setups over using an existing C64 (or in cases where they are hard to come by). Has my vote anyway. Quote Link to comment Share on other sites More sharing options...
dreamer Posted July 21, 2011 Report Share Posted July 21, 2011 Yeah would be nice to have a nice and safe midibox project to build a custom MBSID power supply. The options to get a new ready built power supply that has the correct specs to power the MB6582 are nihil. Quote Link to comment Share on other sites More sharing options...
m00dawg Posted July 21, 2011 Report Share Posted July 21, 2011 Well, to be fair, you would still have to build it if it were a MidiBox project - keeping in mind the safety considerations when doing so. Having it as a MidiBox project just means it might be easier to get ones hands on pre-printed boards, kits, and schematics. That's not to say having a place where one could by new C64-compatible PSUs would be a bad thing - it just can't be a MidiBox project according to the license (as I understand it anyway). Quote Link to comment Share on other sites More sharing options...
Hawkeye Posted July 21, 2011 Report Share Posted July 21, 2011 (edited) @Dreamer: Cool - but someone else must do this - I didn´t post explicit instructions in the build tutorial, because I didn´t want to take the risk of bad karma, when someone rebuilds this, forgets that it is plugged in and has a hell of an electrifying trip :-). And also, there are many good (probably better) designs out there, some surely being more efficient (e.g. not pumping 9v * 1.4 into a 5V vreg) or having even better ic-controlled over-voltage protection circuits. Edited July 21, 2011 by Hawkeye Quote Link to comment Share on other sites More sharing options...
dreamer Posted July 21, 2011 Report Share Posted July 21, 2011 i understand youre concern. Thats why it should be a safe build. I'm digging into internet to see if there is maybe somewhere on this globe a nice replacement option. Will post the findings in this topic, if i can find any. I noticed the power suplly nothern descriped is hard to get especially in holland. Quote Link to comment Share on other sites More sharing options...
Shuriken Posted July 21, 2011 Report Share Posted July 21, 2011 (edited) @Dreamer: Cool - but someone else must do this - I didn´t post explicit instructions in the build tutorial, because I didn´t want to take the risk of bad karma, when someone rebuilds this, forgets that it is plugged in and has a hell of an electrifying trip :-). And also, there are many good (probably better) designs out there, some surely being more efficient (e.g. not pumping 9v * 1.4 into a 5V vreg) or having even better ic-controlled over-voltage protection circuits. I am going to use the same size Transformer for my psu, but just a 15V version. Since i am going to use a switching psu, i cannot heat my room with it in winter. Simulations suggest it's going to be 40 Degrees Celsius max. Using a switching PSU does not imply not using a transformer. The IC i use are DC-DC switchers and not . Although the later sound a lot cooler :wink: Edited July 21, 2011 by Shuriken Quote Link to comment Share on other sites More sharing options...
dreamer Posted July 21, 2011 Report Share Posted July 21, 2011 Okay i found a nice site: http://www.sunpower-uk.com This site has loads of different power supply's too bad no price and no option to add to basket. But you can request a quote. I checked some specs, i listed a few of them that has I think the correct specs: SPP-D043 - 30-45W Dual Output Open Frame Power Supply http://www.sunpower-uk.com/product/30-45W-Dual-Output-Open-Frame-Power-Supply/SPP-D043/default.htm PD-45A - 40W Dual Output Open Frame Switching Power Supply http://www.sunpower-uk.com/product/40W-Dual-Output-Open-Frame-Switching-Power-Supply/PD-45A/default.htm SNP-YL63 - 57W 5V & 12V Dual Output Open Framed Power Supply http://www.sunpower-uk.com/product/57W-5V-and-12V-Dual-Output-Open-Framed-Power-Supply/SNP-YL63/default.htm RPD-60A - 49W Dual Output Open Frame Medical PSU http://www.sunpower-uk.com/product/49W-Dual-Output-Open-Frame-Medical-PSU/RPD-60A/default.htm SPS-G050-ID1 - 51W Isolated 5V & 12V Output Enclosed Power Supply http://www.sunpower-uk.com/product/51W-Isolated-5V-and-12V-Output-Enclosed-Power-Supply/SPS-G050-ID1/default.htm I don't have a clue if any of these will work on a mb6582 with 8x sid 6582 in it. Maybe someone could give feedback on this. And especially what specs are important for a power supply for a music instrument. Quote Link to comment Share on other sites More sharing options...
middleman Posted July 22, 2011 Report Share Posted July 22, 2011 Dreamer, did you see any prices on this site? Quote Link to comment Share on other sites More sharing options...
Hawkeye Posted July 22, 2011 Report Share Posted July 22, 2011 dreamer, those are all switchers :) brrzzztrzts (<- simulation of very high frequency output on the audio lines. probably too high frequency to hear, though :-)). Quote Link to comment Share on other sites More sharing options...
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