Custom Power Supply for mb6582

[middleman]

If all you need is +12 -12 & +5 volts and don't mind a little HF, a computer psu will do nicely, especially one from a mini itx or similar (small size). They are cheap, reliable (mostly) and efficient. Add a 9 volt regulator to the +12 volt line and a few passives to clean up any residual HF and you have a very flexible unit.

[dreamer]

@hawkeye: I know they are, but i can't find anything else out there that could work. Best would be a lineaire PSU like the one you build but can't find any on the internet. So only option would be a switching supply i guess. And i should find one with the highest brrzzzztrzts out there to not be able to hear.

@middleman: I think a computer psu will have lots of noise on the audiolines so thats why i decided to look for a pro psu that has very high frequency switching. Hard to find a nice one. especially here in holland.

Edit:

OMG i just found a supplier for lineair PSU that possible could work:

http://www.emersonindustrial.com/en-us/egselectricalgroup/products/Control-Power-Solutions/Power-Supplies/SL-Single-Multi-Output-Linears/Pages/default.aspx

Possible candidates:

SLD-12-6034-05T --> Output1: 5V @ 6A output2: 12V @ 3.4A

http://nl.mouser.com/Search/ProductDetail.aspx?qs=Fhl5NpiNeCXzw4jbrRylrA%3D%3D

SLT 12-61818-12T1 --> Output1: 5V @ 6A output2: 12V @ 1.8A output3: -12V @ 1.8A

http://www.remotesiteproducts.com/SPD/sola-slt12-61818-12t1-sola-silver-line-triple-output-linear-power-supply-case-g2-4-87--h-x-11--w-x-2-75--d--output-1=5vdc-6a-output-2=12vdc-1-8a-or-15v-1-5a-output-3=--12v-1-8a-or--15v-1-5a-with-remote-sense-and-built-in-ovp--industry-accepted-foorprint-for-open-frame--low-noise--extremely-quiet-dc-output-for-noise-sensitive-or-analog-circuitry---8000150F-1277743896.jsp

Edited July 22, 2011 by dreamer

[jojjelito]

Those linear PSUs must be nice, you could almost buy somebody's time to solder up something in an evening for that kind of money. Or get a serious amount of filtering components should noise be problem with the switchers. You'd still need -12 or -5V so the SLD-12-6034 is out unless you're willing to employ some voltage inverting trickery, but then you could roll your own PSU fully instead.

[Hawkeye]

dreamer, they do look nice and while they may seem expensive, they are not really, as jojjelito noted correctly, ´cause if you calculate time for building your own and sourcing the parts, they are quite cheap. I´ve also seen, that Conrad sells some "lineare Netzteile" for those from germany...

[m00dawg]

I wish I knew what sort of protection and stuff was built into those things but otherwise, yeah, those are a great find! I like building PSUs but it would be nice to work on designing the stuff that makes noise more than the stuff to power it :)

[Hawkeye]

+1 on the protection thoughts...

hopefully at some time someone here will come up with a PCB using standard parts, linear supply for the audio components, offering protection and a good build tutorial...

[jojjelito]

Dude, don't tempt me. Let's see what happens after the holidays...

[dreamer]

I'm going to use one of these linear PSU's.

Can someone give me good advice which one would work right out of the box.?

http://www.emersonin...es/default.aspx

Possible candidates:

SLD-12-6034-05T --> Output1: 5V @ 6A output2: 12V @ 3.4A

http://nl.mouser.com...4jbrRylrA%3D%3D

SLT 12-61818-12T1 --> Output1: 5V @ 6A output2: 12V @ 1.8A output3: -12V @ 1.8A

http://www.remotesit...-1277743896.jsp

Thanks

[jojjelito]

I'm going to use one of these linear PSU's.

Can someone give me good advice which one would work right out of the box.?

http://www.emersonin...es/default.aspx

Possible candidates:

SLD-12-6034-05T --> Output1: 5V @ 6A output2: 12V @ 3.4A

http://nl.mouser.com...4jbrRylrA%3D%3D

SLT 12-61818-12T1 --> Output1: 5V @ 6A output2: 12V @ 1.8A output3: -12V @ 1.8A

http://www.remotesit...-1277743896.jsp

Thanks

Fixed that for you! Or well... If you ever intend to build an external filterbox you'll need negative voltage as well. If you're going to run the 6582 stand-alone you'll do fine with either plus a 9VDC regulator inside the 6582 (there will be some heat dissipation in the box, maybe not optimal, but working).

Cheers!

J

[orange_hand]

Hi,

I would also appreciate if somebody could come up with a standard design that works as a replacement for the original C64 PSU. I have ordered a kit which is used in connection with a PC PSU, but I don't expect this to be a great solution.

I think it shouldn't be too difficult to optimize Retro Donald's design in order to remove the remaining noise and to protect the 5V voltage regulator. We could then develop a circuit board that could be used as a basis. Unfortunately I am not an electrician, otherwise I would have already done it.

Cheers

orange

[m00dawg]

I would also appreciate if somebody could come up with a standard design that works as a replacement for the original C64 PSU. I have ordered a kit which is used in connection with a PC PSU, but I don't expect this to be a great solution.

I think it shouldn't be too difficult to optimize Retro Donald's design in order to remove the remaining noise and to protect the 5V voltage regulator. We could then develop a circuit board that could be used as a basis. Unfortunately I am not an electrician, otherwise I would have already done it.

You don't need to be an electrician (I think you mean electrical engineer) to design a build a PSU. You need a sense of safety, common-sense, and some concepts (many of which you can find on this very thread).

[Shuriken]

I am working on something, but as it's smd i think it's not going to make it as a standard design. Hawkeye has a good design for a linear PSU with protection.

[Hawkeye]

Thanks, but mine is not perfect, it needs a power resistor for burning off some excess volts just ahead of the vreg, and I had the feeling that using it introduced a little bit of noise to the MB6582,

A-B´ing it with the original PSU revealed it - the effect is not very promiment though, especially regarding the relatively high noise floor of the SIDs...

Need to look at the output of the PSU with a scope and need to perform some capacitator replacement tests...

Dreamer, on second thought, I would not invest 150 bucks in a linear psu but instead recommend to try to build the crowbar protector as a separate "middleware" cirucit ... this has some advantages:

a) cheap

b) non-lethal voltages involved

c) reuse of the C64 brick (we only have one planet)

d) quick to build

All you need is a fuse, and the thrysistor-sub-circuit after the vreg from retro-donald.

Also, you can test it very nicely with a lab psu or a 9v battery (the crowbar triggers at ca 6.2Volts)... this should raise your confidence regarding your SIDs safety :-)

Greets,

Peter

Edited August 8, 2011 by Hawkeye

[Shuriken]

I never said it was perfect :wink:

[orange_hand]

Hi Guys,

let's improve Retro Donald's design and create a layout that can be professionally produced. I have already downloaded the Eagle software and I think the free version will do the job.

Cheers

orange

[Hawkeye]

To be fair, soldering the necessary connections on a vector board did not really take long and the schem is totally straightforward...

If you are creating a PCB, you are dependent on the exact spacing/measurements of the transformer, which is not good (even reichelt does not have my original unit in stock all the time)...

Also, the case needs to be laid out for the size of the transformer and the heat sink... also worldwide availability of those components would be necessary..

So thats why I guess everyone brews their own PSU around here (or buys it)... but if anyone creates a PCB and maybe offers a parts kit including shipping... that would surely count as a heroic job :-). I would not do it, because of the risk of someone touching mains voltage while building that PSU...

Greets,

Peter

[orange_hand]

Hi Guys,

the fuse of the right PSU got broken yesterday after a two hour session. Thank god the box is still alive ... The fuse must have got broken after I had already switched off the PSU .... does it make sense to replace the fuse and carry on ?

I have to do something....

Cheers

orange

[jojjelito]

Hi Guys,

the fuse of the right PSU got broken yesterday after a two hour session. Thank god the box is still alive ... The fuse must have got broken after I had already switched off the PSU .... does it make sense to replace the fuse and carry on ?

I have to do something....

Cheers

orange

Replace away! I destroyed a fuse once during the build of the 6582 in the old style brick. No worries, it was a stupid mistake and no harm done. Pop out, replace and look happy

[orange_hand]

No worries, it was a stupid mistake and no harm done. Pop out, replace and look happy

I wished I was so relaxed to ignore the fact that this fuse burned through for some reason. I think it is better not to carry on with this PSU. I need to place another order at Reichelt :-)

Cheers

orange

[jojjelito]

Ahh, my fuse destructor was my measuring probe so it was possible to explain and not entirely unexpected. If yours did mysteriously go bad you'd better look into replacing the PSU.

Cheers,

J

[orange_hand]

yes, that is what I will do. Has anybody an idea what kind of power resistor we have to put in front of the voltage regulator ? I would like to go with the optimized schematic in the first place :-)

Cheers

orange

[Hawkeye]

I´ve no idea too, but expect it to be less than 8 ohms... so you could buy a few cheap 1R (11W) wire resistors and test with a variable number of them in series... until the voltage regulator gets its optimum voltage (while under load from the MB6582)... Ohms law would prolly help to calculate it :)

Greets,

Peter

[NorthernLightX]

Guys, TK has stated in the past that there will be no official MB PSU module, as tinkering with mains voltages is dangerous and he will not take responsibility. If you cannot design a simple linear PSU you should definitely not try to solder one. You have to understand what you're doing.

(/disclaimer)

Linear PSU's that output multiple voltages (e.g. +9v and +5v) look simple on paper, but are more difficult practically. The easiest way to do this is to use multiple transformers. I have tried to use a single transformer to output multiple voltages in the past and this project failed due to heat production when creating +5v from +12v (even when using properly rated power resistors) and the addedd stress on the 12v rail this caused. It is also not all that easy to find properly rated (toroid) transformers for these projects that are also moderately priced.

PC switching PSUs are notoriously noisy and I would never recommend using one for any synth or audio project.

There is some positive news though: I have used the Mean Well RPT-60B for my MB6582 (which is now a lot closer to completion) without problems. The synth is very quiet, as far as any SID based synth can be quiet.

These type of switching PSU's are not all that expensive and most are equipped with Molex connectors, so integrating these in your synth (or in an external enclosure) should not prove too difficult. It doesn't have to be Mean Well at all, just pull up the spec sheet and look at the switching frequency, if it's above 50KHz you should be fine. Higher than that should mean the existing noise wouldn't even be recorded on higher settings than 48KHz.

So, if you want to design a linear PSU just go ahead. It's fun and it will help you understand electronics a lot better, just don't expect it to be cheap and/or a one shot solution. If on the other hand you want to get it over with; go and find yourself a proper switching PSU.

Cheers.

[orange_hand]

Hi NorthernLightX,

I can understand the background of not publishing a PSU for the MB6582. On the other hand it is more dangerous to leave people alone with this task, especially considering that they are no electronic experts. There is a schematic out there which forms a good basis, so there is just the issue with the power resistor in front of the voltage regulator. I have now lost one original PSU and luckily my MB6582 was not damaged. I am not going to risk my MB6582 with an old power supply any longer. At least I will build the PSU as populated on Retro Donald's page. I will then also try to use a PC PSU with a special adaptor where I have already got the Kit for.

I also can't believe that is is so complicated to come up with a solution here ... Yesterday I also found a description that explains the modification of the original power supply, so that it is more stable. The big issue there is that the voltage regulator in the original power supply is covered with artificial resin, so this is also not really a good option.

Cheers

orange

[NorthernLightX]

I have now lost one original PSU and luckily my MB6582 was not damaged. I am not going to risk my MB6582 with an old power supply any longer.

I understand this and I agree fully. I have had the same problem in the past, and also have abandonned the C64 brick method.

What I am saying is that you should either familiarize yourself with linear PSU's a lot more, or just buy a switcher. Both methods can be used to get a working solution. If you're unable to design your own linear PSU (which isn't that hard!) I would not advise to use a (modified) design you don't understand fully.

Except for a mains level electrical shock there is also the risk of fire and/or small explosion (electrolytical capacitors for example when used incorrectly) if the wrong components are used. Would you risk fire based on someone else's design? Someone you don't know all that well, and someone that might even have a bigger mouth than design skills?

I am not calling anybody incompetent, but please consider the risks a bit more before tinkering with mains voltage. If you understand what it involves: go ahead and have fun. If you don't: there are other, faster, safer solutions :thumbsup: