Hi guys,
I took some pictures when I built my MB6582 custom power supply. Please find attached some selected pictures of the PSU and how it was made. The PSU features 2 streams with each 5V DC and 9V AC. So you can run 2 devices in parallel with this PSU (e.g. C64 and one MB6582 or two MB6582).
Preparation of the enclosure:
The components:
more pictures to come …
Looking good so far. Cutting big holes is a lot easier with a hole saw 
I can’t wait for 3D printers to come down in price, will make producing plastic cases easier. Well, so long as you are good at CAD.
Who sell this plastic box?
The assembled PSU:
And finally some pictures of the PSU together with my mean green machine 
Looks nice. What switching PSU module did you use? and what case?
Here are some links:
Enclosure:
Transformer:
Mini PSU:
Mains Connector with switch and fuse holder:
Fuse Holder:
Output Plug:
Output Jack:
Various Fuses:
Internal Fuse Holder:
External Fuse Holder:
Cable:
I hope that helps.
Cheers
orange
Looks very nice.
Well done + thanks for documenting it
Edit: just for reference, here is a link to photos of its moar hot-blooded and far less power efficient brother, a linear-only version with overvoltage protection, using the same case, same transformer, same plugs:
http://discourse.midibox.org/t/topic/14451
Greets,
Peter
Anyone know if it would be easy to do one PSU that would power MB6582 and the OPL module which requires +12 -12v?
So one output would do MB6582 and the other would do a Midibox Fm unit, 1xPIC Core and 1xOPL.
Hi,
yes, this should be possible with the following additional mini PSU:
Cheers
orange
@ gilesjuk.
PSU with positive and negative voltages aren’t hard, it is basically the same as positive only, u just need it twice. One rail for + and one for -.
And another transformer. Two outputs with centertap.
I have several sort of finished designs, none wich I actually finished building yet, in my ammo clip. They are aimed at powering sid machines, but to change the design to support +/-12 and +5v only is just a matter of very small changes in the design, and would be slightly less complicated than my original schems too.
I can post my schem drafts with docu if this is of any interest, just let me know.
Hi,
yes I am looking forward receiving your schematics.
Cheers
orange
This is great. I’d like building this myself. Can you please post schematics and values for capacitors etc. The photo’s explain a lot but it’s a bit difficult to see how everything is connected.
Hi Guys,
a couple of people asked me how to wire the PSU. Please find attached the schematic for the wiring:
Please note that TR2 is the 5V switching PSU. The unit I listed in the BOM has a built in protection (against shortage, etc., please see the data sheet).
Attached a measurement of the ripple of the 5V PSU:
I hope that will help you !
Cheers
orange
Thanks Matt.
I think it might be possible to adapt the circuit above to supply 12v (well 15v?) and 5v, instead of your 9v and 5v. Then I could just use 7812’s for the old sid chips and 7809’s for the newer ones on the relevant individual sid_boards:http://ucapps.de/mbhp/mbhp_sid_v3.pdf Does this make sense?
If so, would it simply be a matter of replacing the transformer with a different one with a higher voltage output (and any relevant fuses)? e.g. this one?
15v in seems ok for a 7812, would the 7809’s handle that? or I should I take the input for the 7809’s from the output of the 7812s?
The problem with the 15v transformer above is the current is about half the output of that on your 9v… although if that’s not enough I could always just use both of the 2 outputs (half the sids each). That would be enough once I eventually get all 8x sids, and the full control surface right?
I realise that’s a lot of noob questions in one go, but any input from previous posters or new in this thread would be appreciated.
Thanks
Hi,
the problem with the combination of a transformer with 12V or 15V and a voltage regulator of 9V (7809) or 5v (7805) is that the voltage regulators have to “burn” the unused energy. If you read the documentation of the alternative C64 PSU from hawkeye, you will see that the conversion from 9V down to 5V via the voltage regulator 7805 is only possible with a massive heat sink (which fills half of the encolsure already ). The same applies for the step down from 12V or 15V to 9V. At the end of the day you need the 5V for the uController and its periphery, so you need to have a proper 5V supply.
Having said that, I would stick to the 5V switching PSU. But if you read all the other threads about replacement PSU’s you will find a lot of other proposals. So my solution is just one of many and I am happy with it, although I have investigated all the others. At the end of the day it is also a matter of how much time you would like to spend to come up with your own solution…
Cheers
orange
My PSU (5VDC (7805) and 9VAC ) I dont like switching-PSUs for some reasons… and use a big wire-diameter because of resistance!
Resistance is futile… seriously, wire diameter doesn’t play any role at all here.
However, I would really recommend against a metal enclosure for anything that operates at mains voltage levels. You did not even connect the protective earthing conductor. Life can be so short…
+1 on ilmenators comments!
Go plastic, man!
Wire diameter is only important when drawing lots of amps, for example AWG 16 (1,29mm copper diameter, 1,305mm² wire surface area) is easily good enough for 15Amps, which are never reached in synth applications (excluding amps ;-)).
Have a great weekend!
Peter
Indeed, you better connect the earth connector to the case. And i hope that you have one of those fuses on the mains input, otherwise if the thing short circuits, it wont turn off…
