AC/DC & POWERSTATION KIT BUILD THREAD

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

Thewotan wrote:
Wed Jan 12, 2022 3:49 am
Hi there!

I intend to build a PSU for an 11 slot 51x rack (although it will be used mainy for 500 modules, I would like to have the option to add some 51x in the near future). I got the project second hand from a user in groupdiy. It came with a Kraftwerk PSU populated, but unforunately it was ruined when I tried to desolder most of the components, so I decided to use a Powerstation (Ver. 3) PCB that I had lying around with the Kraftwerk heatsink and with a 2x 25v 3.2 Amp transformer, but I'm going to buy new most of the BOM.


My question is: what wattage should the resistors be? Does 1/4 W suffice for all of them or are there any that should be higher?


Thanks for your help!
We use 0.6w metal film but 0.25w is fine. The large 47R is 1W. The Powerstation to run a full rack of 500/51X will need more capacitor bank added to the +/-V as it only has 2 x 3300uF and you will need 2 x 10000uF or more and extreme heatsinking
Joe :-)
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Thewotan
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Thewotan »

Hey Joe!

First, I'd like to thank you for taking some time to reply me. Appreciate it!

Taking a look to the schematic (BTW, the link on the first page takes me to Power station Ver. 2 schematic. I don't know if there is a lot of differences with ver 3, but I suppose there is not) I understand that the capacitors that conform the bank are capacitors C5, C6, C7, C8, C9 and C10. Is that correct?

I'm a bit lost as how it adds up to 2x3300uF, though 🤔. I got the 1000uF capacitors that came with the Krauftwerk kit. I'll study how to implement those on the Power station PCB and report back 😉


Regarding heatsinking... I have the big heatsink of the Krauftwerk kit, and the silicon tubing for the regulators. I was thinking to follow the Krauftwerk heatsinking guidelines to heatsink this. Am I missing something and maybe it is not a good idea?

Easiest thing would be ordering a new Krauftwerk PCB, but living in Europe it is pretty prohibitive between shipping and import taxes. Next easiest thing would be getting one from one of the 51x alliance European vendors, but they only sell complete kits, and I have most of the expensive bits (enclosure, transformer, heatsink). So I'd like to make this powerstation work, but maybe it is going to be a headache...

Once again, thank you for your help. I'll keep on reading this thread, in case some of my doubts have been resolved before (I did read half of it, but I'm close to make an order to Mouser and I'd like to include what I need for this in that order)


Cheers and happy new year!

Fon

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

Thewotan wrote:
Fri Jan 14, 2022 6:33 am
Hey Joe!

First, I'd like to thank you for taking some time to reply me. Appreciate it!

Taking a look to the schematic (BTW, the link on the first page takes me to Power station Ver. 2 schematic. I don't know if there is a lot of differences with ver 3, but I suppose there is not) I understand that the capacitors that conform the bank are capacitors C5, C6, C7, C8, C9 and C10. Is that correct?

I'm a bit lost as how it adds up to 2x3300uF, though 🤔. I got the 1000uF capacitors that came with the Krauftwerk kit. I'll study how to implement those on the Power station PCB and report back 😉


Regarding heatsinking... I have the big heatsink of the Krauftwerk kit, and the silicon tubing for the regulators. I was thinking to follow the Krauftwerk heatsinking guidelines to heatsink this. Am I missing something and maybe it is not a good idea?

Easiest thing would be ordering a new Krauftwerk PCB, but living in Europe it is pretty prohibitive between shipping and import taxes. Next easiest thing would be getting one from one of the 51x alliance European vendors, but they only sell complete kits, and I have most of the expensive bits (enclosure, transformer, heatsink). So I'd like to make this powerstation work, but maybe it is going to be a headache...

Once again, thank you for your help. I'll keep on reading this thread, in case some of my doubts have been resolved before (I did read half of it, but I'm close to make an order to Mouser and I'd like to include what I need for this in that order)


Cheers and happy new year!

Fon
Sorry 3300uF should have been 3000uF = 3 x 1000uF. 3000uF for +V1 & +V2 and a second 3000uF for -V1 & -V2
Joe :-)
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Thewotan »

Ooooohhh, right!

I don't know much about electronics but I was very puzzled with those 3300uF !


I have the 3300 uF capacitors of the Kraftwerk kit. Those would add up to 9900 uF (3x3300 uF) per +-V. Would that be enough or would it be better to go above 10.000 uF?

Cheers and gracias!

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

Thewotan wrote:
Sat Jan 15, 2022 3:18 am
Ooooohhh, right!

I don't know much about electronics but I was very puzzled with those 3300uF !


I have the 3300 uF capacitors of the Kraftwerk kit. Those would add up to 9900 uF (3x3300 uF) per +-V. Would that be enough or would it be better to go above 10.000 uF?

Cheers and gracias!
9900uF is fine
Joe :-)
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g2s
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by g2s »

Hello,

I accidentally purchased AC/DC V5 when I meant to purchase V4.

My question is, can I just score/snap the board behind the regulators, snapping off the extra screw holes to make it a V4 board?

I think this should work but thought I'd ask to make sure since the traces are not visible.

Thank you!

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

g2s wrote:
Sun Feb 27, 2022 12:15 am
Hello,

I accidentally purchased AC/DC V5 when I meant to purchase V4.

My question is, can I just score/snap the board behind the regulators, snapping off the extra screw holes to make it a V4 board?

I think this should work but thought I'd ask to make sure since the traces are not visible.

Thank you!
Yes that would work but if you mount the regs under the pcb you can bolt the ACDC EM to the side of a 2 unit high case or the bottom of a 1 unit high case easier than old version as the tubes just slide over the regs. What are you mounting the ac/dc into and what heatsinking? As usually all options are easier with new EM version.
Joe :-)
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g2s
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by g2s »

Joe Malone wrote:
Sun Feb 27, 2022 10:38 am
Yes that would work but if you mount the regs under the pcb you can bolt the ACDC EM to the side of a 2 unit high case or the bottom of a 1 unit high case easier than old version as the tubes just slide over the regs. What are you mounting the ac/dc into and what heatsinking? As usually all options are easier with new EM version.
I botched the first board when I snapped it - tore off the trace that connects D10 to the middle leg of the middle regulator. However the second one went well and snapped cleanly. Luckily I bought an extra and am confident I can cut the last one cleanly. I need two total.

I am mounting it into a Hammond 14XX series utility enclosure with 2" height. It's tight but works with the regs mounted on the bottom. I will probably mount directly to the case for heat sinking with Keratherm Red as an insulator.I do have a bit of additional height with the snapped off boards and may consider getting an aluminum bar in about whatever thickness I can accomodate. I'm sure directly to the case will be fine, though.

I'm not sure what the current draw will be for the pre's they are powering. But each will be powering 2 simple looking channel's with 2 or 3 opamps each.

Thanks for the quick response.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by zqone537 »

Hey Joe,
Hope all is well. Thanks fo rthe great kits! SO I have built a AC/DC 3 rail power supply 80VA toradial tranny wired for 24v on all 3 rails and 1.5 amps. I am going to be using this with some old german modules. But I'm wondering some things:
1) I only have one -24 rail, do I connect both my modules to this one rail?
2) Do I connect both modules with 2 different wires? Or can I use just one?
3) How many modules do you think I could power with this?
Thanks!

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

zqone537 wrote:
Mon Mar 21, 2022 7:22 pm
Hey Joe,
Hope all is well. Thanks fo rthe great kits! SO I have built a AC/DC 3 rail power supply 80VA toradial tranny wired for 24v on all 3 rails and 1.5 amps. I am going to be using this with some old german modules. But I'm wondering some things:
1) I only have one -24 rail, do I connect both my modules to this one rail?
AC/DC kit only have one -V so yes
2) Do I connect both modules with 2 different wires? Or can I use just one?
The best is to wire from -V terminal to each module with a separate wire
3) How many modules do you think I could power with this?
I do not know the modules you are racking ? or their current draw? But you should be fine with good heatsinking for about 1Amp total -24v is you are using 80VA 2 x 22vac to 25vac. Most old -24v modules draw between 100mA to 250mA each.
Joe :-)
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MAXTHEDOG
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by MAXTHEDOG »

Hi All,
Very new newbie here. I’m wanting to make a 500 series rack but I’m not familiar with the kind of loading the modules use. I’ve used the Xformer/heatsinks calculator, I’m assuming that the field in the top left is the AC voltage of the Xformer secondary.
So my queries are:
1. Have I assumed correctly regarding the AC voltage?
2. What kind of current loading do 500 series modules draw?
3. Would I be better served with an AC/DC kit or a Powerstation 5 rail given that I’m thinking of about 6 modules.
I’ve got experience with electronic kits/ fault finding as I’ve made quite a few Eurorack synthesiser modules and +/-12v PSU for them. I’ve also fault found on a Audiolab 8000P power amp with success! I also was an electrician when I was working full time so I’m knowledgeable regarding 240v here in the UK.
Thanks in advance,
Michael.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by FunkymonkSF »

Hi Michael,

I'll do my best to answer your questions. I too, have questions in a very similar project.

1. Have I assumed correctly regarding the AC voltage? The top left should indicate the AC going into the power transformer.

2. What kind of current loading do 500 series modules draw? The VPR standard specs are a min of 130ma per module, however, module demands can vary. For example CAPI's VP26 (API pre-amp derivative) draws around 45ma. Then there are some, i.e. tube based, modules that draws over 200ma. It's good practice to allow for headroom, so I personally aim for at least 180ma per module/slot as I don't use tube modules.

3. Would I be better served with an AC/DC kit or a Powerstation 5 rail given that I’m thinking of about 6 modules.
I’ve got experience with electronic kits/ fault finding as I’ve made quite a few Eurorack synthesiser modules and +/-12v PSU for them. I’ve also fault found on a Audiolab 8000P power amp with success! I also was an electrician when I was working full time so I’m knowledgeable regarding 240v here in the UK. I am actually curious about this myself. I purchased an AC/DC kit to power +/-16v & +48v for my 8 slot 500 rack. You can increase you're amperage handling to 1.5amps by doubling up the 1N4007 diodes (see build notes). I strongly suggest doing that. You will also want to make sure your power transformer provides enough amps, so you'll want at least 80VA. Heatsink it for sure!

MY QUESTION: To add additional smoothing to my AC/DC PSU, which is powering 8 500 modules with a need of 1.3amps per rails, can I add a larger capacitors (i.e. 4700uf up to 10,000uf) for C5, C6, C7, & C8? Can I just replaced the 1000uf caps with larger values? If so, I'll mount them off the PCB and just wire them in.

Is there anything else I need to do to make the AC/DC strong enough to handle the demands of 8 500 modules? I added the heatsink that is optional to the kit.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by UBK »

Hey there,
I have a 2x30v @120VA (240V mains) toroid feeding the 5 rail powerstation PSU which powers two Quad Eight MP-404 modules.
each module has +28V -28V & 48V
Can you please let me know what would be the correct mains fuse for the transformer and if I should add a fuse on the transformer's secondary ?
Thanks,
Uri.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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UBK wrote:
Thu Sep 28, 2023 11:09 pm
Hey there,
I have a 2x30v @120VA (240V mains) toroid feeding the 5 rail powerstation PSU which powers two Quad Eight MP-404 modules.
each module has +28V -28V & 48V
Can you please let me know what would be the correct mains fuse for the transformer and if I should add a fuse on the transformer's secondary ?
Thanks,
Uri.
Transformer fuse size is often dependent on the transformer power-on surge more than to do with the load and fuse value is often written on the side of the transformer. 120VA at 240vac is 0.5A. Try fast and if it blows after a couple of on and off try slow blow. The best fuse value is the smallest that will not blow and slow blow if the transformer has a power-on surge.

2 x 30vac is very high as it will give +/-44vdc unreg. Also the massive oversize of the transformer VA will mean you will be 10 to 20% higher than the stated ac volts. Ideally for +/-28v a 2 x 25vac to 2 x 27vac as is it best to stay under +/-40vdc unreg into the regulators. But usually higher will work but generates more heat, especially in the 48v reg which will be getting about 88vdc unreg which is on the edge of the 40v allowed across the regulator and still regulate the 48v.
Joe :-)
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by UBK »

Joe Malone wrote:
Fri Sep 29, 2023 10:48 am
UBK wrote:
Thu Sep 28, 2023 11:09 pm
Hey there,
I have a 2x30v @120VA (240V mains) toroid feeding the 5 rail powerstation PSU which powers two Quad Eight MP-404 modules.
each module has +28V -28V & 48V
Can you please let me know what would be the correct mains fuse for the transformer and if I should add a fuse on the transformer's secondary ?
Thanks,
Uri.
Transformer fuse size is often dependent on the transformer power-on surge more than to do with the load and fuse value is often written on the side of the transformer. 120VA at 240vac is 0.5A. Try fast and if it blows after a couple of on and off try slow blow. The best fuse value is the smallest that will not blow and slow blow if the transformer has a power-on surge.

2 x 30vac is very high as it will give +/-44vdc unreg. Also the massive oversize of the transformer VA will mean you will be 10 to 20% higher than the stated ac volts. Ideally for +/-28v a 2 x 25vac to 2 x 27vac as is it best to stay under +/-40vdc unreg into the regulators. But usually higher will work but generates more heat, especially in the 48v reg which will be getting about 88vdc unreg which is on the edge of the 40v allowed across the regulator and still regulate the 48v.
Thanks!

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