Bo Nydal, your NAC152 needs two 24V positive voltages, not the positive and negative voltages the studer psu provides. You cannot connect the psu to give you two positive voltages referenced to the same ground/minus pole.
You will need two seperated single psus with two seperated windings or transformers to avoid any supply voltages and grounding conflicts.
You will need two seperated single psus with two seperated windings or transformers to avoid any supply voltages and grounding conflicts.
It seems to me that the 'Studer 900' dual board can be configured either for dual positive supplies or for a +V/0V/-V supply, provided that two separate input windings are connected.
From the eBay description:
"Input voltage range: dual 9V-24V (4 line transformer)
Output: ±DC 5V-28V or dual DC 5V to dual positive 28V with short circuit protection."
From the eBay description:
"Input voltage range: dual 9V-24V (4 line transformer)
Output: ±DC 5V-28V or dual DC 5V to dual positive 28V with short circuit protection."
Hi lohk, thanks for joining in. The board I have is billed as providing either 2 positive voltage rails up to 28V or symmetric positive and negative rails again up to 28V. To this effect it provides 7 output connections, two pairs (each marked as 'vcc' and 'gnd') and a group of three (marked as 'vcc', 'gnd', and 'vss' respectively). Are you saying that the arrangement described cannot provide me with the two +24V connections that the NAC152 clone requires ? If so, can you provide me with more detail of why that is, please.
Thanks in advance,
Bo
Hi Jonners, thanks for getting back to me.
It really is very confusing. If you look closely at the board it comprises of two completely electrically separate circuits. When it is configured to provide a symmetrical supply there is a link that must be added to connect the ground of each side but if that link is absent there is no electrical contact between left and right halves of the board. This visual evidence is completely backed up by meter readings.
If it is true that there is no possible way for a 20V AC supply to generate a DC voltage of 36V (and I am quite happy to accept assurances that is the case) and there is no electrical path between the two halves of the power supply board then it seems to me that the only possible source of the over-voltage problem is the transformer. I am a little loathe to accept it because it seems a bit ridiculous but I can draw no other conclusion at this point.
I have ordered another board, time will tell whether I can resurrect this one for a later project 8^)
Thanks again for your kind contribution.
Cheers,
Bo
Hi Bo,
I think the trouble is that you are creating a link between the two halves of the board with the 0V of your 20-0-20 transformer. The board needs two separate 0-20V windings to be connected, as stated in the eBay description. It's most unlikely that there is a problem with the transformer. I think you said in an earlier post that it measures 21-0-21V AC? That's fine, but it's just not suitable for this application.
Edit: A 20V AC supply won't rectify to 30V or more DC, but you have a 20-0-20V AC supply - which is a different thing.
I think the trouble is that you are creating a link between the two halves of the board with the 0V of your 20-0-20 transformer. The board needs two separate 0-20V windings to be connected, as stated in the eBay description. It's most unlikely that there is a problem with the transformer. I think you said in an earlier post that it measures 21-0-21V AC? That's fine, but it's just not suitable for this application.
Edit: A 20V AC supply won't rectify to 30V or more DC, but you have a 20-0-20V AC supply - which is a different thing.
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Ok, my "Studers" are symmetrical.
But Jonners is right, you are connecting both halves of the regulator together with the transformer. This may give you two positive voltages but only if they will be completely seperated on the preamp side - which they are not with the NAC152, where the 0V = ground lines are connected together on principle.
Your regulators will only work with a transformer with two seperate windings. And of course 20V AC will never give 36V DC after rectification/smoothing. (Maybe your connection involantarily acted as some kind of voltage doubler Rectifier - Wikipedia)
But Jonners is right, you are connecting both halves of the regulator together with the transformer. This may give you two positive voltages but only if they will be completely seperated on the preamp side - which they are not with the NAC152, where the 0V = ground lines are connected together on principle.
Your regulators will only work with a transformer with two seperate windings. And of course 20V AC will never give 36V DC after rectification/smoothing. (Maybe your connection involantarily acted as some kind of voltage doubler Rectifier - Wikipedia)
Hi folks. I’m looking at building a power supply for my RPi3b and Allo Boss dac which has a jumper allowing the dac to be powered separately to the Pi, each via it’s own board. Is it possible/advisable do this from a single studer900 or should I get the dual one? Some of the single ads say dual output is possible but I’m wondering if it’s a mistranslation
Thanks in advance
Thanks in advance
Bo, you have the wrong transformer. The Studer900 board is 2 independent rectifier circuit. You need a dual windings transformer, not a center tap winding transformer. When you get the correct transformer, use the hookup to get the +/-24VDC you want.
Bo needs two positive 24V outputs, one for each board. Is that what your diagram shows?
Any transformer of about 20VA or more, with two 0-9V outputs for the dual board.