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Just finished up the powersupplies for the Opus. I have both a Ballsie PSU and the LCDPS (old version) running from the same toroid. Everything is fine when running the LCDPS by itself without load, but when loaded, R4 turns very hot and almost starts smoking and really smells burned. That part of the PSU is powering the SPDIF module as well as the digital section of the DAC. Is the load to high for a 15VA toroid? I hope not since its the same VA as the one sold on in the webshop. The PSU Its pumping out 7.5V on both sections fine when unloaded. the SPDIF receiver module lights up fine when powering up, but I have no sound out of the DAC. I didnt have it plugged in very long though, since the smell of burning resistors made me turn it off quickly. What could be the problem with my setup? How can I tell if something else is toasted? I would hate it if the DAC module got smoked also. 2x15V 15VA toroid -> LCDPS 1 -> DAC analog section 2x15V 15VA toroid -> LCDPS 2 -> DAC Digital section -> SPDIF receiver module 2x15V 15VA toroid -> Bipolar Supply Module -> Ballsie Edited by moderator Thursday, June 7, 2018 1:09:53 AM(UTC)
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Rank: Member
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Removed the Ballsie supply and Ballsie and I no longer have the hot resistor problem. Will try to wire it up to try single ended without the ballsie.
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Rank: Member
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Ok, I have it up and running without the Ballsie. Sounds fantastic :) Im guessing Im overloading one of the secondaries when the Ballsie is hooked up. Very strange. Maybe my 15VA torid isnt up to the task of driving this setup after all.
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If I understand what you correctly, you have a single 15VA transformer powering both supplies... this is the problem.
The DAC's LCPS (LCDPS) cannot use a center tapped transformer, because the center tap will become the + rail of first supply, and the - rail of the second supply (two distinct supplies on the board). When you connect them to the DAC, the grounds from each supply meet, and you are basically shorting + and -.
The Ballsie's Dual Supply (now LCBPS) does the opposite. The two center secondaries of your dual secondary transformer are joined to form a virtual center tap, and the center (Ground) rail of the supply.
Therefore, when you attach your transformer to both supplies, the Ballsie's power supply is turning your transformer into a center tapped transformer, and that causes a problem on the DAC supply. In the end, you need separate transformers.
The alternative, is use the single transformer to power the Ballsie supply, then use a single set of its secondaries to power both sides of the DAC supply - this will prevent the center tap shorting situation.
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