Hello--
I think this post may already answer my question (in the negative), but wanted to confirm:
https://www.diyaudio.com/community/...upply-section-help-needed.340594/post-5862125
I've got an Audio Note Kit 2.1 DAC. The DAC features an independent power supply. I'm interested in replacing from the stock transformer with a couple toroidal transformers. Am trying to determine if it's possible to use a single 0-9V secondary to power the DAC power supply. If so, it means I can replace the stock transformer with two Antek toroidal transformers. If not, I'll need to order three and wire up the secondaries of a single transformer in series for this power supply module.
The power supply is dual polarity. Beyond that, I don't have much information. No schematic is provided for the module and do not know if this is a full wave or bridge rectification setup. I would ask Audio Note Kits but due to very poor build experience and support history with him, I have not received any e-mail responses for quite some time.
I will provide what information I do have from the manual in the form of a couple images.
This image shows the uncompleted board with some resistors and a couple capacitors. D1-D4 are Schottky diodes.
Image 2 shows expected measurements after completion:
Thank you for any assistance provided,
K
I think this post may already answer my question (in the negative), but wanted to confirm:
https://www.diyaudio.com/community/...upply-section-help-needed.340594/post-5862125
I've got an Audio Note Kit 2.1 DAC. The DAC features an independent power supply. I'm interested in replacing from the stock transformer with a couple toroidal transformers. Am trying to determine if it's possible to use a single 0-9V secondary to power the DAC power supply. If so, it means I can replace the stock transformer with two Antek toroidal transformers. If not, I'll need to order three and wire up the secondaries of a single transformer in series for this power supply module.
The power supply is dual polarity. Beyond that, I don't have much information. No schematic is provided for the module and do not know if this is a full wave or bridge rectification setup. I would ask Audio Note Kits but due to very poor build experience and support history with him, I have not received any e-mail responses for quite some time.
I will provide what information I do have from the manual in the form of a couple images.
This image shows the uncompleted board with some resistors and a couple capacitors. D1-D4 are Schottky diodes.
Image 2 shows expected measurements after completion:
Thank you for any assistance provided,
K
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Yes it's possible. The very famous O2 headphone amplifier does this. So does dual voltage regulator PCB called "VRDN", Gerbers freely downloadable from the diyAudio Forums.
The "how" is pretty straightforward. One diode and a capacitor create the positive DC supply using the Half Wave Rectifier circuit arrangement. A second diode and a second capacitor create the negative DC supply using another Half Wave Rectifier.
The ripple waveform on these supplies will be 2X taller and 2X wider, than the ripple waveform on a supply with a full wave rectifier. That's what you get when you use a single secondary.
The "how" is pretty straightforward. One diode and a capacitor create the positive DC supply using the Half Wave Rectifier circuit arrangement. A second diode and a second capacitor create the negative DC supply using another Half Wave Rectifier.
The ripple waveform on these supplies will be 2X taller and 2X wider, than the ripple waveform on a supply with a full wave rectifier. That's what you get when you use a single secondary.
Make sure the secondaries add their voltages when measured from end to end.
If they instead subtract to nearly zero Volts, reverse only one winding.
I would guess the schematic is somewhat like this:
dual supply with CT Tx
You could turn it into this when you only populate two of the diodes and wire things slightly differently but you are still left with more ripple (and sag) due to the half-wave-rectification (see Marks post #3).
easy dual power supply circuit
(no need for R1/R2 in your case)
Instead of getting another transformer, one could also look for a different PCB (similar to 2nd link) with following post-regulator (LM317/LM337) that should work with an output of +-9V or so or DIY something on perfboard. But the success of such a circuit will depend on actual output current and sag of the voltage rails.
I´d say a new transformer is the easier solution.
And the best solution is probably a new transformer with Mark´s "VRDN" and thus a regulated and really quiet supply.
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Joensd--
You wouldn't know this without being able to see the DAC module, but there is subsequent filtering and, looking at the SS devices, perhaps regulation, all the way down to +/-5V. So I think it's okay for this stage to be a bit crude.
Your advice, asking with Mark's, do seem very achievable with perfboard--which I have! But I also have a 10 month old and a 3 year old and it's practically a miracle that I have even have the time to swap out some transformers.
Thanks for the linked schematics.
You wouldn't know this without being able to see the DAC module, but there is subsequent filtering and, looking at the SS devices, perhaps regulation, all the way down to +/-5V. So I think it's okay for this stage to be a bit crude.
Your advice, asking with Mark's, do seem very achievable with perfboard--which I have! But I also have a 10 month old and a 3 year old and it's practically a miracle that I have even have the time to swap out some transformers.
Thanks for the linked schematics.