Hi,
Because the standard "wall wart" power supply of my Cambridge Audio DacMagic power supply hummed like crazy
(as did the replacement one they sent me), I ended up making my own, using a tranformer from a Goko RM-5000 8mm recording editor from the 70s (made in Japan, it looked well built, and provides the 12V AC the DAC needs):
Recently I noticed the transformer started humming (it always was dead quiet): is it going bad and should I replace it?
with this one for example?
https://www.distrelec.nl/en/ring-core-transformer-60va-2x-12-vac-5a-noratel-aa-98029/p/15613419
(at the back of the DAC it says 12V AC, 1500 mA)
I'm thinking my setup is sounding duller than it used to, but that can be my imagination 🙄
Thanks for any input 👍
Because the standard "wall wart" power supply of my Cambridge Audio DacMagic power supply hummed like crazy
(as did the replacement one they sent me), I ended up making my own, using a tranformer from a Goko RM-5000 8mm recording editor from the 70s (made in Japan, it looked well built, and provides the 12V AC the DAC needs):
Recently I noticed the transformer started humming (it always was dead quiet): is it going bad and should I replace it?
with this one for example?
https://www.distrelec.nl/en/ring-core-transformer-60va-2x-12-vac-5a-noratel-aa-98029/p/15613419
(at the back of the DAC it says 12V AC, 1500 mA)
I'm thinking my setup is sounding duller than it used to, but that can be my imagination 🙄
Thanks for any input 👍
Right, there was, but that's what the DC blocker is for.
I suppose I could measure if the DC blocker is still working, but it seems like the kind of component that doesn't break.
There are electrolytic capacitors inside it, that could be going bad.
Or maybe it isn't a very good design. I'd try a different one.
Or maybe it isn't a very good design. I'd try a different one.
Ok, thanks for the tip, I'll measure first and then maybe get another.
I bought mine at this place: https://www.aeetransformers.com,
but they don't seem to be carrying a DC blocker anymore.
(It's about 4-5 years old, and cost about 27 euros at the time)
Any recommendations?
I bought mine at this place: https://www.aeetransformers.com,
but they don't seem to be carrying a DC blocker anymore.
(It's about 4-5 years old, and cost about 27 euros at the time)
Any recommendations?
Probably this one, if you can build it. Just a bridge rectifier shunted by back-to-back electrolytics.
At least you could fix it when the capacitors eventually fail.
https://sound-au.com/articles/xfmr-dc.htm
At least you could fix it when the capacitors eventually fail.
https://sound-au.com/articles/xfmr-dc.htm
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You may have already fixed your problem, but as an FYI I built a PS unit to replace the old AC wall wart on the DacMagic
I used a twin 15V AC EI transformer from RS, and wired each secondary output in parallel. I am in a 240V region, UK.
I measured the input voltage on the DacMagic regulators to ensure they did not exceed 35V (the maximum they can operate at) and reduced the output through a series of RC filters. I think the output was around 14V from memory, but what matters is to not overload the regulators and in my experience the more voltage (within spec) the better the sound of the DM.
I needed 2 Ohms in total in series to drop the voltage and ended up with 1R, 0.5R, 0.5R each with a capacitor to earth, I used X (240 V) rated PP caps at 6.8uF but the voltage is small so use what is safe.
I also used the Earth on the mains supply to connect to the GND on the DacMagic circuit. I also rebuilt/replaced the electrolytics in the DM as they were all leaking, and ended up putting the original unit into a new case as the replacement caps no longer fitted.
good luck
I used a twin 15V AC EI transformer from RS, and wired each secondary output in parallel. I am in a 240V region, UK.
I measured the input voltage on the DacMagic regulators to ensure they did not exceed 35V (the maximum they can operate at) and reduced the output through a series of RC filters. I think the output was around 14V from memory, but what matters is to not overload the regulators and in my experience the more voltage (within spec) the better the sound of the DM.
I needed 2 Ohms in total in series to drop the voltage and ended up with 1R, 0.5R, 0.5R each with a capacitor to earth, I used X (240 V) rated PP caps at 6.8uF but the voltage is small so use what is safe.
I also used the Earth on the mains supply to connect to the GND on the DacMagic circuit. I also rebuilt/replaced the electrolytics in the DM as they were all leaking, and ended up putting the original unit into a new case as the replacement caps no longer fitted.
good luck
63V caps may be ok for 117Vac I’d prefer higher voltage rated caps in case of shorts or dead diodes. Have 252Vac RMS mains I’d feel happer with 450Vac rated caps as a belt and braces.